[meteorite-list] NEAR Shoemaker's Historic Landing on Eros Exceeds Science, Engineering Expectations

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:41:10 2004
Message-ID: <200102142112.NAA15392_at_zagami.jpl.nasa.gov>

http://near.jhuapl.edu/news/flash/01feb14_1.html

          NEAR Shoemaker's Historic Landing on Eros Exceeds
          Science, Engineering Expectations

          February 14, 2001

          The NEAR Shoemaker spacecraft's historic soft landing on
          asteroid 433 Eros Feb. 12 turned out to be a mission
          planner's dream - providing NEAR team members with more
          scientific and engineering information than they ever
          expected from the carefully designed series of descent
          maneuvers.

          "We put the first priority on getting high-resolution
          images of the surface and the second on putting the
          spacecraft down safely - and we got both," says NEAR
          Mission Director Dr. Robert Farquhar of the Johns
          Hopkins University Applied Physics Laboratory in Laurel,
          Md., which manages the Near Earth Asteroid Rendezvous
          (NEAR) mission for NASA. "This could not have worked out
          better."

          Two days after a set of five de-orbit and braking
          maneuvers brought it to the surface of Eros, NEAR
          Shoemaker is still communicating with the NEAR team at
          the Applied Physics Lab. The spacecraft gently touched
          down at 3:01:52 p.m. EST on Monday, ending a journey of
          more than 2 billion miles (3.2 billion kilometers) and a
          full year in orbit around the large space rock.

          Yesterday the NEAR mission operations team disabled a
          redundant engine firing that would have been activated
          had it been necessary to adjust the spacecraft's
          orientation in order to receive telemetry from it. But
          because NEAR Shoemaker landed with such a favorable
          orientation, and telemetry has already been received, it
          was no longer necessary to move the spacecraft from its
          resting place.

          Mission operators say the touchdown speed of less than 4
          miles per hour (between 1.5 and 1.8 meters per second)
          may have been one of the slowest planetary landings in
          history. They also have a better picture of what
          happened in the moments after the landing: What they
          originally thought was the spacecraft bouncing may have
          been little more than short hop or "jiggle" on the
          surface; the thrusters were still firing when the craft
          hit the surface, but cut off on impact; and NEAR
          Shoemaker came down only about 650 feet (200 meters)
          from the projected landing site.

          "It essentially confirmed that all the mathematical
          models we proposed for a controlled descent would work,"
          says Dr. Bobby Williams, NEAR navigation team leader at
          NASA's Jet Propulsion Laboratory. "You never know if
          they'll work until you test them, and this was like our
          laboratory. The spacecraft did what we expected it to
          do, and everyone's real happy about that."

          NEAR Shoemaker snapped 69 detailed pictures during the
          final three miles (five kilometers) of its descent, the
          highest resolution images ever obtained of an asteroid.
          The camera delivered clear pictures from as close as 394
          feet (120 meters) showing features as small as one
          centimeter across. The images also included several
          things that piqued the curiosity of NEAR scientists,
          such as fractured boulders, a football-field sized
          crater filled with dust, and a mysterious area where the
          surface appears to have collapsed.

          "These spectacular images have started to answer the
          many questions we had about Eros," says Dr. Joseph
          Veverka, NEAR imaging team leader from Cornell
          University in Ithaca, N.Y., "but they also revealed new
          mysteries that we will explore for years to come."

          NEAR Shoemaker launched on Feb. 17, 1996 - the first in
          NASA's Discovery Program of low-cost, scientifically
          focused planetary missions - and became the first
          spacecraft to orbit an asteroid on Feb. 14, 2000. The
          car-sized spacecraft gathered 10 times more data during
          its orbit than originally planned, and completed all the
          mission's science goals before Monday's controlled
          descent.

          "NEAR has raised the bar," says Dr. Stamatios M.
          Krimigis, head of the Applied Physics Laboratory's Space
          Department. "The Laboratory is very proud to manage such
          a successful mission and work with such a strong team of
          partners from industry, government and other
          universities. This team had no weak links - not only did
          we deliver a spacecraft in 26 months, we were ready to
          launch a month early, and that efficiency continued
          through five years of operations. This is what the
          Discovery Program is designed to do."
Received on Wed 14 Feb 2001 04:12:43 PM PST