The leader of U.S. Strategic Command says so few satellites are in queue now for launch for critical missions--such as weather observation satcom or ballistic missile warning--that there is a risk of service gaps that could impede the military's ability to do its job.

Air Force Gen. Kevin Chilton's concern about a launch disaster is strong enough that he says he is willing to give up investing in improvements for spacecraft in favor of simply rebuilding a small stockpile of backups. The general advocates rebuilding a small number of operational spares as a buffer from a launch or orbital disaster.

Noting the tight funding situation at the Pentagon, Chilton is willing to reduce the number upgrades he pursues. "I'll give up improvements in capability for that assurance," he says. "Multiple launches are going to have to go off perfectly for us to be in the position we want to be in." He made his comments last week during the annual Strategic Space Symposium here. While the track record for U.S. launches is strong, he notes, the margin for error is too close for his comfort.

"Over the last 10 years we have gotten into the position of managing efficiency at such a level that it's working against us," says Chilton. "We have fallen into what I will call gap management in the way we manage our constellations on orbit. We need to stop doing this. We need to stop managing the health and sustainment of these critical constellations on the very edge of a gap that could develop."

In 1999, numerous satellites--including GPS, missile warning, protected communications and weather spacecraft--were "in the barn" and ready to go within the 6-12 months it takes to line up a launch vehicle. Among them were 26 GPS satellites, five weather satellites, two protected communications satellites and "several" missile warning spacecraft, says Chilton.

These extra satellites were in queue deliberately to provide a "safety net," he says. An example of what can go awry was a launch failure in 1999 that placed a $1-billion Milstar satellite in the wrong orbit, rendering the protected-communications spacecraft useless. Most recently, the Defense Support Program's DSP-23 has been unable to perform its missile warning mission because of a problem in orbit.

Those satellites that were being built or awaiting launch a decade ago have been lifted into orbit, leaving few spacecraft on the ground as backup.

One mission area that worries Chilton is ballistic missile warning. There are no more DSP missile warning satellites on the ground, and its replacement--the first geosynchronous-orbit (GEO) Space-Based Infrared System (Sbirs) satellite--is not expected to launch until late 2010 at the earliest; these satellites would provide the first indicator in the event of a ballistic missile launch from Iran or North Korea.

Sbirs GEO-1 is slated for delivery to the Air Force by the fourth quarter of 2010, according to Rick Ambrose, Lockheed Martin vice president of surveillance and navigation systems. This will be an important milestone for the $10.4-billion program, which has undergone multiple restructurings, cost overruns and delays. Delivery of the first GEO satellite is at least seven years later than planned, and cost estimates exceed predictions by billions.

Following delivery, Lockheed Martin says integration of GEO-1 onto its booster will take 45-60 days in preparation for launch from Cape Canaveral. Thermal vacuum testing is slated for completion for GEO-1 in mid-November, Ambrose says.