Jens Schweikhardt wrote:
Mike Dworetsky wrote
in :
...
# The main requirement would seem to be an ability to slow the
descent speed # to near zero just before surface contact. This
requires radar and a rocket # engine that can be throttled.

I'd say a rocket engine to change a minuscule delta v of 1m/s of a
100kg mass prior to touchdown is way overkill. A gas bottle of some
sort
probably has enough oomph with much less engineering headaches. But I

"Rocket" does not require ignition of hot gases. As you say, a bottle of
compressed gas could do the trick, or something similar to attitude jets
used on Apollo, Shuttle, etc.

I suspect the landing speed was more than 1m/sec, but even that could cause
a lot of bounce.

doubt that just before landing on an unknown surface with unknown
properties and the desire to analyse it chemically you want to
contaminate it with rocket engine exhaust... I trust the scientist
and engineers of Rosetta/Philae much better understood the problem
as I do.

Regards,

Jens

--
Mike Dworetsky

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