ULA nears second launch of Vulcan Centaur in pursuit of US Space Force approval

No spaceplane in the payload, but it won't be a wasted mission

Updated United Launch Alliance's (ULA) Vulcan Centaur is ready to blast off from Florida this morning, the second flight to space for the rocket.

While the mission, dubbed Cert-2, was originally set to carry Sierra Space's Dream Chaser, delays with the spaceplane have meant that ULA opted to lift-off with an inert payload instead.

ULA needs to get that second attempt under its belt to certify the vehicle for lucrative US national security payloads.

The Vulcan Centaur is ULA's replacement for the Atlas V and Delta IV launchers. Its maiden voyage – which ran later than scheduled, in part due to the slower delivery of the Blue Origin BE-4 engines used to power the first stage – went ahead in January 2024. Named Cert-1, the rocket was carrying Astrobotic's Peregrine lunar lander.

After giving up the wait for Dream Chaser, which should arrive at some point in 2025, ULA is instead going to use a mass simulator along with some experiments and demonstrations to ease the vehicle's passage to US Space Force certification.

According to ULA boss Tory Bruno, ULA waited for Sierra Space until "the last minute," which meant the company was unable to integrate payloads from other customers keen on a ride to orbit.

The variant of the Vulcan Centaur being launched today features a pair of solid rocket boosters strapped onto the first stage, which is powered by two BE-4 engines, each producing 550,000 lbf (2.4 meganewtons) of sea level thrust. Each solid rocket booster contributes an additional 459,600 lbf (2.044 meganewtons) of thrust at lift-off.

According to Bruno, ULA decided on a heliocentric disposal of the upper stage – leaving it in an orbit around the Sun – after some "experimental maneuvers."

If all goes well, ULA aims to launch two more Vulcan Centaur rockets in 2024 before ramping up the cadence in 2025. ULA is planning for an ambitious 20 launches, split between the outgoing Atlas V and the Vulcan Centaur. These aren't SpaceX-level numbers, but considerably more than ULA has managed in the past.

The three-hour launch window opens at 1000 UTC, and there is currently an 80 percent chance that the weather will cooperate. A Wet Dress Rehearsal (WDR) earlier this week, where the rocket was fueled and a countdown performed to just before engine ignition, went well.

The next step will be to ignite the engines and stand back a few hours from now. ®

Updated to add at 1232 UTC, October 4

After a slight delay, the Vulcan Centaur successfully lifted off from Space Launch Complex-41 at 1125 UTC. Five minutes and 30 seconds later, the first stage was jettisoned, and the Centaur V upper stage took over to send itself and the inert payload into an initial parking orbit around the Earth.

At T-plus 35 minutes and three seconds, the engines of the Centaur V upper stage were fired up again to take the upper stage and its inert payload to deep space and into an orbit around the Sun.