Hayabusa - The Return To Earth, The voyage home Options

[Tesheiner]

IIRC Huygens used the kind of separation / spin mechanism I tried to describe.

[djellison]

Beagle 2, to, had a spin up and eject mechanism ( the SUEM ) that basically was spring loaded, but when released, it pushed through a spiral form to impart spin as it went.

[JimOberg]

2010/05/27 04:59 JST: TCM-2 operation was completed
Category: 2010_English Posted by: HayabusaLive

JAXA confirmed that TCM-2 operation was successfully completed.

By this operation, Hayabusa was guided to the outer rim of the Earth and the distance between Hayabusa and the Earth resulted in around 7,600,000km far.

Hayabusa sysytem is going well.

*TCM: Trajectory Correction Maneuver

[pandaneko]

By the way, can anyone confirm that the capsule is spun up upon ejection? I've seen a graphic of some sort that seems to indicate this (my memory's a bit hazy here), but haven't read anything to that effect.

http://www.isas.jaxa.jp/j/forefront/2004/kuninaka/02.shtml

Dear Neprev

above chart indicating delta Vs achieved by various ISAS hardware, I am afraid all in Japanese, 5th from the left is Hayabusa, red is delta V, and the darker bar is the fuel. Those on the left are earlier ISAS missions, such as Nozomi, those on the right are various stages of the solid fuel rocket, M-V.

I read about spin stabilization of Hayabusa only last night, and I can confirm it, but I can no longer find where it is. It was in Japanese, somewhere. What amazed me was that the rate was so small, something like 1 revolution per second, or was it one minute?, I do not remember... It did not say how it may be achieved, though.

One other thing is that JAXA will be televising through internet what will be going on inside the ISAS control centre between 18:00 and 24:00 on 13th June. The format will be either Flash video or WM, with the bit rate of 300 kbps and the size 320x240.

Pandaneko

[konangrit]

One other thing is that JAXA will be televising through internet what will be going on inside the ISAS control centre between 18:00 and 24:00 on 13th June. The format will be either Flash video or WM, with the bit rate of 300 kbps and the size 320x240.

Excellent, presumably those times are JST?

[nprev]

Thank you very much, Pandaneko; much appreciated!

[pandaneko]

Excellent, presumably those times are JST?

I should think so, the announcement was meant for Japanese watchers, I think. I am angry about the degree of publicity by the Japanese press about Hayabusa. Hayabusa is virtually being ignored here. I think that is crazy...

In the meantime, I will try and find about the spin stabilization during the course of this evening.

Pandaneko

[pandaneko]

Thank you very much, Pandaneko; much appreciated!

I tried to get to the same article about Hayabusa spin stabilization and I could not find it, and instead ended up in finding another article. Sources unknown, I am afraid, it is some kind of press report, I think. What it says is;

Both the capsule and its mothership will approach from NW to Woomera at 200 km height, and 8 hours before reentry at the height of 100 km the capsule is given a spin of 0.2 Hertz before release.

At the same time Hayabusa's projectry is changed by the ion engine (courtesy, of course) so she can go back into interplanetary space. Everybody knows that she will not make it.

Immediately after that a timer is activated in response to deceleration and after 150 seconds a parachute is deployed and simultaneously the ablator is jettisoned at the height of 10 km.

The article also says that the approach height is far lower than originally planned to avoid damage to populated areas by mistake. Lack of chemical thrusters and the lower release height means that Hayabusa is doomed.

Pandaneko

[Paolo]

the capsule is given a spin of 0.2 Hertz before release.

that's 12 rpm

[JimOberg]

JAXA appears to have removed one of its website links to its announcement of a successful completion of TCM-2. I don’t know if this is a website management mix-up, or an indication that the claim of a successful TCM-2 is now considered premature. Probably an innocent website problem….

JAXA’s general english-language Hayabusa updates are at
http://www.isas.jaxa.jp/home/hayabusa-live...34&blogid=6

Yesterday [may 27], 11:48 AM I recall that I read this message there, and copied it to
http://www.unmannedspaceflight.com/index.p...1741&st=480

2010/05/27 04:59 JST: TCM-2 operation was completed
Category: 2010_English Posted by: HayabusaLive

JAXA confirmed that TCM-2 operation was successfully completed.

By this operation, Hayabusa was guided to the outer rim of the Earth and the distance between Hayabusa and the Earth resulted in around 7,600,000km far.

Hayabusa sysytem is going well.

*TCM: Trajectory Correction Maneuver

But that message is no longer there.

However, it hasn’t vanished entirely.

Ref: http://forum.nasaspaceflight.com/index.php?topic=7382.45
At nasaspaceflight.com the same message was posted by ‘Yoichi’, who gave this link:
Link http://www.isas.jaxa.jp/home/hayabusa-live...98&catid=34

At THAT link, the message still exists. However, it is not accessible from the JAXA tweet page.

It IS accessible from http://www.isas.jaxa.jp/home/hayabusa-live...47&blogid=6

Any explanation would be appreciated. It does look like a website content control issue
and not a spacecraft issue.

[pandaneko]

Dear Jim

I had a look at JAXA website in Japanese. As far as I can see TCM-2 was completed and that latest message is dated 28 May. I did not find anything unusual. I should perhaps add that I have not been intimately following JAXA website in Japanese, but today's look does not seem to point to anything alarming, I think, and I hope.

Pandaneko

[ugordan]

In anticipation of Hayabusa's return (knock on wood!) to Earth, I thought I'd post a couple of images from the last time he looked at it from up close. The global views you already saw plenty of times, but I haven't seen the closest approach image reproduced often.

[lyford]

Thanks for posting that, ugordon! It also gave me a chance to relive some of the mission going though your flickr gallery

[rlorenz]

Yeah, I never thought it was a brand-new method or anything, just never really knew how it's been done. (I was thinking that there might be some sort of helical groove around the top of the capsule, but that seemed ridiculous...)

I'd be interested to know too - both how it is spun (and how fast) and if there is any harness separation how
that is done.

Approaches for the former include helical rails (as Huygens) or more compact spin-eject devices (Beagle 2 had a neat one),
ejecting from a spin table, and spinning up the mother ship prior to release (e.g. Genesis, Pioneer Venus) : for the
latter function a pyrotechnic cable-cutter can be used (e.g. Genesis) or low-insertion-force connectors are just yanked out
(e.g. Huygens). See my review article http://www.lpl.arizona.edu/~rlorenz/spinjbis.pdf

[Canman]

It will take around 100 hours for ion thrusters to accelerate.

I once heard that ion thrusters give 'A simlar thrust to a small rodent fart'. Proof