[meteorite-list] Minimum asteroid atmospheric entry velocity

From: Matson, Robert <ROBERT.D.MATSON_at_meteoritecentral.com>
Date: Thu Apr 22 09:52:13 2004
Message-ID: <AF564D2B9D91D411B9FE00508BF1C86901B4E2CB_at_US-Torrance.mail.saic.com>

Ron Baalke wrote:

"There are [different?] velocity measurements. There is velocity
relative to Earth prior to accerleration caused by Earth's gravity
(V infinity), and the velocity at atmospheric entry which include's
Earth's gravity field (V impact)."

Agreed. Obviously the velocity we're interested in is the velocity
at impact (or more accurately, the exoatmospheric velocity just
prior to entering the earth's atmosphere). The actual velocity at
impact could be under 200 mph for small meteorites-to-be.

> There is an asteroid on our Risk page, 1994 UG, with a V impact
> of 12.8 km/second, similar to St. Robert's:

I wrote:

>The minimum possible is around 11 km/sec.

Ron replied:

"That would be from an object that has [an] orbit very similar to
Earth's orbit, like asteroid 2000 SG344 which has a V impact of
11.23 km/second:

http://neo.jpl.nasa.gov/cgi-bin/db?name=2000+SG344

Unless there is some very recent radar data that indicates otherwise,
I have serious doubts that 2000 SG344 is an asteroid. After quite a
bit of photometric analysis in November of 2000, I'm fairly convinced
that 2000 SG344 is actually the Saturn V upper stage to Apollo 12
launched in 1969 (COSPAR 69099B).

Cheers,
Rob
Received on Tue 13 Aug 2002 05:13:43 PM PDT