[meteorite-list] NEAR Shoemaker's Silent Treatment

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:53:34 2004
Message-ID: <200212121624.IAA20434_at_zagami.jpl.nasa.gov>

NEAR Mission News

Dec. 12, 2002

http://near.jhuapl.edu

NEAR Shoemaker's Silent Treatment

Even though the NEAR Shoemaker spacecraft had exceeded every mission
expectation, the NEAR team asked for one more spectacular addition to
the mission's legacy: Talk to us one more time.

But NEAR Shoemaker - the first spacecraft to orbit, land on and send
data from the surface of an asteroid - kept mum despite a 12-hour effort to
communicate with it.

"The exercise was an experiment to see how robust the spacecraft and
its instrumentation and subsystems were given the extremely cold
temperature it has been in for nearly two years," says NEAR Mission
Director Robert Farquhar. "We didn't hold out much hope but we had an
opportunity to establish an important data point and didn't want to lose
the chance."

The attempt was initiated at 2:40 p.m. EST, Tuesday, Dec. 10, by the
NEAR mission operations team at the Johns Hopkins University Applied Physics
Laboratory, which managed the mission and built the spacecraft, and the
Deep Space Network team, which supported the effort through their 70-meter
Goldstone antenna. With asteroid Eros only about 86 million miles (138
million kilometers) from Earth - less than half the distance it was
when NEAR Shoemaker landed on it in February 2001 - and NEAR Shoemaker's
solar panels basking in sunlight for the past three months, the timing was
ideal.

First, operators listened passively for a carrier signal from the
spacecraft. Then they sent commands asking NEAR Shoemaker to transmit
data indicating it had survived the last 22 months on the asteroid's
surface, despite temperatures that dipped as low as minus 170 degrees Celsius
(-274 degrees Fahrenheit) and long periods of total darkness.

Not knowing which of NEAR Shoemaker's two computers had access to its
transmitter, mission operators tried sending commands to one, then the
other. Then they waited - in vain - to receive data.

Farquhar says the team will probably never know precisely why NEAR
Shoemaker did not respond and they do not expect to try again.

The first in NASA's Discovery Program of low-cost, scientifically
focused planetary missions, NEAR conducted a yearlong orbit study of asteroid
433 Eros. The Johns Hopkins University Applied Physics Laboratory in
Laurel, Md., designed and built the NEAR Shoemaker spacecraft and managed the
NEAR mission for NASA. For more information and images visit the NEAR Web
site at

http://near.jhuapl.edu.

For more on NASA's Discovery Program visit

http://discovery.nasa.gov.
Received on Thu 12 Dec 2002 11:24:15 AM PST