WASHINGTON — With plans for a new generation of military weather satellites on hold pending a study of options next year, the U.S. Defense Department will continue to rely on a system whose legacy dates to the 1960s and which has experienced technical problems in recent years.

In canceling the planned next-generation Defense Weather Satellite System (DWSS) last year, Congress provided $123.5 million in 2012 for development work on a follow-on system. But the U.S. Air Force is focused instead on refurbishing two aging Defense Meteorological Support Program (DMSP) satellites in preparation for launch in the next few years, and has requested $89 million next year for the effort.

According to budget justification documents sent to Capitol Hill Feb. 13, the Air Force is modifying the last two DMSP satellites to address problems that have occurred on the most recently launched versions. This work includes replacing gyroscopes that failed on in-orbit satellites and sensor modifications, the documents say.

“Premature attitude determination gyro failures on DMSPs F15 (launched Dec 99) and F16 (launched Oct 03) exposed a fleet-wide life-limiting problem with the attitude determination gyros planned for flight on all remaining DMSP satellites,” the documents say. “Mini-Inertial Measurement Units (MIMUs) are being integrated to the remaining DMSP satellites to reduce risk of mission failure due to those gyro problems.

“A number of systemic problems have also been identified with the new suite of microwave and ultraviolet sensors flying on this final block of DMSP satellites. These problems are being mitigated via sensor modifications and repairs for the satellites that remain to be launched.”

The Air Force typically maintains two DMSP satellites in polar orbit for global coverage throughout the day. The most recent of those, DMSP F18, was launched in October 2009. The remaining craft, DMSP F19 and F20, were built in the 1990s and are in storage at prime contractor Lockheed Martin Space Systems of Denver.

According to the budget justification documents, the Air Force is executing a so-called service life extension program on the last two satellites to stretch their on-orbit life expectancy from four to five years. DMSP F19 is scheduled to launch in fiscal year 2014, which begins in October 2013, with DMSP F20 to follow on an as-needed schedule.

In canceling DWSS, lawmakers appropriated $43 million in program termination fees — Northrop Grumman Aerospace Systems was prime contractor — and $123.5 million for an unspecified follow-on system. The Air Force’s 2013 budget request allocates only $2 million for that effort, which would be used for an analysis of alternatives for obtaining meteorological data. 

Richard McKinney, deputy undersecretary of the Air Force for space programs, told reporters Feb. 15 that the service is not sure how it will spend the money appropriated for a DWSS follow-on program in 2012. The Air Force will work with Congress to figure that out, he said, adding that the funds could be used for sensor development.

Part of the problem with DWSS was that it had very “exquisite” sensors, which may not be needed to perform the weather mission, McKinney said. The service will evaluate what sensors should be included in the follow-on program, he said. The Air Force will be “fine” and have enough weather data as long as there are no problems with the launch of the two remaining DMSP satellites, he said.

The DWSS program was hatched in 2010 when the White House terminated the civil-military National Polar-orbiting Operational Environmental Satellite System, which was behind schedule and well over its planned budget. The White House directed the civilian National Oceanic and Atmospheric Administration and the Pentagon to pursue separate systems. From the beginning, however, Congress expressed strong reservations about DWSS.

Scott Pace, director of George Washington University’s Space Policy Institute here, said the plan to fill coverage gaps with two legacy DMSP satellites is “worrisome.” But he said it is nonetheless a logical approach.

Josh Hartman, a principal at the Center for Strategic Space Studies, said the Air Force does not need to rush into decisions on the next-generation weather satellite program with two DMSPs available for launch. He said canceling DWSS in an era of shrinking budgets was a wise decision.

But Loren Thompson, chief operating officer at the Lexington Institute in Arlington, Va., said the DMSP are based on old technology and lack a considerable amount of the capability relevant to modern military operations.

The cancellation of DWSS implies there is not a lot of support in the Pentagon for a new weather satellite program, Thompson said. “I’d like to hear a credible explanation as to why the military doesn’t need some of the atmospheric and ground condition data that DWSS would have provided,” he said.