[meteorite-list] CONTOUR Contact Attempts Continue

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:52:16 2004
Message-ID: <200208160354.UAA28815_at_zagami.jpl.nasa.gov>

http://www.contour2002.org/news.php?id=18

CONTOUR Contact Attempts Continue
August 15, 2002
7:30 PM EDT

Mission operators continue to scan the skies for the CONTOUR
spacecraft, working through a list of strategies for
re-establishing contact with the solar-powered probe through
NASA's Deep Space Network (DSN).

"We're still trying to get a telemetry link," says CONTOUR
Mission Director Dr. Robert Farquhar, of the Johns Hopkins
University Applied Physics Laboratory, Laurel, Md. "We're
trying to send commands to spacecraft to switch between its
two transmitters and use different on-board antennas, in case
they turned off for some reason. But we really won't know what
happened until we contact it."

CONTOUR's STAR 30 solid-propellant rocket motor was programmed
to ignite at 4:49 a.m. EDT and deliver a 1,920 meter-per-second
boost that would send CONTOUR out of Earth's orbit and onto a
path that would eventually take it past two comets. At about
140 miles (225 kilometers) above the Indian Ocean, the spacecraft
was too low for DSN antennas to track it at the scheduled time
of the burn. NASA's Jet Propulsion Laboratory, Pasadena, Calif,
operates the DSN.

The CONTOUR mission operations team at the Johns Hopkins
University Applied Physics Laboratory expected to regain contact
at approximately 5:35 a.m. EDT to confirm the burn. When no signal
was received, the team immediately began working through backup
plans to re-establish contact, searching along the predicted
trajectories for a successful burn.

"We're looking at the nominal path, as if the burn occurred,"
Farquhar says. "We're working on the assumption that the motor
fired, and the team is putting its priority there."

CONTOUR's on-board computer is also carrying a command that, about
24 hours after the scheduled burn time, would turn the craft about
40 degrees and perhaps improve its antennas' fix on Earth. Farquhar
adds that without knowing CONTOUR's status, it is difficult to know
what commands it can, or did, execute. Still, he says, "we're
cautiously optimistic that we will find the spacecraft."

CONTOUR, a Discovery-class mission to explore the nucleus of comets,
was built and managed by the John Hopkins Laboratory Applied
Physics Laboratory, Laurel, Md., for NASA. Additional information
about CONTOUR is available on the Internet at:

http://www.contour2002.org.
Received on Thu 15 Aug 2002 11:54:09 PM PDT