WASHINGTON — The U.S. Defense Department could lose its current source of ocean-wind data this year, well before the planned early 2020s launch of its next-generation weather satellite, and is eyeing an interim satellite to plug the gap as early as 2018, a service official said.

Dave Madden, executive director of Air Force Space and Missile Systems Center in Los Angeles, which buys military space hardware, said the gap-filler mission would launch “very quickly” and feature a government-furnished ocean-wind vector sensor aboard a commercially available satellite platform, or bus.

While Air Force officials have previously hinted at a near-term gap for certain weather-related data products, Madden’s remarks filled in many of the missing details, including the service’s mitigation plan.

With Windsat (above) nearing the end of its functionality and the Weather Satellite Follow-on not expected until 2021, the U.S. Defense Department is looking at launching a gap-filler weather satellite in 2018. Credit: Naval Research Laboratory

The data in question currently comes from the Naval Research Lab’s Windsat satellite that launched in 2003 with a planned three-year design life. The satellite is now expected to fail sometime this year, and the Air Force wants to launch a replacement “as soon as possible,” according to slides the service presented at a March 10 industry day.

Windsat’s main microwave polarmetric radiometer sensor, which provides the ocean-wind data, was built in house at the Naval Research Laboratory in Washington. “Can we produce another one that meets all the requirements for the near-term?” Madden said during at a breakfast here March 11.

The service’s next-generation weather satellite, known as the Weather Satellite Follow-on, is expected to fill three main data requirements: ocean-surface wind speed and direction, tropical cyclone intensity, and charged particles in low Earth orbit with the potential to affect satellites.

But that satellite is not expected to launch until about 2021, and if the Windsat dies as expected in 2015, it leaves the Defense Department with roughly a six-year data gap on ocean wind data.

The Air Force issued a request for information on the sensor Feb. 19, and the industry day slides said it wanted to explore sensor capabilities that can be “delivered as soon as possible.” During the industry day, service officials stressed that the Air Force does not yet have a formal acquisition strategy yet, according to slides and attendees.

But Madden, who spoke the next morning suggested that the service has an idea of how it wants to proceed.

Responses to the service’s request for information are due March 24. Air Force weather officials plan to make a presentation with “an early strategy position” to senior leadership in early April, according to the slides.


Congress provided $76 million for the Air Force’s Weather Satellite Follow-on program in 2015, including $30 million for the space segment. The service is requesting another $76 million for fiscal year 2016.

Once the gap-filler satellite launched, the Air Force would proceed with development of the next-generation system, Madden said.

David Madden U.S. Air Force
Dave Madden, executive director of Air Force Space and Missile Systems Center. Credit: U.S. Air Force

“My bet is we’ll have a broader Weather System Follow-on program,” Madden said. “My instincts are it probably won’t start until the 2018-’19 timeframe because right now with budgets being tight we’re really heavily focused on how we build this gap-filler.”

The Air Force also is studying a second alternative to help fill the gap, which entails analyzing data from other sensors using improved algorithms, the slides said.

The service has said it is considering using its Operationally Responsive Space Office, which is responsible for fielding space capabilities quickly in response to emerging military needs, to develop some or all of its next-generation weather monitoring satellites. It was not immediately clear what role, if any, the ORS Office would play in the gap-filler satellite.

Mike Gruss covers military space issues, including the U.S. Air Force and Missile Defense Agency, for SpaceNews. He is a graduate of Miami University in Oxford, Ohio.