Jet Propulsion Laboratories (JPL) is a NASA center owned and operated by the California Institute of Technology in Pasadena, CA. JPL was started in 1936 by Cal Tech graduate students who wanted to launch rockets. At the time, rockets were an “explosive” business, so their professor Dr. von Karman allowed them to do their research, just as long as they found a location away from Cal Tech. This group had caused nothing but trouble on campus and was known as the “suicide squad” due to the explosive nature of their many failures. Therefore, the group of grad students moved out to the desert, soon finding great success on the side of mountain. Over time, this mountain side became the proud home of JPL.
Initially JPL was primarily a military defense research center, but when Sputnik was launched, NASA looked to acquire the center. The director in that day, Dr. William Pickering, made the decision to entirely switch focuses from military defense to NASA. JPL provided immediate impact by constructing and running Explorer I, the United States’ first satellite. In the fifty years since, JPL has visited every planet in the solar system through robotic exploration, which has become their specialty. With flagship missions such as Cassini and Voyager still sending back data and exciting missions like Juno and Mars Science Laboratory on the horizon, JPL’s spot as a world leader of interplanetary exploration appears secure. The best part is, the NASA Acadamies for Space Exploration from Glenn and Ames Research Centers got to tour!
The first part of the day was a public tour, led by educational outreach specialists Allison and Cynthia. Our first stop was an auditorium with scale models of Cassini, Voyager, and Mars Reconnaissance Orbiter. Here, we learned about JPL and watched a movie about Mars Science Laboratory (MSL), scheduled to launch in November. Next, we went to the Mars Sandbox, a laboratory built for Mars Exploration Rover (MER) testing. The semi-Martian driving environment has been used to figure out solutions to driving issues with the MER rovers, Spirit and Opportunity, as well as MSL testing. MSL, which has undergone seven years of test model developments and testing, is twice as tall as the MER rovers, and is actually the size and weight of a small car. Its larger size makes for a better driving experience and easier navigation work for the ground team. The improvement is important because communications to Mars are subject to anywhere from a 4 minute to a 22 minute delay depending on Mars’ position in the sky. This means that real time tracking is not possible and ground crews must map out the path of the rover from the ground well in advance. MSL also has an improved wheel design compared to MER with holes for sand and great shock absorption. Additionally, the power system of MSL has been upgraded from solar to radioisotope thermal generator (RTG). The RTG, fueled by almost eight pounds of plutonium-238, allows MSL to work at latitudes sixty degrees from the equator and even work at night. MSL has scientific goals of finding and characterizing pockets of organic material on Mars, and it has a two-year minimum window to get that done. The RTG will last for fourteen years, but thermal cycling is expected to cause a mechanical failure before then.
The final stop on the public tour was Mission Control, where JPL controls the Deep Space Network’s three hubs in Goldstone, CA; Canberra, Australia; and Madrid, Spain. After the public tour was over, the Academy Alumni portion of the tour began. Sara Hatch, the trajectory lead for GRAIL, signed us all in and took us to lunch at one of the JPL cafeterias. Also joining us for lunch was Eric Timmons, an Academy alum who walked the group over to the ATHLETE facility. ATHLETE (All-Terrain Hex-Limbed Extraterrestrial Explorer) is a six-legged robot that is designed to provide mobility on the moon. Designed to work in tandem with the Houston-designed lunar vehicles in a “Winnebagos and Jeeps” global-scale exploration concept, the ATHLETE stands thirteen feet tall, weighs 4000 pounds, and can support a 500 kilogram payload while moving in seven degrees of freedom. The ATHLETE project is now in half-scale testing, in fact the current model was built two summers ago in just 46 days! The reason for the large-scale testing is that simulations will not accurately predict dirty surface contact forces, slip, soil mechanics, and ranging sensor data. The mock-up also allows full testing of the software. Built off of the MER rover software, ATHLETE’s control system can be piloted by a Wii Nunchuk or a Kinect-controlled robonaut.
From our spot by a movie-set asteroid, Academy alum Emily Eelkema picked the Academites up and took us to the Mars Yard, where Brian Matthews from the Mars Mobility team showed how they test the rovers. At the Mars Yard, they have special platforms for each rover to test at Mars weight. The important factor here is not actually the weight but the ground pressure, which is the load of each wheel divided by the square feet of wheel touching the ground. Interestingly enough, the ground pressure of the Mars rovers is one fourth that of a human walking on the beach. These platforms usually only carry the drive-train system and differential GPS to precisely measure location. The MSL mobility system is called Scarecrow and can be piloted by iPhone. Brian also showed us Axel, a new two-wheel vehicle meant for extreme terrain. These vehicles are tested in the outdoor Mars Yard, which includes variations in slopes, rock type and shape, as well as a lot of fine sand. After trying to climb up the wooden rock wall, the Academies left with Nora Alonge, another Academy alum, who took the group to the gift shop and a now-empty 100,000 class high bay clean room that used to hold MSL.
After some pictures and final questions the Academy left JPL impressed with all they had witnessed and learned.