Update: Due to a space vehicle processing issue, the new launch date is Dec. 4, 2021.

WASHINGTON — United Launch Alliance is targeting a Nov. 22 liftoff for the U.S. Space Force STP-3 mission aboard an Atlas 5 rocket. 

The mission previously was scheduled to launch June 23 from Cape Canaveral but was delayed to investigate an issue in the Atlas 5’s RL-10 upper stage engine. 

The Atlas 5 551 will fly with five solid rocket boosters and launch two satellites directly to geosynchronous orbit. 

STP-3’s primary payload is the STPSat-6 satellite built by Northrop Grumman. It will carry NASA’s Laser Communications Relay Demonstration (LCRD), an end-to-end optical relay that will send and receive data from space to the ground. According to NASA, LCRD also will conduct optical communications relay services with a future terminal on the International Space Station and will help to prove the viability of using laser communications in future missions to the Moon and Mars.

Also on STPSat-6 is a nuclear treaty verification payload from the National Nuclear Security Administration called SABRS-3, short for Space and Atmospheric Burst Reporting System-3.  The STPSat-6 spacecraft additionally will carry seven smaller science and technology payloads selected by the Defense Department’s Space Test Program.

The secondary payload on STP-3 is a U.S. Space Force small-satellite deployer system called Long Duration Propulsion ESPA-1 (LDPE-1). This is a propulsive ESPA ring (EELV Secondary Payload Adapter) holding up to six payloads.

The launch of this mission has been long awaited. The Air Force in 2017 awarded ULA a $191.1 million contract to launch STP-3 in 2019. The delays were caused by a combination of payload development setbacks, the pandemic and most recently the RL-10 engine issue.

Sandra Erwin writes about military space programs, policy, technology and the industry that supports this sector. She has covered the military, the Pentagon, Congress and the defense industry for nearly two decades as editor of NDIA’s National Defense...