United Launch Alliance’s Atlas 5 rocket marked its final swansong in launching critical missions related to U.S. national security. A dawn launch sent a classified payload as part of the United States Space Force-51 (USSF-51) mission, marking the 100th such operation for ULA.
Liftoff from Space Launch Complex 41 (SLC-41) at Cape Canaveral Space Force Station (CCSFS) occurred Tuesday, July 30, at 6:45 a.m. EDT (1045 UTC), opening a three-hour launch window. ULA’s countdown went smoothly with no hiccups during the fueling process.
Of the 99 national security flights conducted so far, ULA has used an Atlas 5 rocket on 57 of them. That collaboration between the rocket and the Department of Defense dates back to the first such mission, Space Test Program 1 (STP-1), which launched in March 2007.
These national security missions were originally contracted for under the Evolved Expendable Launch Vehicle (EELV) program. The program's name 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 that one, were National Security Space Launch missions and represented the establishment of a tremendous partnership with United Launch Alliance that has continued to this day,” said Dr. Walt Lauderdale, USSF-51 mission director.
“We have put into orbit a tremendous amount of national capability to support our warfighters and our intelligence communities, capabilities that we cannot surpass in some areas, but that help our people at sea, in the air and on the ground 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) journey to the launch pad at SLC-41. This came after ULA Launch Director Steve Huff led and completed the launch readiness review on Friday.
“This is the final launch of the Space Force Atlas 5 and it’s one of the most important payloads we’ve flown to date, I would say,” said Gary Wentz, ULA’s vice president of government and commercial programs. “We can’t talk about it too much, but it’s definitely critical to the defense of our nation and our allies.”
The USSF-51 mission was assigned to ULA as part of the NSSL Phase 2 Year 1 allocation. ULA and SpaceX were awarded $3.4 billion and $3.3 billion Indefinite Delivery Requirements (IDR) contracts in May 2019 to launch an estimated 34 missions, split 60/40.
Earlier this month, a contract modification was announced to “increase the total estimated dollar value of the contact due to the increase in estimated mission quantities to be ordered under the Phase 2 contract.”
“Under DFARS 205.303, a public announcement must be made after the initial estimated face value is met. The government included a manifest good faith estimate in the Phase 2 Request for Proposal, released in May 2019, to allow potential bidders to appropriately develop their proposals,” a U.S. Space Systems Command spokesperson told Spaceflight Now in a July 19 statement. “We estimated 34 missions would be ordered during Phase 2, and the 34 missions (split 60/40) were used to develop ULA and SpaceX’s contract values of $3.4 billion and $3.3 billion, respectively.”
“As fiscal year 2024 is the final Phase 2 ordering year, this modification updated the contracts to the actual number of missions ordered between fiscal years 2020 and 2024, which is 49, and therefore required increasing the contract values to $4.5 billion and $4 billion, respectively.”
The 49th mission, NROL-95, is expected to be awarded in late July, according to the SSC.
USSF-51 was originally planned to launch on a Vulcan rocket, but due to development delays, in June 2021 the U.S. Space and Missile Systems Center (renamed SSC in 2021) approved changing the launch vehicle from Vulcan to Atlas.
The era of 'The Bruiser'
While neither ULA nor the U.S. Space Force offered specific details about the mission, it is using what ULA calls “the highest-performance configuration of the rocket (Atlas) with a full set of five solid rocket boosters.” ULA called it the Atlas 5 551 configuration, or as ULA President and CEO Tory Bruno dubbed it, “The Bruiser.”
This version of the Atlas 5 rocket will be seen several more times before it is retired for good. 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 on this mission we’re flying five GEM (graphite-exposed engine) 63s,” Wentz said. “So we’ll learn from that, continue to get data, and in the future, apply that to future Atlas missions.”
Prior to the launch of USSF-51, ULA had launched 13 previous missions using the 551 configuration. ULA conducted the first flight with an Atlas 5 551 rocket on January 19, 2006, when it launched NASA's New Horizons mission to Pluto. This was the seventh launch of an Atlas 5 rocket in total.
The “Bruiser” version of Atlas 5 also launched the following missions:
- 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 analyzes, models and predicts performance. Then they look at all the flight characteristics, what the mission needs and the margins we have. Then when we get here, the team thoroughly reviews the details — stacking the propellant, mating the solids, the upper stage, integrating the payload,” Wentz said. “They continually focus on the safety of not only the hardware, but also our personnel throughout the process to achieve 100 percent mission success.”
Vulcans on the horizon
Once the USSF-51 mission is behind ULA, it will turn its attention to Vulcan’s second certification flight, known as Cert-2. Its first launch, Cert-1, proved successful in January, when it released the Astrobotic Peregrine lunar lander.
ULA aims for the second launch to take place in September with an inert payload on board that will include some Vulcan technology demonstrations.
“We're in the final stages of our certification. ULA is completing their final qualification testing, which is going well, and we're prepared to complete that and look forward to the data from this next certification flight and then be ready for our first mass national security intake in the October timeframe,” said Col. Jim Horne, Delta's senior material leader for launch execution.
“Things are progressing well. We have had a lot of good feedback, we have overcome some important obstacles and we are excited to get started this year.”
In recent weeks, Bruno has shared several images of the progress of the Vulcan vehicle, stating in a post on X, the former Twitter, that there are currently “23 Vulcans in production!!!”
Other #Vulcan Rocket leaves Alabama and heads to Florida, to make room in our crowded rocket factory. 23 Vulcans in production!!! image.twitter.com/CIfBl8yKMS
— Tory Bruno (@torybruno) July 26, 2024
That exclamation marked the beginning of the third Vulcan rocket leaving ULA's factory in Decatur, Alabama, on its journey to Florida. It will support the USSF-87 mission, which is set to launch in late 2024.
Vulcan's first operational mission will be the USSF-106 mission, which Horne referred to. Before that happens, Horne said he and others are eager to see how the Cert-2 mission performs.
Cert-2 was originally set to launch Sierra Space’s Dream Chaser spaceplane, but because it was falling behind on its final pre-launch work, ULA and Sierra Space decided to postpone that mission to another launch so they could move forward in the certification process.
“At this point, the (Cert-1) data correlated pretty well with our model. So this is another verification that we have the right analysis tools in place for future flights and that we've made sure we've captured the spacecraft and rocket environment,” Horne said.
“This will be a very good verification for us of what we saw in Cert-1. The configuration differences were within our certification plan. Based on that, they just had to make some adjustments for this mission. But we are excited to get the data.”
