United Launch Alliance’s Atlas 5 rocket is preparing for its swan song when it comes to launching critical U.S. national security missions. The launch provider is preparing to send a classified payload on the United States Space Force-51 (USSF-51) mission, marking ULA’s 100th such operation.
Liftoff from Space Launch Complex 41 (SLC-41) at Cape Canaveral Space Force Station (CCSFS) is scheduled for Tuesday, July 30, in a three-hour window that opens at 6:45 a.m. EDT (10:45 UTC). Spaceflight Now will provide live coverage starting nearly two hours before liftoff.
Of the 99 national security flights conducted so far, ULA has used an Atlas 5 rocket on 57 of them. The partnership between the rocket and the Department of Defense dates back to the first such mission, Space Test Program 1 (STP-1), launched in March 2007.
These national security missions were originally assigned to the Evolved Expendable Launch Vehicle (EELV) program. The program’s name was changed to National Security Space Launch (NSSL) in March 2019, approximately nine months before the creation of the U.S. Space Force.
“The next five missions, starting with this one, were national security space launch missions and represented the creation of a tremendous partnership with United Launch Alliance that has continued to this day,” said Dr. Walt Lauderdale, USSF-51 mission director.
“We have deployed many national capabilities to support our warfighters and our intelligence communities, capabilities that we can’t talk about in some areas, but that help our people at sea, in the air and on land around the world every day.”
ULA spent much of Saturday rolling the Atlas 5 rocket out of its vertical integration facility for its final, one-third-mile (550-meter) ride to the SLC-41 launch pad. That came after ULA Launch Director Steve Huff led and completed the launch readiness review Friday.
“This is the final launch of the Space Force Atlas 5 and I would say it’s one of the most critical payloads we’ve put out there to date,” said Gary Wentz, ULA’s vice president of government and commercial programs. “We can’t talk about it much, but it’s certainly critical to the defense of our nation as well as our allies.”
The USSF-51 mission was awarded to ULA as part of the NSSL Phase 2 order Year 1 mission. ULA and SpaceX were awarded $3.4 billion and $3.3 billion indefinite delivery contracts (IDRs) in May 2019 to launch approximately 34 missions, split 60/40.
Earlier this month, a contract modification was announced to “increase the total estimated contract dollar value due to the increase in the estimated mission quantities to be ordered under the Phase 2 contract.”
“In accordance with DFARS 205.303, a public announcement must be made once the initial estimated nominal value is reached. The government included a good faith estimate in the Phase 2 Request for Proposals, issued in May 2019, to allow potential bidders to adequately develop their proposals,” a U.S. Space Systems Command spokesperson told Spaceflight Now in a July 19 statement. “We estimated that 34 missions would be ordered in Phase 2, and the 34 missions (split 60/40) were used to develop the ULA and SpaceX contract values of $3.4 billion and $3.3 billion, respectively.”
“With fiscal year 2024 being the final ordering year for Phase 2, this amendment updated the contracts to reflect the actual number of missions ordered for fiscal years 2020 through 2024, which was 49, and therefore increased the contract values to $4.5 billion and $4 billion, respectively.”
The 49th mission, NROL-95, is expected to be awarded by the end of July, according to the SSC.
The USSF-51 was originally planned to be launched on a Vulcan rocket, but due to development delays, in June 2021 the US Space and Missile Systems Center (renamed SSC in 2021) approved the switch from the Vulcan to Atlas launcher.
The era of “The Bruiser”
While neither ULA nor the U.S. Space Force have provided details about the mission, it uses what ULA calls “the most capable configuration of the (Atlas) rocket with a full complement of five solid rocket boosters.” ULA has called it an Atlas 5,551 configuration, or as ULA President and CEO Tory Bruno has dubbed it, “The Bruiser.”
This version of the Atlas 5 rocket will be seen several times before the rocket is finally retired. Wentz told Spaceflight Now on Saturday that all of its remaining commercial launches will use the 551 configuration, which includes eight missions for Amazon’s Project Kuiper and one for Viasat.
“Every time you fly, you learn a lot, and we have five GEM (Graphite-Expoxy Motor) 63 engines on this mission,” Wentz said. “So we’re going to learn from this, we’re going to continue to collect data, and in the future, we’re going to apply that knowledge to subsequent Atlas missions.”
Prior to the launch of the USSF-51, ULA had already launched 13 missions using the 551 configuration. ULA first launched an Atlas 551 rocket on January 19, 2006, during the launch of NASA’s New Horizons mission to Pluto. This was the seventh launch of an Atlas 5 rocket overall.
The “Bruiser” version of Atlas 5 also launched the following missions:
- August 5, 2011 – Juno
- Feb. 24, 2012 – MUOS-1
- July 19, 2013 – MUOS-2
- Jan. 20, 2014 – MAY 3
- Sept. 2, 2015 – MAY 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
- Sept. 10, 2023 – NROL-107
“The team does the modeling and performance prediction. Then they look at all the flight characteristics, the mission requirements and the margins that we have. Then when we get here, the team goes through the nitty-gritty details, stacking the propellant, mating the solids, the upper stage, integrating the payload,” Wentz said. “They’re constantly focused on the safety of not only the hardware but our people throughout the entire process to ensure 100 percent mission success.”
Vulcans on the horizon
With the USSF-51 mission behind us, ULA will focus on Vulcan’s second certification flight, known as Cert-2. Its first launch, Cert-1, proved successful in January when it launched the Astrobotic Peregrine lunar lander.
ULA plans a second launch in September with an inert payload on board that will include some demonstrations of Vulcan technology.
“We are in the final phases of our certification. ULA is completing its final qualification tests, which are going well, and we are ready to be complete and awaiting data from this next certification flight, and then be ready for our first mass national security admission in the October timeframe,” said Col. Jim Horne, Delta’s senior hardware manager for launch execution.
“Things are progressing well. We’ve received a lot of positive reviews, we’ve overcome some major obstacles and we’re looking forward to launching this year.”
In recent weeks, Bruno has shared several images of the Vulcan vehicle’s progress, specifying in a post on X, formerly Twitter, that there are currently “23 Vulcans in production!!!”
Another #VulcanRocket leaves Alabama and heads to Florida, making room in our crowded rocket factory. 23 Vulcans in production!!! pic.twitter.com/CIfBl8yKMS
— Tory Bruno (@torybruno) July 26, 2024
The exclamation marked the departure of the third Vulcan booster from ULA’s Decatur, Alabama, facility to begin its journey to Florida. It will support the USSF-87 mission, which is scheduled to launch in late 2024.
Vulcan’s first operational mission will be USSF-106, which Horne referred to. Before that, Horne said he and others are eager to see how the Cert-2 mission performs.
Cert-2 was originally scheduled to launch Sierra Space’s Dream Chaser spaceplane, but as it fell behind schedule in its final prelaunch work, ULA and Sierra Space decided to postpone that mission until another launch in order to move forward with the certification process.
“At this point, the (Cert-1) data was pretty closely correlated with our model. So this is another check that we have the right analysis tools for future flights and making sure we’ve captured the environment of the spacecraft as well as the rocket,” Horne said.
“This will be a very good verification for us of what we saw in Cert-1. The configuration differences were very much in line with our certification plan. Based on that, it was just some adjustments they had to make for this mission. But we look forward to getting the data.”
