Hayabusa - The Return To Earth, The voyage home Options

[odave]

...starting a new thread for Hayabusa's sampling feedback and the return voyage.

After its nail-biting success in November, will there be enough fuel for the Falcon to make it home?

[ElkGroveDan]

...starting a new thread for Hayabusa's sampling feedback and the return voyage.

... are we there yet?

[RNeuhaus]

Recent News from Matsuura Newspaper
2005.11.28
" It is quick the ぶ, link ": Finishing the landing mission,

According to the communication from JAXA public information, the pattern which also use of 28 days spends to the return from safe mode. Establishing three axial control, using the high gain antenna, when landing those where it downloads the data which you acquire are after the tomorrow 29 day. The data being analyzed, to reach to publication, furthermore several days will be needed.

It is quick, the ぶ, the predecessor unexplored mission which is called landing and soil sample collection to the asteroid was completed. The last distance which from now on is directed to the earth starts, but the reaction wheel 3 middle 2 bases are broken, the thrusters which become substitution the propellant remaining amount are few. Probably become also road and with difficult ones. It is something which prays the collection success of of safety of road and the reentry capsule which rounds off the mission.

This article is still unclear to me. It seems like that Falcon will be acquainted within 28 days from Safe mode to active mode before returning home...That means that Falcon will start pack its bag to return home by December 24.

Rodolfo

[ElkGroveDan]

This article is still unclear to me. It seems like that Falcon will be acquainted within 28 days from Safe mode to active mode before returning home...That means that Falcon will start pack its bag to return home by December 24.

Rodolfo

I think they were talking about the 28th and 29th days of this month; i.e. November 28th and November 29th.

They have to be on the road home by December 10th or sooner.

Here's an easier article at Space.com Japan's Asteroid Probe to Head Home Despite Glitch

[RNeuhaus]

According to the article of the space.com. By December 10, JAXA team will decide one of two possibles ways to return home: By accompanying the Asteroide Itokawa for 2 years until it crosses close to Earth's orbit before leaving Itokawa.

We will meet that deadline, whatever happens,'' Matogawa said. Otherwise, it would be two more years before the probe _ orbiting the sun between Earth and Mars together with the asteroid _ would be in the right position to return, he said.

or by traveling alone back home for one year and half or later in a route clock's wise to Earth orbit before arriving at Australia.

Rodolfo

[mike]

It would certainly be interesting if Hayabusa followed Itokawa for all that time.. In all likelihood Itokawa doesn't do much of anything as it tumbles around, but who knows, eh? If nothing else I'm sure they would obtain more detailed imagery. They could manuever Hayabusa such that Itokawa was between it and the Sun most of the journey, which would have to provide substantial protection from solar radiation, the most likely hazard when spending time near the Sun (gotta be, right?). Then again, another six months, and if Hayabusa is disabled, that's it, and how interesting is Itokawa, really?

Perhaps they will flip a coin..

[Joffan]

I'm not sure that sitting in Itokawa's shadown would be a great idea for keeping the batteries charged...

It's pretty remarkable how little difference it makes in time though, between powering home and just drifting along with Itokawa.

[mike]

Yeah, I remembered the solar panels need some solar radiation after I posted that.. Half-in-shadow, half-out-of-shadow, then!

[Ishigame]

I would tell you some bad news…
JAXA says Hayabusa has troubled with both of main/backup thrusters.
Main thruster system could turn to ice, the other one have leaked.
Now they are holding press conference now.

According to Matsuura's Blog.
http://smatsu.air-nifty.com/lbyd/2005/11/3_dc16.html

Now we can read translations. Thank you a lot, nao.

[odave]

Good translation! Worrying news, though. The main thruster system is obstructed, the backup system leaks, and they don't have attitude control. Which prevents them from using Hayabusa's HGA, and communications with the other antennae have been spotty.



Here are some snippets:

Kawaguchi:We tried to recover from the safe mode in operation via DSN at 26th night and Usuta on 27th, but the remaining system-A thrusters did not generate enough propulsion force. So we failed to restore the attitude control.

It seems that some trouble in valve may cause obstruction, or the pipes may be frozen.
[...]
Looking at current situation, we think it takes considerable time for recovery.
[...]
We now will concentrate our efforts on recovery of attitude control as the top priority.

But...

Fuel remains enough and the pressure is proper.
[...]
Unknown: Must the vehicle leave Itokawa by the beginning of December? How long can it be extended?

Kawaguchi: We can extend it to the mid of December, if it has only to return.

So they have a little time to play with. Good luck, guys!

[nop]

Sorry for multi-posting.

If your friends are working in NASA/JPL, please show them this message:
"Hayabusa needs help"
http://5thstar.air-nifty.com/blog/2005/11/...usa_needs_.html

We need to make use of NASA 70m parabola for recovery of Hayabusa.
Though we understand this is a selfish request, we can't help asking for your support.




Anyway,

So they have a little time to play with. Good luck, guys!

We have always been encouraged by posts in this forum. We appreciate your posts!
I hope your cheers will touch the JAXA teams and Hayabusa itself

FYI: In Japan, the ad of LIPOVITAN-D symbolizes overcoming and conquest of various troubles. Good luck.

[odave]

I do not mean this to sound rude, but aren't there more direct communications channels between the Japanese and US space programs, rather than hoping that someone on an Internet board will send the message through?

I think 5thstar is a fan, just like us, sending out a personal plea. No doubt JAXA/ISAS are going through whatever official channels they use for DSN access - heck, they probably have them on speed dial

[Orlin Denkov]

Probe returning to Earth after asteroid landing
Alok Jha
Monday November 28, 2005
The Japanese space probe Hayabusa began its journey home yesterday after becoming the first spacecraft to successfully land on an asteroid and collect samples.

Guardian Unlimited

What can we say about the level of credibility of the information provided above.
I wish it would be true... Hope that troubles are surmountable.

[TheChemist]

Probably not good things

There are two press releases for Nov29 at the Jaxa site (in japanese only, so far) with several images and graphs:
http://www.jaxa.jp/press/2005/11/20051129_...busa_td2_j.html babelfish
http://www.jaxa.jp/press/2005/11/20051129_hayabusa_j.html babelfish

Edit : A small piece of the 2nd document appeared in english :
http://www.hayabusa.isas.jaxa.jp/e/index.html

[nop]

Dear 5thstar (if you read this forum), ljk4-1, odave and other guys,

Very sorry for my misleading post. I posted it just as a fan feeling a sympathy for 5thstar's message and I also believe that Prof. Kawaguchi is already doing what to do.

Anyway, sorry if you felt unpleasant, and thank you for your kind replies.

[RNeuhaus]

Dear 5thstar (if you read this forum), ljk4-1, odave and other guys,

Very sorry for my misleading post.  I posted it just as a fan feeling a sympathy for 5thstar's message and I also believe that Prof. Kawaguchi is already doing what to do.

Anyway, sorry if you felt unpleasant, and thank you for your kind replies.

Hello Nop,

Don't worry of your post. This forum is open. Everybody shares the information and we respect the opinion and feeling from others. We are tolerant and educated people as you!

Rodolfo

[hugh]

Kawaguchi: We can extend it to the mid of December, if it has only to return.

But after that, Kawaguchi said that a later return (after early December) means a different (sharper?)re-entry angle, and that the re-entry capsule has little margin to withstand the extra heat.
It doesn’t sound too good. One Hayabusa project manager was quoted weeks ago as being “not optimistic” about there being enough propellant for an earth return at the present rate of usage. That was before the 30-minute “stay” on Itokawa and the leaky thruster, and all the other systems problems. It’s far from over yet, but it might be too high a hill for them to climb….

[deglr6328]

Grist for the Moomaw mill ...

This from the Nature online news article...

"The mission is renewing Japan's confidence in space activities. JAXA has recently tried a string of high-risk missions, but has seen many failures over the past few years. "Hayabusa's success has become a tailwind for Japan's space development," Hajime Inoue, JAXA's executive director, said at a press conference. "It proves that the way we have been doing things wasn't wrong."

I hope that is a translation gaffe and they really don't think that everything is a-ok with thier whole program because of a recent streak of (much needed) luck!

[Guest_BruceMoomaw_*]

Oh dear, oh dear, oh dear. Pride goeth before a leak.

[helvick]

Nice detailed update from Emily over at The Planetary Society

[RNeuhaus]

Dramatic news extracted from Planetary.org:

At this point, Hayabusa's exact location is unknown, although Kawaguchi said that it is "still within several kilometers from Itokawa." Moreover, he added, "there is little chance" they will lose touch with Hayabusa again, at least in terms of where it is now.

Not yet know where Hayabusa is located, perhaps it might fall on Itokawa due to the gravity tug and/or by the Sun wind pressure which is pushing it toward to Itokawa if it is located on the south of Itokawa (the South Polar of Itokawa faces to Sun and Earth).

Rodolfo

[mike]

If Hayabusa's thrusters persist in being only half-useful, traveling with the asteroid until it gets closer to Earth may be the only choice - unless of course they won't be able to generate enough thrust before Earth flies away regardless.. Yet another cliffhanger.

[ElkGroveDan]

If Hayabusa's thrusters persist in being only half-useful, traveling with the asteroid until it gets closer to Earth may be the only choice - unless of course they won't be able to generate enough thrust before Earth flies away regardless..  Yet another cliffhanger.

My understanding is that they have a heating system of some kind but are cautious about collateral effects from too much heat. I would guess that if it came to an all-or-nothing point they could decide to take their chance and try to heat up the frozen thrusters.

[ljk4-1]

Would it be possible to send out a probe to snag Hayabusa and bring it back to Earth with its surface samples? Or maybe remove just the samples and bring them back?

I think either scenario would be easier than trying a landing again on the planetoid at this point.

[RNeuhaus]

There many options. Wait for a while until before than December 10, next saturday to know what will be the final decision for the home return.

1) Travel along with Itokawa and then direct toward to Earth alone (more than 3 years). Their risks are on the power supply or batteries when it approaches to Mars' orbit where there are less sun radiation.
2) Travel alone back home (1 1/2 year). It depends upon to the health of thrusters.
3) Travel along with Itokawa and then wait for a rendezvous probe which will tug it until dropping to Earth.
4) Land on Itokawa and stay dormant upon the future visit.
5) Abandon it to his fate by wandering on the space.

Rodolfo

[Bob Shaw]

If Hayabusa's thrusters persist in being only half-useful, traveling with the asteroid until it gets closer to Earth may be the only choice - unless of course they won't be able to generate enough thrust before Earth flies away regardless..  Yet another cliffhanger.

Mike:

Er, probably not a good idea.

Hayabusa will be expected to travel on some strange variant of a Hohmann minimum-energy orbit (with both Earth's orbit and that of the asteroid being gently touched at start and end of the mission). A 'strange variant' because it's flightpath is constantly altering under the influence of it's ion engines, and active control of the spacecraft (a la SMART-1) will be crucial during the return. So, unlike a traditional 'single impulse' trajectory (with perhaps a couple of tweaking burns halfway or so) Hayabusa can't be left dormant during cruise but will require good communications and good attitude control throughout.

You can't get round this by 'hitching a ride' on a nearby asteroid!

Bob Shaw

[Bob Shaw]

There many options. Wait for a while until before than December 10, next saturday to know what will the final decision for the home return.

1) Travel along with Itokawa and then direct toward to Earth alone (more than 3 years) Their risks are on the power supply or batteries when it approaches to Mars' orbit.
2) Travel alone back home (1 1/2 year). Depends upon to the health of thrusters
3) Travel along with Itokawa and then wait for an rendezvous probe which will hawl it until dropping to Earth.
4) Land on Itokawa and stay dormant upon the future visit.
5) Abandon it to his fate by wandering on the space.

I really think there are very few options!

Option 1) - waiting on-station until the next interplanetary line-up (which might well be many years in the future) *might* work with a probe designed for longevity. Not with Hayabusa, though!

2) - Correct, and the only way to get back home at all.

3) - No, for all sorts of reasons, not least being the fact that we can't even reliably perform such missions in Earth orbit, never mind the depths of space. Anyway, who's paying for a rescue flight - nobody!

4) - 'Dormant' as in, er, deceased. An ex-spacecraft, pining for the Norwegian fjords. I suppose it'd keep the Solar system that bit tidier, and we might see some more closeups on the way down.

5) - Sadly, the most likely outcome. An ion-drive probe has to be *much* smarter and controlled than traditional single-impulse 'artillery' probes, and if the RCS system is almost broken then it's highly unlikely that it'll do more than limp in the general direction of Earth before settling into Solar orbit when the ion drive stops working (at which time we're back in the realms of 'artillery').

Hayabusa is, make no mistake about it, a success - even if no return to Earth is feasible, then it will have carried out an outstanding mission of which JAXA should be very proud.

Bob Shaw

[odave]

5thstar's blog has a few new Hayabusa updates.

No official information from JAXA yet.

JIJI press issued an article. Prof. Matogawa replied to a query from media saying JAXA will complete taking necessary data by December 5, and will try to analyze the cause of the malfunction and resume the recovery operation.

[...]

Next press briefing by JAXA/ISAS is not likely on or before December 5.

They're still not saying anything about the thrusters. Hopefully no news = no news at this time

[RogueEngineer]

Hopefully no news = no news at this time 

Another bad news... They are still struggling in the recovery operation, and the bullet may not be fired during the second touchdown attempt on Nov. 26th. See English translation in the comment area of
Matuura's blog 2005.12.07 #1
Matuura's Blog 2005.12.07 #2
for details.

[Guest_BruceMoomaw_*]

Are they actually saying that they themselves accidentally programmed the craft with a command NOT to fire the bullet, or just that the spacecraft set itself back to a safe mode that kept it from doing so?

At any rate, it looks more and more as though Hayabusa is going to confirm all my dark warnings about the unwisdom of trying to do too complex a space mission with much too little money. (There is, by the way, a lengthy article in this week's Aviation Week suggesting that JAXA has very belatedly caught onto this fact.)

[RNeuhaus]

December 7, 2005 05:42 PM

According to the L/D of the Matsuura Shin 也...
Bulletin
* The possibility the bullet not being discharged is high
* It has not recovered the thruster
* Ion using the engine, attitude control (Correction: Speaking accurately, applying the function of the ion engine system, attitude control)
* I To matte (Itokawa) as for starting even with most speed after 14 days
* Concerning return undecided

From blog: Paku http://translate.google.com/translate?u=ht...Flanguage_tools

Brief summary from the blog: Matsuura' newspaper

December 2nd. The chemical engine (the thruster) restart was tried, but small thrust is verified in earnest not to start.

December 3rd, it was verified that the high gain antenna axis of the probe and the angle which the sun and the earth form have expanded to 20 or 30 degrees. As the attitude control method of emergency, the xenon gas for ion engine driving it starts the compilation of the operational software to the thing which does the attitude control with the injection.

December 4th, it executes the attitude modification with the xenon gas injection.

December 5th, the sun, the earth and the high gain antenna axis recover to 10 degree - 20 degrees, presently by way of the medium gain antenna communication does at speed of 256 bit /s. However, because the probe slowly is turning, as for the communication by the medium gain antenna intermittence ones such as 1 minute in 6 minutes.

As of December 6th, it is (Hayabusa) quick the (Itokawa) ぶ, from the I To matte in gaze direction it is in the place of the 550km. As for distance from earth 2 hundred million 9000 ten thousand km. Presently just 1 basis the reaction wheel which remains verifies the recovery moving and the revolution with the 1000rpm.

In the other word, now Hayabusa is around 550 km distance from Itokawa and is 290,010,000 kilometers from Earth. (almost just in the opposite side) The RCS z-axis still works at 1,000 rpm.

Rodolfo

[nop]

More translations have been added on the comment area of Matsuura's blog.

[Harder]

The Dec 8 update of the Y.M. Column is now online. The main issues with Hayabusa are already known, but this is a Must Read, if only for the intense atmosphere described in it. I wish them success!

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

[odave]

From the above:

During its operation Dr. Kuninaka complained, “Oh boy! We’ve already used as much as 100gr of xenon.” followed by the conversation with a staff, “What? Xenon is getting short so seriously?” “Not necessarily right now but xenon costs as much as 1000 yen per 6gr. So, we’ve used up 20,000 yen worth.” “Don’t be so stingy! Beef steak worth 20,000 yen per 100gr is just common all over in Tokyo, I’ve never had it, though.”

That's about $165 US. If Hayabusa makes it home, everyone on the team should get a steak, chased down with LIPOVITAN-D!

[tedstryk]

From the above:
That's about $165 US.  If Hayabusa makes it home, everyone on the team should get a steak, chased down with LIPOVITAN-D!

I have a stupid question...What is LIPOVITAN-D? I know it is something the Hayabusa team drinks, but what is it?

[odave]

I have a stupid question...What is LIPOVITAN-D?  I know it is something the Hayabusa team drinks, but what is it?

It's the Japanese equivalent of Red Bull, a high-energy drink.

[odave]

Lots of good info in those new translations - the volunteer work is much appreciated! For those who haven't read it yet, there is some hope for getting some kind of sample back:

Asahi: What do you think of the possibility that the sample were stirred up by the landing and actually gathered? [...]

Kawaguchi: Escape velocity from Itokawa is equivalent to the speed of a pencil dropped from 0.5 millimeter height. It would only bounce up 0.5mm on earth, but on Itokawa where the gravity is small it would jump up more than 10 meters. Buton the second touchdown, the vehicle actually touched the ground for only a second and ascended back, so the sampler horn ascended with the sample, thus the sample would not have reached the capsule. In the touchdown on 20th the vehicle landed on the surface for substantially long time, so we think it is highly probable that the sample that were stirred up have entered the capsule.

[ljk4-1]

Status of the Hayabusa

December 7, 2005

Japan Aerospace Exploration Agency


As has been reported, it is estimated that part of a series of
attitude and orbit control commands to restore the Hayabusa from its
safe-hold mode have not gone well, and the functions of its major
systems, including its attitude and communication network, have
significantly deteriorated. However, on Nov. 29, a beacon line through
a low gain antenna was restored.

On Nov. 30, we started a restoration operation by turning on and off
the radio frequency modulation through the autonomous diagnostic
function. Subsequently, on Dec. 1, telemetry data were acquired at 8
bits per second through the low gain antenna, although the line was
weak and often disconnected. According to the data transmitted so far,
the attitude and orbit control commands sent on Nov. 27 did not work
well due to an unknown reason, and either major attitude control
trouble or a large electric power loss seems to have occurred. It is
estimated that the overall power switching systems for many pieces of
onboard equipment were reset as their temperature dropped
substantially due to the evaporation of leaked propellant, and also
because of a serious discharge of electricity from the batteries of
many sets of onboard equipment and systems due to declining power
generation. Details are still under analysis.

On Dec. 2, we tried to restart the chemical engine, but, even though
a small thrust was confirmed, we were not able to restore full-scale
operations. Consequently, the cause of the anomaly on Nov 27 is still
under investigation, and we suspect that one of the causes could be
the malfunction of the chemical engine.

On Dec. 3, we found that the angles between the axis of the onboard
high gain antenna (+Z angle) and the Sun, and also that with the earth,
had increased to 20 to 30 degrees. As an emergency attitude control
method, we decided to adopt a method of jetting out xenon for the ion
engine operation. Accordingly, we immediately started to create the
necessary operation software. As we completed the software on Dec. 4,
we changed the spin speed by xenon jet, and its function was confirmed.
Without delay, we sent an attitude change command through this
function.

As a result, on Dec. 5, the angle between the +Z axis and the sun, and
the earth, recovered to 10 to 20 degrees, and the telemetry data
reception and acquisition speed was restored to the maximum 256 bits
per second through the mid gain antenna.

After that, we found that there was a high possibility that the
projectile (bullet) for sampling had not been discharged on Nov. 26,
as we finally acquired a record of the pyrotechnics control device
for projectile discharging from which we were not able to confirm
data showing a successful discharge. However, it may be because of the
impact of the system power reset; therefore, we are now analyzing the
details including the confirmation of the sequence before and after
the landing on Nov. 26.

As of Dec. 6, the distance between the Hayabusa and the Itokawa is
about 550 kilometers, and that from the earth is about 290 million
kilometers. The explorer is relatively moving from the Itokawa toward
the earth at about 5 kilometers per hour.

We are now engaging in turning on, testing, and verifying onboard
equipment of the Hayabusa one by one to start the ion engine. We
currently plan to shift the attitude control to one using the Z-axis
reaction wheel, and restart the ion engine. The restart is expected to
happen no earlier than the 14th. We are currently rescheduling the
plan for the return trip to earth. We need to study how to relax the
engine operation efficiency. We will do our utmost to solve the
problem with the attitude control (such as the restoration of the
chemical engine), then find a solution for the return trip.

Since Nov. 29, our reports have been limited due to difficulties in
confirming telemetry data. We apologize for any inconvenience.
We will inform you as soon as the ion engine is restarted.


This page URL:

http://www.jaxa.jp/press/2005/12/20051207_hayabusa_e.html

---------------------------------------------------------------------

Publisher : Public Affairs Department
Japan Aerospace Exploration Agency (JAXA)
Marunouchi Kitaguchi Building,
1-6-5, Marunouchi, Chiyoda-ku, Tokyo 100-8260
Japan
TEL:+81-3-6266-6400

JAXA WEB SITE :

http://www.jaxa.jp/index_e.html

[RNeuhaus]

Hope that Hayabusa has a match fire on their side for just in the case that the ion engine won't also be able to be ignited....

I am pessimist of a good trail of "mishapes".

Rodolfo

[The Messenger]

Since the xenon was not intended to be used as an attitude control gas, Are they using a venting valve to adjust the spin and attitude, or can they run zenon into the attitude control system?

In either case, the calculations are quite complex: They would have to maintain a slow rotation rate, and vent the gas at just the precise moment for the right percentage of the roll to adjust the tilt. It would take a very careful trial-and-error assessments to do this (the ultimate $170million dollar video game...and a lot of Lipovan

[ljk4-1]

FATE OF JAPAN'S TROUBLED ASTEROID PROBE UNCERTAIN
-------------------------------------------------

Japanese officials are struggling to fix a horde of problems plaguing the
Hayabusa space mission in time to begin its journey back to Earth with or
without a package of specimens that were supposed to have been collected
from the surface of asteroid Itokawa late last month.

http://spaceflightnow.com/news/n0512/11hayabusa/

[odave]

Since the xenon was not intended to be used as an attitude control gas,  Are they using a venting valve to adjust the spin and attitude, or can they run zenon into the attitude control system?

From Matsuura's blog, it sounds like they're venting the xenon through the ion engine nozzles:

NHK How is the attitude control by xenon gas, concretely?

Kawaguchi: The vehicle has four ion engines, and the orifice of each engine has a neutralizer with four nozzles per engine in order to neutralize the jet gas electrically. The nozzles are openable and closable. By opening or closing the nozzles to emit neutralized xenon gas jets, we are controlling the attitude. Its propulsion force is very small.

Kawaguchi goes on to say that if they are forced to use xenon for attitude control on the trip back, they'll need to stop the ion engines every time they need to adjust attitude, then re-start the engines for thrust afterward. That will be a time consuming process and quite an exercise in patience.

[amezz]

Press Conference about Hayabusa present status, will held at 9:30 14rh Dec. JST.

S.MATSU intend to upload Japanese article at 11:00 or so here http://smatsu.air-nifty.com/lbyd/

[elakdawalla]

Just added this to my blog, I thought I'd add it here for all of your benefit too...We just received the following update from Tasuku Iyori of The Planetary Society of Japan regarding Hayabusa:

JAXA announced to the press that it decided to put off Hayabusa's departure from Itokawa after next fall, thereby expecting spacecraft's return to Earth around 2010. Nothing in detail has yet been reported on the website.

--Emily

[Guest_BruceMoomaw_*]

I very much doubt it will be around by then, and I'm afraid we will soon be able to add Hayabusa to Japan's almost unbroken modern record of space failures -- although at least it came a good deal closer to success than most of Japan's missions do. Space missions simply cannot be done on such low funding levels.

I shudder to report that -- according to the Nov. 28 Aviation Week -- JAXA has been taking its advice on how to reform its space program from Dan Goldin.

[ljk4-1]

So - would another nation be willing and able to recover Hayabusa or at least any samples it may have, or even take over its mission?

If the probe is going to hang around Itokawa for almost another year, will it continue to study the planetoid?

[elakdawalla]

Shin-ya Matsuura's transcript is up in Japanese. Here's the pretty terrible Google translation. Sounds like little in the way of good news --Emily

[lyford]

I shudder to report that -- according to the Nov. 28 Aviation Week -- JAXA has been taking its advice on how to reform its space program from Dan Goldin.

BWAH?!?!?!

"JAXA: Rather than it is better and being faster it is cheap."

[elakdawalla]

A cooperative translation project is taking place here...keep refreshing the screen, they are working diligently on the translation.

--Emily

[lyford]

If the ion engines are ignited again by the 2007 spring, the vehicle can return to the earth on June 2010.

2010? Any massive solar flares scheduled between now and then? I don't know if I can take another Nozomi experience.

I can't even begin to imagine what it would be like to be an engineer on these missions - the long hard work of trying to bring the falcon home to roost. It's crazy making enough as a spectator to see the constant ups and downs - 2 bullets fired! No bullets fired! Sample! No Sample! Leak! "Salvation Mode" let alone having to troubleshoot the beast.

[lyford]

From the translation:
At first when I read the interview it seemed as if they thought they had a 60-70 percent chance of probe recovery - not it seems it just means the chance of getting it communicating!

Asahi Shimbun Press: Is there a possibility for accidents of other equipment by three-year extension? And what about the running cost during the extension?

Kawaguchi: Of course, the probability of equipment accidents will increase. We have to restart them from the almost freezing state. The figures I put before does not mean that "it can return to the earth with 70% probability"; it means that "for the 70% probability of communication recovery, we will continue the operation."

And this doesn't sound too promising:

Astronomy Monthly(Gekkan Tenmon): Are there any change in your view on the sample retrieval after these events? How much scientific discovery could you make out at this point? You're experiencing another difficult situation now, what is the biggest lesson you've learned in these troubleshooting experience?

Kawaguchi: We haven't been able to download any new data, so our view is still unchanged. Status of the vehicle did change, and there are possibility of data being lost. If minimum power supply is available the data will hold, but we can't tell for sure at this point.

As for scientific discovery, we still have undisclosed informations, but the science community plans to open them to the public as soon as possible.

There are considerable amount of information that only Hayabusa could gather. We won't be repeating on its content for today. At some future date we will publish a formal summary. I consider that these results funded by national taxes should be primarily available to this country. We fear that if these data spread, any researcher from other countries could release a paper as first author. And of course contribution to the world must be considered, too.

[amezz]

If the probe is going to hang around Itokawa for almost another year, will it continue to study the planetoid?

Yes! They MUST do it, we all hope to see once more the Enigmatic Stone Garden of Itokawa

[ljk4-1]

*** JAXA MAIL SERVICE ***

Japan Aerospace Exploration Agency
----------------------------------------------------------------------
Status of the Hayabusa

December 14, 2005

Japan Aerospace Exploration Agency

Hayabusa spacecraft currently undergoes the recovery operation to
resume the communication with the ground stations. It was hit by an
abrupt disturbing torque owing to the fuel leak that occurred before,
and has been out of the ground contact since December 9th. The
project team has a good expect to have the spacecraft resume the
communication soon. However, the project is now not so sure to make
the spacecraft return to earth in June of 2007 and has decided to
lengthen the flight period for three years more to have it return to
the Earth in June of 2010.

On December 8th, Usuda station observed the sudden shifts of the
range-rate measurements at 4:13 UTC with the corresponding gradual
decrease of signal intensity AGC (Automated Gain Controller) read.
The measurement and the intensity change slowly and are currently
estimated due to the out-gassing effect that derived from the fuel
leak-out at the end of last month. The leak occurred on November 26th
and 27th. Since the beacon signal communication resumed on 29th, the
project has made an effort to exclude the vapor gas of the fuel from
the spacecraft. The project has by now identified the out-gassing has
successfully been performed, as its exponential acceleration decay
has shown so far.

On December 8th, the spacecraft was under the resume operation phase
for the chemical propulsion, and was given a slow spin whose period
is about six minutes. From the beginning of December, the project has
introduced the Xenon gas thruster control strategy for emergency,
replacing the chemical propulsion system. But the control capability
of it was not enough strong for the spacecraft to withstand the
disturbance on December 8th. Current estimation says the spacecraft
may be in a large coning motion and that is why the spacecraft has
not responded to the commands sent from the ground station.

The spacecraft has been out of communication since December 9th.
Analysis predicting the attitude property relating to both the Sun
and Earth shows that there will be high possibility counted on for
the resumption of the communication from the ground for several
months or more ahead. However, the spacecraft may have to undergo
another long term baking cycle before it starts the return cruise
operation using ion engines aboard. And it is concluded that the
commencement of the return cruise during December is found difficult.
The project has determined that the return cruise should start from
2007 so that the spacecraft can return to the Earth in June of 2010,
three years later than the original plan, as long as no immediate
resumption tales place very soon.

The spacecraft operation will shift from the normal mode to the
rescue mode for several months to one year long. Long term predict
indicates high probability of having the spacecraft communicated
with the ground station again, with the spacecraft captured well in
the beam width of the Usuda deep space antenna.

The spacecraft will take the advantage of Xenon gas attitude control
again after enough length of baking operation. The Xenon gas that
remains is adequate for the return cruise devised by the ion engines
carried by Hayabusa.
The Hayabusa web page will report anything updated, as soon as it
becomes available.


(Supplement) Hayabusa Rescue Operation

http://www.jaxa.jp/press/2005/12/20051214_...busa_e.html#sup


This page URL:

http://www.jaxa.jp/press/2005/12/20051214_hayabusa_e.html

---------------------------------------------------------------------
Publisher : Public Affairs Department
Japan Aerospace Exploration Agency (JAXA)
Marunouchi Kitaguchi Building,
1-6-5, Marunouchi, Chiyoda-ku, Tokyo 100-8260
Japan
TEL:+81-3-6266-6400

JAXA WEB SITE :

http://www.jaxa.jp/index_e.html

[nop]

English version of JAXA press release:
http://www.jaxa.jp/press/2005/12/20051214_hayabusa_e.html
http://www.isas.jaxa.jp/e/snews/2005/1214.shtml

Translation of the press conference is now completed.
http://smatsu.air-nifty.com/lbyd/2005/12/2...7.html#c5380890
http://smatsu.air-nifty.com/lbyd/2005/12/1...2.html#c5385838

A follow-up article seems now being translated. Wait a moment.
It includes a nice episode about LIPOVITAN-D

Guys, wait with patience for the return in 2010 !

[abalone]

Guys, wait with patience for the return in 2010 !

By then it would have to qualify for Saint Hayabusa

[djellison]

All sounds a little bit Nozomi-ish really I just hope they can keep the think held together for another 5 years

Doug

[ljk4-1]

All sounds a little bit Nozomi-ish really   I just hope they can keep the think held together for another 5 years

Doug

Speaking of which - is Nozomi still alive? Is it returning any data on the interplanetary environment?

Any chance it could make another attempt at Mars down the road? If JAXA thinks Hayabusa can last five more years, why not Nozomi?

[nop]

Speaking of which - is Nozomi still alive?  Is it returning any data on the interplanetary environment?

Any chance it could make another attempt at Mars down the road?  If JAXA thinks Hayabusa can last five more years, why not Nozomi?

Nozomi is alive, I think, but it lost the way to send data to us. Though it captured pictures of the Mars surface from 1000km altitude even on the day of the last operation in 2003, we have no way to get them. We cannot even locate the probe. The transmitter was stopped according to some laws. Now it circles the sun as an artificial planet.

P.S. I fixed my mistake about the year of the last operation. (2004 -> 2003)

[ljk4-1]

Nozomi is alive, I think, but it lost the way to send data to us.  Though it captured pictures of the Mars surface from 1000km altitude even on the day of the last operation in 2004, we have no way to get them.  We cannot even locate the probe.  The transmitter was stopped according to some laws.  Now it circles the sun as an artificial planet.

Japan should send out a rescue mission (or ask someone else to do it) to collect both Nozomi and Hayabusa to recover their data and samples. I admit it may take a while to find Nozomi.

While they are at it, someone should find Mariner 9 and get those last few images it took that are still stored aboard the probe. See Carl Sagan's The Cosmic Connection for the details.

[djellison]

It'd be cheaper, and the results would be better to just bolt on instruments to another spacecraft rather than trying to rescue another one

Doug

[RNeuhaus]

Indeed yes, but we are still with diaper in space robotic technology. For Hayabusa, it would be much easier by releasing its outside canister but for Nozomi's case is not possible since it was not designed to release anything. I think so

Rodolfo

[ljk4-1]

It'd be cheaper, and the results would be better to just bolt on instruments to another spacecraft rather than trying to rescue another one

Doug

But Nozomi and Mariner 9 contain data on Mars at a particular time and place that cannot be repeated again.

Plus it would be so cool! And it would be good training for recovering future space probes, both ancient and modern.

Some day archaeological expeditions will be sent to recover and study old spacecraft to see what has become of them.

[djellison]

Some day archaeological expeditions will be sent to recover and study old spacecraft to see what has become of them.

Some day being Apollo 12

Doug

[ljk4-1]

Science/Astronomy:

* Asteroid Probe Yields Insight For Planetary Defense

http://www.space.com/businesstechnology/05...r_hayabusa.html

Following roughly two months of notable operations at asteroid Itokawa, Japan's
Hayabusa probe is damaged goods. Hindered by thruster and gyroscope breakdowns,
the spacecraft is under makeshift attitude control with engineers hoping to
finesse the craft onto a homeward-bound trajectory back to Earth.


* Black Hole Swallows Neutron Star, Observations Suggest

http://www.space.com/scienceastronomy/0512..._collision.html

A distant eruption of high-energy gamma rays is evidence for a black hole
swallowing another dense object called a neutron star, astronomers announced
today.

[RNeuhaus]

Example for Hayabusa return starting in June 2007

Hayabusa leaving 2007 to Earth 2010


New trajectory (red line) leaving Itokawa vicinity in spring of 2007, returning to Earth
in June of 2010 is shown here. The Xenon gas consumption meets the current
amount that remains. There will be some strategy needed and left for the operational discussion on how the attitude is protected against unexpected disturbance.

Interpreting the above picture, in the year 2007, Hayabusa will leave Itokawa by orbiting around to Itokawa before taking the orbit around the Sun in the clockwise. The Earth will orbit in counter-clockwise around the Sun. See the red line which is the proyected return home in 2007. The blue line is the proposed route to home in this year.

The question is why Hayabusa will make a small loop in the half way of orbit? (see on the left side)

Rodolfo

[ljk4-1]

Some day being Apollo 12

Doug

Nah, that was a fluke.

[nop]

The question is why Hayabusa will make a small loop in the half way of orbit? (see on the left side)

In this figure, the sun and the earth are fixed. That's why the orbit seems strange.

[Phil Stooke]

ljk4-1 :

"QUOTE(djellison @ Dec 14 2005, 03:30 PM)
Some day being Apollo 12

Doug


Nah, that was a fluke. "


No - Apollo 12 collecting bits of Surveyor 3, not the return of its SIVB, which must be what you are thinking of...

Phil

[ljk4-1]

ljk4-1 : 
 
"QUOTE(djellison @ Dec 14 2005, 03:30 PM)
Some day being Apollo 12

Doug
Nah, that was a fluke. "
No - Apollo 12 collecting bits of Surveyor 3, not the return of its SIVB, which must be what you are thinking of...

Phil

Just being facetious. I do consider Apollo 12 to have conducted one of the first space archaeology missions. I was initially referring to a future time when there is a real plan and system in place for organized space archaeology.

Funny and sad how schools do not recognize the Space Age as a historical period to study in its own right. That too shall change.

[edstrick]

The Hayabusa orbits plot is in sun-earth-fixed ROTATING coordinates. The loops are where the spacecraft, I think at perehilion, is travelling faster than Earth, while the rest of the orbit it's travelling slower.

[deglr6328]

Heathens! How dare you try to explain away Hayabusa's divine epicycles as a mere illusion of refrence point!!

[Bob Shaw]

Yes! They MUST do it, we all hope to see once more the Enigmatic Stone Garden of Itokawa

I suspect that 'hanging around' Itokawa would not actually involve being near enough to see anything - if the spacecraft has to be kept simply ticking over, then they won't want to waste resources doing extended station-keeping with what turned out to be a very small and difficult target.

Except for the return element, Hayabusa has been a stunning success, and I hope we don't see the mission downplayed a la Nozomi.

Bob Shaw

[MahFL]

"Except for the return element, Hayabusa has been a stunning success, and I hope we don't see the mission downplayed a la Nozomi. "

I disagree, so far its robot missed the asteroid, they did not know it had touched down, they don't know if they have any samples, and its out of control and pretty much disabled, it will be a miricle if it ever makes it back to earth, which I doubt, it'll proberbly die in the cold of space.

Thats IMHO.

[Guest_BruceMoomaw_*]

Well, it did everything NEAR did on only about 2/3 of the money, which is not to be sneezed at -- especially since it gave us nice comparative data on another asteroid. Unfortunately, it now looks as though everything it tried to do BEYOND what NEAR did will be a washout.

[Bob Shaw]

Well, it did everything NEAR did on only about 2/3 of the money, which is not to be sneezed at -- especially since it gave us nice comparative data on another asteroid.  Unfortunately, it now looks as though everything it tried to do BEYOND what NEAR did will be a washout.

Bruce:

o It used an ion engine operationally in deep space
o Made use of sophisticated auto-nav and rendezvous systems
o Demonstrated close-in maneuvers in multiple ways

And performed a NEAR-like mission, too!

All in all, a helluva mission!

Bob Shaw

[Holder of the Tw...]

Well, it did everything NEAR did on only about 2/3 of the money

Hayabusa had no gamma ray spectrometer, and no magnetometer. To my knowlege, Hayabusa did not return surface pictures of Itokawa as detailed as the final pictures of Eros from NEAR. And while touch-and-go landings are impressive, orbiting small irregular bodies - which Hayabusa never did - is pretty impressive, too.

[Guest_BruceMoomaw_*]

Let me amend: ALMOST everything. (Its best photos of Itokawa's surface were as high-resolution as NEAR's best photos of Eros' surface -- and its maneuvers around the asteroid were at least as intricate as NEAR's.)

[tedstryk]

Well, it did everything NEAR did on only about 2/3 of the money, which is not to be sneezed at -- especially since it gave us nice comparative data on another asteroid.  Unfortunately, it now looks as though everything it tried to do BEYOND what NEAR did will be a washout.

It also gave us closeup data on a class of world that, other than Galileo's glimpses of Dactyl, we had never seen close up. A very important mission. I must admit that I have no confidence now that it will return to earth. My hope is that it will regain orientation long enough to transmit the data (and possibly more images) from its last landing attempt.

[odave]

And also remember that this is primarily an engineering mission, and as such even the failures are valuable. I'm sure JAXA/ISAS is keeping a list of what went right and wrong. Hopefully backup reaction wheels are near the top under "what to do better next time"

[hugh]

To my knowlege, Hayabusa did not return surface pictures of Itokawa as detailed as the final pictures of Eros from NEAR. 

This 11-17 JAXA release claimed a resolution of 1.5 - 2.0 cm a pixel for the closest image obtained by Hayabusa. NEAR Shoemaker’s last image had a resolution of about 1.1cm, but covered a smaller area, and had about 1/8 the number of pixels that were in the Hayabusa image.

[edstrick]

Hayabusa returned a huge amount of infrared spectrometer data. The NEAR instrument failed early in the mission, and the high-orbit data (as I recall) didn't tell much about surface composition variation, as it was mostly unresolved. The X-Ray composition data may be significantly better than NEAR's, but published data in science result papers will tell.

[lyford]

Heathens! How dare you try to explain away Hayabusa's divine epicycles as a mere illusion of refrence point!! 

Well - I think Hayabusa's epicycles ARE part of a divine plan - from the JAXA home page, it appears no one less than The Pope himself is working on their Vision:


I mean, who else besides Elvis wears all white?

And while we're at it, does anyone else think Harrison Schmitt is slowly morphing into Von Braun?

As for Hayabusa being an engineering mission, JAXA itself only weighted science observations as 50 points out of 500 total for mission success. Though it does appear that some encounter data has been useful, that still leaves :

3. Touch-down and Sample
4. Capsule Recovered
5. Sample obtained for Analysis

as unfulfilled criteria. Without 4 and 5, we may never really know if 3 was accomplished it seems. Space science can't be done on the cheap, not even by the Japanese.

[The Messenger]

Does anyone have any insight into why reaction wheels have been such a bug-a-boo? I know, from my own work with inductive circuits in a vacuum, there are always serious overheating issues when radiation is the only way to disappate heat energy. Are the reaction wheels being driven to greater loads than expected?

[Holder of the Tw...]

Hayabusa returned a huge amount of infrared spectrometer data.  The NEAR instrument failed early in the mission, and the high-orbit data (as I recall) didn't tell much about surface composition variation, as it was mostly unresolved.  The X-Ray composition data may be significantly better than NEAR's, but published data in science result papers will tell.

The NIS instrument on NEAR returned three solid months worth of data from Eros before it failed. At the time, it was in a 50 km circular orbit, and able to resolve a spot 330x650 meters. This is 1 to 2 percent the length of Eros, so it was resolving the asteroid just fine. The reason it didn't show much surface variation is because, as this instrument discovered, there was no significate variation to report. The NIS also made significant contributions to studying the spectra of asteroid 253 Mathilde and comet Hyakutake.

I'll concede the point made by Hugh on the picture resolution.

[Phil Stooke]

Even if Hayabusa only returned a quarter of NEAR's data volume (and I'm not suggesting I know what the fraction would be) - it's still important because it's a different world. We now have a very nice new data set for Itokawa which we didn't have before, so that's good. I absolutely agree JAXA's efforts are underfunded, but that's a political issue for Japan to resolve itself.

Actually, I think JAXA hurt itself a bit in its list of mission objectives. They assigned points to each mission phase, but they were too much weighted towards the final stages. I would have weighted them more heavily for the work done up to now, so that a more substantial degree of success would be shown today. The remote sensing was very valuable. Then the sample return would be 'icing on the cake' if it could be pulled off.

Ahh... I can almost hear the sound of the milk of human kindness sloshing around in me today. 'tis the season... I guess.

Phil

[edstrick]

Holder of the Two Leashes:
"The reason it didn't show much surface variation is because, as this instrument discovered, there was no significate variation to report. "

I remain unconvinced of that. The areas of greatest color and albedo variation, or features where composition variations might be expected, were generally well below 1/2 km in size. I'm specifically referring to the high albedo steep slopes inside the freshest craters and the small, slightly darker than general regolith smooth "ponds" in crater bottoms.

I note that the camera, which had a TINY CCD detector with non-square pixels and high noise levels (obvious in low-contrast stretched images of a high contrast target) had real trouble seeing color variations, but they were there once enough pixels on a target were averaged.

Global color variations are near zero, but weak local ones, mostly on 100 or 50 meter scales and smaller are present. I expect/suspect similar ones were present in infrared wavelengths but were undetected due to resolution and possible signal/noise factors.

[ljk4-1]

Would it have been easier to have Hayabusa touch down on several different places on Itokawa to take images and data, rather than have brought Minerva along to do that job?

Or even just one stationary lander to leave on the planetoid?

[RNeuhaus]

Minerva would do much better the job with imaging and temperature than Hayabusa but due to a bad luck it has gone away forewer. Hayabusa ANC wide camera is not designed to take close pictures but unless up to 50 meters from Itokawa.

Hence, Hayabusa has no legs to sit on Hayabusa.

The initial mission, JAXA took this as an engineering mission with much greater points (see the Lyford's previous comments) than the scientific mission.

Rodolfo

[Holder of the Tw...]

I note that the camera, which had a TINY CCD detector with non-square pixels and high noise levels (obvious in low-contrast stretched images of a high contrast target) had real trouble seeing color variations, but they were there once enough pixels on a target were averaged.

Global color variations are near zero, but weak local ones, mostly on 100 or 50 meter scales and smaller are present.  I expect/suspect similar ones were present in infrared wavelengths but were undetected due to resolution and possible signal/noise factors.

I misunderstood you completely. I thought you were saying that the NIS could not resolve any part of Eros. One theory about part of the variation you're talking about is that the color differences are due to the fresh material being "unweathered".

One other thing I don't understand, though, is what your whole point is. Are you saying NEAR should have been put off for five years in order to get more advanced infrared detector technology? Or perhaps you are saying the United States should have scuttled the NEAR and Deep Space 1 programs, waited for some other nation (perhaps Japan) to fly both a dedicated asteroid mission and ion engine driven spacecraft first, and then build our own programs on their experience more cheaply?

[Joffan]

One other thing I don't understand, though, is what your whole point is.  Are you saying NEAR should have been put off for five years in order to get more advanced infrared detector technology?  Or perhaps you are saying the United States should have scuttled the NEAR and Deep Space 1 programs, waited for some other nation (perhaps Japan) to fly both a dedicated asteroid mission and ion engine driven spacecraft first, and then build our own programs on their experience more cheaply?

I thought that the general mood of the board, the spirit of this thread, was that Hayabusa is a success of comparable magnitude to NEAR even without the sample return. It seemed to me that it is you that has a point to make, Holder, to whit that NEAR was hugely better than Hayabusa. Your brinkmanship in suggesting that the participants here would like to see any exploration programs whatsoever scuttled, no matter the host nation, is political posturing.

[Holder of the Tw...]

I thought that the general mood of the board, the spirit of this thread, was that Hayabusa is a success of comparable magnitude to NEAR even without the sample return.

The general sense of the spirit I was picking up was Hayabusa was the equal of NEAR for less money, or that it actually accomplished far more in certain areas such as infrared remote sensing. Hayabusa had the advantage of superior technology and the prior experience of NEAR to draw on in making it's specs for it's instrumentation, along with all the other flight operations planning.

It seemed to me that it is you that has a point to make, Holder, to whit that NEAR was hugely better than Hayabusa. Your brinkmanship in suggesting that the participants here would like to see any exploration programs whatsoever scuttled, no matter the host nation, is political posturing.

Your opinions about my post are duly noted, Joffan. Thank you very much.

There is no doubt that Hayabusa has made a significant contribution to the study of NEOs, and has paved the way for more successful missions in the future, which the Japanese by all rights should be in the forefront of pursuing.

I earlier made a rather snide comment in one posting about the possibility of what kind of sample Hayabusa would be bringing back. This was during a time of frustration over all the problems it was having. I also earlier voted on a poll in this forum on whether Hayabusa would succeed in returning to earth with a sample. I voted "no". I'm more confident in that vote than ever. I trust most of you (certainly not all of you) will believe me when I say I will take no joy in it if I turn out to be right, and would be happy to be wrong.

[lyford]

And NEAR never found a Red Light District, either.
I, too, hope to be wrong, but I don't hold much hope for our little friend. Let us hope that the engineering lessons JAXA has learned include what to do and what NOT to do in the future.

[tedstryk]

The NIS instrument on NEAR returned three solid months worth of data from Eros before it failed.  At the time, it was in a 50 km circular orbit, and able to resolve a spot 330x650 meters.  This is 1 to 2 percent the length of Eros, so it was resolving the asteroid just fine.  The reason it didn't show much surface variation is because, as this instrument discovered, there was no significate variation to report.  The NIS also made significant contributions to studying the spectra of asteroid 253 Mathilde and comet Hyakutake.

I'll concede the point made by Hugh on the picture resolution.

Also, it mapped the whole asteroid except those parts that were seasonally in shadow. And, most importantly, it lasted as long as it was designed to last - had NEAR not arrived late, the nominal mission would have been over by the time it failed.

[edstrick]

Holder of the Two Leashes:
"...One other thing I don't understand, though, is what your whole point is. ..."

I guess my points is that NEAR was the first of the Smaller, Cheaper, Faster, Better missions, but there is an ongoing debate on whether it was even good enough to accomplish what I thought was it's primary mission objective: determining whether S-type asteroids are or are not the parent bodies of ordinary chondrite meteorites. While the indications of a space-weathering modified surface were at least somewhat expected to cause potential problems in linking the two, the mission that was flown carried instruments that simply did not have the signal-to-noise ratio AND the resolution to clearly sort out what appear to be end-members of the weathering sequence. It was good, but like Boris, it wasn't good-enough.

Where NEAR really shined is in photo-geology, where it mostly made up for it's dinky camera with scads and scads of images that can be mosaiced into global coverage, and revolutionized our understanding of geologic processes on asteroids.

[JRehling]

Both missions were successful. Note that they were quite different operationally in that NEAR orbited Eros, while Hayabusa more or less "escorted" Itokawa, and so far as I have seen, ended up with mainly high phase angle images. Of course, this was part of the mission design.

I would think that in retrospect, one might try to emulate NEAR again staying rather close to the mission's goals/money ratio, whereas Hayabusa was a bit too far over the edge for a novel spacecraft... perhaps with legacy components a future mission could be as ambitious and as cheap, but clearly the mission had more than one failure to execute -- the blessing is that it suceeded in every way needed to produce good science. Was it by design or luck that the "optional" portions of the mission were the ones to fail? Contrast Nozomi, which had lots of systems operational, but the one that failed to execute meant no Mars encounter at all.

NEAR had the advantage of treating Eros like it was a planet, but alternately easier (since light thrusters could perform the manuevers) and harder (strange gravity field made it). Hayabusa had a different challenge, and one felt as though it was awkwardly dancing with the asteroid. We can divide future asteroid missions between those that can orbit their worlds and those that must undertake many, frequent propulsive manuevers to execute. Given speed-of-light time, an autonomous system that was foolproof in gracefully dancing with its target would be a tremendous accomplishment.

One accomplishment of Hayabusa was in showing us an entirely new kind of world, at the smallest-yet end of the spectrum, whereas Eros looks on the whole like Gaspra, and is not too different from Phobos, the first "small" world seen by spacecraft. In a sense, Hayabusa "finished" the size spectrum, because yet smaller "worlds" are likely to be boulder heaps like Hayabusa in every way but the reading on the tape measure -- Hayabusa is clearly at the point where gravity ceases to rework the "world" in any way except to hold it together and pool its dust.

[Holder of the Tw...]

I guess my points is that NEAR was the first of the Smaller, Cheaper, Faster, Better missions, but there is an ongoing debate on whether it was even good enough to accomplish what I thought was it's primary mission objective: determining whether S-type asteroids are or are not the parent bodies of ordinary chondrite meteorites. 

Hmmm. Okay.

You'll please forgive my earlier lashing out. NEAR was a mission I had a great fondness for. I perceived some slights directed at John Hopkins APL and the NEAR team, whom I thought pulled off a remarkable mission given the resources at hand, and reacted defensively. I believe the merits of Hayabusa can stand on their own without much comparision to specific previous missions, but rather what was gained in comparison to everything we had before.

NEAR was able to narrow things down. Eros appears to be a type L or type LL chondrite. Bear in mind, no one had examined an asteriod from this close a range before, and it was inevitable that a lot of lessons were going to be learned on how asteroid missions should be conducted in the future.

Persons close to the Hayabusa team have reported in here before, and I would love to hear what they think in regards to how NEAR influenced the planning for their mission. In the meantime, here is what I can note ostensively -

Some of the most interesting and intriguing images from Eros were the very last ones at closest range. It's obvious the Hayabusa team wanted very close and very detailed images from several points on Itokawa, hence Minerva.

The X-ray spectrometer on NEAR performed brilliantly. A similar device was included on Hayabusa.

The gamma ray spectrometer on NEAR was a real problem child. It never got the data it was designed for until after they pulled off that unlikely landing on Eros, and it had sat there for a week. Hayabusa didn't carry any similar instrument.

The magnetometer on NEAR never detected any intrinsic magnetic signature at EROS. When it failed to do so even after the landing, it was quickly and unceremoniously turned off. Hayabusa carried no magnetometer.

The NIS performed well according to it's design. As you have pointed out so well, edstrick, the reality of Eros was that more resolution, even from it's planned 35 km orbital results, would have been highly desirable. Hayabusa carried an instrument with improved resolution.

After all was said and done, the comparison of Eros with meterorite samples was not definitive. Hayabusa bringing back two samples from Itokawa would absolutely NAIL the comparisons, along with much else.

Part of what I was trying to allude to with my "scraping NEAR and Deep Space 1" remarks was to point out that Hayabusa would have been a very differently designed, and undoubtedly more costly, mission had it not had previous experience to draw on. Part of what was learned this time around was that Eros and Itokawa were more different than expected, which created some problems for Hayabusa's landing attempts. This points to a need for a CONTOUR type mission to visit several different NEAs.

[Guest_BruceMoomaw_*]

Hawaii's Jeffrey Bell has been telling me for years that remote sensing -- even with high-quality instruments -- simply isn't adequate to answer the "ordinary chondrite" question, and that a sample return will be necessary. The evidence seems to be growing that he's right -- simple element measurements and near-IR spectra don't seem to be adequate to nail it -- and this is one reason why I regard "Hera" as one of the more likely candidates for selection in the next Discovery AO.

[The Messenger]

Where NEAR really shined is in photo-geology, where it mostly made up for it's dinky camera with scads and scads of images that can be mosaiced into global coverage, and revolutionized our understanding of geologic processes on asteroids.

Can you point me to a good paper on this?

[Phil Stooke]

I just noticed this, though it may not be brand new. I don't think I had seen the false-color view at the bottom of the first page before this.

Phil

http://www.jaxa.jp/news_topics/column/special-4/index_e.html

[ljk4-1]

Maybe if we wait a few million years, we'll get all the samples of Itokawa we will ever need - or want:

Smooth Sections on Asteroid Itokawa

Credit & Copyright: ISAS, JAXA

Explanation: Why are parts of this asteroid's surface so smooth? No one is yet sure, but it may have to do with the dynamics of an asteroid that is a loose pile of rubble rather than a solid rock. The unusual asteroid is currently being visited by the Japanese spacecraft Hayabusa that is documenting its unusual structure and mysterious lack of craters. Last month, Hayabusa actually touched down on one of the smooth patches, dubbed the MUSES Sea, and collected soil samples that will eventually be returned to Earth for analysis. Unfortunately, the robot Hayabusa craft has been experiencing communications problems and so its departure for Earth has been delayed until 2007.

Computer simulations show that 500-meter asteroid Itokawa may impact the Earth within the next few million years.

http://antwrp.gsfc.nasa.gov/apod/ap051228.html