[meteorite-list] Hayabusa 2 to visit asteroid 1999 JU3 in 2018

From: Robin Whittle <rw_at_meteoritecentral.com>
Date: Fri, 29 Mar 2013 03:38:48 +1100
Message-ID: <51547218.9080908_at_firstpr.com.au>

There's a detailed account of the second Japanese mission to visit an
asteroid and return samples:

  http://www.spaceflightnow.com/news/n1303/27hayabusa2/

which will be similar to the first one:

  http://en.wikipedia.org/wiki/Hayabusa

On 14th June 2010, my wife Tina and I happened to be en-route to the
Nullarbor Plain National Park. We spent the night at the Nuttbush
Retreat, about 30km WSW of Port Augusta. There was some high cloud but
it was clear in the direction of the expected re-entry. We, and a few
other people there, saw the whole re-entry perfectly clear and bright in
front of our own eyes, maybe 20 degrees above the horizon, with the
craft moving west to east and somewhat downwards.

We saw a moving light appear, get brighter, become very bright and then
break into many pieces. At that time we noticed a duller, more orange
object ahead of and somewhat lower than the bright-white breakup
fragments. This was the sample return capsule, which I now understand
was released from the main craft about three hours earlier. I am not
sure of the landing location, but I guess the events we saw took place
300 to 500km to the WNW. All was still, apart from the gentle
excitement of several gatherings of people who saw it as well. I tried
to take a photo, but it was no use - it would have been better to keep
my eyes on it all the time. What we saw resembled the NASA video, but
with not as much detail.

I recall seeing the complex return trajectory and reading of how they
made a final ion engine thrust operation four days before the craft
reached Earth. I think it is extraordinary that they could do so and
have the capsule land so exactly, considering the velocities, rotation
of the Earth, interaction with the atmosphere etc. Of course the whole
business of launching machinery off the Earth, sending it somewhere,
where it must interact with other objects without real-time control from
the home planet - and then having the machine return and re-enter, is
extraordinary. All the more so considering the technical difficulties
which developed during the mission. These included power reduction,
loss of reaction wheels and ion engines - and a three month loss of
communications.

In terms of pure science, it could be argued that we know enough about
asteroids already from meteorites. However I think the Hayabusa
missions are somewhat like the Apollo missions to the Moon. I think
they are primarily human adventures in our long tradition of exploration.

To actually see this little craft come home, exactly as planned, was
really great!

  - Robin
Received on Thu 28 Mar 2013 12:38:48 PM PDT