Counting Down to Blast-Off: An "A" Student Who's Proud to be on the "B" Team
Jeannette Dehmer, 21, is shooting to become an astronaut some day, and she's already got one foot on the launch pad!
Date: 12/1/2003 8:00:00 AMHer California co-op has been a dream come true for Jeannette Dehmer of Western Hills.
By: Mary Reilly
Phone: (513) 556-1824
Photos By: Andrew Higley and courtesy of NASA
Come spring 2004, the work done by the UC aerospace engineering junior throughout this year will help launch a historic space mission – called Gravity Probe B – that’s been more than 40 years in the making.
It’s all thanks to a special year-long work experience Jeannette designed as part of her college cooperative-education requirement. Co-op, or cooperative education, refers to the practice in which students alternate time spent in the classroom with paid, professional work related to their major. It had its global start at UC in 1906.
Since April 2003, Jeannette has been co-opping with Lockheed Martin Space Systems Company in Sunnyvale, California, helping to prepare a NASA/Stanford University satellite for its coming lift-off. It’s a project that’s been long in the making since the idea for this probe and the scientific experiment it will carry were first proposed in 1960. Lockheed Martin has been working on the project for just shy of 20 years.
The satellite, known as Gravity Probe B, will remain in space for about 18 months and will use the world’s most precise gyroscopes to test two important aspects of Albert Einstein’s General Theory of Relativity that deals with the curvature of the time/space continuum and Earth’s effect on the continuum. Basically, Einstein predicted that space and time are distorted by the presence of massive objects, like planets. The GP-B mission will shape our understanding of Einstein’s theory and will help solidify our understanding of topics like black holes and the evolution of the universe. If the results of the relativity probe are not consistent with Einstein’s theory, it would significantly change the scientific perception of the universe’s structure and the motion of matter. If you’re really into it, look below for more links. For the rest of us, it pretty much suffices to know that the project is one of the most sophisticated physical experiments ever attempted, and it’s making scientific history.
As a member of the Gravity Probe B team, Jeannette is also making some significant history of her own. She’s one of only a very few students to ever help launch a satellite at Lockheed Martin, and she’s the first UC student in almost 100 years to spend an entire academic year (three quarters straight) on co-op! Normally, students alternate one quarter (three months) in class with three months on the job. Jeannette says she petitioned UC to remain on the job because she wants to “finish the project. I’ve fallen in love with this co-op job, and it’s hard to let go. Honestly, I could talk about it forever, and I very often do!”
For Jeannette, the whole experience is a high -- high-profile, high-stakes, high-flying and yes, sometimes high-anxiety. “I wanted to do this! I learned about the probe my first day at work, and by the third day, I was in the hi-bay actually staring at it. I was hired into a group that worked one test for the spacecraft and was supposed to move on to other things at its completion. By that time, however, I wasn’t ready to move on, so I asked to join the Gravity Probe B team, I thought, ‘What’s the worst that can happen? They say, ‘No.’”
Obviously, that didn’t happen. And it’s been good for both Jeannette and the project. Gravity Probe B deputy program manager, Jeff Vanden Beukel, who himself started with Lockheed Martin as a student worker, says it’s rare to have a student involved in getting a project like this literally off the ground. “She’s unique in that she’s involved in the launch phase of this project. We have a small handful of students from across the country work with us every year, but normally, they’re involved in the design phase,” says Jeff, who adds he wasn’t surprised Jeannette sought out a position on the launch team. “Everyone who works with her is very impressed with her initiative. She doesn’t say, ‘I don’t have the experience.’ Jeannette dives right in and does any job regardless of whether it’s her specialty or not.”
Says Jeannette, “The excitement of it all is incredible. There have only been about 200 people all told who have worked on this project at Lockheed Martin over the last 20 years. They’ve been working on this almost as long as I’ve been alive, and yet, they’re trusting me with so much.”
While Stanford and NASA have designed the experiment within the satellite, Lockheed Martin has been designing and testing the satellite itself. Making sure the vehicle is ready to launch is where Jeannette comes in. “All satellites are different,” she explains. “Each one is built for a different purpose, so each one is a unique challenge. And, with each one, you’re not going to get another shot at it, so everything has to be rigorously prepared, tested and retested for the big day.”
Jeannette’s been running a variety of checks, including what’s called the “thermal vacuum test.” In this procedure, the 21-foot-long satellite is placed within a sealed chamber. The air is pumped out, thus simulating the vacuum of space. Lamps above the surface of the satellite mimic the heat and radiation of the sun to assess the craft’s ability to withstand the temperature extremes Gravity Probe B will encounter in orbit.
Jeannette was monitoring the thermal vacuum tests for about a month back in the spring, and she admits to being nervous at being given so much responsibility. “I was both happy at being treated like a regular employee, but I was also happy that there was another thermal engineer on hand,” she recalls.
Another test that Jeannette helped to run involved the craft’s propellant. Basically, Gravity Probe B will move in space under power provided by helium. Liquid helium will be stored on the craft in a container called the “dewar” which Jeannette likens to a thermos. Some of this liquid helium will be evaporated as a gas that is then vented through the 16 thrusters, which will, in turn, then power the vehicle’s movement. Says Jeannette, “It’s like how an air-filled balloon is propelled when you let go of the balloon neck, and the release of air sends the balloon airborne.”
Jeannette has been has been performing flow-rate testing of the spacecraft’s 16 thrusters. “It all takes much longer than it probably sounds,” she adds. “It takes time to set up the equipment for each thruster, run the test and log the results. Because of the effects of gravity, we have to test the thrusters while they’re in a horizontal configuration. Therefore, we had to tilt the vehicle into a vertical position to test the last four.”
In all of the tests, Jeannette reports that nothing went terribly wrong. “We found that some of the thermostats weren’t hooked up correctly to the heater tape (through which current passes to heat components of the spacecraft when it’s not exposed to the sun’s heat). We also found some contamination of one of the thrusters, and that was cleaned up.”
Because the satellite’s launch is approaching, the vehicle was moved in July to California’s Vandenberg Air Force Base. That’s where it’s slated to launch in spring 2004 aboard a Boeing Delta II rocket. Once in space, it will settle into an almost perfect circular polar orbit around the earth.
Jeannette helped with the loading, transport and unloading of the craft, all of which is a very delicate process: “You have to be so careful when you’re putting it on the truck. We’re constantly testing the vibrations and how those are affecting the craft. It took an entire day just to load the probe on a truck….”
While it’s been hard to be away from home for so long – this is Jeannette’s first extended time away from her family – it’s been worth it all the way around. Jeannette admits, “My mother doesn’t understand what I do, but she knows that I’m really excited about it. And that makes her happy too, and my dad is good about following the online updates about the project so when I call home, he’ll ask me to fill him in on the details.”
Links for more info on Gravity Probe B: