Printable Version of Topic

Posted by: hendric Apr 15 2005, 05:03 AM

Anyone seen any recent updates on this? Last I saw was in December timeframe. We're so spoiled with MER now, I look at the MUSES-C website and just shake my head...

Posted by: cIclops Apr 15 2005, 06:40 AM

Thanks for the reminder! It seems to be happily on its way to rendezvous with Itokawa, according to http://solarsystem.nasa.gov/missions/profile.cfm?MCode=MUSES. Of course it's going to do more than just rendezvous, it'll land, take a sample and return to Earth!

Posted by: hendric Apr 20 2005, 04:29 AM

Well, I guess no news is good news...I tried the Muses-C/Hayabusa website, but all it had was an outline, no details on instruments or a detailed mission timeline.

Posted by: BruceMoomaw Apr 20 2005, 10:28 AM

The word I've been seeing from abstracts in places like the recent LPSC meeting is that it is continuing to work absolutely perfectly -- which makes it stand out like a non-sick thumb in Japan's ill-fated recent space program. We'll see.

Posted by: djellison Apr 20 2005, 10:37 AM

People berrated the poor ESA Press efforst around Huygens landing. It was a PR masterstroke compared to the japanese space program

Doug

Posted by: ilbasso Apr 20 2005, 02:16 PM

Do you suppose the lack of news is a cultural thing?

Posted by: tedstryk Apr 21 2005, 03:12 AM

Hard to tell. Also, with the way things have been going, the lack of PR may be do to the poor results in the Japanese program in the last few years. If Hayabusa is a great success, it will be interesting to see how that is publicized.

Posted by: Gsnorgathon Apr 21 2005, 07:11 AM

I'm having a slight flashback to the early Soviet space program...

Posted by: tedstryk Apr 21 2005, 07:26 PM

True, but outright denial and claims of sabatoge are on a different level than just not saying much.

Posted by: odave Apr 25 2005, 12:50 PM

The newest issue of Sky and Telescope (June 2005) has a nice writeup on Hayabusa, as well as a cover story on Deep Impact.

I'm a subscriber, so get mine a little early - I don't think it's available at newsstands yet. Lots of planetary stuff in this issue, it's probably a good one to pick up!

Posted by: tedstryk Apr 25 2005, 01:16 PM

I will second that!

Posted by: maycm Apr 28 2005, 04:35 PM

A possible answer to the non-information here....

http://www.space.com/news/jaxa_trouble_050428.html

Posted by: Bob Shaw Apr 28 2005, 07:27 PM

See my comments in the Manned Spaceflight thread; Japan's space enterprises are sadly ineffectual.

Now, India...

Posted by: maycm Jun 13 2005, 03:59 PM

An update....


http://msnbc.msn.com/id/8131678/

Posted by: Bob Shaw Jun 13 2005, 08:09 PM

That's one hard place they're in - I hope they succeed...

Posted by: djellison Jun 13 2005, 08:12 PM

I cant wait to see what imagery we get from the 'hopper' - it will be the first PROPER landing on a small body if they can pull it off

Doug

Posted by: Toma B Jul 7 2005, 03:26 PM

I have just find this site... Maybe they are updating it daily

http://www.isas.jaxa.jp/e/enterp/missions/hayabusa/today.shtml

Posted by: djellison Jul 7 2005, 03:40 PM

Wow - it's not far out now

It's closing speed is very slow as I understand though.

Doug

Posted by: BruceMoomaw Jul 10 2005, 09:42 PM

Astro-E2 has just been successfully launched:
http://www.jaxa.jp/press/2005/07/20050710_m-v-6_e.html

Is it possible that Japan is finally coming out of its space funk? (Although the solar-panel problem with Hayabusa is worrisome. It's increasingly apparent that radiation is not only the biggest threat to manned deep-space travel; it's a serious problem for the UNMANNED variety.)

Posted by: deglr6328 Jul 10 2005, 10:26 PM

So I guess it DID launch with some type of external mobile device! I kept hearing conflicting reports that nasa was supposed to supply the tiny rover and it didn't and then that it wasn't going to have one at all and now that it does have a hopper. Was it slapped together quick after the nasa nanorover deal fell through or planned on al along or what...? This http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1517.pdf doesn't say too much....

Posted by: Stephen Jul 11 2005, 05:05 AM

Try http://www.lpi.usra.edu/meetings/lpsc2005/pdf/2289.pdf instead. It's fairly brief, but it does tell you a little about the little "hopper" craft (called "Minerva", BTW).

This http://en.wikipedia.org/wiki/Hayabusa also has some (less technical) tidbits, while http://www.jaxa.jp/news_topics/vision_missions/solar/pages/hayabusa3_e.html looks like it might be useful.

In general, though, http://neo.jpl.nasa.gov/news/news143.html seems to sum up pretty much all that's out there about Minerva:

"Upon its arrival at the asteroid in the summer of 2005, the Hayabusa spacecraft will hover near the asteroid's surface for about four months. Its instruments will study the surface in detail, determine the asteroid's mass and bulk density and determine which minerals are present. A small coffee-can-sized surface hopper, called MINERVA, will leap about the asteroid taking surface temperature measurements and high-resolution images with each of its three miniature cameras."

Posted by: deglr6328 Jul 15 2005, 05:09 PM

Its at less than .5 earth-moon distance now. Still no images....? I need "http://www.isas.jaxa.jp/e/enterp/missions/hayabusa/index.shtml"!!

Posted by: Phil Stooke Jul 15 2005, 05:20 PM

The reason there are no images is simple: the asteroid is only a few hundred m across, so from 150 000 km it would only be a pixel or two across in an image. The camera is designed to operate from 20 km distance. They are presumably taking navigation images, but not worth releasing.

Phil

Posted by: djellison Jul 15 2005, 07:15 PM

Yeah - this is one TINY asteroid - I think Dactyl ( Ida's tiny moon - an asteroid that Galileo flew past en route to Jupiter) is the only thing even remotely on the same size - but the asteroid Hayabusa is visiting is even smaller than THAT

It's like visiting a single block of houses.

Doug

Posted by: maycm Jul 22 2005, 07:35 PM

I've been tracking the distance to target from http://www.isas.jaxa.jp/e/enterp/missions/hayabusa/today.shtml website.

On June 13th it was 135,172Km
On June 21st it is 97,614Km

Getting closer!

At this rate they will be there in a couple more weeks.

Posted by: maycm Jul 25 2005, 03:19 PM

Update from the webpage indicated above.

Posted by: tedstryk Jul 25 2005, 06:57 PM

I am very interested to see an asteroid of this size close up. I am curious to see if it has any significant loose material on its surface, given its low gravity. I am also wondering how, if the mission is successful, the Japanese will do with image releases. They haven't ever had much to release - there were a few neat Nozomi pictures, but they were highly compressed and limited in quantity. The ultraviolet image results from Susei were very limited as well, and were of course pre-internet era. I hope that they will improve their releases if they have a successful imaging mission.

Posted by: Phil Stooke Jul 25 2005, 07:57 PM

This page:

http://pds-smallbodies.astro.umd.edu/missions/hayabusa/index.html

gives some information on plans for data archiving. It looks as if PDS will hold the Hayabusa archive. Which is good news for everybody, I would say.

Arival in mid-September... Darn! I'll be on vacation at the time. I'll have to sneak into an internet cafe for my fix.

Phil

Posted by: maycm Aug 2 2005, 12:54 PM

Distance to target:

July 21st : 97,614Km
August 1st : 63,0808km

Closer....closer...

Posted by: tedstryk Aug 2 2005, 02:34 PM

This looks cool:

In-situ exploration of the surface of asteroid Itokawa by MINERVA engineering rover on board HAYABUSA
Sho Sasaki
Tetsuo Yoshimitsu
Masahisa Yanagisawa
Hajime Yano
Keisuke Teramoto




National Astronomical Observatory of Japan
ISAS/JAXA
Univ. Electro-Comm.
ISAS/JAXA
ISAS/JAXA




ISAS/JAXA in Japan has launched an engineering spacecraft Hayabusa to Itokawa, a small S-type asteroid with approximate size 600m x 300m. A small rover called MINERVA (MIcro/Nano Experimental Robot Vehicle for Asteroid) is on board HAYABUSA. The rover has a hexadecagonal shape with diameter 12cm and heigh 10cm. Weight of the rover is 591g. MINERVA, which is the first asteroid rover in the world, will be deployed onto the surface of Itokawa at altitude around 17m shortly before the surface sampling touch-down of Hayabusa. After landing on the surface, MINERVA moves over the surface autonomously by hopping for a couple of days. On rotating a torquer inside the rover, a reaction force against the surface friction can hop the rover. MINERVA has three CCD cameras (RGB color) to capture surface images. Two of the cameras consist of a stereo pair and have short focal length to observe nearby targets, and the last camera has focal length to observe more distant targets. To protect solar cells, MINERVA has 16 pins sticking out of both ends of the body. Six of the pins are thermal probes by which variation of surface temperature is directly measured. The scientific objectives of MINERVA are as follows: (1) To obtain images of the asteroid surface in visible wavelength. (2) To construct a detailed surface model especially using stereo images taken by short-focal length pair cameras. To discuss presence and characteristics (sand/rock ratio etc.) of surface regolith. (3) To obtain the brightness and color variation of the surface especially for discussing the ongoing space weathering. (4) To investigate the thermal properties of the surface regolith from temperature history of the same place. (5) To measure local gravity direction and surface friction coefficient.
Presenting author: Sho Sasaki

Posted by: Toma B Aug 3 2005, 11:18 AM

...just find this...

JPL radar model of Itokawa!!!

http://www.isas.jaxa.jp/e/snews/2004/0525_2.shtml

Posted by: tedstryk Aug 3 2005, 03:06 PM

Cool! Great find.

Posted by: Phil Stooke Aug 8 2005, 05:10 PM

Phil reporting from vacation la-la-land... there is a much more detailed up-to-date model of Itokawa from more recent radar data. I will post info when home on 19th...

Phil

Posted by: paxdan Aug 9 2005, 07:29 PM

you tease

Posted by: Phil Stooke Aug 10 2005, 06:06 PM

Oh yes, I'm a tease.

This shape result will be revealed at the DPS in September (Ostro has a good abstract on it), but an animation of it can be found at:

http://www.jaxa.jp/news_topics/column/no13/p3_e.html

(lower on page).

I made a composite view of different sides by grabbing frames from it. But I shouldn't really post it! So just look at the animation. When I get back to my office I might be able to do more.

Phil

Posted by: BruceMoomaw Aug 10 2005, 08:17 PM

Given the fact that Japan has now added to its near-perfect record of recent space failure by losing the crucial instrument on Astro-E2 due to a liquid helium leak, I sincerely hope they don't bungle Hayabusa. If they do, maybe they had better consider getting out of space exploration completely until they either fund it properly and/or revamp their management system.

Posted by: tedstryk Aug 10 2005, 09:49 PM

Glad people didn't say that of us after the sixth consecutive Ranger failure, after all the Pioneer Moon failures, and the fact that the first two Mariner pairs lost a spacecraft and the Mariner 4 spacecraft had to have its ultraviolet photometer removed and had a camera light leak.

Posted by: BruceMoomaw Aug 11 2005, 02:28 AM

First, all the Pioneer Moon failures were launch failures very early in the US space program -- akin to the inability Japan had to successfully launch a satellite for 4 straight years. Their current monotonous parade of failures, however, is occurring at a time when they SHOULD have a command of space technology, and in fact they used to have a much better success record. One internal government study had already indicated that much of this was due to attempts to fly wildly overambitious missions on much too small a budget -- but the problems seem to be continuing even after the measures they had announced to try to correct this.

Second, JPL DID come within a hair of having the Ranger program taken away from them, after four straight spacecraft failures. Had Ranger 7 failed, they certainly would have had it taken away from them, and they would have deserved it. Well, Japan's current run of spacecraft failures -- not even counting their recent booster failures -- goes beyond that point.

Posted by: maycm Aug 11 2005, 05:15 PM

Distance to target -

August 1st : 63,808km
August 11th : 34,058km

Posted by: djellison Aug 11 2005, 05:25 PM

Wow - I wonder if they'll use the ion engine all the way up to arrival - or if they'll coast in and then come to a near standstill with thrusters.

At this rate - they'll be there in another 10 days

Doug

Posted by: dilo Aug 11 2005, 05:55 PM

So close... Any asteroid image???????

Posted by: deglr6328 Aug 11 2005, 06:24 PM

I'm confused, this is non US so is that really a comma or a decimal....?

Posted by: djellison Aug 11 2005, 11:19 PM

No - it's really <10% of the earth-moon distance.

Doug

Posted by: Myran Aug 12 2005, 02:23 AM

Comma is used in many countries for "decimal point", including mine.

So August 11 distance is 34 058 km and not 34 km 58 m.

Posted by: BruceMoomaw Aug 12 2005, 04:55 AM

A new piece on the Astro-E2 failure (and it IS a failure -- it ruins the central scientific purpose of the mission, and NASA is considering yanking its grants to help continue the mission):

http://www.space.com/astronotes/astronotes.html (August 11 entry).

It turns out that this was not exactly unexpected -- the helium coolant system had been showing a whole series of "mysterious" but serious malfunctions since July 29, and finally simply ran out of helium. (The Japanese space agency didn't utter a word about any of this until the final, irreversible failure.) Moreover, it does seem likely that the satellite, like so many other Japanese space failures, was simply underfunded -- its development cost was only $150 million, for a quite sophisticated astronomy satellite. Shades of Dan Goldin!

Now it will be at least another five years before the X-ray Calorimeter Spectrometer -- originally intended to be a very important part of the Chandra Observatory -- can get a third chance to fly. One hopes that Hayabusa will do better, but -- given the solar power problem which it's already developed -- I'm not counting on it.

Posted by: dilo Aug 12 2005, 06:30 AM

About Hayabusa, there is an article http://neo.jpl.nasa.gov/missions/hayabusa.html from Don Yeomans...

Posted by: Phil Stooke Aug 14 2005, 06:24 AM

I don't know anything about the Hayabusa optics, but working with the Voyager camera rule-of-thumb that 100 000 km range gave 1 km per pixel, the 35 000 km range to Itokawa at the moment would give us about 300 m/pixel resolution. In other words the asteroid would still be only 1 to 2 pixels across. Presumably they are taking navigation images now. But fairly soon we might see an image with the shape roughly resolved...

Phil

Posted by: Toma B Aug 15 2005, 10:14 AM

FIRST IMAGES FROM HAYABUSA!!!!!!!!!!!!!!!!!

http://www.isas.jaxa.jp/e/snews/2005/0815_hayabusa.shtml

Posted by: helvick Aug 15 2005, 11:20 AM

Phil's estimate looks to have been bang on. Neat.

Posted by: dilo Aug 15 2005, 12:45 PM

Wow, finally informations arrived! ...cannot wait for first Optical Navigation Camera (ONC) high resolution images!
I thing we should strongly congratulate with Jaxa (and NASA too) for this achievement, after all "bad things" and difficulties mentioned here...
Really hope that final approach will still smooth (apart reaction wheel issue).

Posted by: maycm Aug 17 2005, 06:56 PM

August 17th : 20,199km

Posted by: RNeuhaus Aug 17 2005, 11:18 PM

I just discoverd it as an interesting project. By October 2005, hope that the space Hayabusa will land on the asteroid Itokawa located in a belt between of Mars and Jupiter. Hope that the Japanese electronic won't fail again. I speculate that the Itokawa land is covered of full of powder like the comet which was hit by a deep impact. Does the Hayabusa have a shovel or spade to pick up small stones to be brought back to Earth?

Rodolfo

Posted by: dilo Aug 18 2005, 06:27 AM

"...asteroid Itokawa located in a belt between of Mars and Jupiter...."
Rodolfo, Itokawa is a Near Earth asteroid, in fact now both (asteroid and probe) lies only slightly outside Earth orbit...
For infos, take a look here:
http://neo.jpl.nasa.gov/missions/hayabusa.html
or here:
http://planetary.org/news/2004/hayabusa_earth-swingby_preview.html

Posted by: Bob Shaw Aug 18 2005, 08:14 AM

Rodolfo:

They're gonna shoot at the poor thing and capture the debris in a horn pointing down to the surface, so their sampling system is probably as good as you'd get for dust.

Isn't it a bid sad that Earth has decided to declare war on the Asteroids? Still, I suppose this time the Americans shot first!

Bob Shaw

Posted by: tedstryk Aug 18 2005, 12:40 PM

Given the lack of gravity on such a small world, I would be afraid their was no loose material, so I think this is a good way to get a sample.

Posted by: garybeau Aug 18 2005, 01:12 PM

Hmmm.... I had the opposite thought, I would think because of the very low gravity, not the lack of, there would be lots of extremely loose material.

If they fail to capture any material with the shoot and catch method, do you think they might attempt to get in closer?

Posted by: djellison Aug 18 2005, 01:13 PM

Do they even have a way to check if they got any material?

Posted by: AndyG Aug 18 2005, 01:24 PM

The collections will be made from about 30m of the surface, so it's likely there will be "some" grains of material blown off that will hit the collection funnel.

Is there anyway to measure the impact of this material on Hayabusa? That would ensure you know you've got something.

And I suppose given the mass of Hayabusa (~500kg) you could measure the difference in acceleration with or without a few grams of material added...though that would mean you'd need to accurately judge the amount of consumables (chemical and xenon) before and after the collection procedure.

The Jaxa website is awful for details, though. (Addendum: maybe it's just me, and the fault lies in the finding of those details...)

Andy G

Posted by: paxdan Aug 18 2005, 02:10 PM

My understanding was that the contact of the collection tube with the asteroid would trigger the firing of the pellet. http://www.newscientistspace.com/article.ns?id=dn7863NewScientist article has a bit more info, including mentioning that they aim to collect 100 milligrams of material and that the hopper will make 10 metre hops. I wonder if they will do imagery during the flight of the hops?

Doug, as for Don Yeomans, the US project scientist for the mission, perhaps you should invite him over to the board. From TFA: “This is a stealth mission, nobody knows it’s there.”

Posted by: paxdan Aug 18 2005, 02:45 PM

More info about the sampling from the http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=2003-019A.

Surface Sample Collection:
The lander will be equipped with a universal sample collection device which will gather roughly one gram of surface samples taken from the landings at 3 different locations. The device consists of a funnel-shaped collection horn, 40 cm in diameter at the end, which is to be placed over the sampling area. A pyrotechnic device fires a 10 gram metal projectile down the barrel of the horn at 200 - 300 m/sec. The projectile strikes the surface producing a small impact crater in the surface of the asteroid and propelling ejecta fragments back up the horn, where some of it is funnelled into a sample collection chamber. Prior to each sampling run, the spacecraft will drop a small target plate onto the surface from about 30 m altitude to use as a landmark to ensure the relative horizontal velocity between the spacecraft and asteroid surface is zero during the sampling. After sampling the samples will be stored in the re-entry capsule for return to Earth.

Posted by: djellison Aug 18 2005, 02:50 PM

It's a bold mission design - you have to give them that

Doug

Posted by: tedstryk Aug 18 2005, 02:57 PM

Even if the sampling/landing fails, If it provides global coverage at 1 meter resolution of a world this size, it will have provided some interesting data. It is strange to be 20,000 km out from an arrival and have the object being approached still be a mere speck!

Posted by: RNeuhaus Aug 18 2005, 03:47 PM

Dilo, Thank you for pointing this out. As Itokawa is an asteroide, then I tought it is located on that belt... It is a another surprise for me because any asteroide is not always located on that belt but also wandering in anywhere? I am starting to think that I have no good concept to differentiate between comets and asteroids. Now I am guessing that any comets are defined as ones which loops around sun with periapsis and apoapisis. Otherwise, the asteroids does not loops around the sun and they remains stable on their orbits? They can be in any distance from sun?

According to the picture, the probe has no long legs (a land must be very FLAT!!) to land on asteroid and it will touch down, with the propulsion ion engine will be turned off previously. This is to prevent the jets from contaminating the asteroid surface by coming too close to it. I am afraid that the probe might bounce back into the space...

"The other challange is when the next task -- collecting a sample -- may be an even greater challenge. The surface gravity of the asteroid is really small and is less than 1/100,000 of that of the Earth. Anything -- a drill or any other digging tool - that is not secured by a strong anchor into the surface may just be pushed away before the drill actually bores a hole." I would imagine that each legs must have own motor with screws in order to nail down the surface....

"Since we do not know what the asteroid is really made of, there is no way of knowing how hard the surface will be or how difficult this collection of surface dust will be. The Japanese are employing a simple, direct strategy -- to "break the surface" by using a tiny pyrotechnic device to fire 'sampler horns' into the three targeted sites on the asteroid." This is another risk or adventure. I don't know how it will hapen with its explosion wave (in space has no air and I seems that the explosion wave won't push to the probe?? ).

"Once the collections of surface dust are completed, the spacecraft will start the engine, lift off, and resume its hovering position at 100 meters altitude as it waits for the next order from Mission Control. Here does not say anything about the mechanism in order to make sure that the samples are already collected!!! The samples will no be greater than one gram for Earth gravity." As the most samples are in dust, I assume, one gram of dust is a enough for a facial makup.

Rodolfo

P.D. "Ithalic" are extracts from the http://planetary.org/news/2004/hayabusa_earth-swingby_preview.html

Posted by: paxdan Aug 18 2005, 05:57 PM

indeed it is, they are cramming a host of tech into a very compact mission. The low mass of the target simplifies things somewhat making the sampling the result of a heliocentric orbital rendezvous as opposed to a landing involving the complexities of orbiting and/or descending around a larger mass.

But a sample and return from an asteroid as well, gotta hand it to them it will be quite a first!

Heck like tedstryk i'll be happy if they manage some decent imaging. I am really looking forward to seeing what this object looks like, the scale is almost human! So only a matter of weeks before a new world hoves into view.

rubbing hands in anticipation.

Posted by: BruceMoomaw Aug 20 2005, 11:17 AM

Abstract #4024 in the new "Dust In Planetary Systems" abstracts ( http://www.lpi.usra.edu/meetings/dust2005/pdf/program.pdf ) confirms something hinted at in a recent Space.com article: because of the delay in its arrival at asteroid Itokawa due to the weakening of its SEP drive by that big 2003 solar flare, Hayabusa will now sample only two sites on the asteroid -- instead of the originally planned three -- before departing for home.

Posted by: paxdan Aug 20 2005, 02:27 PM

This question was asked earlier in the thread and i've looked but can't find an answer myself, but do we know if they have a means of detecting if the sampling has been successful?

Posted by: paxdan Aug 20 2005, 05:30 PM

Well i've been doing some digging and found this http://www.jaxa.jp/news_topics/vision_missions/solar/pages/hayabusa2_e.html which has some more info and photos. On http://www.jaxa.jp/news_topics/vision_missions/solar/pages/hayabusa3_e.html there are a couple of short movies, one showing a animation of the approach and sampling sequence, the other showing a test of the hopper mobility system.

I still don't see any sort of page set up to handle the raw image release. Bah.

Posted by: tedstryk Aug 20 2005, 06:09 PM

Cool!

Posted by: Toma B Aug 22 2005, 12:56 PM

Today:
Distance from Itokawa : 11,320km

Geting realy close now!!!

Posted by: Toma B Aug 22 2005, 06:29 PM

Does anybody knows where can I find more Earth images from Hayabusa's flyby May18 2004???
I have find only one image taken from far away (295.000 km.)



Flyby's closest point was 3700 km.... That's allmost 80 times closer than on this image...

Posted by: MaG Aug 22 2005, 06:55 PM

I found something!

http://www.jaxa.jp/missions/projects/sat/exploration/muses_c/backnumber_e.html

and here bigger version http://www.planetary.org/news/2004/images/hayabusa_earth-from-flyby_768x768.jpg

Posted by: paxdan Aug 22 2005, 07:10 PM

OK so i've been looking again for a Hayabusa image release site and found this section of the jaxa website called the http://jda.jaxa.jp/index_e.html the search bars have drop down fields but frustratingly the 'mission' drop down field where you might expect hayabusa to get a mention is blank. I can't even find the image you posted above on this site.

Somewhere someone must have access to the raw images. I know hayabusa stuff is going to be archived by the PDS but doesn't this happen to processed stuff sometime after it is taken? Oh well back to fiddling with URLs.

Would it be rude to email Don Yeomans? I really do want to follow this 'live'.

Posted by: paxdan Aug 22 2005, 07:21 PM

Yup and you can get to http://www.jaxa.jp/missions/projects/sat/exploration/muses_c/index_e.html, the two flash movies are quite good fun. Will someone on a windows box tell me what the .exe screensaver does.

Posted by: djellison Aug 22 2005, 09:00 PM

Dont think much of their co-registering of the R,G,B's for that - it's a bit off

This is perhaps a smidge better
http://www.unmannedspaceflight.com/doug_images/hayb.jpg

Doug

Posted by: Bob Shaw Aug 22 2005, 09:54 PM

Doug:

You can see my house from up there!

Bob Shaw

Posted by: djellison Aug 22 2005, 10:34 PM

I only noticed the bad registration because I was about to put a big "I AM HERE" arrow on it

Doug

Posted by: paxdan Aug 22 2005, 10:42 PM

ha ha yeah been thinking the same thing, sadly i think that band of cloud across the midlands covers my location though.

It is a very nice image. At least they have managed to bung up a camera that appears to be in focus and hasn't got covered in crap during the launch.

Posted by: Phil Stooke Aug 23 2005, 03:35 AM

Here:

http://www.planetary.or.jp/en/column/index.html

is another Hayabusa article. More images expected at the end of the month.

Phil

Posted by: abalone Aug 23 2005, 06:29 AM

Is this unusual?

Posted by: paxdan Aug 23 2005, 08:00 AM

ha ha, not really.

Posted by: BruceMoomaw Aug 23 2005, 08:29 AM

New, very detailed Hayabusa article:
http://www.spaceflightnow.com/news/n0508/22hayabusa/

Right now it's 10,000 km out, and should get to the 20-km "gate position" in about three weeks.

Posted by: paxdan Aug 23 2005, 10:28 AM

I take it you seperated the layers in photoshop and shifted them about rather than having access to the original raw images.

Posted by: djellison Aug 23 2005, 10:47 AM

Yup -just moved the channels in photoshop

If I had the raw data - I'd be shouting about it

Doug

Posted by: paxdan Aug 24 2005, 11:57 AM

8,880 km.........

Posted by: Decepticon Aug 24 2005, 12:21 PM

As long as we get any pictures I'll be happy.

Posted by: paxdan Aug 24 2005, 01:01 PM

seconded...

Posted by: tedstryk Aug 24 2005, 02:10 PM

Thirded. I would like to see complete success. But this is an ambitious mission, especially for a space program that hasn't had any major success since its Halley spacecraft, which were very simple, relatively speaking.

Posted by: Myran Aug 24 2005, 02:18 PM

Fourded!

Posted by: djellison Aug 24 2005, 02:23 PM

Umm. Fithted? Sounds rude

Doug

Posted by: paxdan Aug 24 2005, 02:24 PM

hah ha ha ha snort...

Posted by: Phil Stooke Aug 28 2005, 02:02 AM

ISAS Hayabusa update...

http://www.isas.jaxa.jp/e/snews/2005/0826.shtml

Phil

Posted by: alan Aug 28 2005, 03:03 AM

Looks like you can see its shadow in those images. Gives me the impression that it has a thin atmosphere like a weakly active comet. Probably just an imaging artifact though.

Posted by: Bob Shaw Aug 28 2005, 02:27 PM

Alan:

The 'shadow' runs in the same direction as the herringbone noise pattern across the whole of the image, so I'd say it's in the camera!

Bob Shaw

Posted by: RNeuhaus Aug 29 2005, 02:32 PM

New updates
The orbit maneuver of HAYABUSA spacecraft was handed over from the ion engines to the bi-propellant thrusters on August 28 JST.
After the solar conjunction the microwave discharge ion engines were turned on again at the end of July and accelerated with their full throttling so as to approach to the target.
At the end of August HAYABUSA stays 4,800km (3,000 miles) apart from Asteroid ITOKAWA and is still closing it at 32km/h (20 milles/h) velocity with the ion engines off.

Calculating the time required to reach Itokawa = 4,800 km/32 km/h = 150 hours (6 days and 6 hours) and the space will be stopped at 20 km before of Itokawa. At this distance, the potato's shape image will be pretty tasty

Rodolfo

Posted by: djellison Aug 29 2005, 02:41 PM

Less than a week until it gets to the asteroid then - at which point I assume they'll match speed using bi-prop thrusters.

Doug

Posted by: Toma B Aug 30 2005, 04:14 PM

Distance from Itokawa 3220 km... and closing in...
I just can't wait...

Posted by: antoniseb Aug 30 2005, 07:10 PM

I can't either, but so far I haven't seen a lot of details on the English language site for this probe. I hope that they manage to make the images and data from this probe available using the Mars MER model as opposed to the ESA Huygens model, or worse yet the NASA WMAP model.

Posted by: deglr6328 Aug 31 2005, 12:11 AM

What was wrong with the Wilkinson probe? They needed to take data for the whole 2 year (?) mission before it could be assembled cleaned and presented visually....

Posted by: djellison Aug 31 2005, 07:05 AM

Yeah WMAP was one of those missions that isnt a 'pretty' mission -it's just data coming down, takes a while to assemble it into anything visual.

Doug

Posted by: Myran Aug 31 2005, 10:17 AM

Lets see whats wrong with Huygens, we had 3 decent images within an hour of the signal reaching Earth, and all images from the decent plus some data from the decent publicly available in two days.
Now tell me whats wrong with that?

Posted by: antoniseb Aug 31 2005, 04:28 PM

Hi Myran, I'm not looking for a fight here, but I was pretty disappointed that Huygens did not post all raw images, and more importantly didn't (as far as I could find) publish the data from the mass spectrometer or other instruments. So, compared to the relative openness of the MER data, the Huygens data looks fairly protected from public scrutiny... As I noted above, the WMAP data is much more secret. Huygens is not the worst case.

Posted by: tedstryk Aug 31 2005, 04:40 PM

Actually, you are wrong on that one....the Huygens raws are released and have been since not long after the descent. And refer to others' comments on WMAP.

Posted by: TheChemist Aug 31 2005, 04:51 PM

To be fair to Huygens...

Only the images from the MERs are released immediately to the public, not the various spectrometry data. We only see a fraction of Mossbauer, XPS and TES data once in a while, and that's how it should be, these need careful analysis and proper presentation in peer reviewed publications.

Huygens had only one chance for photography and spectrometry readings, and we got to see all images plus GC-MS data very quickly.

Posted by: Myran Aug 31 2005, 05:04 PM

I wasnt trying to pick a fight either, only asking what was wrong with a press release and 3 images just hours after the infomation had been brought to Earth.
Images plus webcasts of the press releases were available for dowload from a website hosted in Darmstadt within hours, also from the British interplanetary society. Livecasts were sent over the web from Darmstadt, I followed that myself.
Information were quickly handed over to various scientific publications who had presentation on their online enditions within days of the early scientific results from Huygens.
ESA main headquarters was beaten by a private webpage at Arizona university in the USA at: http://www.lpl.arizona.edu/~kholso/data.htm for releasing the full set of images.
Like on this website were amateurs space buffs (and image pros) makes pans of Mars, amateurs put together a panorama of the decent images from Heygens that were spread several days ahead of one such panorama appeared on ESA' main web.
Those are the facts. You cant ask for any more transparency in a spacemission than this.

Posted by: Bob Shaw Aug 31 2005, 05:15 PM

I think we've all been soured by SMART-1 and Mars Express, where the merest t-r-i-c-k-l-e of uber-blandness has marked ESA's PR aimed at the general public - never mind it's responsibilities towards us guys!

It makes ESA's good-ish efforts vanish in a tide of disgruntled complaints about when things *are* terrible!

Posted by: deglr6328 Aug 31 2005, 05:16 PM

Anton, I really don't think there was anything really "secret" about WMAP. Until you have the entire dataset from the probe you cant really begin assembling a meaningful image of anything. They HAD to wait until data taking period was over untill they released any worthwhile images to the public. Releasing WMAP data before then would be pretty meaningless to 99.9999% of the public, as it would be raw and totally unprocessable by the common image manipulation methods done here.

Posted by: antoniseb Aug 31 2005, 08:20 PM

I agree that they needed to get a full year of observing to produce something meaningful, my concern is with the giant delay and silence connected to the second release. It has been a few years now since WMAP finished collecting a second year of data. They must also have had time to collect and assemble polarization data by now. The story seems to be that there are some unexpected aspects to the data that need some new looks (such as alignment of the octopole signal), and certainly they are trying to do their best job of finding a way to sort out what is cosmic signal from what is heliopause signal from what is SZ signal.

I would have hoped for some more openness about this data, or the nature of what the problems they are facing are.

Concerning Huygens and raw images... apologies for expressing some way out of date frustration. Yes, they were good about handing out a nice samples right away, and TheChemist is right that the detailed science data from MER is just has hard to come by as the MassSpec data from Huygens.

Posted by: BruceMoomaw Aug 31 2005, 10:11 PM

WMAP data -- especially polarization data, which is especially weak -- takes a huge amount of analysis (future satellites, starting with Planck, will be far more sensitive to it) -- and there is absolutely no point in the group jumping the gun and releasing preliminary interpretations that turn out later to be incorrect. (The same thing, by the way, is true of the data from the radar sounders on the Mars orbiters -- I'm content to wait a long time for the data from those.)

Posted by: tedstryk Sep 1 2005, 12:28 AM

But the entire Huygens dataset was released in at least as good quality a form as the Cassini's raw page within a few days.

Posted by: dvandorn Sep 1 2005, 07:03 AM

So -- is the octopole signal alignment issue something that was observed and discussed out of the first year's observations? I've read a couple of articles on the subject, and I sort of got the notion that the octopole signal alignment measurements that are at issue had come out of the second year of observation...

I guess I'm wondering if this issue is something that might turn out later to be incorrect? Or are we looking at a serious weakness in the expanding universe (with massive dark matter) theory?

-the other Doug

Posted by: antoniseb Sep 1 2005, 03:31 PM

I'm guessing not, but my experience so far is that the WMAP team is being unusually tight-lipped about this. I believe they simply want to be able to say something they are certain of, but it is really leaving a lot of room for odd speculations.

I started a new thread in "Space Based Observing" to discuss WMAP, as Hayabusa is a completely different probe investigating something that probably isn't the CMB.

Posted by: JRehling Sep 1 2005, 04:11 PM

The entire DISR imaging dataset... which was an American-run instrument. In fact, the Americans released the imagery too early for ESA's liking and it caused a flap. I still haven't seen the GCMS data in as complete a form as I'd like. Galileo Probe's equivalent was presented to the public 7 weeks after its descent. (Note: There were initial confusions over those data, but that was because of the unique trickiness of making hydrogen measurements, which is a minor concern re: Titan.)

ESA's track record on getting quality data out to the public promptly is right up there with the Soviets'/Russians' success in Mars exploration. Informing the public is something that they have obviously deprioritized, and Jeffrey Bell's comments, to the effect that European academia is more so an oligarchy than the American equivalent, have resonated with me as a possible explanation.

I'm also struck by the quirks even in their MEx releases, which are beautiful. Namely, that they seem to be applying mysterious color calibration, changing that formula over time, without giving that process a public face; then they release everything with a small thumbnail and a bandwidth-breaking full-size image orders of magnitude bigger than the thumbnail, with no middle route.

As a former resident of a European country, from a time when they had nothing going in terms of space exploration, I would love to know more about what the reaction "on the street" is like regarding ESA's successes. I have heard there's enthusiasm, but I haven't been in Europe when there was an opportunity to see for myself.

Posted by: BruceMoomaw Sep 2 2005, 12:48 AM

The report I heard was that Paris taxi drivers were briging up the subject of Titan to their passengers immediately after the landing.

Posted by: SFJCody Sep 2 2005, 07:39 AM

http://www.isas.jaxa.jp/e/enterp/missions/hayabusa/today.shtml

1550 km! Can anyone here read Japanese?

Babel fish attempt:

http://babelfish.altavista.com/babelfish/trurl_pagecontent?lp=ja_en&trurl=http%3a%2f%2fwww.isas.jaxa.jp%2fe%2fenterp%2fmissions%2fhayabusa%2ftoday.shtml#today

http://babelfish.altavista.com/babelfish/trurl_pagecontent?lp=ja_en&trurl=http%3a%2f%2fwww.isas.jaxa.jp%2fj%2fsnews%2f2005%2f0902.shtml

Posted by: tty Sep 2 2005, 09:52 AM

"Hayabusa" means Peregrine Falcon. "It is quick + (untranslated Kanji)", isn't that bad a try really.

tty

Posted by: tedstryk Sep 2 2005, 02:29 PM

Gosh it is strange being 1550 km out and no great images! Puts in perspective how small this thing is!

Posted by: Phil Stooke Sep 4 2005, 05:09 AM

This site:

http://www.hayabusa.isas.jaxa.jp/e/index.html

has some recent updates - check the column at left - the Sept 2 one has things I don't think have been seen elsewhere yet. No resolved images released yet, but they can't be far away.

Phil

Posted by: Phil Stooke Sep 5 2005, 04:02 AM

The latest distance reported... 750 km! And at the speed of approach they quote they will be there within two days... except of course they may slow down for the final approach.

This is at:

http://www.isas.jaxa.jp/e/enterp/missions/hayabusa/today.shtml

I'm in the mode I always get into for a first view of a new world, or a new landing... obsessively checking in all the time. They always report "over two billion hits today", not knowing over a billion were just me.

Somebody asked elsewhere on here about reaction in Europe to recent ESA missions. I was just looking at various japanese newspapers etc. online - nothing on Hayabusa! But if this mission succeeds it will be something of a first for Japan, their first successful major exploration mission with their first images of a new world. I hope that will make a difference to their approach to public relations.

Do we have any members or lurkers from Japan?

Phil

Posted by: dilo Sep 5 2005, 05:38 AM

http://www.isas.jaxa.jp/e/snews/2005/0905.shtml
Finally, two Optical Navigation Camera pictures taken yesterday from 1000 Km... a mere 5/6 pixel wide asteroid in the best condition!

Edit: looking more carefully, mentioned pixels are in fact "macro" pixel, probably artifacts resulting from some "bad" rescaling/magnification from original image. Using press release pixel, asteroid size is about 20x10; based on declared image size, asteroid measures 2x1 arcminutes or 580x290m at 1000Km, as expected.
Herebelow I magnified x2 the starting images, processed them in order to better see artifacts and real shape, then compare it with Oostro model (scale is 3 arcsec/pixel in all images). Agreement is good, but we still cannot see surface detail...

Posted by: alan Sep 6 2005, 03:20 AM

Down to 500 km
http://www.isas.jaxa.jp/e/enterp/missions/hayabusa/today.shtml

Posted by: Comga Sep 6 2005, 04:01 AM

First, I agree, this is tremendously exciting stuff. A fourth space program has returned meaningful remote sensing from deep in the solar system. With a little luck, it will keep getting better and better. If only their press releases matched their accomplishments.

As for the image scale, I count 19 "pixels" in the image, give or take one. If we use the 600 meter value and the 1000 km range, the individual "pixels" are 7.0 arc seconds or 34 microradians. This is very close to one third of the 100 microradian IFOVs of the camera (20.6 arc seconds). This is in agreement with their appearance as being oversampled from multiple images. In this case, it looks like they are trying to get 3X resolution. To me it looks like a "good rescaling", not a "bad" one. Of course, it would be better to have from JAXA the actual manner in which these images were prepared.

The attached image is a composite of the two, blurred with an 0.75 pixel radius Gaussian kernel (a matter of taste after a few tries). Details are not yet visible, but there are great hints as to the shape.

Posted by: dilo Sep 6 2005, 07:00 AM

Maybe they tried to make oversampled super-resolution image, but original pixel pattern appear too evident and masks finer details...

Posted by: Toma B Sep 7 2005, 07:52 AM

Itokawa's rotation...

This site:
http://www.hayabusa.isas.jaxa.jp/e/index.html

Image:

Posted by: maycm Sep 7 2005, 02:24 PM

That is so cool!

Posted by: RNeuhaus Sep 7 2005, 02:56 PM

The asteroide Itokawa spins its axis every 12 hours. The spacecraft will have a hard time to approach it. The shape of the asteroide is not symmetrical and the Hayabusa's low speed ion engine to approach to the asteroide that cannot avoid it.

The rock might slam Hayabusa spacecraft. So it must land as close as possible at the rotation axis. Is that true or not? Otherwise Hayabusa can land anywhere. Will the Hayabusa spacecraft be able to thrust its ion engine in order to remain at the same position of Itokawa during its rotation?

Rodolfo

Posted by: Myran Sep 7 2005, 03:10 PM

In response to RNeuhaus: Hayabusa will have to approach at the axis of rotation, or rather near that at least. The ion engine was used for the cruise phase reaching the asteroid and are turned of fnow I think.

Posted by: antoniseb Sep 7 2005, 04:00 PM

If this rock is a few hundred meters long and spins once every twelve hours, I'm not sure that there's any special need to land near a rotational access point. How many meters per second will the surface be moving because of the spin?

BTW, the spacecraft haas chemical rockets for these manuevers.

Posted by: djellison Sep 7 2005, 04:13 PM

Assuming an 800m sphere at 12hrs rotation ( which is probably ballpark-ish-right )

Circum= 2500 metres, so it's rotating at about 200 metres per hour - 3 1/3 per minute - - 5.5 cm / second

Doug

Posted by: tty Sep 7 2005, 05:06 PM

Putting Hayabusa in the way to be "swept up" may actually be a rather good way of effecting a soft landing!

tty

Posted by: ElkGroveDan Sep 7 2005, 05:26 PM

Call me crazy, but the longer I watch this, the more I get the feeling that this looks like a "contact binary" body. Those lobes seem to jut off at a sharp angle -- maybe even three bodies in contact.

Posted by: antoniseb Sep 7 2005, 05:41 PM

Maybe. To me, the curved shape when seen the long way suggests one big piece. In any case, the craft should be just about on top of the asteroid now, and we'll probably get a good close image soon, and have more solid hints. Either way will be interesting.

Posted by: djellison Sep 7 2005, 06:05 PM

Reminds me of a baby Eros, or even a bit like Comet Borrelly

Posted by: Toma B Sep 8 2005, 07:54 AM

Posted by: SFJCody Sep 8 2005, 08:13 AM

They're both S-class, so it's possible...

Posted by: djellison Sep 8 2005, 08:42 AM

Wow - it REALLY does...just 10 x smaller

http://near.jhuapl.edu/iod/20000121/index.html

Doug

Posted by: edstrick Sep 8 2005, 10:26 AM

From the rotation clip, it looks like a junebug on it's back, trying to get upright, or mabe a kidney bean.

BUGS IN SPAAAAAACEEEEEEEEE!

Posted by: antoniseb Sep 8 2005, 09:27 PM

It should be there now, just firing the engines to place itself along side the hunk of bean-shaped rock. I'd love to see some images.

Posted by: dilo Sep 9 2005, 06:39 AM

Finally, surface detail!
http://www.jaxa.jp/missions/projects/sat/exploration/muses_c/index_e.html
now only 220Km from Itokawa!

Posted by: tedstryk Sep 9 2005, 09:37 AM

Cool image! Of course, you have to love bad translation like "calm but hectic discussion."

Posted by: Bob Shaw Sep 9 2005, 10:58 AM

It's worth checking out the Japanese language section of the Hayabusa site as although it's in, er, Japanese, the images seem to be updated faster than on the English language version...

http://www.hayabusa.isas.jaxa.jp/j/index.html

Posted by: SFJCody Sep 9 2005, 11:23 AM

A Babel Fishified version:

http://babelfish.altavista.com/babelfish/trurl_pagecontent?lp=ja_en&url=http%3A%2F%2Fwww.hayabusa.isas.jaxa.jp%2Fj%2Findex.html

Posted by: Myran Sep 9 2005, 11:54 AM

Umm wouldnt say its 'details' yet, but the truth are getting obvious.
Its a cheesdoodle!

Posted by: odave Sep 9 2005, 03:07 PM

All your soil are belong to us...


(sorry, had to do it )

Posted by: Chmee Sep 9 2005, 05:36 PM

So the conclusion is ... that this asteroid is a giant bean??

Posted by: RNeuhaus Sep 10 2005, 03:57 AM

This was slipped from a farmer's bag at billions years ago.

New update:

Today's HAYABUSA
As of 9:30 2005/09/09(JST)

Distance from Earth : 322,725,650km
Distance from Itokawa : 99km

Wait for less than 79 km to arrive at the gate...to take more pictures at this...

Thinking that by now that Hayabusa must be navigating at lower than 7km/h when it was 220 km from Itokawa and I calculate that between 2 and 3 more days, on next Monday September 12, Hayabusa will be hovering on Itokawa.

cross fingers...

Rodolfo

Posted by: Toma B Sep 10 2005, 01:04 PM

New images from 70 km...

Posted by: tedstryk Sep 10 2005, 02:11 PM

http://www.isas.jaxa.jp/e/snews/2005/0909-2.shtml
http://www.isas.jaxa.jp/e/snews/2005/0910.shtml

Here are the links to the tiff images from the last few days. We are at 47 KM. It will have arrived at 20 km. Although I am looking forward to these images, I am especially looking forward to the second phase of global mapping, when it will take high phase angle images.

This is also cool.

http://www.isas.jaxa.jp/e/snews/2005/0908.shtml

Posted by: ElkGroveDan Sep 10 2005, 02:37 PM

I hope it has a higher res imaging capability than what we are seeing now from just 47km.

Posted by: tedstryk Sep 10 2005, 04:26 PM

The closest released images are from 70 km, not 47. So much more good stuff will come soon!

Posted by: peter59 Sep 11 2005, 07:34 AM

The closest released images are from 30 km
http://www.isas.ac.jp/e/snews/2005/0911.shtml

Posted by: Toma B Sep 11 2005, 08:22 AM

No impact craters???

Posted by: SFJCody Sep 11 2005, 08:26 AM

It's tiny. Compare it with pictures of dusty and bouldery parts of (433) Eros at the same scale and the surface texture starts to make sense.

Posted by: abalone Sep 11 2005, 09:07 AM

Looks to me like a few lumps just held together by gravity and fine dust filling the spaces between. If anything were to hit it the whole pile would just fall apart and gently settle back together again. There would be no crater I think

Posted by: Myran Sep 11 2005, 09:16 AM

I think there might be some craters, have indicated some on this image but theres some hestitation on my part on the identification, so lets see when we get closer.

Posted by: tedstryk Sep 11 2005, 12:10 PM

I agree that we must consider the possibility that other than the small craters relative to the size of the asteroid, this little asteroid is so fragile that an impact simply breaks a chunk off. Something about this little world feels Deimos-like.

Posted by: David Sep 11 2005, 05:15 PM

What are the dimensions of 25143 Itokawa?

Posted by: RNeuhaus Sep 11 2005, 06:13 PM

The asteroide Itokawa is potato-shaped asteroid, is named after Hideo Itokawa, a Japanese rocket pioneer. it measures 630 meters long. Up to here I have not found more information such as its width.

Rodolfo

P.D.For comparisions purpose, I don't know about the sizes of the comet Tempel 1.

Posted by: djellison Sep 11 2005, 06:15 PM

800m is the onyl number I've seen batted around.

Is that an average diameter, a length...I dont know.

Doug

Posted by: Jyril Sep 11 2005, 07:10 PM

7.6 km x 4.9 km x 4.9 km

For example Eros is 33 km x 13 km x 13 km

So Tempel 1 is roughly 10 and Eros 40 times larger.

Posted by: tedstryk Sep 11 2005, 07:22 PM

For Itokawa, according to the NSSDC, 0.3 x 0.7 km. This is a radar derived figure, and based on imagery so far, I think that the model is holding up quite nicely.

Posted by: RNeuhaus Sep 11 2005, 09:57 PM

A funny news:

Hayabusa will also employ a hopping small robot called Minerva, about coffee size, which can move around on the asteroid’s surface." During the first descent to fire a pellet into the surface, a small coffee-can-sized surface hopper, called MINERVA, will be dropped slowly onto the asteroid's surface. For one to two days it will slowly leap about the asteroid taking surface temperature measurements and high-resolution images with each of its three miniature cameras.

The other funny thing is that Hayabusa will also release is a small tenis ball: Target Marker to the surface. "In order to successfully descend on a candidate-landing point, it not only uses an artificial target called Target Marker that is released from the spacecraft to the surface, but also adjusts its position by processing the images sent from the camera and keeping an eye on landmarks."

That is intrigating stuff and it is very funny at the same time. How do a such thin device: Minerva is considered as the world smallest spacecraft? Measure the temperature, take pictures and send images to the Mother spacecraft.

One more point, according to the Ion Engine Cruise route map (http://www.isas.jaxa.jp/e/enterp/missions/hayabusa/data_050902.shtml) is that the spacecraft Hayabusa will make a loop around Itokawa during its breaking process.

I tought that Hayabusa will go directly to Itokawa and stop at a gate position at 20 km above of the asteroide's surface. But , now I am not sure what will be the future route of Hayabusa before returning home (Earth) by December.

Rodolfo

Posted by: SFJCody Sep 12 2005, 05:44 AM

Arrival!

http://www.hayabusa.isas.jaxa.jp/e/index.html

What a fascinating little world.

Posted by: dilo Sep 12 2005, 06:04 AM

If I remeber correctly, the Target Marker include also signatures from worldwide people (like Cassini DVD)... Now I regret to not partecipate to this initiative!

Posted by: Toma B Sep 12 2005, 06:42 AM

Color composite image will be available soon.

That is a promise they should keep...

It's allways nice to see new member of the Solar Sistem even so small...

Posted by: Rakhir Sep 12 2005, 06:43 AM

Here is a description of Minerva science capabilities.

Rakhir

Posted by: Toma B Sep 12 2005, 07:34 AM

I tried to bring forward some details...

Posted by: tedstryk Sep 12 2005, 10:08 AM

I can't wait to see the color image. And I am now eagerly anticipating the landing. Until now, I have tried not to get my hopes to high about this mission. But it looks like they are pulling it off!

Posted by: maycm Sep 12 2005, 01:15 PM

Congratulations to the JAXA team on this achievement so far.

The really exciting stuff is still to come of course but there is no doubt about the dedication and patience that the team took to get here.

Posted by: djellison Sep 12 2005, 01:17 PM

Much like the colour image from DI, or the occasional colour image from NEAR...it showed very little colour variation. It's only when stretched to hell and back that you get something like the freaky colours Galileo showed us of the asteroids it visited en-route.

Doug

Posted by: ljk4-1 Sep 12 2005, 01:25 PM

Perhaps I am speaking too soon, but the planetoid does not seem to have very many impact craters, at least large ones.

Posted by: djellison Sep 12 2005, 01:27 PM

I see lots of small ones on the latest image, but any large ones would have smashed what is likely to be a fragile body to pieces.

Doug

Posted by: Phil Stooke Sep 12 2005, 02:36 PM

Woo-hoo! I'm on vacation in the UK, starved for information on anything other than celebrity weddings, and finally I find a cyber cafe... yes, I know, it's a trifle obsessive of me... - so today I first saw these new images of Itokawa. Fabulous! This should be a really interesting mission.

Eros had 'ponds' of smooth material filling deprssions. Maybe the large central smooth area is such a pond here. Electrostatic processes were thought to be responsible, I think.

Phil

Posted by: hendric Sep 12 2005, 02:39 PM

I agree with what others have posted, it looks like about 2 large and 1 small body attached together in a peanut shape, with dust infill between the bodies. Hopefully they'll try sample return from both types of "surfaces". I'll bet those "smooth" areas are extremely fluffy dust...Hopefully Minvera will work without just falling into a dust-drift!

Posted by: djellison Sep 12 2005, 02:39 PM

I apologise, on behalf of the whole nation, for the total and utter Cricket obsession that's going to at the moment. It looks like we might actually win something, and that's a rare enough occasion to warrent plenty of attention

Enjoy the UK

DOug

Posted by: ElkGroveDan Sep 12 2005, 02:53 PM

One sharp fellow actually suggested that back on September 7 when the images were just a few pixels wide.

http://www.unmannedspaceflight.com/index.php?showtopic=870&st=120&p=19494&#

Posted by: RNeuhaus Sep 12 2005, 03:39 PM

Many thanks for posting a Minerva's document.

Rodolfo

Posted by: 4th rock from the sun Sep 12 2005, 05:52 PM

1/2 Asteroid rotation!

Made from the last days images.

Posted by: Bob Shaw Sep 12 2005, 08:46 PM

Phil:

What's your itinery? If you hit Scotland, let me buy you a pint!

Bob Shaw

Posted by: Bob Shaw Sep 12 2005, 08:49 PM

Toma:

Interesting images - the spiky horizon is quite odd, though it may be an artefact of the processing and the direct down-sun illumination. JAXA have really done well this time!

Bob Shaw

Posted by: tedstryk Sep 13 2005, 10:13 AM

http://www.hayabusa.isas.jaxa.jp/e/index.html

Some cool new graphs up. No color image yet. I think that if this asteroid is as gray as others we have explored, it may be harder than they thought to make a color image look convincing, particularly if there are color flecks due to noise.

Posted by: deglr6328 Sep 13 2005, 04:31 PM

I think it was recently shown somewhere (nature?) that they were not a result of electrostatic processes but instead were formed when the asteroid was struck by another body (do we call smaller objects striking larger asteroids, "meteors"?) making the whole thing ring like a bell and vibrating fine dust into pools in low lying areas....

Posted by: paxdan Sep 13 2005, 06:26 PM

I have a feeling the spiky horizon may well be large boulders, a similar thing was seen in a few of the eros images. However, Ikotawa is so tiny in comparison to everything else we've visited (heck it's smaller than dactly!) the boulders would only have to few tens of meters in size to be very prominant against the horizon.

Can someone photoshop into the image a scale bar or and object we all know the size of so i can get a handle on the size. I reakon we've made manmade objects as big as this lump of rock.

Posted by: ElkGroveDan Sep 13 2005, 06:55 PM

Apparently it's 630 meters long, which is 2067 feet. The aircraft carrier Eisenhower is 1092 feet long (333 meters). So here's a rough comparison of Hayabusa with two images of the USS Dwight D. Eisenhower.

Doug, perhaps like NASA, I have created a new unit of measure....the aircraftcarrier.

Posted by: djellison Sep 13 2005, 08:22 PM

No, no, no, no, no - you've got it all wrong, it's 6 football fields.



Doug

Posted by: David Sep 13 2005, 08:30 PM

That's 7 football fields for us Yanks with our 90-meter fields.

Personally, I make it out to be a little smaller than the rock of Gibraltar.

Posted by: Chmee Sep 13 2005, 08:43 PM

Well, for any Robotech / Macross fans out there, this rock is actuallly half the size of the SDF-1!

Posted by: antoniseb Sep 13 2005, 09:04 PM

We haven't actually built this, but it might be interesting to see it in relation to the 8km long Babyon 5 station.

Posted by: paxdan Sep 13 2005, 10:11 PM

Obligatory link to http://news.bbc.co.uk/1/hi/sci/tech/4242076.stm.

This is turing into quite a coup for JAXA.

Ever since I heard first heard of the notion of a contact binary i always imagined the contact point to be free of dust, i.e., rock in contact with rock. Over the years (eros, ida, etc..) my minds-eye view of bare rock asteroids has been replaced by dusty little worldlets covered in boulders and craters. Of course now looking at Itokawa it makes sense that the dust would gravitate (pun intended) to the contact point as this, for equally sized bodies, would represent the deepest part of the gravity well of the contact-binary system that the dust could fall to (please correct me if i'm wrong).

I am really looking forward to seeing some decent 3D models of this rock. As for sampling both lobes, i would hazard a guess that the dust is going to be pretty homogenous across each site.

Oh and here is a pretty extensive http://www.johnstonsarchive.net/astro/asteroidmoons.html#1 with lots of info about asteroids with satellites and contact binaries

Posted by: lyford Sep 14 2005, 12:00 AM

Maybe http://www.merzo.net/ could help....

Posted by: Decepticon Sep 14 2005, 12:47 AM

I have been a fan of this site for a long time. It has almost all Sci-Fi/ Real Objects comparison charts.


V'Ger is MASSIVE!

Posted by: edstrick Sep 14 2005, 07:29 AM

I ran bandpass filtering on the 3 best images to bring out fine details without being swamped in noise. The 2 jpg's from 9/11 have some jpg noise but still show more detail, the better gif from 9/12 crisped up nicely.

Of particular interest, it looks to me like the rough material between protruding knobs is darker than the smooth fines or regolity filling in major depressions and the area between the 2 parts of what really does look like a contact binary. In the bottom image, part of the fill looks like dark rubble and not smooth fines.

Posted by: dvandorn Sep 14 2005, 08:52 AM

Hmmm... I don't see a lot of albedo difference in the top images between the depression fill and the general fine fill between the two ends of what may well be a contact binary.

The bottom image seems to show, to my eye, a large dark fine fill that could well cover the contact between the two main objects in the contact binary. Yes, there is a rougher and somewhat darker fill in the upper part of the image, and yes, that does look like a somewhat rougher part of the fill between the two bodies. But it very much looks to me that the darker, rougher fill and the slightly lighter fine fill are both performing similar functions, covering the contact point between the two larger masses within the asteroid.

We can now also see many small craters, and it almost seems like these are the largest craters that this body could withstand before it would blow apart into smaller fragments. I'm also thinking that the fine fill might not show craters -- any impact would blow the fines away, and the asteroid's microgravity would, over the course of centuries, draw the fines back into place, obscuring any crater that might have formed.

We need to model the gravitational and trajectoral influences on very small pieces of rock dust liberated from very small bodies, I think. Over the course of centuries and millennia. It would be very instructive to see if rock dust ejected by small impacts on small bodies would tend, over long time periods, to gather back onto those bodies as fines. Because we need to have some decent theories to explain the abundance of fines we're seeing on the surfaces of the asteroids we look at...

-the other Doug

Posted by: edstrick Sep 14 2005, 09:01 AM

DVandorn: ".....Yes, there is a rougher and somewhat darker fill in the upper part of the image, and yes, that does look like a somewhat rougher part of the fill between the two bodies. But it very much looks to me that the darker, rougher fill and the slightly lighter fine fill are both performing similar functions, covering the contact point between the two larger masses within the asteroid. ..."

I completely agree. I think one is rubble, the other may be electrostatic-levitation <or whatever> transported dust.

I hope the camera has the S/N ratio to see spectral/color differences between the materials. NEAR's camera was so noisy, it really couldn't see color differences at the single pixel level, and barely could see them over multi-pixel averages. For most bodies in the solar system, other than Earth, Mars, Io, Jupiter, etc., you need to design cameras with a very high signal/noise ratio to be able to do any useful color or multispectral imaging at all.

Posted by: BruceMoomaw Sep 14 2005, 09:46 AM

There are at least three current theories as to what could create Eros' "ponds": seismic shaking, electrostatic levitation due to charging of dust particles by solar radiation, and even the idea that Eros -- being a fragment from a bigger asteroid shattered by collision -- may have contained some water ice in its rock pores if it came from that asteroid's interior, and may thus have been gently outgassing water vapor since then and thus swept the dust into depressions: http://www.aas.org/publications/baas/v37n3/dps2005/622.htm . It's perfectly possible that all three mechanisms have operated. One possible fourth one: since there is now a strong feeling that some rubble-pile asteroids are actually split apart by tidal forces when they make a close flyby of a planet, it's possible that more distant flybys by Eros have been tugging dust particles a small distance off its surface, so that they tend to stay more in local depressions when they fall back.

Jeffrey Bell of Hawaii takes the more radical view that Eros' "ponds" may not be dust at all, but pools of solidified lava left over from the asteroid's creation, since he thinks that the S-type asteroids like Eros actually do have a separate origin from the smaller Q-type asteroids that have the same spectral makeup as ordinary-chondrite meteorities. But in that view he's in the minority; most scientists think that the S-type asteroids are indeed made of ordinary-chondrite rock, and that "space weathering" by micrometeoroids and solar radiation have been what's modified their surface near-IR spectra away from those of OC meteorites. And the evidence for the latter does seem to be growing steadily.

Posted by: MiniTES Sep 14 2005, 02:06 PM

Could someone make an image highlighting these fill lines so I know exactly what you're referring to? It does look like a contact binary to me...

Posted by: dilo Sep 15 2005, 06:21 AM

First color image! (+ rotation sequence + CG animations... )
http://www.isas.jaxa.jp/e/snews/2005/0914.shtml
Very poor colors, indeed. Here an enhanced version:

Posted by: Toma B Sep 15 2005, 06:26 AM

Nice Rotation sequence too ...

Posted by: ljk4-1 Sep 15 2005, 02:33 PM

If Deep Space 1 could have imaged Braille more clearly, would it have looked like Itokawa?

Any chance that Braille can be radar-imaged from Earth?

Posted by: tedstryk Sep 15 2005, 02:34 PM

http://www.isas.jaxa.jp/e/snews/2005/0915.shtml

More!!!

Posted by: djellison Sep 15 2005, 02:38 PM

Noticeable rotation between the filters there.....

Almost anaglyphable


.

Doug

Posted by: paxdan Sep 15 2005, 03:07 PM

And to think we were worried about slow release of data. Puts ESA to shame. Anyone dug up a link to the raws yet?

Posted by: odave Sep 15 2005, 03:13 PM

Indeed. I'm just finishing up Roving Mars, and if the Hayabusa team is feeling anything like the pressure the MER team felt due to the previous Mars mission failures, they must be jumping for joy.

Though there is still a lot for Hayabusa to do before its mission ends, congratulations to all at JAXA for the success so far!

Posted by: Sunspot Sep 15 2005, 03:14 PM

Is that the actual size of the asteroid on the original images - or do you think the images have been reized down at all?

And look at that rock sticking out of the asteroid in the "270" image rotation sequence

Posted by: paxdan Sep 15 2005, 03:37 PM

The AMICA CCD is 1024x1024 with a FOV of 5.7 degrees. The images are captioned saying they represent a 2 degree FOV, and http://www.isas.jaxa.jp/e/snews/2005/0915.shtml is 363x368 so i would say yes, they have been cropped.

Posted by: djellison Sep 15 2005, 03:39 PM

If it was MER they would be an ESF

Doug

Posted by: SFJCody Sep 15 2005, 03:54 PM

You can see it on 135 through 225. Looks a bit flattened and mesa-like. On 180 and 196 the "bird in flight" shaped shadow turns up quite clearly.

Posted by: tedstryk Sep 15 2005, 04:27 PM

One has to remember that Nereus was the original target for the mission. Due to a launch slip, this opportunity was lost so they moved on to this asteroid. Nereus is much larger and would have filled more of the field. It is important to remember that while the images look small, they are similar in resolution to a high resolution MOC image - this is just a very little asteroid! Also remember that when it goes in to sample and deploy Minerva, it will obtain images from closer range, which will be larger. As for the raws, I am very happy with the fact that they have released PNG versions of a lot of the releases so there haven't been JPEG effects in the press images, making them closer to raw. And the images are supposed to be released in both some Japanese archive AND on NASA's PDS after the year-long proprietary period. So this won't be like dealing with ESA. I think that part of the reason that JAXA hasn't crowed about its planetary missions more in the past is that it hasn't had much to crow about, especially with regard to things that would garner public interest. In other areas, it has been much better. Look at Yohkoh (I hope I spelled that right), their highly successful solar satellite. They were extremely cooperative in releasing all the data immediatly and cooperating with NASA and NOAA. And their press releases, while a bit awkward due to the extreme language barier, are at least informed and accurate.

Posted by: odave Sep 15 2005, 04:48 PM

Two other protruding features can be seen in 30-225:

Looks like the best view of them is in 196 - almost like a flat plate sticking out sideways. Or, in keeping with our past feline themes, "cat ears" in 225

Posted by: Palomar Sep 15 2005, 04:51 PM

http://www.spaceref.com/news/viewsr.html?pid=18082

*Hayabusa has performed a short chemical-thruster burn which slowed its speed by 7 cm per second. It's begun hovering operations. Is in good health, all instruments functioning normally.

(It looks like a sweet potato )

Posted by: Chmee Sep 15 2005, 05:00 PM

(It looks like a sweet potato )

[/quote]


Actually it looks like a potato spinning in the microwave...

Posted by: ljk4-1 Sep 15 2005, 05:04 PM

Will there be any problems with Minerva, since I am assuming it was designed to work on a bigger planetoid?

And to restate a question I had asked earlier, but I think got lost admist the images and potato comparisons: If Deep Space 1 had taken better images of Braille, do you think it would have looked similar to Itokawa?

And I think Japan deserves to crow about this mission!

Posted by: Gsnorgathon Sep 15 2005, 06:11 PM

Say - does anyone have any notions as to how (if at all) Minerva's camera lenses are to be protected from Itokawa's dust? http://www.unmannedspaceflight.com/index.php?showtopic=870&view=findpost&p=20029 earlier in this thread, but it doesn't mention any means of protecting the camera lenses.

There are 8 pins that protrude from each end of Minerva. I'm wondering if they're supposed to hold Minerva far enough off the surface that no other protection is necessary. Seems a bit dodgy to me.

Posted by: tedstryk Sep 15 2005, 06:54 PM

I would definitely agree that they deserve to crow! They should be proud of this (and no doubt are). I am pretty sure they did tests to make sure Minerva would work on Ikotawa.

As for Braille, it was similarly lumpy and somewhat larger (somesing like 1.3x0.6 km), very similar in size to Dactyl on its long axis. But Braille was of the Vesta family, and had a basaltic composition. I believe Ikotawa is a chondrite. So while their overall shapes are similar, they might have a different appearance at high resolution - but of course with Braille we are left guessing. Here the best I could get out of the two views DS-1 got. The reddish color is based on spectral data indicating that it is reddish.

Posted by: dilo Sep 15 2005, 07:01 PM

Great idea, Doug! (I have impression that anaglyph colors should be inverted - I must rotate my glasses to see it correctly!)

Posted by: BruceMoomaw Sep 15 2005, 08:31 PM

Is Itokawa a contact binary, or just a single asteroid with one extremely large chunk lopped out of
one side?

http://www.hayabusa.isas.jaxa.jp/e/index.html

http://www.hayabusa.isas.jaxa.jp/e/index_14.html

At any rate, we still are not seeing any major craters whatsoever, but we're
seeing what looks like a VERY rough, textured surface. It may be that (in
accord with http://www.aas.org/publications/baas/v37n3/dps2005/381.htm ),
Itokawa is a "rubble-pile' NEA which happened to fly close to a planet not
too long ago and had its surface so affected by the tidal forces as to erase
all its crater population up to then -- and it may even have been almost
pulled in two by the same tidal forces (as Abell predicts often happens).

Posted by: edstrick Sep 16 2005, 08:12 AM

I think they've probably done very very little to protect the cameras on Minerva. The hopper is probably pretty much a high-tech jury-rig that cost relatively little using mostly off-the-shelf hardware to achieve fairly impressive ability. Even a few pictures before lenses get bunged or dirty will be very valuable. Having extra cameras increases the probability of success.

I'd assumed it was battery powered, but has solar cells. So I wonder what it's real lifetime is limited by.. it may surprise us and last and last.

I'd land it in a flatter but non-dust surface in one of the hollows in the rough terrain. Give the best views of rock and dust.

If it lands in dust, they might get some interesting views from the main probe of it kicking up dust during hopping or landing.

Posted by: djellison Sep 16 2005, 08:36 AM

The force of 'gravity' will be so very very weak for Minerva that even though it's held up by little more than some knitting needles, I doubt it will sink in much

It'll be our first images-from-the-surface-of-a-new-body since Hugyens

Doug

Posted by: mhall Sep 16 2005, 12:17 PM

> It'll be our first images-from-the-surface-of-a-new-body since Hugyens


Gosh, it'll be nearly a whole year between extraterrestrial landings!

Time was, we got one or two a decade, and were grateful; these days, I think we're getting spoiled, I'm glad to say.

Posted by: abalone Sep 16 2005, 12:19 PM

I did a back of the envelope calculation that a 1000Kg car would weigh the Earth equivalent of 3 grams and escape velocity is an energetic rollover in bed.

This last point could well account for the extinction of the Itokawans and the apparent inexplicable uninhabited nature of this otherwise desirable piece of Solar Sytem real estate. They either all rolled off into orbit in blissful ignorant unconsiouness while sleeping, or simply refused to engauge in their normal acts of procreation, form fear of a lustful orbital insertion manoeuver at the hands of an overenthusiastic bedspring. Either way extinction was just around the corner.

I expected to see a thiving community after following a discussion along those lines in another thread recently, I know that Bob Shaw will be equally dissappointed.

Posted by: RNeuhaus Sep 16 2005, 03:51 PM

It is possible that Minerva will have bouncings of different height due to the different impact absorption capacity between the dusty and rocky parts of Itokawa. The best hope is that Minerva will not be lost due to much bouncing. I think that Hayabusa will release it VERY SLOW to the surface as one very good billboard player can do.

Rodolfo

Posted by: Bob Shaw Sep 17 2005, 01:40 PM

Nice Earth swing-by screensaver from JAXA:


http://www.jaxa.jp/news_topics/vision_missions/hayabusa/index3_e.html

Posted by: elakdawalla Sep 17 2005, 04:32 PM

Thought I'd point out http://planetary.org/news/2005/hayabusa_itokawa-beckons_0916.html, which was posted yesterday....

--Emily

Posted by: dilo Sep 17 2005, 05:11 PM

Thanks, Emily, this article is very interesting...
By reading it, however, a lot of questions hit my mind.
For example:
1) how Hayabusa wills stay anchored (if so) to Itokawa during sample collection?
2) Are we sure that 'target marker' fired on asteroid's surface will stay here and will not bounce in the space or will be buried under the powder?
3) Which kind of 'state-of-the-art material' will be used for heatshield?
4) How collected samples will be preserved from Earth chemical/bilogical contamination?
Do anybody already knows some answer ? (probably no one knows exact #2 answer!).
Thanks again...

Posted by: BruceMoomaw Sep 17 2005, 07:12 PM

I can answer questions #1 and 2 immediately:

(1) Hayabusa will just use its thrusters to press the bottom edge of its "sample collection cone" onto the surface very briefly -- just long enough to fire a gun at the top end of the cone, whose bullet will kick a few bits of surface debris back up into the collection chamber at the top of the cone. The craft will then immediately take off from the surface again after just a couple of seconds. (This very-brief-touchdown mode seems to be the best way to collect samples from the surface of very-low-gravity small bodies -- at any rate, there are variations on it in the "Hera" and "Hummingbird" proposals for collecting surface material from a near-Earth asteroid and a comet nucleus, although they use a sticky pad or a short high-speed drill instead, to obtain bigger samples.)

(2) The landing marker will just drift down very slowly onto the surface in the asteroid's extremely low gravity. Even if it bounces slightly, it makes no difference. (Indeed, as I understand it, Hayabusa can land even without the marker -- it just makes it easier to come down with no relative horizontal velocity as the asteroid rotates slowly at about 5 cm per second.)

Posted by: dilo Sep 17 2005, 07:30 PM

Thank you very much, Bruce!

Posted by: edstrick Sep 18 2005, 05:04 AM

Bruce Moomaw: ...." there are variations on it in the "Hera" and "Hummingbird" proposals for collecting surface material from a near-Earth asteroid and a comet nucleus, although they use a sticky pad or a short high-speed drill instead, to obtain bigger samples.) "

On one of the later Apollo missions, they took a special lunar sample with a special single-use instrument: They had a handle and something like a piece of velvet free-floating in a wire frame but attached at the edges. They pressed it flat against a flat spot of undisturbed regolith so that the very uppermost grains of soil would be caught by the fibers in the velvet. Then they detached the velvet from the frame, rolled it up on a rod or pin (probably pre-attached to the side of the fabric) and stuffed it neatly in a tube and capped the tube.

I never heard any results of analysis or inspection of the sample and have wondered if it's still in the sample tube somewhere in the bowls of the lunar sample storage facility, lost like the ark in "Raiders"

Posted by: BruceMoomaw Sep 18 2005, 07:50 AM

That was either Apollo 16 or 17, and I have a very faint and possibly false memory that they DID analyze it. The sticky pads on the proposed "Hera" (which I think may well be picked as the next Discovery mission) would be coated with 1 cm of silicone grease to pick up a much bigger sample -- about 100 grams from each of nine sites on three different near-Earth asteroids:
http://www.lpi.usra.edu/meetings/lpsc2003/pdf/1032.pdf
http://www.lpi.usra.edu/meetings/lpsc2003/pdf/1047.pdf
http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1716.pdf
http://www.lpi.usra.edu/meetings/lpsc2005/pdf/1452.pdf
http://www.lpi.usra.edu/meetings/lpsc2005/pdf/1464.pdf



Meanwhile, there are some excellent descriptions of the Hayabusa mission at http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1521.pdf and http://www.lpi.usra.edu/meetings/lpsc2004/pdf/2161.pdf -- including a description of the curation procedures for the returned samples. And there are detailed descriptions of the Minerva hopper at http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1517.pdf and http://www.lpi.usra.edu/meetings/lpsc2005/pdf/2289.pdf .

Finally, http://www.lpi.usra.edu/meetings/lpsc2004/pdf/2058.pdf notes that Earth-based studies already suggested that there might be something unusual about Itokawa's surface. While its color curve resembles that of a standard S-type asteroid, its albedo is distinctly higher -- and it is a less diffuse scatterer, suggesting to me that it may indeed have a rocky surface mostly bare of ejecta (which would mesh nicely with the lack of craters, both suggesting that it may be a fragment quite recently broken off a bigger asteroid). However, the little Q-type asteroids, whose spectra resemble ordinary-chondrite meteorites and which are also believed to be relatively fresh pieces broken off bigger asteroids and so exposed to little "space weathering" (which would give them an S-type coloring), are a distinctly different color. Tune in for our next exciting chapter...

Posted by: dvandorn Sep 18 2005, 07:50 AM

NASA has top men working on it...



I only have one other thing to add to this -- the sampler was indeed flown on Apollo 16, and the description of the sampling process that Young and Duke gave during the EVA was that only one corner of the velvet actually touched the surface, because the surface was very uneven, even at small scales.

So, they did get a sample and it was returned, but it covered less than a quarter of the collector cloth. I *seem* to recall a description of the time the very top layer of the regolith at that location had been in place, based on this sample, but I'd be at a loss to tell you where I might have read that, or when.

-the other Doug

Posted by: RNeuhaus Sep 19 2005, 03:28 PM

I have the curiosity about the long distance iwhere Hayabusa remains as gateway at 20 km from Itokawa. Why it so far instead of closer distance? I have many suppositions; these are:

1) Better control for approaching with long time for adjusting the propulsion.
2) Better picture focus according to the camera photography.
3) Outside of Itokawa gravity's attraction.

Any comments?

Rodolfo

Posted by: djellison Sep 19 2005, 03:52 PM

It'll take less fuel to hover at 20km that it would at say, 5km

Doug

Posted by: volcanopele Sep 19 2005, 07:44 PM

Nothing special, but I made an animated gif out of their rotation sequence:

http://pirlwww.lpl.arizona.edu/~perry/images/Itokawa.gif

Posted by: Bob Shaw Sep 19 2005, 08:01 PM

Some of those sticky-out-bits (a technical term, I'm sure!) really *do* stick out! The closeups will be great...

...I hope!

Posted by: RNeuhaus Sep 20 2005, 01:27 AM

Less fuel with greater distance?

At 5 km from Itokawa, Hayabusa will need to adjust its position from Itokawa more often due to the gravity attraction or not?

Rodolfo

Posted by: JRehling Sep 20 2005, 02:32 AM

Remember, the skinniest dimensions of Itokawa are only about 250 meters -- half a pixel in ISS's best images of Titan! It's about 1/50th the size of Eros! It's tiny.

Look at the limb of Itokawa in the JAXA releases and think of the horizon in snapshots Apollo astronauts took on the Moon -- those are similar scales. You don't see many craters on the near-horizon of the Apollo photos, either.

I'm not sure if a world Itokawa's size *can* show much in the way of craters. It may be in that all asteroids this small will have surfaces completely flattened by to saturation, like a World War I battlefield.

Posted by: djellison Sep 20 2005, 07:33 AM

I think it would take more fuel to maintain a station keeping posititon at 5km, because gravity decreases with r^2 - so going to 5km would increase the gravitational attraction ( however small ) by 8x

I'm sure they'll do lots of observations from closer in - but it's like a field geologist. Find high ground and look around first...THEN tackle the target.

Doug

Posted by: abalone Sep 20 2005, 10:52 AM

If you are comparing 20km to 5km , its 16X the force for 1/4 of the distance.

Posted by: djellison Sep 20 2005, 11:02 AM

Opps - yup - it's GM1M2/r^2 - I knew that, just didnt have my maths hat on before breakfast

If I was feeling brave - I'd calculate the actual gravitational attraction between asteroind and spacecraft.

Doug

Posted by: Bob Shaw Sep 20 2005, 11:16 AM

Doug:

It's just over .005 of a Tad (3/8 of a Smidgeon in Old Money).

Bob Shaw

Posted by: abalone Sep 20 2005, 11:19 AM

The force is so pathetically small whether you are at 5km or 20km I wonder if this is really the reason or is it simply a convenient staging distance to gather visual info without the danger of some small error sending it smashing into it. If they go too close too soon the camera is not capable of taking full global images ( if that is not an overstatement for this small gravel patch in space)

Posted by: RNeuhaus Sep 20 2005, 02:06 PM

Doug, Hope that with a coffee drinking, the brain will work much better with maths.

It is very interesting to know the comments relating to the selection of the distance: 20 km from Itokawa. The gravity attraction between the space and the asteroide is almost nil at 5 km.

Maybe, the distance selection of 20 km, is due to approaching command control reasons. This large distance gives the electronic instruments to control better the feedback in order to adjust with very high precision the point of landing. On the other hand, the maneuver of approach to Itokawa does not rely to Earth control command unless the Hayabusa will perform its automatic control approach.

All at all, I think that the distance is somewhat exaggerated. but this approaching maneuver is the first ones of this kind. Hence Hayabusa might be taking this extra room (distance) in order to know better the interaction behaviour between the hardware and software of approach command and also give the spacecraft the needed time to adjust if anything goes wrong.

Rodolfo

Posted by: BruceMoomaw Sep 20 2005, 04:01 PM

I don't really see why -- look at the closeup views of the Moon's surface from various descending spacecraft (from the Rangers on) and they're speckled with clearly visible craters down to just a meter or two in diameter. After all, the size distribution of meteoroids -- and thus of the craters they gouge out -- is fractal; the relative number of craters of different relative sizes remains the same on any size scale. No; something has genuinely caused a shortage of craters on Itokawa -- either seismic shaking like that which obliterated all the smallest craters on Eros (which could be more extreme in this case, if Itokawa also has a regolith), or else the simple fact that Itokawa is a relatively fresh fragment of a bigger asteroid and so just hasn't had time yet to accumulate many craters.

Posted by: Bob Shaw Sep 20 2005, 04:35 PM

Bruce:

Yup, quite right - and even if the surface *was* a WWI battlefield, the *last* craters would show up - and generally you'd start with bigger, older ones, and move down to smaller, more recent ones (well, more-or less). So, as you say, either something wipes the slate clean, or the surface is fairly fresh.

The devil will be in the detail...

Bob Shaw

Posted by: Toma B Sep 20 2005, 06:33 PM

What has hapened to regular (daily) updates and NEW IMAGES?!?

Posted by: dvandorn Sep 20 2005, 07:03 PM

I think that, while Itokawa is quite small, it's also massively uneven in its mass distribution. It took the guys controlling NEAR quite a while to be able to perform maneuvers in which they had any confidence of the resulting trajectory -- all because Eros' gravity field was extremely uneven.

At 25km, the small mass of Itokawa won't have much of a measurable effect on Hayabusa. As it approaches, the gravity effects become more noticeable -- and as the uneven field passes through Haybusa as Itokawa rotates, the *cumulative* accelerations (in all different vectors) will be difficult to predict.

I think they'll likely approach slowly and try to model the gravity field as they close in, so that they don't end up getting swatted badly out of position as they get *really* close.

-the other Doug

Posted by: tedstryk Sep 20 2005, 07:43 PM

If it is very loosely packed, it might just knock a bunch of material off rather than make a crater. Also, there would, I imagine, be a lack of ejecta formations because so little would come back.

Posted by: tedstryk Sep 20 2005, 07:44 PM

I wonder if there is any debris around it. It couldn't hold it there, but if the thing has had so much of a bump recently, I wonder about small objects overing around it.

Posted by: JRehling Sep 20 2005, 08:48 PM

I'm not quite sure if it makes sense to say that the distribution is fractal. I have a sense of what you're saying, but only a vague sense. The distribution fits a power law, but that does not mean that the presence of impact craters looks the same at all scales.



Here are some pictures from airless worlds that show what I'm talking about. Craters absent? No. But on the small scale, they start to be hard to find.

http://spaceflight.nasa.gov/gallery/images/apollo/apollo11/lores/as11_40_5903.jpg

http://nssdc.gsfc.nasa.gov/imgcat/hires/a11_h_37_5458.gif

http://www.nasm.si.edu/collections/imagery/apollo/AS12/images/AS12-47-6898.html

http://nssdc.gsfc.nasa.gov/planetary/image/near_descent_157415053.jpg

Put a piece of paper with an Itokawa-shaped hole cut into it over any of those images, and you won't see more than two craters. The Eros descent pictures make this phenomenon stand out.

If it were a fractal, you'd see craters in images like this:

http://nssdc.gsfc.nasa.gov/planetary/mission/near/descent_images/near_descent_157416593.html

You don't.

The devil is in the details. First of all, it certainly doesn't seem to be a fractal: For the Apollos and NEAR, you certainly can tell the difference between high-up images and down-lower ones. Itokawa's craterlessness may show something more than the Apollo and NEAR closeups, but those don't look like orbital views, either.

Posted by: BruceMoomaw Sep 21 2005, 12:00 AM

(1) All the lunar photos you've shown have been taken from the surface, at a very oblique angle -- which tends to conceal small craters on the Moon. Just take a look at the Moon's surface from ABOVE -- either from descending Rangers and LMs, or high-resolution orbiting Lunar Orbiters and Apollos -- and it's veritably peppered with clearly visible craters down to a meter or less in size.

(2) There's no doubt that there is a striking shortage of small craters on Eros -- and the suspect, as I said, is seismic shaking due to the small size of Eros relative to the Moon. And, as I said, this is also the likely cause for Itokawa's shortage of craters IF it has a regolith. If it doesn't -- if it's bare rock -- then the other explanation, that it's a recently detached fragment, is presumably the explanation.

I tell you, though: when you look at the latest photos of Itokawa, it looks to me as though it's quite densely covered with crap. Those spiky protrusions or "warts" all over it look to me like impact-detached boulders that fell back onto the surface, just as with Eros -- but bigger compared to the total size of the asteroid.

Posted by: JRehling Sep 21 2005, 02:47 AM

On further review, I suspect you are right on this... BUT in lunar descent images from Apollo, the remaining difference is phase. All of the Apollos landed shortly after local dawn, giving stretched out shadows. Looking at the full Moon, you hardly see craters in the highlands, save a ray system or five, which we can't expect Itokawa to have. We're seeing most of Itokawa at a pretty full phase. And I think I see a pale crater rim in one of the Sept. 10 images. I agree with your overall sense given the high-phase images, but it isn't data yet. And I realize that I switched my argument from "closeup, the Moon has no craters" to "maybe Itokawa does"!

Posted by: BruceMoomaw Sep 21 2005, 03:28 AM

There are pretty good shadows in the Sept. 11 image ( http://www.hayabusa.isas.jaxa.jp/e/index.html ) -- but I can only see one possible crater (over on the right end). Certainly it has very few of them compared to either the Moon or Eros -- and, given the amount of loose junk on its surface that one can clearly see in that photo, the explanation has got to be seismic shaking. An impactor that would gouge out quite a small crater on the Moon shakes the whole of Itokawa so much that ALL its regolith jumps off the surface in that super-weak gravity, and then slowly sprinkles back evenly all over the asteroid.

I agree with Bell, though, that at the core it's just a single lump of rock with a large chunk knocked out of one side -- I don't see how that peculiar shape could be a contact binary.

Posted by: JRehling Sep 21 2005, 03:41 AM

I disagree that there are good shadows there. The weird shape of Itokawa means that the upper middle in this picture is in favorable illumination, but seen obliquely. For the most part, the left end is a "full" spheroid and the right end is a gibbous spheroid. The left end there looks just as washed out as a full Moon, and the rest of it is favorably lit mainly when oblique to the camera.

Posted by: jaredGalen Sep 21 2005, 09:25 AM

Here a two frame animated gif that kind of enhances the shadows.

Posted by: tedstryk Sep 21 2005, 09:27 AM

Well, in a few weeks, Hayabusa is supposed to move from its current spot to look study Itokawa at a lower phase angle. That should resolve this shadow issue.

Posted by: dvandorn Sep 21 2005, 09:44 AM

In fact, people who are paid to investigate these things have found the the Moon is in a complete steady-state saturation state in all craters smaller than about one kilometer. There is a constantly maintained population of craters of all sizes below one kilometer -- including craters only microns in size. Lunar rocks feature "zap pits" which are the result of impacts from very tiny dust-mite-sized particles. So the instance of lunar craters from one meter to only a few microns in size is well-established as being maintained at its saturation point -- there are as many craters evident as is possible, considering the erasure of earlier craters by later cratering events.

The fact that the terminator regions of Itokawa do *not* show a saturation level of cratering, down to the resolution limit, is indeed a telling observation. This is in no way similar to lunar surface cratering in abundance or size distribution, even at the same scales.

-the other Doug

Posted by: AndyG Sep 21 2005, 10:09 AM

I suspect there isn't any debris to speak of.

Given a mass for Itokawa of about 4.8*10^10kg (about right for a 2000kg/m^3 body of dimensions 600*290*260m) the escape velocity is only 10 to 12cm/s depending on your starting altitude on the surface. Any impact by another body at crossing-orbit speeds, even if as low as a few tens of metres per second, will knock chunks off Itokawa that are likely never to return to the parent body. And those (few?) remnants that fortuitously don't achieve escape velocity have likely had centuries to land again.

Looking at a simple spreadsheet for orbiting Itokawa, my personal favorite altitude is some 540m from the centre of gravity. An orbit here - albeit perturbed by the weird gravity in orbiting a shape like this - will be asteroid-synchronous, allowing some really good opportunities for data collection to be made for one spot over the course of a local day. I'll take the animated movie, please!

Andy G

Posted by: abalone Sep 21 2005, 10:31 AM

Anything that does not reach escape velocity will be launched into an eliptical orbit and return to its point of origin after one complete orbit. This will probably mean that it will hit the ground again quite quickly

Posted by: Bob Shaw Sep 21 2005, 10:50 AM

Except that the asteroid is irregular in shape, with a similarly irregular gravity field. I bet that between the rotating body and the funny gravity something knocked off could stay up for a while - or even meet a speeding part of the surface and be whacked again - and that applies doubly to a fragile littel spacecraft. The guys in Japan are being rightly cautious about getting too near - perhaps they'll power in down the axis of rotation...

Posted by: AndyG Sep 21 2005, 12:00 PM

The speeding part of the surface is only rotating at about 4cm/s compared to the centre of gravity...so maybe whacked isn't the right word. If the surface of Itokawa is dusty, covered with a reasonably deep and friable regolith, these sorts of ejecta impacts might be more of a s-s-s-splurge than a thwack.

As to closing on the object, the escape velocity and the rotation means that the highest speed a free-falling body could hit the surface at is...16cm/s. A third of a mile per hour, without using rockets to slow down. My car bumpers wouldn't notice that!

While approaching the axis of rotation makes some sense, it does limit what material sources you could retrieve. Given that the ion drive has enough umph to counter the local gravity, all the way down to the surface if need be, and the reaction rockets have the perhaps more useful momentary acceleration to adjust speeds relative to the surface (unlike the ion's ~900 seconds for 0-4cm/s), I don't see that there's necessarily a need to head only for the poles...as long as, of course, the autonomous control is up to the task.

Andy G

Posted by: RNeuhaus Sep 21 2005, 03:05 PM

The ion engine is not well positioned for approaching and deviation off from Hayabusha asteroide. Its position is horizontal and their 4 chemical propulsors are on the bottom along with the horn and an Optical Navigation Camera (ONC), a LIght Detection And Ranging (LIDAR), a Laser Range Finder (LRF) and Fan Beam Sensors (FBS) to gather topographic and range information about the asteroid's surface.

Hence, I don't think that the ion engine will be utilized for descendent and ascending phases.

The spaceship will start to aim the landing when it is 100 meters above of Itokawa. Mmm... so close....

The enclosed article : To land upon and gather fragments from the surface of the asteroid, the spacecraft has optical autonomous navigation, guidance and control system, which employs ONC and LIDAR above 100m altitude. For the measurement of the relative position and attitude to the surface in the final landing phase under 100m altitude, ONC, LRF and a Target Marker ™, which is an artificial target and released at about 100m altitude, are used. FBSs are also used for obstacle detection.

For more details, http://www.hayabusa.isas.jaxa.jp/e/outline/landing.html

Rodolfo

Posted by: BruceMoomaw Sep 21 2005, 05:05 PM

There are indeed no shadows on the left end of Itokawa in that latest photo -- but the shadows on the entire right half look pretty good, and what they show is lots of debris bumps but no craters yet (with the possible exception of the one over on the mostly-shadowed far right end). At this relative resolution, Eros was showing far more craters. (Not that this strikes me as much of a mystery -- as I said, seismic shaking seems entirely adequate as an explanation.)

And, yes, Hayabusa will do all its maneuvering around the asteroid -- including landings -- using its small chemical thrusters. The ion drive is hopelessly unwieldy and sluggish for the purpose; its sole purpose is for really low-rate but long-term acceleration to get to the asteroid and back.

Posted by: Sym05 Sep 22 2005, 09:08 AM

New document: "Hayabusa arrived at Itokawa" (Sept 21):
http://www.hayabusa.isas.jaxa.jp/e/Hayabusa_SAC14SEP_e.pdf

and new page with proposals for surface features names (today):
http://www.hayabusa.isas.jaxa.jp/e/index.html

Posted by: djellison Sep 22 2005, 09:36 AM

Muses Sea...that's BAD

(for those that dont know, Japan usually has a bland name for a spacecraft at launch, in this case Muses-C, and then renames it after launch, in this case to Hayabusa)

Doug

Posted by: Bob Shaw Sep 22 2005, 10:51 AM

And here's the image:

Posted by: ElkGroveDan Sep 22 2005, 03:38 PM

More proof that the English language has become so universal in science. The Japanese are making puns in English (barring the unlikely possibility that "sea" and "C" are also homonyms in Japanese).

Posted by: tty Sep 22 2005, 05:46 PM

I don't think so, I'm fairly sure that sea is "kai".

tty

Posted by: tedstryk Sep 22 2005, 08:24 PM

Well in that case, the MUSES-C itself is the English import, - After all, the Muses (and other) series seem to be following our alphabet.

Posted by: maycm Sep 26 2005, 12:56 PM

http://www.isas.jaxa.jp/e/enterp/missions/hayabusa/today.shtml

She's moved in a bit closer. Now only 16km away.

Posted by: Sunspot Sep 26 2005, 12:58 PM

Sadly they've stopped posting images.

Posted by: SFJCody Sep 27 2005, 08:19 AM

Now 12km

Posted by: Toma B Sep 29 2005, 08:18 AM

Now only 10 km away...
But stil no new images...
AAAARRRGGGGHHH!!!!!

Posted by: djellison Sep 29 2005, 02:19 PM

http://news.bbc.co.uk/1/hi/sci/tech/4291258.stm

Posted by: ljk4-1 Sep 29 2005, 02:28 PM

They seem to be following ESA's lead with Huygens.



The most amazing explorations happening these days, complete with pictures, and the media and space agencies are flubbuing the publicity.

Posted by: odave Sep 29 2005, 02:38 PM

To be fair, they may not be taking that many images as they bump closer, and the detail level may not be that much better.

I do agree that every mission should have a "raw images" page from now on - MER set the benchmark for that. But I'm going to cut JAXA some slack, they've had a rough go of it over the last few years, and if they want to concentrate their resources on executing the mission, that's fine with me. As long as they do throw us a bone every now and then

Posted by: paxdan Sep 29 2005, 02:50 PM

Obligatory http://news.bbc.co.uk/1/hi/sci/tech/4291258.stm article.

Posted by: alan Sep 29 2005, 02:54 PM

from the BBC article

"Hayabusa has been collecting spectral data and images of Itokawa from its "gate" position, about 20km (12 miles) from the asteroid.
Over the next few days, the probe will move into its "home" position, just 7km (4.3 miles) from the asteroid. "

I expect we will see a new batch of images after it reaches the 'home' position.

Posted by: Toma B Sep 29 2005, 04:47 PM

That's allright with me to , but if they can't update their web site with new images every once in a while......arghhh that is not posible....
They threw us last NEW bone 14 days ago!!!

I'm starving...

Posted by: RNeuhaus Sep 29 2005, 08:05 PM

The Hayabusa space program is very slow and long that takes months. We are going to have to wait until November to know any exihilarating news with the landings and hoppings on the Itokawa asteroide. So be ready to wait for such a long time.

I think that the Hayabusa team has not hurry to perform all thing fast on Itokawa since they have to wait for the best date for the home Earth return that would be on December 2005.

Rodolfo

Posted by: 4th rock from the sun Sep 29 2005, 11:50 PM

Can the probe navigate and take images at the same time ?
Perhaps it has to point away from the asteroid to slow down...

Posted by: tedstryk Sep 30 2005, 02:42 AM

That is a good point...we don't even know if it is taking pictures during the approach. And they have been good about releasing stuff from the first position. I think it is a shame that after years of having to wait months to see a few scraps in Sky and Telescope and Astronomy, there is the need to complain when something just takes a few days.

Posted by: dilo Sep 30 2005, 06:19 AM

Finally some info, not a real "update"!
http://www.hayabusa.isas.jaxa.jp/e/index.html
Based on plots, Hayabusa reached a minimum distance of 15Km on Sep,19 (however, now should be closer)...
"The next web report will introduce how Hayabusa lowers its altitude and reach the Home Position"

Posted by: RNeuhaus Sep 30 2005, 01:43 PM

According to the above report, it looks that it is almost impossible to remain fixed at a distance from Itokawa. This report shows a graphic about the position of Hayabusa in almost every day which varies. The Hayabusa teams is trying to control it by learning the controls adjustments. So, it is nothing easy. Lucks for Hayabusa's team

Rodolfo

Posted by: djellison Sep 30 2005, 01:49 PM

You can see that they needed several burns to station keep at 20km, as I suggested it would. It'll just get worse the lower they get

With NEAR at Eros, it was a lumpy and bumpy orbit, but you COULD actually orbit it - Hayabusa is just that bit too small to do so I guess.

Doug

Posted by: RNeuhaus Sep 30 2005, 02:18 PM

Doug,

Aja!

Yes, I now realice about why the Hayabusa's team has selected the home position such a long distance from Itokawa. It is due that what you have told previously. The long distance is saving the propulsion fuel by minimizing the altitude adjustments.

Rodolfo

Posted by: ugordan Oct 1 2005, 06:29 PM

Boy, some folks really are spoiled. The spacecraft team obviously has many better things to do than constantly taking pictures of the asteroid. It's not like it's changing its appearance every second or anything.

Maintaining the "gate position" is a feat by itself, even a residual speed of 1 cm/s would add up to 860 meters over a course of one day. The team really has to control the spacecraft very often. Slow science is better than NO science if anything goes wrong.

On a side note, some of you guys really are coming down too hard on ESA, concerning its policy with the Huygens images. While it's true the initial 3 images were presented horribly, they did release the raw images very fast. They also intend to archive the data at NASA's PDS system, after the proprietary one-year period has passed...

Posted by: deglr6328 Oct 1 2005, 07:57 PM

Well to be fair though they released the images to the DISIR team immediately. They then released them to us.

Posted by: dilo Oct 2 2005, 07:23 AM

The plot of Z-distance suggests a free-fall gravitational decay with periodic small chemical thrusts in order maintain an average distance close to 20Km. It's something like ISS periodic http://www.heavens-above.com/issheight.asp, with the important difference that here we do not have an orbital movement with a decay induced by atmospheric drag but there is a simple free-fall acceleration. So let's do some newtonian calculation based on this idea! (if you don't like math, jump to final conclusions).
I concentrated on the 15-19 September time window, where a complete re-boost+parabolic free-fall seems to happens.
In fact, a parabolic curve fits very well with data ponts... (I'm making assumption that asteroid dimension is negligible and distance variation is small relative to absolute distance, both true in this case):

Based on curve fitting, the re-boost done around Sept 15.2 produced a vertical positive velocity of 1.6 cm/sec and was followed by a uniformly decelerated free-fall with a=-1.34E-7 m/s2 (slightly above 1 cm/s each day).
Based on the average distance of 16.5Km, we can calculate the resulting Itokawa mass:
M = - a R2 / G = 2,73E+11 Kg
This mass is larger than expected... in fact, based on radar model of Itokawa (an ellissoid with 550x305x275 meters), it give a mean density of about 22.5 g/cm3, an order of magnitude too high!
Based on Hayabusa imagery, I have impression that actual asteroid dimensions are even smaller, so density would be even higher!!!

In conclusion, my simple "newtonian" approach cannot explain spacecraft motion and, probably, we have some other unexplained effects. Are there some ideas about this?

Posted by: edstrick Oct 2 2005, 11:02 AM

Orbital mechanics over a few days in solar orbit can result in non-intuitive behaviour, same as 10 minutes of trying to station keep with a sat in orbit around Earth.. If you're not right on the orbit, you find yourself drifting relative to the target.

Posted by: djellison Oct 2 2005, 12:05 PM

There spoke the voice of a man who's tried the Gemini scenarios in Orbiter

Or at least - it sounds like you have

Doug

Posted by: edstrick Oct 2 2005, 12:18 PM

I haven't played with orbital sims much, but I've been watching rendezvous "antics" since Gemini (audiotaped 2/3 of Gemini 3 and parts of missions starting with the Gemini 6a pad shutdown) and knows some of the hassles they got into when they tried to force rendezvous by just using more propellant and finding the target slipping off to one side.

Posted by: Bob Shaw Oct 2 2005, 12:40 PM

Yup, until Buzz Aldrin came along (with, obviously, other folk involved) the fighter jocks thought you could just point the capsule, burp the thrusters and arrive - hence the terrible problems the early Gemini crews had with station-keeping even with the Titan II second stage. By the time the Agena was ready they'd learned the lesson!

Posted by: abalone Oct 2 2005, 01:49 PM

Would be interested to know what the magnitude of solar pressure is on the craft, it has of course got big solar panels and is situated directly upsun from the asteroid

Posted by: dilo Oct 2 2005, 08:49 PM

I don't know if you are referring to solar wind or light pressure... Anyway, I considered light pressure explaination.
I do not know exactly Hayabusa mass and solar panels extention, but even assuming a very optimistic (and surely wrong) 500Kg mass and specular panels, we need at least 6.5 square-meters panels in order to justify residual acceleration (1.2E-7 m/s2). This is based on a distance of 1 au from the Sun and a perfect alignment between Itokawa, Hayabusa and Sun (both assunptions should be roughly respected).
My impression is that, probably, pressure radiation can explain a significant part of observed acceleration (probably more than gravitational effect); other residuals could arise from solar wind pressure or even orbits small mismatch mentioned by others...
Do someone can make more realistic/precise figures?

Posted by: abalone Oct 2 2005, 10:44 PM

With solar pressure I was assuming the combined effects of both solar wind and light pressure and yes the solar panel would be large to power the ion thruster and yes the allignment would be quite favorable, so this might explain it

Posted by: dilo Oct 3 2005, 06:27 AM

New interesting update on the site, with other technical nav infos and no images.
Now they explain this policy: "High resolution images themselves can be readily used for improper and inaccurate interpretation. And Hayabusa project intends to add adequate calibration and speculation to those data and will make them public later but in timely manner. To this end, Hayabusa project for the time being will not release every detailed information. We in advance would appreciate the understanding of the Hayabusa supporters in the world."
http://www.jaxa.jp/missions/projects/sat/exploration/muses_c/index_e.html

Posted by: edstrick Oct 3 2005, 07:02 AM

Bob Shaw: "....the fighter jocks thought you could just point the capsule, burp the thrusters and arrive ..."

That, of course, works just fine, if you have rocket propellents made of unobtanium with a specific impulse of 2000 or 20,000 instead of 200, and can burn to make delta-V like crazy and go from here to there in a straight line and just stop and do it in a few minutes. ]

THAT is the fundamental problem of Astronautics. Chemical bonds just don't have enough bounce-per-ounce to make Buck Rodgers/Flash Gordon/Tom Corbett rocketships, where the loaded fuel tanks are say 15 or 30% of the mass of the vehicle. There was a general assumption that there'd be a way to do it with "Atomics", but with the real nuclear physics we have to deal with, instead of Pulp Scientifiction nuclear physics... we sure don't have a clue how to do it.

Ghods, I want TorchShips!

Posted by: odave Oct 3 2005, 02:25 PM

But that's the fun part!

Seriously, I'm little disappointed in that attitude. I'm all for having the scientists on the team having the first crack at the data, but I don't think any harm has been done to the MER or Cassini missions by having the raw images published on the web.

Posted by: ljk4-1 Oct 3 2005, 02:30 PM

Is it a cultural thing as well? I wonder if Japanese scientists and space administrators are used to the level of public participation as Americans
conduct with their space missions?

Posted by: RNeuhaus Oct 3 2005, 02:44 PM

Thanks Dilo for your comments and Maths,

Yes I agree that the density of Itokawa (22,500 kg/m3) is exaggerated. I tought that their density would be around 2,000 kg/m3.

Rodolfo

Posted by: The Singing Badger Oct 3 2005, 05:20 PM

To be fair, the person who writes the Hayabusa website does not have the best English skills in the world. He/she may not mean exactly what they seem to be saying here.

Posted by: helvick Oct 3 2005, 06:11 PM

22.5g/cm3 would make it just slightly less dense than solid iridium or osmium which would be a great scientific discovery but unfortunately _very_ unlikely. Clearly it's an order of magnitude or two out. Asteroid densities vary from the low end (for very porous rubble piles) around 0.2g/cm3 to 3g/cm3 for solid chondrites.