Early rover prototypes

However, the space agency decided to cancel the SLRV program, choosing instead to rely on the forthcoming Surveyor lander missions and photography from the Lunar Orbiter probes that were scheduled for their first mission in 1966. GM's SLRV was returned to JPL and went into storage, all but forgotten. More than ten years later, the SLRV was rediscovered and restored to functionality on a shoestring budget and the reborn project became a technology testbed. The first thing to be developed was a new vision system, employing stereo TV cameras to provide a 3-D view of terrain to monitors at a remote location. Next came Computer-Aided Remote Driving (CARD) and then "Semi-Autonomous Navigation." Several years of development work went into these new rover technologies and by 1986 the Blue Rover, as it was nick-named, was gaining attention at JPL. It was successfully able to navigate the rugged Arroyo Seco, near JPL. Refinements in these and related rover systems would come into play with the announcement, at JPL in the late 1980s, of the Mars Rover Sample Return (MRSR) program. The centerpiece of the research at the time was to be the Pathfinder Planetary Rover Navigation Testbed vehicle, unofficially known as Robby. This vehicle would not be designed to explore Mars, but to prove the necessary hardware and technologies that would make such rovers successfully operate on Mars. JPL brought its best and brightest to the program, drafting in engineers who specialized in mechanical design, electrical power, thermal control, telecommunications and electronics, as well as software programmers and even orbital mechanics planners. All this was being done under the umbrella of the bigger MRSR program. The purpose behind this mission was to send a lander and rover to Mars. The rover would be deployed to collect samples, selecting the most interesting samples after returning them to the lander and loading them into a return launcher that would bring them back to Earth for study.

The Blue Rover and Robby were testbeds for evolving technologies, but their size and weight precluded anything of similar specification actually being launched to Mars. Much smaller rovers would have to be developed and behind the scenes, this was already happening. A rover is nothing if it does not have mobility, and with a much smaller vehicle size, the suspension design was quite a challenge. Dr. Bekker had done much pioneering work in this respect, but his vehicle designs were always quite large. One of JPL's design engineers, Don Bickler, devoted years to developing and refining the necessary suspension design that would permit a rover to surmount virtually all potential obstacles while remaining stable. Bickler did much of this development on his own time, after work, building prototype micro rovers in his garage. He made a discovery with respect to six-wheeled vehicle suspension design, and with refinement, this became identified as the rocker-bogie. The first of the prototype rovers employing the rocker-bogie suspension design was named Rocky. It was the first of a generation of rovers that would be built at JPL to validate this suspension design, as well as navigation capability, vision systems and the other technologies being explored. This suspension design was eventually patented by JPL, and would be employed on its future Martian rovers.

The Mars Rover Sample Return program proved too complex and expensive to continue and it was cancelled. Instead, there was a new push within NASA for smaller interplanetary and deep space exploration missions with smaller, fixed budgets, as part of the Discovery Program. In 1990, Dr. Wesley Huntress, director of NASA's Solar System Exploration Division (SSED), asked a scientific working group to propose specific missions that would fit the Discovery profile, as put forth by the Jet Propulsion Laboratory and the Johns Hopkins University Applied Physics Laboratory (JHU/APL). Among the first proposals was the Near-Earth Asteroid Rendezvous (NEAR), proposed by JHU/APL themselves. Also under consideration was JPL's Mars Environmental SURvey (MESUR) Pathfinder. Both missions received Congressional support and both would eventually be funded, along with follow-up missions in the Discovery manifest.

The Mars exploration and scientific community is an extremely diverse one, spreading from NASA Headquarters itself in Washington, D.C. to various NASA centers and affiliated universities across the United States, and including JPL in Pasadena, California. NASA's approach to program suggestion, consideration, evaluation and finally approval, is an arduous one - some would say positively

Darwinian. It is a process of evolution, adaptation and survival and even then, there is no guarantee that the program will see launch day. Nevertheless, with the support of Congress and under the direction of JPL, work began in earnest on developing new Martian missions under the Discovery umbrella.

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