[X] My Assistant

[dilo]

About Hayabusa, there is an article here from Don Yeomans...

[Phil Stooke]

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

[Toma B]

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

Hayabusa

[helvick]

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

[dilo]

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).

[maycm]

Distance to target -

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

August 17th : 20,199km

[RNeuhaus]

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

[dilo]

"...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:
Don Yeomans article
or here:
Planetary Society

[Bob Shaw]

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

[tedstryk]

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.

[garybeau]

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.

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?

[djellison]

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

[AndyG]

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

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

[paxdan]

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.

My understanding was that the contact of the collection tube with the asteroid would trigger the firing of the pellet. This NewScientist 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.”

[paxdan]

More info about the sampling from the NSSDC Master Catalog.

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.