Pending Space Junk: A Very Close Call with the ISS

Is anyone else concerned that our $100 billion International Space Station (ISS) could have been gold-plated space debris last weekend?  It was a scary situation with the astronauts huddled in the Soyuz capsules hoping for the best.  This piece of debris threatening the ISS was from an old one-ton Russian Cosmos 2551 satellite that collided with an Iridium 33 satellite in 2009. The earlier Russian collision left behind thousands of pieces that need to be tracked forevermore since they threaten space craft. In June 2011 the astronauts had a similar close call with this same Russian space junk, causing them to also take shelter in the capsules.

This past January, the ISS also needed to fire its thrusters to dodge debris from a Chinese weather satellite intentionally destroyed by the Chinese military back in 2007.  And in April 2011 the ISS astronauts had to stay in the capsules to avoid this very junk.  It is not clear why the Chinese are creating lethal space junk while also planning to put their own manned space station into orbit. 

It would seem orbiting the Earth is becoming more dangerous each day.  Fortunately, we have the U.S. military's space surveillance network (SSN) tracking much of this debris.  The mission of SSN is to:

• Analyze new space launches and evaluate orbital insertion
• Detect new man-made objects in space
• Chart present position of space objects and plot their anticipated orbital paths
• Produce and maintain current orbital data of man-made space objects in a space catalog
• Inform NASA and other government entities if objects may interfere with the orbits of the Space Shuttle, the International Space Station, and operational satellite platforms
• Predict when and where a decaying space object will re-enter the Earth's atmosphere
• Prevent a returning space object, which to radar looks like a missile, from triggering a false alarm in missile-attack warning sensors of the U.S. and other countries
• Determine which country owns a re-entering space object
• Predict surface impacts of re-entering objects and notify the Federal Emergency Management Agency and Public Safety Canada if an object may make landfall in North America or Hawaii.

Of course, SSN can only track the larger pieces of space junk, though even debris the size of a grain of sand can cause serious problems.  SSN is already tracking space junk that is at least 4 inches (10 cm) in low-Earth orbit, the region where the ISS operates. In total, some 19,000 man made objects this size or bigger were orbiting Earth as of July 2009, mostly in low-Earth orbit.

What we really need to be wary of is the Kessler syndrome, proposed by NASA scientist Donald J. Kessler in 1978.  This idea related to a cascade of collisions in low-Earth orbit leading to the abandonment of this area, and potentially space exploration, because of the significant danger to all spacecraft.  What can we do?  Future postings will discuss some of the ideas being proposed to clean up this space debris.