U.S. Air Force DSX Mission To Carry Range of Experiments

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The U.S. Air Force plans to launch a set of space experiments geared toward objectives ranging from developing high-altitude radar satellites to protecting spacecraft from nuclear-blast radiation in 2009 aboard a single rocket, a service official said.

The Deployable Structures Experiment (DSX) package would be carried aloft by an Air Force Evolved Expendable Launch Vehicle equipped with a ring-shaped structure designed to carry secondary payloads. But unlike the experimental satellites slated for launch on the first flight of the secondary payload adapter ring, scheduled for 2006, the DSX payloads will remain attached to the structure in orbit.

Greg Spanjers, DSX project manager at the Air Force Research Laboratory’s Space Vehicles directorate at Kirtland Air Force Base, N.M., said the DSX payloads will rely on a central system for support functions such as power, avionics and data handling. The cost of the mission, including upgrades to the secondary payload adapter ring but not including launch vehicle integration, is about $75 million, he said.The laboratory hopes to piggyback the DSX package on a rocket launch whose primary payload is a Defense Meteorological Satellite Program spacecraft, Spanjers said. The launch scenario calls for the rocket to release the weather satellite in low Earth orbit and then restart its upper-stage engine to carry the DSX platform to a higher orbit, he said.

The DSX mission, which is ranked as the Air Force Research Laboratory’s top space experiment, and is ranked number two Air Force-wide for consideration for flight priority through the Defense Department’s annual Space Experiments Review Board process, is designed for medium Earth orbit, Spanjers said. Two of the experiments could have applications for a future constellation of radar satellites that would track moving targets on a global scale, he said.

The Pentagon hopes to deploy a low Earth orbiting version of the Space Based Radar starting around 2012. A medium Earth orbit system would provide global coverage with fewer satellites but is not feasible with current technology. One of the biggest barriers is the size of the radar antenna that would be required for the medium orbit system.

Accordingly, the DSX’s Large Deployed Structures experiment is intended to help engineers design payloads such as radar antennas and large structures for other types of satellites that can be folded into small packages for launch and unfurl to a much larger size once on orbit, Spanjers said. The System ID and Adaptive Control experiment, meanwhile, would aid in designing systems for controlling large deployable structures on orbit, he said.

The Defense Advanced Research Projects Agency’s Innovative Space Based Radar Technology program also is intended to develop the technology necessary for a medium Earth orbit radar system. However, DSX will take a broader look at structures that can be used for a variety of different types of satellites including, but not limited to, radar applications, Spanjers noted. The two projects share some common staff, which helps avoid duplication of effort, he said.

Another DSX experiment, called Radiation Belt Remediation, is intended to help the military devise methods for countering the effects of a nuclear blast in space. Although the final details have yet to be worked out, the experiment could feature a transmitter that uses radio waves to push charged particles out of the radiation belts, Spanjers said. This could help pave the way for systems that would push nuclear blast radiation away from satellites and into the atmosphere, where it could be safely absorbed, he said.

A fourth DSX experiment, dubbed the Space Weather Sensor Array, is intended to measure radiation at an altitude of 10,000 kilometers, Spanjers said. Spacecraft builders are interested in this orbital belt because it is known to have low levels of space radiation, which can be harmful to satellites, he said.

Finally, there is the Thin Film Photovoltaics experiment, which could lead to spacecraft solar cells that generate more power and are more radiation-tolerant than current systems, Spanjers said. Researchers previously have experimented with thin-film photovoltaic structures in space, but this will be the first using structures large enough to power a satellite on orbit, he said.

Several congressional aides said the DSX mission sounds like an innovative way to use the secondary payload adapter ring to carry out small space experiments. However, the Air Force Research Laboratory should continue to push ahead with the development of inexpensive small rockets that can carry experiments on a more frequent basis, the aides said.



http://www.isrjournal.com/story.php?F=375007
 
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