More Details Emerge About US Air Force Satellite Explosion

A US Air Force satellite exploded, and its debris could pose hazard to other spacecraft for years.

by Steven Tomaszewski
Mar 6 2015, 8:07pm

Image via US Air Force

It could have been a scene from Gravity, although Sandra Bullock and George Clooney were safely on Earth: In early February, a previously classified military weather satellite exploded, and analysts are still putting together the last moments of the satellite's operational life and assessing what impact the event will have on the growing problem of space debris.

This week has seen more details emerge: What scientists do know is that the satellite suffered an unexpected "sudden spike of temperature" while orbiting about 525 miles above the surface of the Earth. In response, Air Force satellite operators in Nebraska tried to put the satellite in a safe mode and "shut down all non-essential systems" in an attempt to recover it, but instead the satellite started to spin out of control. Shortly after that, DMSP F-13 (aka Defense Meteorological Satellite Program Flight 13) broke into multiple pieces, the Joint Space Operations Center in California observed.

With the satellite now defunct, ground-based operators could only watch as the satellite continued to disassemble like an extra in Gravity. Each chunk of satellite is moving faster than a bullet and could crash into other satellites, adding to space debris.

There's no evidence of foul play from other countries that led to the demise of the satellite, and Aviation Week reported that the Air Force is attributing the catastrophic malfunction to a problem in the power subsystem. That could mean a battery got too hot, the solar panels short-circuited, or another piece of space debris may have hit a critical component of the 20-year-old, 1,800 pound weather satellite.

The DMSP constellation first started development in the 1960s and was declassified in1972. The primary purpose of the satellites is to track space and terrestrial weather patterns for the military. Sensors on board the spacecraft help predict severe storms and can even put together three-dimensional models of clouds. Weather data is also shared with civilian agencies like the National Oceanic and Atmospheric Administration to help them make their forecasts.

The Air Force claims the loss of DMSP F-13 will have a minor impact on operations, since there are currently six other DMSP birds in orbit doing the same mission. F-13 was moved into a backup role in 2006, and another satellite in the series is scheduled to be launched sometime later this year. This isn't the first time a DMSP satellite has exploded; the last one to break up was F-13's older brother F-11 in 2004.

Private companies and backyard astronomers who track objects currently in orbit have counted at least 46 uncontrolled pieces of debris from F-13 hurling around the Earth at approximately 17,500 miles per hour. So far there aren't any confirmed collisions with other operational satellites, but the debris will continue to pose a risk for years, until the pieces eventually enter back into the Earth's atmosphere and burn up.

As the latest US National Security Space Strategy notes, space is becoming an increasingly congested environment, and will be home to more and more spacecraft. The Department of Defense is tracking at least 22,000 objects in their databases that are four inches or larger, and speculates there could be half a million pieces of space debris too small to detect.

The last time a satellite explosion made the headlines was back in 2007, when China shot down one of its own spacecraft in an anti-satellite ballistic missile test that created more than 3,000 pieces of extra space junk. The orbital debris created by the explosion continues to descend from its original altitude of 530 miles above the Earth, destroying a Russian satellite in January 2013 and still posing a threat to this day.

Objects moving at orbital velocity can cause grave damage to other satellites in a similar orbit. Space is big, so crashes don't occur on a daily basis, but when they do, they cause hundreds of millions of dollars of damage. At orbital velocity a tiny piece of space debris one third of an inch long in orbit packs as much punch as an entire Harley motorcycle cruising down the highway at 60 miles per hour.

In 2001 this US-made titanium rocket motor casing fell from space, crashing into the desert about 150 miles from RIyadh, the Saudi Arabian capital. Photo via NASA.

When the Space Shuttle was still operational, tiny micrometeoroids the size of a fleck of paint did major damage to the craft's windshield on every flight. The triple-paned fused glass got so badly damaged on each mission that engineers decided it was easier and cheaper to replace the windows after every flight than repair the damage. Fortunately, the debris cloud from F-13 is far enough above the International Space Station—which usually orbits approximately 250 miles up—that the six astronauts currently on board shouldn't be affected.

That doesn't mean that everyone should breathe easily, though. NASA scientist Donald Kessler proposed a scenario for the future—now known as the Kessler syndrome—in which debris hit and break apart satellites and other debris, which results in even more collisions, eventually making an impenetrable wall of junk so dense that no spacecraft can safely navigate through. If manmade objects continue to explode and collide, this could one day become a reality.

The international community recognizes space debris as a major challenge that will shape the way we operate in space for the foreseeable future; now new satellites and rockets must reduce the amount of debris they produce. Even so, there aren't a lot of laws and enforcement mechanisms to make sure countries pick up the existing litter in space.

Scientists and engineers have proposed a bunch of ways to take care of the space junk problem and start cleaning up the cosmos, including a space janitor, a laser broom, air puffs, giant nets, and solar sails. The European Space Agency even has an animation showing several theoretical options for removing space debris.

The problem with these solutions—and why few have left the concept phase—is finding someone to pay for them. There isn't any economic incentive for companies or governments to remove spinning pieces of metal from space. The cheaper and easier solution is to execute a minor maneuver that would reduce the risk their operational satellites would be hit. That's fine for preventing one collision, but doesn't address the problem of debris hitting other junk and creating even more shrapnel. The space environment suffers from the tragedy of the commons where no one wants to spend the time or money to clean up their mess.

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