On 23 September 1999, the Mars Climate Orbiter reached Mars and executed a 16 minute 23 second orbit insertion burn. It passed behind Mars at 09:06 UT, which was marked by the loss of signal. The ground tracking station should have reacquired the probe's signal at 09:27 UT, but no signal was ever received. Repeated efforts to establish contact failed and the mission was declared a loss. A review board determined that commands sent in English instead of metric units for a critical trajectory correction burn had resulted in the probe crashing onto the Martian surface. This was an embarrassing loss for the Jet Propulsion Laboratory, and of great concern because it had another probe already on its way to Mars. The Mars Polar Lander, with a pair of microprobes named Scott and Amundsen, entered the Martian atmosphere on 3 December 1999. The microprobes were to be released at high altitude, and were designed to penetrate the Martian surface and then begin to send back data. But the tracking station lost data from the Mars Polar Lander, and never received data from the microprobes. JPL spent a month trying to acquire a signal from the lander and the probes before declaring the mission a loss. A subsequent mission review determined that the lander's legs had issued spurious signals causing a premature shutdown of the descent engine, resulting in the destruction of the spacecraft. NASA and JPL had lost two space probes within the space of three months.
NASA Administrator Daniel S. Goldin appointed Thomas Young, a respected space industry executive, to form the Mars Program Independent Assessment Team (MPIAT), which would conduct a top-down review of the programs, management,
contractors and relevant issues and present its findings to NASA. In presenting the report in mid-March of 2000, Young emphasized the difficulty in successfully accomplishing such logistically and technologically challenging missions.
"One of the things we kept in mind during the course of our review was that in the conduct of space missions, you get only one strike, not three,'' Young explained. "Even if thousands of functions are carried out flawlessly, just one mistake can be catastrophic to a mission. Our review confirmed that mistakes can be prevented by applying experienced oversight, sufficient testing, and independent analysis.'' Key findings of the MPIAT report were:
• Mars exploration is an important national goal that should continue.
• Deep space exploration is inherently challenging, but the risks are manageable and acceptable.
• NASA, the Jet Propulsion Laboratory (JPL), and U.S. industry have the unique capabilities required to conduct successful planetary and deep space missions.
• NASA's "faster, better, cheaper'' approach, properly applied, should be continued as an effective means of guiding program implementation.
• There were significant flaws in the formulation and execution of the Mars program, but all of the problems uncovered were correctable in a timely manner to allow a comprehensive Mars exploration program to continue successfully.
That comprehensive Mars exploration program had been under carefully reexamination, reorganization and rescheduling for months. One mission proposal involved the landing and deployment of a bigger and more sophisticated rover that carried all the scientific instruments with it. It had been a concept first put forth by Steve Squyers years before and had evolved as it competed with other lander and orbiter proposals submitted to NASA. Not only would NASA approve the rover proposal, it would ask JPL for two of them.
Was this article helpful?