WASHINGTON — The U.S. Air Force has made some of the final decisions about its new generation of military weather satellites, and the service is now waiting for Congress to decide how much can be spent on the program this year.

Since the White House dismantled the joint military-civilian National Polar-orbiting Operational Environmental Satellite System (NPOESS) in February, the Defense Department has been crafting a new plan to build dedicated military weather satellites. Separately, NASA and the National Oceanic and Atmospheric Administration are working on a new civilian weather satellite program.

Pentagon leaders in June presented to Congress an initial outline of the new Defense Weather Satellite System (DWSS) that could begin launching as soon as 2018. The Air Force told lawmakers it plans to use satellite platforms built by Northrop Grumman Aerospace Systems of Los Angeles, which remains under contract as the NPOESS prime contractor. The new DWSS craft will carry the Visible Infrared Imager Radiometer Suite and Space Environmental Monitoring sensors originally planned for NPOESS, plus a to-be-determined microwave sensor.

The U.S. Naval Research Laboratory has been building the Microwave Imager Sounder planned for NPOESS, and the Air Force in recent months conducted an analysis of alternatives. A recommendation on which microwave sensor to use has been given to the head of Air Force Space and Missile Systems Center, said Col. Stephen Pluntze, commander of the Defense Meteorological Systems Group. Pluntze, however, would not reveal the recommendation.

The Air Force also has settled on the satellite bus design Northrop will build for DWSS. The satellite platform Northrop was developing for NPOESS would have supported as many as 10 weather and climate instruments. With just three instruments manifested for DWSS, Northrop  scaled back its design to about two-thirds of the mass of the original bus and half the power, said company spokesman Lon Rains. Northrop  has completed an engineering model of the avionics suite for the new spacecraft.

“The DWSS spacecraft retains the core design, functionality, and reliability developed through government investments to date on the [multi-agency] NPOESS program, while optimizing the size and power to the payload requirements of the DWSS mission,” Rains said.

The Air Force has separated out the instrument contracts that were part of Northrop’s NPOESS contract and handed them over to be managed by NASA. The Air Force has asked Northrop to resubmit its bid for the work to be done under DWSS, which it expects to receive before January, Pluntze said.

Meanwhile, progress on DWSS has been slowed by the failure of Congress to pass appropriations for the U.S. government’s 2011 fiscal year, which began Oct. 1. As a result, the Air Force, like the rest of the government, is operating at 2010 budget levels under a spending resolution that runs through Dec. 3. It remains to be seen whether lawmakers will pass the 2011 budget during the upcoming lame-duck session, or wait until the newly elected Congress convenes in January.

Either way, the $325.5 million the Air Force requested for the DWSS program for 2011 stands to be scaled back. The Senate Appropriations Committee, for example, included just $50 million for the program in the defense spending bill it passed in September. Details of a House version of the bill have not been released, but industry sources said it included $175 million for DWSS.