[meteorite-list] Come ON, NASA!!!

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:52:23 2004
Message-ID: <200208271608.JAA28913_at_zagami.jpl.nasa.gov>

>
> Yes, we know that some maneuvers must be carried out "behind" the
> planet...this has been true of orbit insertion and de-orbit engine burns
> as far back as the Surveyor and Apollo missions.
> It's always been a mission risk without telemetry.
>
> But just think about it for a second... the Contour spacecraft was only
> 140 miles or so away from Earth when some catastrophic failure
> apparently occurred, and it was "out of radio contact with controllers".
>

It turns out that because CONTOUR was so close to Earth when it began its burn,
the spacecraft was "behind" the Earth in relation to the DSN antennas.
Also, note these comments by APL:

http://planetary.org/html/news/articlearchive/headlines/2002/contour_lookingahead.html

  The [APL] project leaders strongly defended one feature of the launch that has
  been the subject of some second-guessing - the fact that the booster rocket
  was fired at a point where the spacecraft could not be monitored by radar, and
  was not in radio contact with its handlers. The exact point where the burn
  was initiated, they said, was completely determined by the trajectory that
  the spacecraft would have to follow in order to encounter the two comets.
  As luck would have it, it was a location not covered by NASA's Deep Space Network,
  but this could not be helped. Furthermore, the fact that CONTOUR was not in
  radio contact with mission controllers at the time was no oversight:
  sending radio signals into the hot plume of the rocket is risky, and could
  damage the sensitive transmitters which would be needed later in the mission.

Anyway, even though the mission was not in radio contact, it was not totally
in the blind during the burn. A military satellite did observe the burn.
The satellite did confirm that the burn executed on time, and
at about 2 to 3 second before the burn was to end, it observed a bright flare.
Obviously, this data will be scrutinized by the investigation team to determine
the cause of the mishap.

Ron Baalke
Received on Tue 27 Aug 2002 12:08:44 PM PDT