A senior U.S. Air Force official said that in spite of the latest troubles with the Space Based Infrared System (SBIRS) missile warning program, the service should begin investing in parts for a fourth satellite once it formally commits to buying a third.

Gary Payton, deputy undersecretary of the Air Force for space, said the service has yet to order a third SBIRS satellite formally from prime contractor Lockheed Martin Space Systems of Sunnyvale, Calif. Based on the projected lifetime of the existing Defense Support Program missile warning satellites, however, a third SBIRS craft likely will be necessary, he said.

While a fourth SBIRS satellite is not a “done deal,” the Air Force “might as well” buy parts for the fourth satellite if it already is ordering them for the third spacecraft, Payton told reporters Oct. 11 during a press briefing here at the Strategic Space and Defense conference. He also said the Air Force has parts obsolescence issues to address before it orders the third satellite.

Tentative plans to buy a fourth SBIRS satellite were thrown into doubt Sept. 26 by a memo from Air Force Secretary Michael Wynne that disclosed more troubles with the program, which has a long history of cost growth and delays. In 2005, the Air Force restructured the program, reducing the number of dedicated satellites from five to no more than three, and hatched a replacement program dubbed the Alternative Infrared Satellite System. Earlier this year, however, the service, buoyed by what senior officers characterized as progress on the program, announced its intent to buy the third and possibly a fourth satellite.

Payton said the latest SBIRS woes probably will not change that plan, and pointed out that any follow-on program is likely to face its own learning-curve issues. He also said measures taken following the SBIRS restructuring will make it easier to resolve the problems outlined in Wynne’s memo, which was addressed to Pentagon acquisition chief John Young.

The memo said the SBIRS satellites have a design similarity to an unidentified U.S. government satellite that failed due to a faulty safe-hold mechanism. Safe hold refers to measures a satellite automatically takes to protect itself from further damage when something goes wrong in orbit. The memo also pointed to a problem with the “timing loop” on the SBIRS computer architecture.

Payton declined to identify the satellite that failed but did say that ground controllers were able to communicate with the stricken craft for only seven seconds before it went into safe hold and did not come out. He said the satellite still was in orbit.

The Air Force discovered significant problems with the SBIRS flight software following thermal vacuum testing in January – along with other tests – on the first satellite intended gauge how it would react to stressful situations in space, such as having its solar panels pointed in the wrong direction, Payton said. Program officials soon found themselves discovering errors faster than they could correct them, he said.

In a written response to questions Oct. 5, Lt. Col. Cheryl Law, a spokeswoman for the Space and Missiles Systems Center in Los Angeles, said an analysis of the test issues subsequently revealed “fundamental design issues” with the SBIRS flight software. Law said the analysis, completed over the summer, found cases where the satellite’s flight software could not perform the safe-hold function properly.


timing loop issue noted in

Wynne’s memo refers to spacecraft health-monitoring and troubleshooting

software that was running

too slow, Law said. That problem potentially

could have allowed

problems to mount

to the point where recovery would not be possible, she said.

The plan for fixing the problems, to include cost and schedule impacts, likely will be set in mid November following a review involving Lt. Gen. Mike Hamel, commander of the Space and Missile Systems Center, and Joanne Maguire, executive vice president of Lockheed Martin Space Systems, Payton said. Wynne may be involved as well, he said.

Payton said he believes the problems can be resolved through modifications to the flight software that will enable a smoother flow of data through the spacecraft processors, which are based on technology that is more than a decade old.

Payton said a software “anomaly resolution unit” established after the SBIRS restructuring will allow program officials to work out the bugs without halting spacecraft assembly to test the new code. He noted , according to some projections, that the program’s latest delay could be a matter of a few months rather than a year as Wynne’s memo warned.

While confident that the issues can be resolved solely through software modification, Payton said Wynne has asked program officials to study the option of replacing processor hardware. This would be a more complex and time-consuming solution, he said.

Prior to the discovery of the latest problems, the SBIRS satellites were expected to launch in the fourth quarter of 2008, or about six years later than originally planned. Now that launch has been pushed back at least until early 2009, Payton said.