U.S. military and commercial satellites, long considered out of harm’s way, are vulnerable to multiple types of attack, an assault a determined enemy someday will attempt, according to military, government, industry and think tank experts testifying before the House Armed Services Committee strategic forces subcommittee June 21.

"It would be imprudent for us to not assume that a determined adversary would try to eliminate what is one of our greatest warfighting advantages," said Air Force Lt. Gen. C. Robert Kehler, deputy commander of the U.S. Strategic Command. Space assets are critical, because they "enable the American way of war," reported sister publication Defense Daily.

Some adversaries already are trying to develop ways to jam the U.S. GPS satellite system, and other examples that may conceivably occur include a country detonating a nuclear weapon in space to knock out satellites. An enemy lacking the advanced sophistication of the U.S. space program also could loft microsatellites equipped with an explosive charge, and then maneuver them close to a U.S. satellite before detonating the charge.

Michael O’Hanlon, senior fellow with the Brookings Institution, a moderate Washington think tank, said potential adversary nations currently do not have the ability to launch a major attack on U.S. space assets but may some day.

Protecting space assets can be accomplished, O’Hanlon said. Satellite manufacturers could reduce the vulnerability of their spacecraft by having backups in orbit, developing the ability to replace damaged satellites more quickly or harden satellites to make them less vulnerable to radiation, a practice that has been reduced since the end of the Cold War. All of these options would be expensive for satellite operators, he said.

As far as the greater expense of satellite makers hardening the satellites, "If our customers ask for that and are willing to pay for it, we can do that [at] substantial additional cost," said David Cavossa, executive director of the Satellite Industries Association.

Non-space redundancy also can be provided, O’Hanlon said. For example, airborne platforms can be used in addition to satellite networks, or fiber optic landlines can provide a backup to communications satellites.

O’Hanlon also said some smart moves might include minimizing U.S. use of space bandwidth capacity in event a satellite or other asset is lost, such as jettisoning use of video in videoconferences and retaining only the audio transmission.

But satellites must be equipped with systems capable of recognizing potential hostile nations from space and comprehending potential threats, Kehler said. "The number one thing we need to do is improve our space situational awareness," he said. The United States must comprehend "who’s on orbit, and what are they doing there," he said. If something unusual occurs, the United States must be able to determine whether it is a harmless anomaly, or whether it is "a hostile attack" on an American satellite.

Subcommittee members and witnesses also discussed whether there should be military rules of engagement that would apply in space.

Kehler observed there already are some rules on locations of spacecraft, adding that there currently are some 9,000 objects in space. U.S. officials need to know where they are and will be. "We have to work this very carefully," he said.

While there should be limitation on debris in space, the U.S. military may not wish to tell other nations where it is shifting space assets, such as those which can scan the Earth to track movements of people, vehicles, ships and other items. "We don’t want to be obliged to tell people where we’re moving" satellites, he said.

–Dave Ahearn