[X] My Assistant

[Guest_Myran_*]

I agree Joffan Minerva are dead by now, and also on the idea to try the sample return regardless even if it comes to not having any sample. Hayabusa is as much a technical demonstration and testbed learning to fly a spacecraft as much as it is a true explorer.

RNeuhaus said: The previous intent has failed due to the problems with the Laser Finder Range (LFR) which is a big dish under the belly of Hayabusa, probably because of excesive heat radiated from the Itokawa surface...

This possible explanation is as good as any else I have been thinking of, if that is the case they might save a bit of Infrared heat if they tried to drop the last target on a spot that recieves sunlight at an angle and sample there. Again that might be even more risky since the solar panels could end up in shadow and it need to be possible to remain in contact with Earth at the same time. So perhaps that idea only to be used as a last attempt if Hayabusa fails at this position again.

[odave]

Some good news from 5thstar, scroll down to heading "Hayabusa regained the control".

According to the Sankei Web article (11/21 22:13) JAXA announced that they regained the control of Hayabusa ON the 21st. It is now 50 km from Itokawa as of the afternoon and is returning to the " home position " with its ion engine.

JAXA also said the communication link had been reestabilshed. They will resume the appoaching operation ON the 22nd and will try to touch down again ON the 25th.

[ElkGroveDan]

According to the Sankei Web article (11/21 22:13) JAXA announced that they regained the control of Hayabusa ON the 21st. It is now 50 km from Itokawa as of the afternoon and is returning to the " home position " with its ion engine.

JAXA also said the communication link had been reestabilshed. They will resume the appoaching operation ON the 22nd and will try to touch down again ON the 25th.

If they succeed, it's a round of LIPOVITAN D for everyone -- on me!

(Somehow the Mars Bars are not nearly as appropriate here.)

[RNeuhaus]

Hayabusa's Team should Lift their punch for the final round and then...celebrate with LIPOVITAN D.

I imagine that this last assault to Itokawa would be out of pronostics...ignoring everything signals from LIDAR and FLR with just one aim which is to touch down, of course as slow as possible, let say 2 cms/sec but with good aim with the help of LIDAR at some distance, 100 meters, on the surface in order to trigger automatically the firing machine, "to absorb" the dust and also lately to ignite the asceding thrusters.

I don't know how Hayabusa will *absorb* the dust samples thru the trunk vacum? The space has no air. Some chemical or mechanical action to capture the dust or sand?

Rodolfo

[Bob Shaw]

I don't know how Hayabusa will *absorb* the dust samples thru the trunk vacum? The space has no air. Some chemical or mechanical action to capture the dust or sand?

Rodolfo

Rodolfo:

I think the word is 'ballistics'.

The debris will spray out and bounce off the sides of the tube in a random-ish way, with a tiny fraction being channelled (can I say that word?) into the collection chamber.

Bob Shaw

[RNeuhaus]

I am thinking that the collection chamber is on the wall of the trunk, this wall is very porous so they can retain some sand or dust. Later, this trunk chamber will be retracted like a submarine telescope becoming a small roll which would be deposited into one of the two canisters which is inside of Hayabusa and just upper of the trunk.

Can anyone find a complete information about the dust or sand capture process?

Rodolfo

[odave]

Can anyone find a complete information about the dust or sand capture process? 

I poked around on the JAXA/ISAS sites and found this slide preso. Scroll down to page 14 and there are some details about the ballistics & capture process. From that description, I assume that the sample chamber is at the top of the horn.

I wasn't able to find any detailed drawings of the sample horn and chamber - unfortunately I just can't grok the JAXA/ISAS web site structure/layout.

[RNeuhaus]

I am thinking that the collection chamber is on the wall of the trunk, this wall is very porous so they can retain some sand or dust. Later, this trunk chamber will be retracted like a submarine telescope becoming a small roll which would be deposited into one of the two canisters which is inside of Hayabusa and just upper of the trunk.

Can anyone find a complete information about the dust or sand capture process? 

Rodolfo

I found a pdf document with detailed information about sample return:

However it is still not possible to fully understand surface conditions of such minor bodies only from ground observation. Thus HAYABUSA employs a sampling mechanism that suits for a diverse heterogeneity of target surfaces, from metal-silicate hard surfaces to regolith layers covered with fluffy microparticles [4]. It carries a 1-m horn made from:

1) Al metal cylinder horn at the tip,
2) foldable, compliant fabric horn (Vectoran) and
3) Al metal conical horn connected to the sample catcher inside.

The sampling mechanism is attached to the basement of the spacecraft and consists of

1) a sample catcher canister coated with 99.9999% Al,
2) a transfer mechanism to the re-entry capsule, and
3) projectors whose gun powder cartridges conceal residual gas inside.

Within 0.3 seconds after the tip of the horn touches on the asteroid surface and the laser range finder detects deformation of the fabric horn in >1cm. Simultaneously,
a Ta projectile of 5-g mass is shot at velocity 300 m/sec by a small projector onto the asteroidal surface. Impact of the projectile produces surface ejecta, which are concentrated through the conical horn toward the catcher. The catcher is finally transferred into the reentry capsule and tightly sealed.

Rodolfo
P.S. Odave, I owe you a LIPOVITAN D

Attached File(s)

 Hayabusa_2161.pdf ( 48.63K ) Number of downloads: 595

 

[odave]

P.S. Odave, I owe you a LIPOVITAN D 

No problem!

Mountain Dew is more my thing

My wife found an applicable T-shirt and is threatening to give it to me for Christmas. It says "PROGRAMMER: An organism that is capable of converting caffeine into code."

[Kei-ichiro Sakur...]

Gosh, I'm really glad to know that there indeed are people who are interested in Hayabusa here.
Hope this would help you:

On Minerva's lifetime: The expected 1.5day-lifetime was due to the high temperature on the ITOKAWA. As it is a free-flyer now, a longer lifetime can be expected.
In Matsuura's 11/12 and 11/13's blogs, Kawaguchi's words are noted:
'Minerva's lifetime was to be limited by the lifetime of the capacitor in the power circuit. The capacitors degrade in 1.5 earth-day due to the high temperature.
As Minerva is not on the surface (of ITOKAWA) and the temperature have not risen yet, the capasitor will hold. However, we don't know how the Minerva's lifetime will end.'
'Minerva can possibly be blown back by the solar wind. The velocity of MINERVA at release was calculated to reach 8.3cm/s at infinite distance from ITOKAWA.
The solar wind applies an acceleration of 1.4cm/s/day to Minerva. Thus, (if we're lucky enough) Minerva would stop ascending in 6-7 days, and return around ITOKAWA in about 2weeks.
And if it comes back close enough to ITOKAWA, it has a chance to collide with ITOKAWA's surface. However, if it just passed by, then it would not head to the sun and never come back.
We should keep monitoring for the signal, for a bit more than 2 weeks. At least, it will come back by the solar wind.
Whenever it comes back in HAYABUSA's receiving antenna's range, we would be able to communicate with Minerva.
If we 'lock-off' the signal for some amount of time, we can determine the Minerva's orbit.'

Touch-down simulation movies (by Tohoku Univ., Yoshida Lab.)
http://www.astro.mech.tohoku.ac.jp/muses-c3.html
Just click the '(MPEG, *.*M)' links :)

'Hayabusa' means 'FALCON' in Japanese, not 'it is quick the ぶ'...
Well. I guess you're using it as an irony,,, but please forgive JAXA.
Believe it or not, the publicity service owes quite a bit to the very mission-critical staff. X-p

[Rakhir]

Touch-down simulation movies (by Tohoku Univ., Yoshida Lab.)
http://www.astro.mech.tohoku.ac.jp/muses-c3.html
Just click the '(MPEG, *.*M)' links

Another movie is available here for the whole mission. http://www.isas.jaxa.jp/e/enterp/missions/...sa/movie.shtml#

In this movie, a sequence is showing in detail what should happen during the sampling, with the ejecta collected in the canister at the end of the horn, and then the canister pushed in the re-entry capsule.

Rakhir

[helvick]

Gosh, I'm really glad to know that there indeed are people who are interested in Hayabusa here.

This is fantastic news. We know that the team are under a lot of pressure, we complain a lot but that's just because we really are interested and we really do appreciate whatever information we can get.

[Rakhir]

'Hayabusa' means 'FALCON' in Japanese, not 'it is quick the ぶ'...
Well. I guess you're using it as an irony,,, but please forgive JAXA.
Believe it or not, the publicity service owes quite a bit to the very mission-critical staff. X-p

'It is quick the ぶ' was not ironic at all.
It is just the translation of 'Hayabusa' coming out from Google automatic translation tool.

[Kei-ichiro Sakur...]

This is fantastic news. We know that the team are under a lot of pressure, we complain a lot but that's just because we really are interested and we really do appreciate whatever information we can get.

Whoops, I'm not a JAXA worker, just a fan.
But as this forum is now being linked from multiple related sites in Japan, it's just a matter of time until the staff will know about you --- and I'm sure it will encourage them.

[TheChemist]

Well. I guess you're using it as an irony,,, but please forgive JAXA.

Forgive JAXA ? We get our space exploration fixes from anywhere, no questions asked
We are grateful to JAXA