DARPA hands over space tracking telescope to the Air Force


WASHINGTON — The U.S. Defense Advanced Research Projects Agency has transferred operations of a telescope designed to track objects in Earth orbit to the U.S. Air Force, ahead of a move of that telescope to Australia.

In a ceremony in New Mexico Oct. 18, DARPA formally handed over operations of the Space Surveillance Telescope (SST) to Air Force Space Command. The transfer comes after several years of testing and operations of the 3.5-meter telescope by DARPA on a mountaintop at the White Sands Missile Range.

DARPA developed the telescope to be able to scan large regions of the sky, particularly in the geostationary arc. “SST is focused on tracking and identifying debris and satellites about 36,000 kilometers the Earth,” said Lindsay Millard, the telescope’s program manager at DARPA, in a conference call with reporters. “It can survey its entire GEO belt in its field of view, which is about one-quarter of the sky above New Mexico, multiple times in one night.”

Millard said DARPA developed several key technologies for the telescope. They include the telescope itself, with a steeply curved primary mirror to enable a large field of view. DARPA also developed the first curved charge-coupled device detector for the telescope’s camera, enabling it to take images from the telescope without distortion. A high-speed shutter allows it to take thousands of images a night.

Those capabilities allow SST to see more, and smaller, objects than existing systems, like the network of optical telescopes known as the Ground-based Electro-Optical Deep Space Surveillance (GEODSS). Millard declined to say how small of an object SST could detect in GEO, but said it can detect many more objects than other systems. “We can definitely see many more what we call ‘uncorrelated’ tracks than the Air Force can today,” she said, with “about an order of magnitude better performance” than GEODSS.

Millard pegged the cost of the SST program at $150 million, which covers the telescope itself, its original camera and a second, more sensitive camera. She declined to estimate how much it would cost to build a second, similar telescope, and said DARPA is currently not pursuing a next-generation telescope.

With the Air Force now responsible for the telescope, it will move ahead with plans first announced in a 2013 agreement with the Australian Ministry of Defence to move SST to Australia, helping fill a gap in coverage in the Southern Hemisphere.

“That’s kind of a second ‘DARPA-hard’ challenge that we have,” Millard said of moving the telescope. The Australian government will build a new dome for the telescope at the Harold E. Holt Naval Communication Station in Western Australia. Air Force Space Command will disassemble the telescope, ship it to the new site and assemble it there. The telescope should be operational there by 2020, she said.

The telescope has applications beyond tracking objects in Earth orbit. Millard noted that the telescope has also observed millions of asteroids, including discovering 3,600 new ones. “SST has become the most prolific tool for asteroid observations in the world,” she said. NASA is in discussions with Australian officials about continued access to the telescope for asteroid observations once it’s moved to Australia, she added.