Hayabusa To Begin Long Journey Back to Earth

Sparky writes "Japan is planning to set the Hayabusa spacecraft on a trajectory back to Earth next month after a delay of more than a year, but it's far from certain that it will get back safely. It was supposed to retrieve asteroid debris, but it's thought that a computer error prevented that from happening. A fuel leak means that its chemical thrusters are out of action, and the craft is relying on its weaker ion engines. The journey back will take 3 years, and the capsule will be on Earth in June 2010 — even if it is empty."

Re:Why not park it in high orbit?

[biocute]

Maybe to test if the re-entry works.

Re:Why not park it in high orbit?

[stratjakt]

Because they don't know if it is empty, and because it's neither possible nor at all easy to "just park it out of the way somewhere and go get it later".

Re:Why not park it in high orbit?

[LiquidCoooled]

Because they spent however million building a ship capable of a return voyage.
It will be wasted if they just give up.
I think this is invaluable research and has taken a tremendous effort by the crew to even get this far.
There may not be humans on-board this time but years in the future someone may end up being saved by lessons learnt in the Hayabusa incident.

(yes, it does sound star trekkish)

Why not another attempt?

[ClayJar]

Basically, the technology to retrieve a satellite from where it is now is likely just as hard as the original mission. Additionally, by the time retrieval would be possible, what would be the point? Technology marches ever on; even if they could retrieve Hayabusa, it's old technology now.

Additionally, such probes are one-shot devices. The components are built to specs to survive hard solar radiation, exposure to space, and all the extreme temperatures involved. I'd venture to guess they'd have to basically rebuild the satellite almost completely to be able to make another attempt with it. It's cheaper to just start from scratch and include the advances available to you.

Now, why bother trying to get it home? It's by no means as important as Apollo 13 (in that no lives are depending on it), but to take a probe that's seen better days and get it all the way back home in the face of what appear to be nearly insurmountable odds has quite a bit of sentimental value. For Japan to get Hayabusa home even in such a depleted state, it would be a great honor to their scientists. (And the fact that there's still *some* chance, albeit very small, that there may have been some material captured just makes it that much better.)

It's the "Incredible Journey" of satellites, or perhaps more apropos, it's the wounded samurai doing everything he can to make it back home before he dies. Very Japanese, and quite a good potential story, too. :)

Re:Why not park it in high orbit?

[Richard_at_work]

Its highly likely that none of the parts that malfunctioned will be contained within the reentry package - theres no point in having those parts retrievable, all you want is the science package so thats all you bring to the ground. The rest will burn up in the atmosphere after seperation.

They are going through with the reentry because theres a chance they did get some debris, and they want to see if the reentry procedure works.