By Frank D. Roylance , frank.roylance@baltsun.com|September 07, 2009
Darren Hitt's work really is rocket science. But forget about blinding flames and thundering engines generating millions of pounds of thrust.
The Baltimore native is working on propulsion systems built on silicon chips that would generate thrust in tiny puffs of steam. They're the kind of thrusters NASA will need to maneuver a new fleet of 10- or 20-pound "nanosatellites" - spacecraft no bigger than beach balls.
His research team at the University of Vermont's School of Engineering in Burlington just received a $750,000 grant to advance development of the technology. He is partnering with engineers at NASA's Goddard Space Flight Center in Greenbelt.
Hitt calls the term nanosatellites "ridiculous," because "nano" refers to scales measured in billionths of a meter. The mini-satellites NASA wants to build are a billion times bigger.
But they're far smaller - and cheaper - than the hulking spy satellites and communications "birds" whose weights are measured in tons.
"One that was being developed ... at NASA Houston was an autonomous camera," he said. "It would be released outside the shuttle or other spacecraft to inspect for damage, rather than one attached to the robotic arm on the shuttle or space station. It's a free-floating satellite that can maneuver around the spacecraft and take pictures."
Hitt, who grew up in Essex and Parkville and got his degrees from University of Maryland, Baltimore County and the Johns Hopkins University, worked for several years on two Air Force grants to develop miniature thrusters for such spacecraft.
The military, he said, is interested in lofting "sensor nets" - swarms of tens or hundreds of little satellites to provide continuous battlefield awareness.
"Instead of one satellite circling the globe every 80 minutes, you would have 'distributed architecture' missions. ... So suddenly you have a bunch of eyes in the sky." If some fail, there are plenty more to fill in and carry on the mission.
Hitt says his team is getting "very close" to a prototype thruster design.
Conventional rocket engines get their power by combining a fuel with an "oxidizer," which provides the oxygen unavailable in space. A spark produces the combustion.
Once in orbit, however, the small thrusters needed for aiming or maneuvering a satellite have typically relied on simpler systems. They pump liquid hydrazine across a catalytic material that chemically changes the fuel to produce a gas, and thrust.
