The Mars Pathfinder mission was widely proclaimed as "flawless" in the early days after its July 4th, 1997 landing on the Martian surface. Successes included its unconventional "landing" -- bouncing onto the Martian surface surrounded by airbags, deploying the Sojourner rover, and gathering and transmitting voluminous data back to Earth, including the panoramic pictures that were such a hit on the Web. But a few days into the mission, not long after Pathfinder started gathering meteorological data, the spacecraft began experiencing total system resets, each resulting in losses of data. The press reported these failures in terms such as "software glitches" and "the computer was trying to do too many things at once".
For no apparent reason, Pathfinder’s onboard computer would spontaneously reset itself. This happened about a half dozen times in the first few weeks after the landing. Contrary to press reports at the time, no data was lost, but data collection was delayed by a day every time Pathfinder reset itself (Rothwell).
“Reports of the problem in the popular press were generally incoherent, and in some cases wildly wrong,” according to David Wilner, chief technical officer of Wind River Systems of Alameda, Calif. In a Dec. 3, 1997, keynote address to the 18th IEEE Real-Time Systems Symposium in San Francisco, Wilner explained that the media couldn’t grasp the complexity of the problem – much less the answer – “because of the difficulty of explaining the issues to non-engineers.” However, because he was speaking to real engineers Dec. 3, Wilner detailed precisely what went wrong last summer, why it went wrong – and how it got fixed. Wilner was uniquely qualified to speak on the subject, because Wind River makes the RTOS (real-time operating system) – VxWorks – which was embedded in Pathfinder’s onboard computer (Smith, 1997).
