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What's Up With Hayabusa? (fka Muses-c)
jaredGalen
post Nov 24 2005, 12:33 AM
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QUOTE (helvick @ Nov 23 2005, 09:42 PM)
I respectfully bow to the collective wisdom of UMSF.
*


Okay, ditto. laugh.gif But I was looking at asteroid landings which, in fairness, I don't believe there have been many. smile.gif


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RNeuhaus
post Nov 24 2005, 03:19 AM
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I am still doubtfull about the Hayabusa landing confirmation because of the following reasons.

1) The confirmation of landing was processed according to the analysis of downloaded data. This report does not mention what kind of data they have analyzed.
2) No one picture from wide view camera ONC-W and neither from telescope narrow angle camera ONC-T when Hayabusa was close enough to testify it, perhaps, few meters from the surface. The first picture of Viking was taken on of the legs touching down on the Mars' surface as a show proof.
3) Why did not the horn fire a ball to the surface? If it is not touched, so it has not fired a ball since it has incorporated the impactor sensor which will automatically fire a ball when it senses some flexing to horn.
4) If JAXA says that the spacecraft was seemingly at rest with the sampler horn and an edge of the body or a solar panel wing laying on the surface, anyway, the horn have already posed on the Itokawa's surface and why it did not fire a ball?
5) The landing detector did not realize it. This might probably be that there were no landing.

I am still cautious about the truth of the new due to lack of more proofs or a more detailed information such as convicent pictures (closer, perhaps, 1-4 meters), and explain what kind of information they have analyzed.

I must ignore the data from LIDAR since it was switched to LRF (Laser Range Finder). Now, as the previous report says that it has failed to work properly due to high radiation and heat from Itokawa. However, the recent report confirmed it has worked. Not sure about which of them is the indeed.

However, the following http: The results and future landing plan of Hayabusa. These graphs are edited in Japan (neigher Google and Babelfish were able to translate them) and they does not mention about the source of information: Doppler radar? If it is so, it would not be reliable to measure Hayabusa and Itokawa by around 290 millions kilometers within in few meters.

Rodolfo
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Jkoro172
post Nov 24 2005, 03:40 AM
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QUOTE (odave @ Nov 24 2005, 03:51 AM)
I think this means that Hayabusa needs to come home to Earth no matter what happens in the next sampling attempt.  If there is any chance that a sample was taken accidentally, it needs to be recovered.

IMO this would qualify the sampling process as an "ugly win".  Being a Detroit Lions fan, I've learned to be happy with any kind of win, ugly or otherwise  biggrin.gif
*


I add a supplementary explanation. I suppose that the sample is too small for adequate analyzing it because the landing sequence, including metal ball shooting to Itokawa’s surface, had not be done. I am expecting the second landing and sampling.
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CosmicRocker
post Nov 24 2005, 06:42 AM
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QUOTE (odave @ Nov 23 2005, 02:06 PM)
...but maybe there's another reason Hayabusa aborted...

"This is Red 5, I'm going in!"

[attachment=2490:attachment]

tongue.gif
*

That was hilarious. The humor in this forum is sometimes quite obvious and sometimes subtle, but it is almost always quite good. This thread has managed to capture both species.

That image did make me seriously think about science, though. Serendipitously, I read Emily's recent blog entry regarding "Thanksgiving Skies," which led me to this link.
Could the brightening toward the center of that image be caused by the "opposition effect?"


QUOTE (helvick @ Nov 23 2005, 03:42 PM)
I respectfully bow to the collective wisdom of UMSF.


*

That eloquent quote is one I need to remember. I could have effectively used it a few times in the past.

Getting back to Hayabusa...I send my enthusiastic applause to the capable Japanese team. I suspect that is going to translate improperly, but good luck, Google.

...and yes, even if one mote of dust can be collected from the event, it can be analyzed with modern tools. Still, let us keep our fingers crossed for the second attempt.


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hugh
post Nov 24 2005, 07:56 AM
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QUOTE (RNeuhaus @ Nov 24 2005, 03:19 AM)
No one picture from wide view camera ONC-W  and neither from telescope narrow angle camera ONC-T when Hayabusa was close enough to testify it, perhaps, few meters from the surface.
*


Hayabusa may not be able to take pictures any closer than the ones already released because of the camera optics-according to the caption for the NEAR-Hayabusa comparison release, the ONC-T telephoto cannot focus much closer than about 60 meters. Presumably the ONC-W wide angle camera can focus much closer, but these cameras might not be designed to take true “touchdown” pictures.
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edstrick
post Nov 24 2005, 08:26 AM
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Holder of two leashes noted: "Besides the before mentioned Soviet Lunas, an American Surveyor lunar lander, I believe it was Surveyor 6, briefly re-fired it's engines to lift off the moon, and moved a few feet away before landing again. This was the first controlled extraterrestrial liftoff.

Before Surveyor 6's "Bunny hop", Surveyor 3 did the first controlled but utterly unintended liftoffs from the moon. As it was descending toward landing, the spacecraft crossed over the rim of Surveyor Crater and lost lock on the (deflected off to one side) radar return from the surface. Without height and doppler velocity data, the spacecraft went into "constant velocity descent" (the design was necessarily assuming momentary radar loss) untill it hit the surface at not much more than it's 12 feet/second (or whatever the number was) descent rate, tilted somewhat to the side on the sloping terrain, AND LIFTED OFF.....sailing a few tens of meters high and arcing down slope further into the crater. It impacted a second time, lifted off some ten feet high and sailed downslope about ten feet, hitting the surface a third time approximately at the same moment as a frantic direct command from ground to shut down the engines reached the vehicle. It bounced/slid another couple feet and shuddered to a stop.

One the second touchdown, many of the engineering telemetry channels became scrambled. The damage was later attributed to electrical arcing and/or corona discharge in the exhaust gas surrounding the vehicle. For a while, they were afraid they were losing the vehicle. A nearly complete power down and selective power-up showed that the vehicle was mostly healthy, and many of the telemetry channels were readible at the lowest data rates of a few bits/second. The only other substantial damage was about 30% of the camera mirror was fairly severly dusted with blown-up moondust, which was hell on pictures when that part of the periscope mirror was sunlit or picking up strong surface bounce light.
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Guest_BruceMoomaw_*
post Nov 24 2005, 08:27 AM
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When you take a look at the Babelfish-translated version of yesterday's announcement, it's quite clear that they do have proof that Hayabusa contacted the surface, and then (after bouncing) simply sat there for half an hour before responding to the ground command to take off again. Indeed, the account is surprisingly understandable.

As for R. Neuhaus' objection: the account says clearly that the reason the sampling bullet wasn't fired is simply that the craft aborted its entire normal landing sequence after its range finders detected a dangerous-looking obstacle -- and that the only reason it didn't then lift back off from the asteroid is that its attitude, for some reason, was tilted at an angle that would have made this dangerous. So, instead, the craft decided to abort by putting itself into "safe mode" and simply dropping to the surface (on its side) until it received that later ground command.

It begins to look as though the central problem is simply that Itokawa's boulder-studded surface is much more rugged than Hayabusa's designers had ever anticipated when they were designing its landing control system -- a more forgivable slip-up than the more outrageous causes to which I had initially attributed the failures. (It may be, though, that the attitude-control problems resulting from its use of thrusters rather than reaction wheels are also a major cause.)
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Guest_BruceMoomaw_*
post Nov 24 2005, 08:31 AM
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Brief consideration was made to launching Surveyor 6 off the surface a second time -- this time to several hundred feet altitude! Apparently they had the fuel for it, but decided it wasn't worth the risk, although I have never heard the details.

I was told at an AIAA meeting this January that, after NEAR's survivial of its landing on Eros, its controllers hatched a hasty plan to have it lift off again from the surface so that it could re-orient its high-gain antenna to Earth and transmit its recorded very closest images of the asteroid's surface (which it had not sent during the original descent, because it had to tilt the antenna away from Earth during the final part of its landing). Unfortunately, nobody had thought to command it to turn off its attitude control system -- with the result that, while they were developing the plan, it quietly exhausted all its remaining fuel trying to stop the entire asteroid from rotating!
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edstrick
post Nov 24 2005, 08:46 AM
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I think the reason for abandoning the second Surveyor 6 hop was there was simply not much time left before lunar sunset.
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Toma B
post Nov 24 2005, 10:20 AM
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QUOTE (BruceMoomaw @ Nov 24 2005, 11:31 AM)
I was told at an AIAA meeting this January that, after NEAR's survivial of its landing on Eros, its controllers hatched a hasty plan to have it lift off again from the surface so that it could re-orient its high-gain antenna to Earth and transmit its recorded very closest images of the asteroid's surface (which it had not sent during the original descent, because it had to tilt the antenna away from Earth during the final part of its landing).  Unfortunately, nobody had thought to command it to turn off its attitude control system -- with the result that, while they were developing the plan, it quietly exhausted all its remaining fuel trying to stop the entire asteroid from rotating!
*


So that's what hapened to NEAR space probe...
Poor little spacecraft trying to stop that big old asteroid from rotating... sad.gif
I have never find an oficial explanation on what hapened to other close-up images taken during descent or why didn't the "JUMP" went as planed...
That was first major space project that I folowed every day using INTERNET...how time flies....
Anyway thanks "BruceMoomaw"...
huh.gif blink.gif huh.gif blink.gif huh.gif


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My "Astrophotos" gallery on flickr...
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Rakhir
post Nov 24 2005, 10:56 AM
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QUOTE (BruceMoomaw @ Nov 24 2005, 10:31 AM)
Unfortunately, nobody had thought to command it to turn off its attitude control system -- with the result that, while they were developing the plan, it quietly exhausted all its remaining fuel trying to stop the entire asteroid from rotating!
*


And so it was also the first asteroid deflection attempt (even if unwanted and with no measurable effect). smile.gif
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Bob Shaw
post Nov 24 2005, 11:32 AM
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QUOTE (edstrick @ Nov 24 2005, 09:26 AM)
Before Surveyor 6's "Bunny hop", Surveyor 3 did the first controlled but utterly unintended liftoffs from the moon.  As it was descending toward landing, the spacecraft crossed over the rim of Surveyor Crater and lost lock on the (deflected off to one side) radar return from the surface.  Without height and doppler velocity data, the spacecraft went into "constant velocity descent" (the design was necessarily assuming momentary radar loss) untill it hit the surface at not much more than it's 12 feet/second  (or whatever the number was) descent rate, tilted somewhat to the side on the sloping terrain, AND LIFTED OFF.....sailing a few tens of meters high and arcing down slope further into the crater.  It impacted a second time, lifted off some ten feet high and sailed downslope about ten feet, hitting the surface a third time approximately at the same moment as a frantic direct command from ground to shut down the engines reached the vehicle.  It bounced/slid another couple feet and shuddered to a stop.

One the second touchdown, many of the engineering telemetry channels became scrambled.  The damage was later attributed to electrical arcing and/or corona discharge in the exhaust gas surrounding the vehicle.  For a while, they were afraid they were losing the vehicle.  A nearly complete  power down and selective power-up showed that the vehicle was mostly healthy,  and many of the telemetry channels were readible at the lowest data rates of a few bits/second.  The only other substantial damage was about 30% of the camera mirror was fairly severly dusted with blown-up moondust, which was hell on pictures when that part of the periscope mirror was sunlit or picking up strong surface bounce light.
*



During the second EVA on Apollo 12 Conrad and Bean visited Surveyor III, and both photographed it and the surface upon which it had come to rest (clearly recording a final series of 'bump-slide-stop' footprint impressions). I knew that the Surveyor had performed an *interesting* landing, but was unaware of a series of more distant hops around the crater. Were any of these landing marks ever photographed? I've never noticed them myself in the ALSJ images or on any other sites.

Bob Shaw


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JTN
post Nov 24 2005, 11:39 AM
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I have no substantial contribution, I'd just like to say: "laser cooking stove finder"
(from this translation of Matsuura's blog)
Thank you, please do carry on.
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edstrick
post Nov 24 2005, 12:31 PM
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Bob Shaw: "...Were any of these landing marks ever photographed? I've never noticed them myself in the ALSJ images or on any other sites."

The second set of landing marks were visible from Surveyor quite a way upslope from the final landing site. The view was very oblique and didn't have much useful detail. I have NO idea if they are visible in Conrad and Bean's photographs. There should have been interesting vernier engine exhaust markings at the touchdown points, but you'd have gotten close to see them.

The first set of landing marks were over the local horizon which was below the curving rim of the subdued crater Surveyor landed in. I expect the first touchdown point was only a little below the rim. I'd have to dig out the Surveyor 3 reports to look at their diagrams. I do recall a nice "side view" diagram of the hop sequence, I think.

GHODS.... the control room must have been a scene.... The @#$@# networks had a segment of live broadcast of the landing attempt at the end of the local evening news, but the actual landing was after they'd gone to the ad break and the start of local news, leaving me SCREAMING in frustration. I have a complete audio tape of the landing of Surveyor 1 off TV, I've wanted to hear the landing commentary and communications loop for 3 ever since.
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foe
post Nov 24 2005, 12:54 PM
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English ver. arrival on ISAS site.

Hayabusa Landed on and Took Off from Itokawa successfully Detailed Analysis Revealed
http://www.isas.jaxa.jp/e/snews/2005/1124_hayabusa.shtml


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