Debate continues about what caused the breakup of a Russian satellite in orbit, underscoring the need for improvements to the ability to track and identify objects in space.
Space has become more littered with debris since the 2007 China anti-satellite test that shattered a satellite target. And operators, including the U.S. national security establishment, fear just such an incident, in which a satellite is damaged in orbit but the cause is impossible to pinpoint due to insufficient space surveillance and tracking capabilities.
Russian scientists first detected a change in the Blits (Ball Lens In The Space) nanosatellite Feb. 4. It was launched in September 2009 from a Soyuz by the Federal Space Agency of Russia and used for precision laser-measurement experiments.
These scientists subsequently postulated that a close approach to a piece of orbital debris—left after China conducted an anti-satellite test using its own defunct Fengyun 1C satellite as a target in 2007—must have collided with the spacecraft.
But what the mainstream press has reported as a late-January collision between this debris and Russia's ball-shaped satellite never happened, according to U.S. defense officials.
“There is no conclusive evidence to support that a piece of a Chinese Fengyun-1C debris, or any other piece of tracked debris, was the cause of the event,” says Lt. Col. Monica Matoush, aspokeswoman. The Joint Space Operations Center (JSPOC) maintains a catalog of 23,000 objects in orbit, including satellites and debris roughly 5 cm (2 in.) or larger. It “detected an event involving the Russian Blits satellite resulting in a single piece of debris in addition to the payload,” she says. The center is continuing to track the two objects.
A known and cataloged piece of debris from the destroyed Chinese weather satellite actually came 3.1 km (1.9 mi.) from the Blits satellite, three times the 1-km distance required for notification to an operator of a potential collision, a separate defense source adds, on the condition of anonymity because he has not been authorized to speak publicly about the matter.
The piece of orbital debris cited in news articles as being from the destroyed weather satellite has an “unchanged orbit,” indicating it never collided with anything, the official says.
The Air Force routinely notifies operators if their satellites appear to be too close to one another, or to debris, in an effort to reduce the chances of such an incident. American and European space agencies say as many as 400,000-500,000 objects are routinely orbiting Earth, many of them too small to detect.
Just such a piece of debris could be the culprit for the apparent break-up of the Blits spacecraft. Though the JSPOC tracked a piece of Fengyun debris near Blits, it is impossible to know with today's sensor capability whether something smaller, also perhaps from the weather satellite debris field, collided with Blits.
“No matter what, there was an external force, outside of the standard natural perturbations, that acted on the Blits satellite and changed its orbit and spin. The two possibilities are either it just broke up on its own, or it was hit by something else,” says Brian Weeden, a technical advisor for the Secure World Foundation.
The defense official says a collision is unlikely because such events at orbital speeds typically cause objects to shatter into a large field of debris.
Weeden, however, says that Blits's design, “essentially a bowling ball made of two outer halves and an inner sphere,” could prevent it from shattering into tiny pieces. “It all depends on the size of the impacting object, the composition of the two objects, and the relative speeds and angles of the impact . . . . It didn't have any fragile solar panels or other things that could have created debris,” Weeden says. “It is possible that Blits was struck by a piece of uncataloged debris that is not being tracked by the U.S. military.”
This scenario of a satellite seemingly damaged in orbit without a definitive cause is one that U.S. military leaders fear for their constellations. As U.S. forces have grown increasingly dependent on satellite-based services, from GPS to weather to imagery to missile-warning, commanders are more concerned about operating in a medium about which they have poor situational awareness (SSA). Such awareness is needed not only for debris mitigation, but also potentially to detect hostile actions in space.
Weeden notes that the JSPOC, the nerve center for the best SSA in the world, runs using 1980s-era computer technology that is, at best, stretched to its limits.
“Material, cultural and bureaucratic shackles are preventing the United States from developing the SSA capabilities it requires to meet its own national security needs and thereby contribute to the long-term sustainability of outer-space activities,” he writes in the report titled “Going Blind: Why America is on the Verge of Losing Its Situational Awareness in Space and What Can Be Done About It.”
“As long as the U.S. military continues to use these two legacy IT systems, it will face severe restrictions on the number of space objects it can catalog and track, the speed and accuracy of calculations to determine potential on-orbit collisions and warn satellite operators, its capability to share SSA data with partners and allies and ingest outside data, and its ability to take full advantage of the billions of dollars in new SSA sensors that will be coming online in the next few years,” he writes.
A new Space Fence—two to three S-band radar sites for improved SSA—is slated to be fielded starting in 2015 at the earliest; the Air Force took over the program from the Navy in 2004. And in 2010 the Air Force lofted the Space Based Space Surveillance electro-optical satellite designed specifically to spy on other orbiting satellites, principally in the crowded geosynchronous belt.
These are two of the new sensing capabilities that are being and will be hampered by inadequate information technology systems at the JSPOC, Weeden says.
However, there is pressure to reduce defense spending. Thehas struggled to keep funding in place for SSA activities as it has had to address bloated satellite pricing for its primary missions in the last decade.