Advanced Solar Thermal Propulsion System Intended To Increase Orbital Control for Small Satellites


SpaceDev has been picked by the U.S. Defense Advanced Research Projects Agency (DARPA) to lead the development of a solar thermal propulsion engine and tiny spacecraft bus for the High Delta-V Experiment (HiDVE) satellite program.

Under an initial six-month contract worth $3.75 million, the Poway, Calif.-based space technology company and its larger teammates General Atomics and BAE Systems

are to complete the initial design for a 15-kilogram nanosatellite platform

equipped with a solar thermal propulsion engine that would enable the spacecraft to raise and lower its orbit and change orbital planes.

Mark Sirangelo, SpaceDev’s chairman and chief executive, said he expects to “complete a full-on system design” under the initial six-month contract, which was signed Sept. 28. If all goes well and DARPA provides follow-on funding, SpaceDev would expect to start fabricating ground test equipment within a year. The envisioned satellite could be ready for its flight demonstration before the end of 2010, Sirangelo said.

was one of about a half-dozen teams to bid for the work.

According to a written overview posted on the DARPA Tactical Technology Office

Web site, the goal of the HiDVE program is to design, develop and demonstrate a small solar thermal propulsion system capable producing a substantial change in velocity, or delta-V, for small satellites.

“A HiDVE system will provide small satellites, historically constructed without propulsive capability, with substantial delta-V affording nanosatellites increased orbital range, in terms of both attitude and plane,” according to DARPA. “In addition, this flexibility will be essential to future nanosatellite mission designers and operators, who will be able to take advantage of less-than-optimal insertion orbits and later move to an intended mission orbit.”

Solar electric propulsion systems, such as the ion drive engine that powered NASA’s Deep Space 1 craft for more than three years and currently is being used

for the U.S. space agency’s Dawn mission, rely on an on-board electrical generator to convert solar energy into electricity that reacts with a propellant to create thrust.

Solar thermal propulsion systems eliminate the need for an electrical generator and use the heat of the sun to warm a propellant and channel the heated gas through a rocket nozzle to create thrust.

According to DARPA, the key enabling technologies for such a system are very high-temperature materials and innovative solar receiver and concentrator designs.

declined to describe the technical approach SpaceDev intends to take, or even identify the propellant the system would use. “I can’t tell you that at this juncture. Some of this is classified,” he said.

“It’s a proprietary system we’ve been developing,” he said. “What’s unique about this is not only the technology, but also the size of it.”

program manager for HiDVE is U.S. Air Force Lt. Col. Fred Kennedy, who served as program manager for the recently completed Orbital Express satellite-fueling demonstration.

said San Diego-based General Atomics brings to the SpaceDev team a background in engine design. BAE Systems’

expertise, he said, would come into play down the road, providing the systems management know how to turn the DARPA HiDVE concept into “a network of satellites.”