The House Committee on Science and Technology's Subcommittee on Space and Aeronautics held a hearing to examine the challenges faced by civil and commercial space users as space traffic and space debris in Earth orbit continue to increase.

Subcommittee Members questioned witnesses about potential measures to improve the information available to civil and commercial users to avoid in-space collisions and discussed ways to minimize the growth of future space debris.

Ensuring the future safety of civil and commercial spacecraft and satellites is becoming a major concern. The February 2009 collision between an Iridium Satellite-owned communications satellite and a defunct Russian Cosmos satellite highlighted the growing problem of space debris and the need to minimize the chances of in-space collisions.

"It was such a surprise to me and many others when we heard the news that two satellites had collided in orbit in February of this year. It was hard to believe that space had gotten that crowded. It was equally difficult to believe that nothing could have been done to prevent the collision, given that one of the satellites was active and by all accounts would have had the capability to maneuver out of harm's way," said Subcommittee Chairwoman Gabrielle Giffords (D-AZ).

"I'd like to know where things stand, and what we're going to do to keep such an event from happening again."

While several nations such as Russia, France, Germany and Japan have some form of space surveillance capability, these systems are not interconnected and are neither as capable nor as robust as the United States' Space Surveillance Network (SSN).

SSN consists of a world-wide network of 29 ground-based sensors that are stated to be capable of tracking objects as small as five centimeters orbiting in Low Earth Orbit (LEO)-that is, the region of space below the altitude of 2,000 km (about 1,250 miles).

For the last four years, the Department of Defense (DOD) has undertaken a Commercial and Foreign Entities (CFE) pilot program to make collision avoidance information available to commercial space users. Commercial users have found the service to be very useful and have been concerned about uncertainty concerning the CFE program's future.

At the hearing, Gen. Larry James, Commander of the Joint Functional Component Command for Space, testified that the DoD would transition the CFE to an operational program later this year.

Since 1957, there have been several thousand payloads launched into space. After the first fragmentation of a man-made satellite in 1961, there have been more than 190 fragmentations and 4 accidental collisions. Since January of 2007, there have been three major debris generating incidents, which have significantly increased the Earth's orbital debris environment: Iridium 33 - Cosmos 2251 Satellite Collision; Chinese A-SAT test on Fengyun-1C; and Russian spent stage explosion - Russian Arabsat 4.

At this point, the DoD is tracking more than 19,000 objects in Earth orbit, and witnesses at the hearing testified that there are more than 300,000 objects of a half-inch in size or larger orbiting the Earth, with further growth in the debris population anticipated in the coming years.

"One thing is already clear-the space environment is getting increasingly crowded due to the relentless growth of space debris. If the spacefaring nations of the world don't take steps to minimize the growth of space junk, we may eventually face a situation where low Earth orbit becomes a risky place to carry out civil and commercial space activities," said Giffords.