A Vulcan Centaur rocket launched a pair of space surveillance satellites for the U.S. military early Thursday morning (Feb. 12).
The Vulcan Centaur lifted off Thursday from Cape Canaveral Space Force Station in Florida at 4:22 a.m. EST (0922 GMT), kicking off the USSF-87 mission for the U.S. Space Force (USSF).
USSF-87's primary payloads were two satellites for the Geosynchronous Space Situational Awareness Program (GSSAP), a U.S. reconnaissance system.
Six GSSAP spacecraft had reached the final frontier before today — two apiece on launches in July 2014, August 2016 and January 2022. These satellites, which are built by Northrop Grumman, operate high above Earth, keeping a close eye on activities in geostationary orbit (GEO).
GEO lies 22,236 miles (35,785 kilometers) above Earth. At that altitude, orbital speed matches our planet's rotational speed, allowing satellites to "hover" over a particular patch of land or sea continuously. For that reason, GEO is a popular destination for weather, reconnaissance and communications satellites.
The GSSAP spacecraft operate "as a high-performance, dedicated Space Surveillance Network sensor," Space Force officials said in an emailed statement about the USSF-87 mission on Monday (Feb. 10). "They provide 'neighborhood watch' services in the geostationary Earth arena, improving flight safety for all spacefaring nations operating in that orbit."
Better information about the position and activities of satellites "within the increasingly crowded GEO drastically speeds USSF space operators' ability to warn others if another object is anticipated to approach too closely or creates a hazardous situation," they added. "Data from the GSSAP will uniquely contribute to timely and accurate orbital predictions, enhancing our knowledge of the GEO environment and further enabling spaceflight safety, including satellite collision avoidance."
The Vulcan Centaur successfully delivered the two GSSAP satellites to their designated orbit on USSF-87 despite suffering an anomaly with one of its four solid rocket boosters (SRBs), ULA said in an emailed statement after launch.
Also going up on USSF-87 were some research and development payloads, which will aid the precision of orbital maneuvers and improve the resilience of U.S. assets in GEO, among other functions, according to the Space Force statement.
USSF-87 was the fourth mission for the 202-foot-tall (61-meter) Vulcan Centaur, ULA's replacement for its workhorse Atlas V rocket.
Vulcan debuted in January 2024, sending Astrobotic's Peregrine lunar lander aloft. The launch went well, but Peregrine suffered an anomaly shortly after deployment and ended up crashing back to Earth.
Vulcan Centaur flew again in October 2024, on a successful mission that also overcame an SRB anomaly, and then again in August 2025. That latter launch was the rocket's first national security mission; it successfully sent an experimental navigation satellite to GEO for the Space Force.
The August 2025 mission employed the most powerful version of the Vulcan Centaur to date — one with four SRBs strapped to the core stage. USSF-87 used that same variant, which is known as the VC4S. The Vulcan can accommodate up to six SRBs.
Editor's note: This story was updated at 12:30 p.m. ET on Feb. 12 with news of the SRB anomaly and successful satellite deployment.
