Despite the projected delay of at least several years in the first launch of the United States’ next-generation weather satellite, the availability of current environmental sensing spacecraft should prevent a gap in coverage, officials involved in the development of the National Polar-Orbiting Operational Environmental Satellite System (NPOESS), as reported in Satellite News‘ sister publication Defense Daily.

At the same time, they said they continue to explore contingency options since they cannot exclude the possibility of a coverage gap stating around the end of the decade in at least one of the three polar orbital planes in which the United States operates its weather satellites.

"The highest priority is no gap in service," Greg Withee, associate director of the National Environmental Satellite Data and Information Service within the National Oceanic and Atmospheric Administration (NOAA), told the Senate Commerce, Science and Transportation disaster prevention and prediction subcommittee on March 30.

NOAA, a division of the U.S. Department of Commerce, is developing NPOESS along with the U.S. Department of Defense and NASA. The Air Force, on behalf of the Pentagon, oversees the satellite’s acquisition, while NOAA will manage satellite operations. NASA provides technology support.

NPOESS spacecraft is intended to replace the Air Force’s Defense Meteorological Satellite Program (DMSP) and NOAA’s Polar Operational Environment Satellite (POES) weather- sensing systems. Northrop Grumman Corp. has been the prime contractor for NPOESS since 2002.

The program currently is undergoing a Defense Department-led review, per a U.S. law called the Nunn-McCurdy provision, since its projected lifecycle costs have grown by at least 25 percent. Indeed, throughout the last two years, the program’s estimated price tag has increased from approximately $7 billion to about $10 billion, according to the U.S. Government Accountability Office.

Government and industry officials have cited technical and engineering challenges with the satellite’s main sensors as one of the chief causes of the cost growth and delays. The Pentagon reported the cost growth to the Congress in January and is carrying out the review in coordination with NOAA and NASA.

Per the law, the Pentagon must recertify to the Congress by June 6 that the program remains essential to national security to warrant its continued development. As part of the NPOESS recertification process, the Defense Department, along with its partners, is examining a range of alternatives, including cancelling the project.

Gary Payton, deputy undersecretary of the Air Force for Space Programs, told the same oversight panel that he did not think the Pentagon is leaning toward cancellation. "Going without a polar-orbiting environmental satellite is not acceptable," due to the fact that "the nation needs this environmental data for real-time operations, both military and civil," he said.

Knowledge of the weather is critical for conducting military operations, he said. In tomorrow’s world, NPOESS is expected to play an equal if not more important role with its advanced capabilities such as even the ability to determine soil conditions to help planners gauge the ease of movement of friendly and enemy forces.

Under the program’s current schedule, which is expected to change as part of the recertification process, six NPOESS satellites will fill the three orbital planes around the poles. The first launch of a NPOESS satellite is expected to slip from its current 2009 date to no earlier than 2012.

Payton said the Air Force still has four DMSP satellites in reserve, each of which could be launched when an on-orbit asset reaches the end of its operational life. The service projects that these reserves would prevent any gap in the orbital planes in which the DMSP currently operates until about 2014. The life of a DMSP satellite is between five and seven years, he said.

One option under consideration is to install new inertial measurement units in the four DMSP spacecraft to extend their on-orbit lives, Payton said.

Of perhaps more concern is the remaining life of the POES fleet. Withee said that NOAA has one remaining POES satellite in reserve and anticipates launching it around 2009. "If the launch goes right, we should be able to have no gap," Withee said.