 NASA E.T. Lab |
 Caleb Strothers logging data from one of the rasp tests. |
Maranatha High School
Pasadena, CA
Graduating Year: 2007
This summer I have had the privilege of working at the Jet Propulsion
Laboratory in Pasadena, California, part of NASA. There, I worked in the
Extraterrestrial Materials Simulation Lab. This lab is designed to
create and test reproducible materials that mimic those on other planets
and moons. Essentially, it is a place to manufacture, well, dirt. This
summer, I have spent my time testing the effects of various equipment
on a simulated Martian soil. On this soil I have been testing the
effects of a drill for the next Mars vehicle, Phoenix, scheduled to
launch Spring 2007.Phoenix will be landing at one of the polar caps on Mars and its chief duty is to find ice, sample and analyze it. The problem is that, as a result of Mars' pressure and temperature, there is no liquid stage for water. When drilled into, some of the ice melts and transforms immediately into vapor. This is called sublimation. Phoenix cannot analyze gas so it is important to know how much water is lost in the drilling process. The ice after all is what holds the data scientists are looking for.
To simulate these conditions, I use cylindrical sampling containers that are about the same size and shape as hockey pucks. I fill these pucks with a material that is part water and freeze them in the -80 degrees Celsius freezers and let them sit for a couple hours. Then I take one out, chip off a piece, weigh it and stick it in the oven. Next I place what is essentially a wire thermometer in the puck and set the puck in a drilling machine. I say drill but it is really just a spiky piece of metal designed to scrape off material that we call a rasp. This machine is inside a vacuum chamber that I pump down to the pressure of Mars, which is many times less than that on earth. I then rasp off material from the still frozen puck, weigh it and put it in the oven also. A couple hours later I return to the oven take out the pre-rasp chunk and the rasped sample and weigh them again. Based on these measurements, I can determine what the percent water was in the pre-rasp sample and what it was in the rasped sample and compare the two.
It is very exciting to have the chance to work at an internationally known science facility and to help with things like a vehicle going to another planet. I think it is also very cool that I can work with dry ice and liquid nitrogen and vacuum chambers all day, a teenager's dream. Not many other high schoolers can say their job is out of this world!