With thermal vacuum testing having begun April 16, the next space-based missile warning satellite has reached a major milestone, the Space and Missile Systems Center announced April 24.

The Space Based Infrared System, or SBIRS, satellites use infrared surveillance to provide global missile warning capabilities for the U.S. military. The system currently consists of four satellites in geosynchronous orbit and two active satellites in highly elliptical orbits that provide full coverage of the Earth’s surface.

Lockheed Martin was awarded a $1.86 billion contract in 2014 to produce the fifth and sixth geosynchronous SBIRS satellites, which will replace the first two in the constellation. The two new satellites are derivatives of the third and fourth geosynchronous satellites and are expected to improve overall system resiliency.

Lockheed Martin began thermal vacuum testing — which simulates the effects of the vacuum of space — on the fifth geosynchronous satellite, or GEO-5. The test cycles through hot and cold temperature ranges to ensure that the satellite will work in the harsh environment of space. According to SMC, the testing is a major milestone that drives final testing and assembly.

“TVAC testing represents the culmination of hundreds of thousands of hours of work by both the government and Lockheed Martin Space ensuring that we are giving the warfighter a national asset. I am proud of the men and women of the SBIRS program and their families for the years of sacrifice to get us to this point.” said Lt. Col. Ryan Laughton, SBIRS GEO-5/6 program manager.

SBIRS GEO-5 is expected to launch in 2021.

The fifth and sixth geosynchronous satellites will be the final additions to the SBIRS constellation. Plans for two additional geostationary satellites were scrapped in 2018 in favor of a new system — Next Gen Overhead Persistent Infrared. Next Gen OPIR will consist of three satellites in geosynchronous orbit and two covering the polar regions. Lockheed Martin was selected to build the former while Northrop Grumman was selected to build the latter. Next Gen OPIR is expected to be delivered in 2025.

Through a series of reprogramming requests in 2019, the Air Force has worked to deliver more money up front for the system to accelerate development. In October, SMC credited those reprogramming requests with keeping the program on pace for delivery of the first satellite in 2025.

Nathan Strout covers space, unmanned and intelligence systems for C4ISRNET.

More In Space