MIT-designed satellite to be tested in space
One day in 2001, MIT student Simon Nolet was walking down one of the school's long corridors when he bumped into professor David Miller of the department of aeronautics and astronautics. The chance meeting, he says, turned out to be a lucky break.
A few months later he was floating weightlessly in NASA's zero-gravity test plane, taking part in experiments that could shape some of the space agency's most important future missions.
Now, after two years of hard work and three years of delays, it's about to get exciting again. Next week the first of three satellites designed by students and faculty at MIT's Space Sciences Lab will start a series of experiments aboard the International Space Station.
Nolet, accompanied by Miller and MIT postdoctorate student Alvar Saenz-Otero, who has been working on the project since 1999, will be sitting inside Mission Control in Houston watching the action and interacting with the astronauts as they carry out the tests.
That's just the first step in what is planned as a years-long series of experiments that could develop basic software necessary for a wide variety of NASA projects. These include everything from assembling huge rockets in orbit to bringing back samples from Mars to test for signs of past life and, ultimately, to the creation of the largest telescope ever designed, an orbiting constellation of satellites spanning miles of space that could be powerful enough to take pictures of Earth-sized planets around other stars and even detect evidence of life there.
Not bad for what began as an undergraduate class project, which about 30 students have worked on over the years.
The project is called SPHERES, for Synchronized Position Hold Engage Re-orient Experimental Satellites. In plain English, they're teaching satellites how to fly together in precise, tight formation without any outside help. All of the intelligence has to be built into each of what, in their test form, is a set of colorful satellites each no bigger than a volleyball.
Each satellite contains gyroscopes to help it keep its orientation, ultrasonic detectors to pick up signals sent from little beacons attached to the station walls, computers to figure out where it is and which way it's pointing, and little canisters of carbon dioxide -- the kind that powers paintball guns -- to provide little puffs of gas that push the satellite one way or the other.
Even the bright colors of the satellites have a serious purpose: To make it easier to tell which is which during the formation-flying tests, which are expected to begin later this year.
For now there's just a single satellite aboard the space station, delivered two weeks ago by a Russion supply vessel. Two more are supposed to be carried up on the next two shuttle missions, scheduled for July and November.
But members of the MIT team learned the hard way not to hold their breath: The satellites have been ready to fly since just before the Columbia space shuttle accident resulted in a grounding of the shuttle fleet in February 2003. They had been scheduled for the next flight and have been waiting ever since. Most of the students who first worked on it have graduated and moved on to other things.
The first tests will explore the single satellite's ability to hold its position and then to rendezvous with beacons attached to the station walls with Velcro. The simple ability for one satellite to find its way autonomously to a specified point will be important in developing automated supply vessels and for rockets that could be assembled in orbit from pieces launched separately from earth.
Testing the complex computer systems in the real weightless -- but safe -- environment of the space station is an ideal way to work out the bugs before trying it out on real missions. Aero-astro professor Jonathan How, who also works on the project, says, ''If you're going to build a mission that requires rendezvous and docking, or formation flying, do you want to be the first one to use the software?"
The whole experience has been both thrilling and sobering for the students involved.
From the first tests aboard NASA's zero-gravity plane, says Saenz-Otero, ''It was fun, it was exhilarating. But starting with the flights when the four of us graduate students were getting the flight hardware developed and tested and demonstrated, it became a real job."
''Now I'm extremely excited that we're going to fly on the station," he said, ''but because it is work, it is real research, I'm also extremely nervous."
