United Launch Alliance’s Atlas 5 rocket is preparing for its final leg in terms of launching missions critical to U.S. national security. The company is preparing to launch a classified payload as part of the United States Space Force Squadron 51 (USSF-51) mission, which will mark ULA’s 100th operation.
The liftoff from Space Launch Complex 41 (SLC-41) at the Cape Canaveral Space Force Station (CCSFS) will take place within a three-hour window beginning at 6:45 a.m. EDT (10:45 a.m. UTC) on Tuesday, July 30. Spaceflight Now will provide live coverage beginning approximately two hours before the liftoff.
Of the 99 national security flights to date, ULA has used the Atlas 5 rocket for 57. The rocket’s partnership with the Department of Defense dates back to its first mission, Space Test Program 1 (STP-1), which launched in March 2007.
These national security missions were originally contracted under the Evolved Expendable Launch Vehicle (EELV) program, which was renamed National Security Space Launch (NSSL) in March 2019, about nine months before the establishment of the U.S. Space Force.
“Starting with this mission, the next five will be national security space launch missions and represent the building of a great partnership with United Launch Alliance that continues to this day,” said Dr. Walt Lauderdale, USSF-51 mission director.
“We’ve put a lot of national capabilities on track to support our warfighters and our intelligence communities. There are capabilities in some areas that I can’t say any more about, but it’s the ones that are helping our people every day at sea, in the air and on the ground around the world.”
ULA spent much of Saturday transporting the Atlas 5 rocket from its Vertical Integration Facility for the final one-third of a mile (550 meters) journey to the launch pad at SLC-41, after ULA launch director Steve Huff led and completed a launch readiness review on Friday.
“This is the final launch of Space Force Atlas 5 and I would say it’s one of the most significant payloads we’ve ever launched,” said Gary Wentz, ULA’s vice president of government and commercial programs. “I can’t say too much about it, but it’s certainly important to the defense of our nation and our allies.”
The USSF-51 mission was awarded to ULA as part of the NSSL Phase 2 Order Year 1 allocation. ULA and SpaceX signed a $3.4 billion/$3.3 billion Indefinite Delivery Requirement (IDR) contract in May 2019 to launch an estimated 34 missions in a 60/40 split.
A contract modification was announced earlier this month that “results in an increase in the estimated total contract value due to an increase in the mission quantity that will be ordered under the Phase 2 contract.”
“Per DFARS 205.303, initial estimates must be reached and then made public. The government included good faith estimates in the Phase 2 request for proposals released in May 2019 to allow potential bidders to develop their proposals appropriately,” a spokesperson for the U.S. Space Systems Command told Spaceflight Now in a statement on July 19. “We estimated that 34 missions would be ordered in Phase 2, and those 34 missions (split 60/40) were used to bring the contract values for ULA and SpaceX to $3.4 billion and $3.3 billion, respectively.”
“Because FY24 is the final ordering year for Phase 2, this change required us to update the actual number of missions ordered from FY20 to FY24 to 49 and increase the contract values to $4.5 billion and $4 billion, respectively.”
The 49th mission, NROL-95, is expected to be ordered by the end of July, according to SSC.
USSF-51 was originally scheduled to be launched on a Vulcan rocket, but due to development delays, in June 2021 the United States Space and Missile Systems Center (renamed SSC in 2021) approved changing the launch vehicle from Vulcan to Atlas.
The Bruiser Era
Neither ULA nor the U.S. Space Command have released details about the mission, but it will employ what ULA calls “the highest-performance configuration of the (Atlas) rocket, fully loaded with five solid rocket boosters.” ULA is calling this the Atlas 5 551 configuration, which ULA President and CEO Tory Bruno has dubbed “Bruiser.”
This version of the Atlas 5 rocket will be seen a few more times before it is eventually retired, and Wentz told Spaceflight Now on Saturday that all remaining commercial launches will be in the 551 configuration, which includes eight of Amazon’s Project Kuiper missions and one ViaSat mission.
“You learn a lot every time you fly, and on this mission we’re flying five GEM (Graphite Epoxy Motor) 63s,” Wentz said. “We’ll learn from that and continue to take data and apply it to future Atlas missions.”
Prior to the launch of USSF-51, ULA had launched 13 missions using the 551 configuration. ULA’s first launch of an Atlas 5 551 rocket was for NASA’s New Horizons Pluto probe on January 19, 2006. This was the seventh launch of the Atlas 5 rocket overall.
The next mission was also launched in Atlas 5’s version of “The Bruiser.”
- August 5, 2011 – Juno
- February 24, 2012 – MUOS-1
- July 19, 2013 – MUOS-2
- January 20, 2014 – MUOS-3
- September 2, 2015 – MUOS-4
- June 24, 2016 – MUOS-5
- April 14, 2018 – AFSPC-11
- October 17, 2018 – AEHF-4
- August 8, 2019 – AEHF-5
- March 26, 2020 – AEHF-6
- December 7, 2021 – STP-3
- September 10, 2023 – NROL-107
“The team does the modeling and predicts performance. Then they look at all the flight characteristics, what the mission requires, the margins. Then when we get here, the team does the very detailed work of stacking the boosters, bonding the solids, the upper stage, integrating the payload,” Wentz said. “They’re constantly focused on the safety of not only the hardware but also the personnel throughout the entire process to make the mission 100 percent successful.”
Balkans on the Horizon
With the USSF-51 mission behind it for ULA, the company will now turn its focus to Vulcan’s second certification flight, known as Cert-2. The first launch, Cert-1, was a successful one, delivering the Astrobotic Peregrine lunar lander in January.
ULA aims to conduct a second launch in September with an inert payload that will include demonstrations of several Vulcan technologies.
“We are in the final stages of certification. ULA has completed final qualification testing and is progressing well. We are poised for completion and awaiting data from the next certification flight to prepare for the first national security package approval sometime in October,” said Col. Jim Horn, senior materiel leader for launch execution Delta.
“Things are going well, we’ve received a lot of positive feedback and we’ve overcome some big obstacles. We’re excited to get started on the year.”
Bruno has released several images over the past few weeks showing the Vulcan’s development progress, stating in a post on his Twitter account that there are currently “23 Vulcans in production!!!”
another #VulcanRocket Leaving Alabama and heading to Florida to make room in a crowded rocket factory. 23 Vulcans in production!!! pic.twitter.com/CIfBl8yKMS
— Tory Bruno (@torybruno) July 26, 2024
The shout-out highlighted the third Vulcan rocket booster leaving ULA’s factory in Decatur, Alabama, on its journey to Florida. The rocket will support the USSF-87 mission, scheduled to launch in late 2024.
Vulcan’s first operational mission will be the one Horn mentioned, USSF-106, but before then, Horn said he and others are eager to observe the results of the Cert-2 mission.
Cert-2 was originally scheduled to launch Sierra Space’s Dream Chaser spaceplane, but delays in final pre-launch tasks led ULA and Sierra Space to decide to postpone that mission to a separate launch to allow time for the certification process to proceed.
“At this point, the data (from Cert-1) was correlating pretty closely with our model, so this is just further proof that we have the right analytical tools in place for future flights and that we have a robust understanding of the spacecraft and rocket environment,” Horn said.
“This is a really good opportunity to prove what we saw with Cert-1. The configuration differences were within the scope of our certification plan. Given that, we just had to make some adjustments on this mission. But we’re excited to get the data.”
