WASHINGTON — Space debris has passed the "tipping point," according to a report released Thursday by the National Research Council, which called on NASA to find ways to better monitor and clean up the orbiting junk threatening active satellites and manned spacecraft.

"We're going to have a lot more (debris) collisions, and at an increasingly frequent rate," said Don Kessler, a former NASA scientist who chaired the committee that prepared the report. The orbiting objects include ejected rockets and broken satellites.

Kessler first predicted in 1978 that the number and size of objects in Earth's orbit would eventually become so large that they would continually collide with one another and create even more debris — a chain reaction known as a "collision cascade." Recent data underscore the growing problem: Two collisions since January 2007 helped at least double the number of trackable debris fragments that are in Earth's orbit, according to the NRC report.

U.S. Strategic Command, a military unit able to track man-made objects 10 centimetres and larger, says there are now more than 22,000 such pieces in orbit. NASA estimates there could be hundreds of thousands — or even millions — of smaller, non-trackable pieces of debris also in space.

Active satellites are at risk of damage and "as the amount of debris increases, there will be increases in the cost of operating" satellites, said Brian Weeden, a technical adviser with the Secure World Foundation, which focuses on space sustainability.

Manned spacecraft are also in danger. The International Space Station had a close call in late June when an unidentified object came within 330 metres but caused no damage; astronauts were pre-emptively evacuated to emergency spacecraft.

NASA's chief of safety and mission assurance, Bryan O'Connor, asked the National Research Council in 2010 to independently examine the agency's work on debris. While the report does not offer many specifics for strategy, it further emphasizes the need for NASA to come up with a plan that centralizes staff and better utilizes the agency's limited resources.

"We thank the National Research Council for their thorough review in this report," said NASA spokeswoman Beth Dickey. "We will study their findings and recommendations carefully and use them to advise our future actions in this important area of work."

The agency currently has several programs related to debris with only one staff member each, according to the NRC report, making those programs vulnerable to staff changes and budget cuts. Kessler said NASA will have to make tradeoffs and reallocate funding if it's going to improve debris management.

The NRC also recommends further engaging the U.S. State Department for work on the international front. Less than one-third of space debris can be attributed to the U.S., and it will be important to have Russia, China and other players in space pursue cleanup as well, Weeden said.

The report provides no timeline for NASA to implement changes in its debris programs, but given the tipping point we have passed, Kessler said, "The earlier we [deal with the problem], the cheaper it's going to be in the long run."

Weeden said that space debris won't be a major concern within the next couple of years, but it will be within 10 or 20 years—and that's a relatively short lead time given the scope of the issue.

"You can't fix the problem quickly," Weeden said. "We've had 50-plus years of activity in space bring us to this point, so the answers are not going to be easy."