COLORADO SPRINGS -- Earth orbit is such a mess! Chunks of space junk like dead or dying satellites, down to specks the size of paint chips, mingle with an ever-growing constellation of navigation, telecommunications and remote sensing spacecraft.

So crowded is near-Earth orbit that experts have begun calling for a space-traffic control -- and violators are likely to get ticketed.

William Ailor, director of the Aerospace Corporation's Center for Orbital and Reentry Debris Studies in El Segundo, California, said future growth in satellite traffic means some kind of "cop-on-the-beat" is now being given serious attention.

Ailor said that many of those lofting satellites still feel space "is a big sky" and are slowly evolving to an appreciation of the complex nature of operating in an increasingly crowded near-Earth space. "There are a lot of issues left to resolve, such as what kind of service would be available, and whether this would be a military kind of service or not," he said.

"There's always a threat of somebody throwing a bucket of bolts at you, basically, to take out your satellite."
     

"We're seeing satellite operations becoming much more complex," Ailor said. There are station-keeping maneuvers, moving spare satellites into operational slots to replace defunct or aging spacecraft, as well as plopping multiple satellites into precise slots to create clusters of Earth-circling spacecraft.

Then there is the issue of safely disposing of satellites. "When satellites are brought down, this has to be done without posing any threat to human-carrying or unmanned systems. There needs to be a way of assessing those kinds of hazards," Ailor said.

Ailor said he believes that elements of space-traffic control will entail use of hardware both in space as well as on the ground. Cost and technical issues, as well as how such a system gets paid for, are still unresolved.

Tending the space commons is critical for all satellite operators said William Bohl, senior engineer at the University of Denver Research Institute. Space pollution is getting worse, not better, he said.

"Obviously, it would be great to limit the problem by keeping debris out of orbit. That is awful hard to do ... and it's getting worse all the time," Bohl said.

Both Bohl and Ailor are here taking part in the 16th National Space Symposium being held April 3 to 6 and sponsored by the Space Foundation.

Like Ailor, Bohl is engaged in working on making spacecraft tough enough to survive natural and human-made debris strikes. For example, some hardware such as propellant tanks have to be protected from such impacts. Not doing so would likely result in the catastrophic loss of a satellite, he said.

Attention to space debris protection is on the rise, with the U.S. Air Force taking real interest in these hazards, as are commercial satellite firms.

For the military, Bohl said, there is one added concern. That is the threat to critical military and intelligence-gathering satellites from terrorist attack. "There's always a threat of somebody throwing a bucket of bolts at you -- basically to take out your satellite," he said. Space systems survivability is a growing enterprise, he noted. Even a ground-based laser attack that can blind or cripple a spacecraft is a worry.

These types of threats, and others, are to be discussed in a special Space and Air Survivability Workshop, to be held in mid-June at the U.S. Air Force Academy in Colorado Springs.

Protection from natural, as well as human-made threats -- both accidental and intentional, will add up to having an ability to quickly maneuver out of harm's way, adding more credence to the idea of real space-traffic control.

Ailor said the government is starting to put guidelines on the table, many of them hammered out by NASA for bringing down or placing a spacecraft in safe mode at the end of a mission. But the commercial sector wants to make sure a "level playing field" is achieved, whereby all satellite owners and operators must abide by the same regulations. Lack of enforceable rules could lead to unfair economic advantage of one company over another, he said.

"Who is going to be looking to see whether one satellite owner is doing what he or she should be doing compared to the competition?" Ailor said. "So there needs to be somebody watching. Right now, who that will be has not been connected with this issue."