Tuesday, February 19, 2013

Viking Mars Lander

Zero gravity and turning stomachs
by Richard P.

I was employed by Martin Marietta for 33 years and retired in 1992. I began my career in the manufacturing test department, later transferring to the research and development laboratory. There, I worked on a number of interesting programs, including Titan Ground Control Systems, the Skylab Space Station and the Viking Mars Lander, which was the most fun.

I was a member on the Viking Mars Lander Surface Sampler project team, testing prototypes. The robotic arm and collector were designed to scoop soil and rocks from the surface of Mars and deposit them into the sampler for analysis. Although the prototype worked well in the lab, we needed to know how it would react in the reduced gravity of Mars, which is about one-third less than that of Earth.

We needed to test the units in Martian gravity aboard an Air Force KC-135 Stratotanker, a zero gravity aircraft based at Wright-Patterson Air Force Base. We built several text fixtures with electrical controls, high-speed cameras and monitoring equipment. We installed the samplers to the fixtures, tested them and transported them to Wright-Patterson in Dayton, Ohio.

Before our test team would be allowed to fly in a KC-135, we were required to learn what to do should the aircraft lose pressure at high altitude. Training was at the Johnson Space Flight Center in Houston, Texas. Here, we were escorted into a large pressure chamber; the chamber was pressurized, then suddenly depressurized, simulating an aircraft losing pressure at 30,000 feet. During decompression, we were supposed to count backwards from one hundred by three. That was to show us the confusion one experiences in low oxygen. You become disoriented and react slowly if you should loose consciousness.

After training, we flew to Wright-Patterson to spend two weeks flight testing the units. We flew almost daily, testing the units at different levels of gravity. The pilot would fly the aircraft over a parabolic arc. (Flying into an arc, the aircraft climbs to 35,000 feet, then the pilot flies over a long, slow arc. He pulls out at the bottom of the dive, and starts back up again.) Once in “Martian” gravity, we ran tests for about 30 seconds, and accomplished much. When the aircraft pulled out the dive, we weighed twice our normal weight—two G’s, making movement difficult.

After completing testing for the day, the pilot flew several arcs at zero gravity. Everyone bounced around, floating from one end of the aircraft to the other and trying to catch water bobs that floated in the air. We would have enjoyed more! That being said, the flight crew had a sneaky sense of humor and didn’t bother telling us about not moving around during the two-G pullout. They thought it funny when we turned green! Moving your head back and forth was not recommended!

At the end of two weeks, we successfully completed all tests and were more than ready to come home. The flight crew gave us a farewell gathering, coffee and doughnuts, complete with a diploma inducting us into the “Society for Interplanetary Free Floaters.” They also made a film record of the flights that we brought back to Denver to be shown at staff meetings. There were more than a couple raised eyebrows during the zero gravity segments. However, management did give us a recognition diploma, conferring membership in the “Green Earthman Society.” The diploma gave us authority to tremble at the thought of another KC-135 flight, air sickness bags optional.

Society for Interplanetary Free Floaters