[meteorite-list] NEAR Mission Extended Through February

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:41:11 2004
Message-ID: <200102222139.NAA01021_at_zagami.jpl.nasa.gov>

http://near.jhuapl.edu/news/flash/01feb22_1.html

          NEAR Extended Through February
          February 22, 2001

          NASA has given the go-ahead for the NEAR mission to
          collect data from the surface of Eros through Feb. 28,
          tacking four days onto an extension granted after the
          NEAR Shoemaker spacecraft's historic landing on the
          asteroid last week.

          The extension gives NEAR Shoemaker's gamma-ray
          spectrometer additional time to observe the elemental
          composition on and below Eros' surface, and the NEAR
          team at least two more opportunities to download this
          information through NASA's heavily used Deep Space
          Network of antennas.

          "This allows us to build a much better sample," says
          Jacob Trombka, of NASA's Goddard Space Flight Center,
          team leader for NEAR Shoemaker's X-ray/Gamma-ray
          Spectrometer. "The longer you accumulate data the more
          you can reduce the uncertainty of your results. When you
          look at a little bit of data you see clues, but when you
          get more data down you can be a bit more definitive."

          Touching down on Eros certainly hasn't kept NEAR
          Shoemaker from touching base with NEAR scientists. The
          spacecraft has returned readings from its magnetometer,
          and today mission team members are downloading the
          latest information from the gamma-ray spectrometer.

          The gamma-ray instrument can measure elemental
          composition to a depth of about 4 inches, and is much
          more sensitive on the surface than it was in orbit.
          Mission engineers fine-tuned the device last week to
          account for things it hadn't encountered in orbit; it
          operates at a higher temperature near the surface, for
          example, because it can no longer radiate heat into
          space.

          "We optimized the instrument for collecting science in
          its new environment," says John Goldsten, of the Johns
          Hopkins Applied Physics Laboratory (APL), lead engineer
          for the gamma-ray spectrometer. "Now that we know how
          well it's operating . . . the data we expect from here
          on is prime science data."

          While Trombka says they'll need months to interpret that
          data, it won't take nearly as long for mission
          scientists to get a clearer picture of the asteroid's
          magnetic properties - or lack thereof. NEAR Shoemaker's
          magnetometer found no evidence of magnetism at its
          landing site. Having returned data from the surface, the
          instrument's work is done and it has been turned off.

          "We already knew there was no global magnetic field, but
          measuring this close dramatically increased our ability
          to see if there was evidence for localized 'hot spots'
          on the surface," says Brian Anderson, magnetometer
          instrument scientist at APL. "The landing site shows no
          evidence for an intrinsic magnetic field. Since the
          sensor is only two meters above the surface this is a
          pretty definitive measurement."
Received on Thu 22 Feb 2001 04:39:02 PM PST