End of an Era for Atlas V
Early in the morning of July 2nd, the United Launch Alliance Atlas V rocket flew in its heaviest configuration for the final time. Indeed, the Atlas V Amazon Leo 8 (LA-08) mission marked the last time Atlas will carry a typical payload inside a fairing, closing one of the final chapters in the rocket’s storied history. Now, only a handful of purpose-built Atlas vehicles remain, destined to fly an uncertain number of Boeing’s Starliner spacecraft. The end of Atlas as a traditional commercial launch vehicle is sorely felt as ULA awaits the return of its next-generation Vulcan rocket.
Atlas V leapt off of Space Launch Complex-41 at Cape Canaveral Space Force Station at 12:30 AM Eastern time, a few minutes past the top of its window. The rocket completed a nominal ascent into space, shedding its five solid rocket boosters and 5.4-meter diameter payload fairing in sequence. Live updates from ULA confirmed that all 29 satellites were successfully deployed into their target orbit. They join a growing number in Amazon’s Leo (formerly Kuiper) internet constellation, which aims to provide satellite internet to underserved communities across the globe. At roughly 16,800 kg, the 29-satellite stack flown on the last four Atlas V Leo missions is the heaviest payload the family has ever flown.
The Atlas rocket family history traces back all the way to the SM-65 Atlas, the United States’ first operational ICBM. The rocket uniquely featured thin-walled “balloon” tanks, which required internal pressure to stay rigid, and a half-stage design whereby the two outer engines were jettisoned partway through ascent. Variants of this rocket sent the first Americans into orbit as Mercury-Atlas; the rocket was briefly paired with the Agena upper stage before being matched with Centaur, forming the basis for the rest of the Atlas family.
Stretched fuel tanks, reinforced structures, improved electronics, a new fairing, and other upgrades eventually carved out the niches of Atlas I and II. The unique half-staged engines were later replaced with a single Russian-built RD-180 engine in Atlas III. Finally, the modern Atlas V eliminated the “balloon” tanks and offered a wider range of customizability for commercial markets, including anywhere from one to five solid rocket boosters and two sizes of payload fairings.
Atlas V has flown 110 times, and was often NASA’s go-to launcher for interplanetary and deep space missions, including New Horizons, the Lunar and Mars Reconnaissance Orbiters, Curiosity and Perseverance, and OSIRIS-REx. Now, Atlas V has just a single customer remaining: NASA and Boeing’s Starliner spacecraft. However, the future of the Starliner program remains unclear nearly two years after the launch of its troubled Crew Flight Test. Though NASA has reaffirmed its desire to continue flying astronauts aboard Starliner, it remains to be seen how many missions it will actually fly to the ISS before the station’s decommissioning.
Meanwhile, ULA has once again been frustrated in its effort to bring the Vulcan Centaur rocket online to replace Atlas V. Vulcan’s debut has been marred by delays to its payloads, the loss of its solid rocket booster nozzles in flight, and most recently the explosion of Blue Origin’s New Glenn rocket. The BE-4 engines which power both launch vehicles may be implicated by this failure, forcing ULA to pause launches of Vulcan as it awaits the results of Blue Origin’s investigation.
All the same, Atlas V closes the penultimate chapter in its history with a simple, clean success, the kind the rocket is well known for. Save a few Starliner flights, the story of Atlas is functionally complete, leaving very big shoes for its successor to fill.
