WASHINGTON—In March, six astronauts living in the International Space Station were forced to take shelter in an escape capsule as debris from a Russia Cosmos satellite passed nearby. The incident, which is the third time in 12 years that the space station faced a possible collision with space junk, underscores the increasing security threat posed by such debris.
According to NASA, there are more than 21,000 pieces of orbital debris larger than 10cm, and the Space Surveillance Network, a worldwide network of 29 space surveillance sensors, routinely tracks their whereabouts. The number of smaller pieces of debris exceeds 100 million. The average frequency of collision in Earth’s orbit is one in every five years and only a minority such collisions produces large debris clouds.
Though experts generally agree that space debris will be manageable within the next few decades, there is an increasingly strong call to deal with the debris’s long- term threat. In January, Secretary of State Hillary Clinton proposed an International Code of Conduct for Outer Space Activities, calling for responsible use of outer space that ensures the stability, safety, and security of the space systems, which are of “vital interest to the United States.”
“Unless the international community addresses these challenges, the environment around our planet will become increasingly hazardous to human spaceflight and satellite systems, which would create damaging consequences for all of us,” she said in an online statement.
According to Air Force Space Commander General William Shelton, the total amount of space trash is likely to triple by the year 2030.Scott Pace, director of the Center for International Science and Technology Policy and the Space Policy Institute at George Washington University in Washington, D.C, said many satellites, but not all, can maneuver out of harm’s way but that such evasive maneuvers increase fuel consumption and shorten a satellite’s life.
“The most important need is for information on the location and trajectories of space debris to predict potential collisions and to avoid unnecessary maneuvers,” he said. “Since there are tens of thousands of pieces of debris, space object tracking by radar and optical systems is very challenging.”
In 2009, a functional U.S. communication satellite slammed into a defunct Russian satellite. The incident, the worst of its kind so far, greatly increased the amount of large debris and together with China’s intentional destruction of a weather satellite in 2007, accounts for one-third of all cataloged orbital debris, according to NASA.
Countries and organizations such as Russia, China, France, the European Agency and the U.S. have all issued orbital debris mitigation guidelines. But technical and legal issues are still vexing problems, according to Henry Hertzfeld, research professor at the Space Policy Institute at George Washington University in Washington, D.C.
Hertzfeld said space debris-removing technology is far from mature. Currently, proposals range from debris-snagging nerf balls to firing pulses of atmospheric gases in the path of targeted trash. Objects in higher orbits would require a type of docking device to drive them back into the Earth’s atmosphere.
Hertzfeld said the plans are all likely to cost hundreds of millions of dollars. “We know when you launch something it is not cheap,” he said.
The coming of an international rule is slow because of legal concerns. Under the 1967 Outer Space Treaty, no one country or group of countries has the sovereign authority or responsibility for regulation space. Space objects are owned by countries of registry or the launching state. Touching them without permission, no matter their conditions, may be considered as a violation of sovereign.
“Every nation approaches things differently,” Hertzfeld said. “Frankly there is still a long way to go.”
