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.