Debris Threatens Future Space Travel
U.S. space officials are turning to Internet-based, network-centric capabilities to mitigate against future space collisions with orbiting debris. It can't happen fast enough, a panel of experts told a House subcommittee April 28.
Since the Russians successfully launched Sputnik 1 in 1957, more than 4,600 space missions have been conducted worldwide, leaving behind not only a legacy of space exploration but also a swirling mass of flotsam: defunct spacecraft, derelict launch vehicle orbital stages, intentional refuse and the debris of more than 200 satellite explosions and collisions.
The most recent space collision, a February smashup of an Iridium communications satellite and an inactive Russian satellite, added nearly 900 pieces to the debris and has raised questions about the safety of future space travel. Last year, NASA twice maneuvered robotic spacecraft to avoid collisions and, more recently, the ISS (International Space Station) had to change orbits to avoid being smacked by 10-year-old debris from a Chinese satellite launch.
"The space environment is not safe-it might be fairly characterized as an environment in which everything is trying to kill you and your spacecraft," Dr. Scott Pace, director of the Space Policy Institute at George Washington University, told the House Subcommittee on Space and Aeronautics.
Nicolas L. Johnson, NASA's chief scientist for orbital debris, added, "The recent collision of two intact satellites ... reiterated ... that the amount of space debris already in Earth orbit is sufficient to lead to more accidental collisions, which in turn will lead to an unexpected increase in space debris and increased risk to operational space systems."
The Air Force told the lawmakers it is currently tracking 19,000 objects in space: 1,300 active payloads and 7,500 pieces of space junk. Lt. General Larry James, commander of the Joint Functional Component Command for Space, estimated that the number of active satellites will grow from 1,500 within the next 10 years and the overall number of tracked objects could grow to 100,000 with the use of better space sensors in the U.S. Space Surveillance Network.
"However, there will still be potentially lethal objects in space too small to be tracked by the Space Surveillance Network," he said.
The Air Force is hoping the Internet will help mitigate some of the crisis.
James said space situational awareness is more than understanding the space environment, tracking objects and conducting what the military calls "conjunction assessments" (that is, the odds of a spacecraft hitting another object in space). James said space officials need to be able to discriminate between natural and man-made threats in addition to understanding the location, status and purpose of the objects.
"To get there we require more automated, net-centric capabilities to command and control space forces, and networked sensors and information systems that seamlessly share information to more effectively use our resources," James said.
The Air Force Space Command's Space-track.org Website already allows qualified commercial space interests and other countries to obtain unclassified data on catalogued space objects. To date, the site has hosted more than 37,000 users across 110 countries with 75 percent of the users from the United States, Canada, France, the United Kingdom and Australia.
Since space is not owned by any one country, and nations (including the United States) are often inclined to not reveal the full scope of their space operations for security reasons, future curtailment of space debris will depend on the voluntary involvement of countries, such as China, that are actively building a space program.
"There is a clear need for better space situational awareness for all space sectors-civil, commercial and national security," George Washington's Pace testified. "While space traffic control may not be feasible, better space traffic monitoring is feasible."