[meteorite-list] More on the NEAR landing

From: Matson, Robert <ROBERT.D.MATSON_at_meteoritecentral.com>
Date: Thu Apr 22 09:41:10 2004
Message-ID: <AF564D2B9D91D411B9FE00508BF1C8692C5F1E_at_US-Torrance.mail.saic.com>

Hi Ron,

> As mentioned at the press conference, there was always the
> possibility of a small bounce. There was never a possbility
> of the spacecraft bouncing off the asteroid, as someone
> had suggested earlier.

If anybody suggested that, it had to have been entirely
tongue-in-cheek. (Either that, or a misunderstanding about
what is meant by "bounce off", e.g. "a rubber ball bounces
off the floor" does not mean it leaves earth-orbit.) Anyone
with an even rudimentary understanding of orbital mechanics
recognizes that an object in freefall (let alone decelerating)
toward a larger object has zero chance of achieving escape
velocity following impact -- no matter how elastic the
collision. The only exception would be in the case of a
significant non-gravitational force (e.g. an explosion).
That, or if NEAR (or Eros) was made out of Flubber. ;-)

> Even though the mission has been extended 10 days, I wish
> they would keep the mission going as ong as the spacecraft is alive.
> As long as we're getting a signal from the spacecraft, this acts
> as a beacon, and we can really nail down the rotation rate of
> the asteroid.

I quite agree. With enough imagination, other experiments
might be devised to take advantage of this unexpected
asset. It would be a pity to abandon it unless the quality
of any additional science data is out of proportion with
the cost of maintaining communication (and taking time
away from other programs that use the Deep Space Tracking
Network).

Cheers,
Rob
Received on Wed 14 Feb 2001 07:32:57 PM PST