WASHINGTON — A U.S. Air Force missile warning sensor has cleared testing and been shipped for integration with its classified host satellite, which will operate in a highly elliptical orbit, the service said in a June 17 press release.

The sensor is the third elliptical-orbit payload in the Air Force’s Space Based Infrared System (SBIRS) missile warning constellation, now undergoing deployment. Dubbed HEO-3, the sensor is the first major hardware delivery under the SBIRS follow-on production contract, the Air Force said.

When fully deployed, SBIRS will consist of four dedicated satellites in geosynchronous orbit and two infrared sensors hosted aboard classified satellites in elliptical orbits. The original contract covered the first two dedicated satellites and elliptical-orbit sensors — these are all in orbit — and the follow-on production contract covers two more of each. 

Lockheed Martin Space Systems of Sunnyvale, Calif., is the SBIRS prime contractor; Northrop Grumman Electronic Systems of Azuza, Calif., is the payload manufacturer.

The HEO-3 sensor completed thermal vacuum testing March 30, demonstrating performance equal to or better than its predecessor, HEO-2, the Air Force said. The satellite was cleared for delivery June 11 and shipped the following day, the service said.

“I am extremely proud of the hard work and dedication of the joint Air Force and contractor team, that worked long hours to ensure HEO-3 satisfied all requirements,” Air Force Maj. Eric Neubert, the HEO program manager, said in the release. “The shipment of this payload meets an important commitment for our production program and keeps us on track to sustain the unprecedented infrared surveillance capabilities that we provide to our warfighters and the Nation.”

Mike Gruss is a senior staff writer for SpaceNews. He joined the publication in January 2013 to cover military space. Previously, he worked as a reporter and columnist for The Virginian-Pilot in Norfolk, Va. and The Journal Gazette in Fort Wayne, Ind. He...