re: Lunar Prospector Visibility

Philip Chien (
Sun, 4 Jan 1998 22:17:45 -0400

Brian Webb <> said:

>If the Lunar Prospector booster will climb nearly straight up and burn for
>13 minutes, it may be visible over a vast area.

Yes, with an 8:31 pm (local) launch time it should be fairly dark.  However
there is expected to be scattered clouds which may affect visibility.  Even
with the 'straight up' trajectory I still would not expect this to be as
visible from as far away as say a shuttle launch.  (BTW - the record for
line-of-sight distance visibility for a shuttle launch is about 1000 km. -
from Mir!)

>I believe that the booster is an Athena (fomerly "LMLV"). I saw an LMLV night
>launch last August from Vandenberg for several minutes after liftoff. All of
>the stages were very bright.

Same vehicle plus an additional Castor 120 stage.  The August 1997 launch
from Vandenberg was the Lewis spacecraft.  In that case the launch vehicle
worked, but the satellite died.  I saw the launch pad when I was out in
California in December and I've got to say that it really is a piece of
overkill.  Looks like somebody spent about 4 Billion on it.  ;-)

>It might be worth contacting Lockheed-Martin in Denver to get more info on
>trajectory, burn times, etc.

So what do you think I was doing on Sunday?  Attending a press conference
(he asks semi-sarcastically) ;-)

I may not have made it clear in my previous posting.  The Lunar Prospector
spacecraft is destined for a Lunar polar orbit.  The initial orbit will
have a period of 12 hours (hmm, what's GM for the moon and the SGP model
for the moon's gravity?  I wonder if I can adapt my satellite tracking
program for lunar orbits ...) and three maneuvers will be used to lower the
spacecraft in a 100 km. high 'mapping' orbit.  Mapping as in
spectrometer/reflectometers not mapping in terms of visual maps.

The Trans Lunar Injection module (TLI) which sends Lunar Prospector to the
moon clearly will not go in to orbit around the moon.  It will either end
up in a highly elliptical Earth orbit or may be nudged in to a solar orbit.

Philip Chien [M1959.05.31/31.145//]