Historian’s Corner (Jan. 2010)
By: Ben Clark

    MGS is Dead.  Long Live MGS !

    Our Mars Global Surveyor (MGS) mission was born out of the ashes of a failed mission, the Mars Observer (M.O.) spacecraft, which went silent before reaching Mars in the summer of 1993.  M.O. was built by GE Astro Space and launched just as Martin Marietta bought that division from General Electric.  NASA and JPL quickly initiated studies seeking an affordable path forward.  Fortunately, some science instruments had significant residual hardware, and most of the spacecraft’s black boxes existed as flight spares.  Contracts were awarded to eight aerospace institutions, and from feasibility studies a low-cost approach was crafted.  All but two instruments would be hosted on a new spacecraft, using a streamlined “Faster, Better, Cheaper” approach.  We competed and we won.  MGS was to be developed on a fast-track and launched in October 1996, only slightly more than 3 years after the sudden demise of M.O. 
    Our team succeeded in designing a spacecraft which could squeeze out the maximum science by switching from an aluminum body to graphite-epoxy honeycomb structure; saving more mass  by accomplishing the first aerobraking at Mars; by instituting dual-mode propulsion; and by providing the capability to point simultaneously in three directions – solar arrays toward the sun, instruments looking down at Mars, and antenna tracking Earth.  The failure of a damper caused an excessive deployment force and structural damage to one of the solar wings after launch.  An innovative method of flying the mission saved the day.
    The magnetometer experiment not only verified that Mars’ magnetic field is virtually non-existent now, but revealed evidence for an ancient field stronger than ours, preserved as “magnetic stripes” in crustal rocks.  This discovery was announced by the Vice-President of the United States, Al Gore, in a press conference on Sept. 17, 1997, in which he stated "Mars Global Surveyor has been in orbit for only a few days, yet it already has returned an important discovery about the red planet.  This is another example of NASA's commitment to faster, better, cheaper Mars exploration . . .”
    The TES mapping spectrometer discovered deposits of crystalline hematite mineral in the plains of Meridiani.  As a result, the MER rover “Opportunity” was targeted to land there.  Only weeks after landing, Opportunity accomplished the primary goal of both rover missions.  A press conference held in March 2004 revealed to the world that the MGS/TES discovery was indeed the smoking gun evidence for pools of actual liquid H2O in previous times on Mars.  Amazingly, the gray hematite is in the form of trillions of BB-sized spheres, called “blueberries” by the rover team. 
    The MOC camera on MGS has discovered incredible amounts of layering in various terrains and thousands of “gullies” that occur on steep slopes of crater walls.  Overall, MOC returned more than 240,000 high-resolution images.
    The MOLA laser altimeter generated a topographic map of the surface of Mars more detailed, comprehensive, and accurate than for any other body in the solar system.  It aso discovered a huge expanse of the northern hemisphere that has some of the flattest terrain in the solar system.  Although still controversial, the possibility of a former martian ocean remains under study.  All four discoveries have great significance -- mind-bending new knowledge about the red planet. 
    Our first study of a successor to refly instruments from M.O. was led by Terry Gamber in my Advanced Missions group.  Ed Dorrah was the original Proposal Manager for the RFP, but Jim McAnally as head of Denver Space Systems designated Bud McAnally under Noel Hinners as the program manager, telling the JPL customer during Orals this program was so important that he was assigning his own brother to lead it.
    The heroes of MGS, of course, are not only all of the above and our JPL partners but most of all the several hundred employees in Denver who brought to the program intense levels of dedication and talent.  MGS was developed in a record 26 month time period, with miniscule growth in cost and mass.  Almost exactly 10 yrs after launch but far beyond its design life, MGS finally ceased operations in November 2006, due to a ground command error, after persistent decreases in budgets while attempting to maintain complex operations.  MGS discoveries are still being folded into the results of other Mars missions, providing a scientific legacy for decades to come.