United Launch Alliance’s Vulcan rocket, designation V-005, is seen at the pad at Space Launch Complex 41 at Cape Canaveral Space Force Station prior to the launch of the USSF-87 mission for the U.S. Space Force. Image: Michael Cain/Spaceflight Now
United Launch Alliance is gearing up for a predawn launch of its Vulcan rocket on Thursday morning, the companies first flight of the year.
The United States Space Force (USSF)-87 mission consists of multiple satellites, though the exact number was not publicly disclosed prior to launch. This is ULA’s second national security mission using its Vulcan rockets and will also be the company’s longest mission to date.
“This mission will last, total duration from launch to end of mission, 10 hours. As has been stated before, Vulcan was purpose built and this is the type of mission that the team actually designed this launch vehicle to support,” said Gary Wentz, ULA’s vice president of Atlas and Vulcan Programs.
“It’s significant payloads to very complex orbits, multi-manifested national security space, direct to GEO (geosynchronous Earth orbit). So this is tailor fit for that mission. This is why we put the Vulcan in place and designed it this way.”
Liftoff from Space Launch Complex 41 at Cape Canaveral Space Force Station is scheduled for 3:30 a.m. EST (0830 UTC), at the opening of a two-hour window. The rocket will fly on an easterly trajectory upon leaving the launch pad.
Spaceflight Now will have live coverage beginning about an hour prior to liftoff.
The 45th Weather Squadron forecast idyllic weather during the launch window, showing a 95 percent chance for good conditions at liftoff. However, they are keeping an eye on solar activity, anticipating “an increased probability of X-ray flares” during the primary and backup launch dates.
“With light winds overnight, there’s a chance shallow mist may decrease visibility in the early morning hours on Thursday morning,” launch weather officers wrote. “The surface high begins to break down on Thursday as a weak frontal boundary approaches in the afternoon. No significant precipitation is expected with this boundary.”
United Launch Alliance’s Vulcan rocket, designation V-005, is seen at the pad at Space Launch Complex 41 at Cape Canaveral Space Force Station prior to the launch of the USSF-87 mission for the U.S. Space Force. Image: Adam Bernstein/Spaceflight Now
The rocket is flying in a VC4S configuration, meaning it has four, side-mounted Graphite Epoxy Motor (GEM) 63XL solid rocket boosters (SRBs) and a ‘standard’ 51-foot-long (15.5 m), 17.7-foot-diameter (5.4 m) payload fairing.
The SRBs will jettison less than two minutes after liftoff, which will be followed by the separation of the Vulcan booster from the Centaur 5 upper stage about five minutes into the mission.
In typical fashion for a mission designated as supporting U.S. national security interests, the exact timing of payload deployment is not disclosed.
What’s onboard?
The Vulcan rocket, designated as V-005, has the Geosynchronous Space Situational Awareness Program (GSSAP) system as its primary payload. In a statement, the U.S. Space Force’s Space Systems Command (SSC) described it as “a high-performance, dedicated Space Surveillance Network sensor” designed to augment the U.S. Space Command’s awareness of activities in geostationary Earth orbit, roughly 22,000 miles (35,000 km) above the Earth.
Neither the Space Force nor ULA would confirm in the week leading up to launch how many GSSAP satellites were manifested on the mission. During a prelaunch briefing, Wentz said, “I can’t say that it’s two or one or three or any other number.”
United Launch Alliance’s Vulcan rocket, designation V-005, is seen at the pad at Space Launch Complex 41 at Cape Canaveral Space Force Station prior to the launch of the USSF-87 mission for the U.S. Space Force. Image: Adam Bernstein/Spaceflight Now
That said, historically, these satellites flew in pairs. The first two pairs launched on Delta 4 Medium-plus rockets, first in July 2014, followed by the next set in August 2016. The third and most recent pair, GSSAP-5 and 6 launched on an Atlas 5 rocket in January 2022.
One of the first two satellites, GSSAP space vehicle 2, was taken out of service and put in a graveyard orbit, according to a statement from Lt. Col. Greg Fertig, the then deputy program manager of the SSC’s GSSAP Program Office, to Space News in August 2023.
Fertig also told Space News at the time that the Space Force had ordered two more of these GSSAP satellites to be built by Northrop Grumman.
“In addition to the GSSAP payload, USSF-87 will include additional research, development and training systems. Guardians will use these systems to refine tactics, techniques and procedures for precision on-orbit maneuvers,” SSC said in a statement. “These systems will also enhance and validate resiliency and protection in geosynchronous orbit.”
These additional payloads will be mounted to Northrop Grumman’s ESPAStar platform, a maneuverable spacecraft capable of housing up to six hosted payloads and up to 12 deployable payloads.
An artist’s rendering of two Geosynchronous Space Situational Awareness Program (GSSAP) satellites in orbit. Image: Northrop Grumman via U.S. Space Force