(Tribune News Service) — United Launch Alliance is about the surpass its total number of launches in 2023 with a planned mission for the Space Force early Tuesday.

An Atlas V rocket on the USSF-51 mission is set to lift off at 6:45 a.m. at the opening of a three-hour window from Cape Canaveral Space Force Station’s Space Launch Complex 41.

This is the 100th national security mission flown by ULA across its fleet of rockets. It will be the final one on an Atlas V, which has just 16 rockets left. Eight of those are set aside for Amazon launches of its Project Kuiper internet satellites, six set aside for Boeing’s Starliner and one set to fly a communications satellite for ViaSat.

Future ULA launches will be on its new Vulcan Centaur rocket, which flew for the first time in January and is set for a second flight as early as September.

This is just the fourth launch for ULA in 2024, which followed up the Vulcan debut with the final launch of the Delta IV Heavy in April and an Atlas V for the Starliner Crew Flight Test in June. ULA only managed three launches in 2023. The most ULA has flown is 16 launches in 2009.

ULA CEO Tory Bruno, though, said the company is on target still for eight launches before the end of the year. USSF-51 will be followed by the Vulcan Cert-2 mission, which will simply launching a mass simulator as part of ULA’s efforts to get the OK to use Vulcan on future national security missions.

Already two years behind schedule, ULA has 26 missions worth $3.1 billion under National Security Space Launch (NSSL) contracts. USSF-51 was originally supposed to fly on Vulcan, but ULA opted to switch to one of its remaining Atlas V rockets to get the ball rolling on the contracts.

If Vulcan gets certified after September’s planned mission, that will set up ULA to be able to fly two of those NSSL missions — USSF-106 and USSF-87 — before the end of the year. ULA has the rockets and BE-4 engines supplied by Blue Origin already in hand for those.

It also could fly one more Atlas V before the end of the year on the first operational mission for Amazon’s Project Kuiper, but that depends on that company’s delivery of its satellites.

But first up is USSF-51, for the Space Force’s Space Systems Command (SSC) with a classified payload.

“The Space Force Atlas V team has an amazing record of serving our National Security Space lift needs,” said USSF Col. Jim Horne, senior materiel leader for SSC’s Launch Execution Delta in a press release. “We have always worked extremely well with this team, and this mission, our last launch with the Atlas V, is looking great.”

National security flights have been using the Atlas family of rockets since 1957. The last generation of the rocket — Atlas V — had its first national security flight in 2007. USSF-51 will mark the 58th national security mission of Atlas V, 53 of which were for either the Air Force or Space Force.

“The Atlas V launch system has been the stalwart for national security launches over the past 20 years,” said Walt Lauderdale, USSF-51 mission director. “This mission, together with all those preceding, demonstrates the Atlas V integrated government/industry team’s commitment to safely deliver critical assets to space.”

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