WASHINGTON — The U.S. intelligence community — which builds and operates Earth observation and communications satellites for military or intelligence applications — is looking for solutions to the space debris problem.
The Intelligence Advanced Research Projects Activity (IARPA) in a request for information posted Feb. 10 asks for “innovative approaches to detect and track currently undetectable orbital space debris.” Responses are due March 11.
IARPA, an agency under the Office of the Director of National Intelligence, says a key concern for the intelligence community is the danger that tiny pieces of debris — currently not tracked by surveillance sensors — could pose on “our valuable government and commercial space assets.”
“Orbital debris collisions are a significant risk to Earth orbiting spacecraft,” says the RFI. “Even the smallest pieces of debris can cause serious damage.”
According to IARPA, there are more than 500,000 pieces of debris between 1 and 10 centimeters in diameter, and over 100 million particles smaller than 1 centimeter orbiting the Earth.
“Sub-centimeter debris cannot be detected with ground-based methods and on-orbit detectors can only sample the population at the detector altitude by colliding with the debris,” the RFI says. “Since the retirement of the Space Shuttle program in 2011, the U.S. government no longer has a dedicated, calibrated on-orbit orbital debris detection sensor.”
Traditional ground-based sensors are improving but the detection sensitivity rapidly decreases with increasing altitude and is limited to observing high latitudes, says the agency. “Unfortunately, the collection modes for ground-based sensors are not able to track small objects due to the relatively high angular velocity and must remain in staring mode to count the number of objects passing through the field of view.”
Another problem is debris from objects in highly elliptical orbits known as Molniya orbits that cannot be detected since the U.S. ground-based sensors are in the Northern Hemisphere.