ULA prepares for its first ever Vulcan flight

United Launch Alliance (ULA) is gearing up for the launch of its new Vulcan rocket from Space Launch Complex (SLC) 41 at the Cape Canaveral Space Force Station in Florida. The inaugural flight is scheduled for January 8, 2024, and will carry Astrobotic’s Peregrine lunar lander as part of NASA’s Commercial Lunar Payload Services (CLPS) initiative and the Artemis program.

The Vulcan Centaur is set to replace ULA’s Delta IV family of rockets and its workhorse Atlas V. With a height of 61.6 meters (202 feet) and a diameter of 5.4 meters (18 feet), the Vulcan rocket features two different-length payload fairings, a 15.5-meter (51-foot) “short” fairing and a 21.3-meter (70-foot) “long” fairing, with the short fairing being used on this first flight.

The first stage booster of the Vulcan rocket is made of aluminum orthogrid tanks that can hold over 450 tonnes of liquid oxygen and liquid natural gas, which in this case is pure liquid methane. This makes it ULA’s first methalox vehicle, utilizing liquid oxygen as an oxidizer and methane as fuel. The stage is powered by two BE-4 engines developed by Blue Origin, each producing 2.45 meganewtons (550,000 pounds) of thrust at sea level. The Vulcan rocket can also accommodate GEM 63XL solid rocket boosters (SRBs) manufactured by Northrop Grumman Space Systems, with options for zero, two, four, or six SRBs for additional thrust. The inaugural flight will feature two mounted SRBs.

The Centaur V second stage, powered by liquid hydrogen and liquid oxygen, will separate from the first stage after the depletion of the SRBs. This marks the first redesign of the fully cryogenic Centaur since 2002. The Centaur V has a diameter of 5.4 meters (18 feet) and is equipped with two RL-10 engines from Aerojet Rocketdyne, capable of multiple relights with a maximum thrust of 213.5 kilonewtons (48,000 lbs).

During a propellant loading and tank pressurization test in March 2023, a test article of the Centaur V upper stage was destroyed due to a hydrogen leak ignition. However, ULA quickly made modifications to strengthen the affected area and sent another Centaur upper stage for the inaugural Vulcan launch.

ULA has been preparing for the Vulcan’s launch campaign since 2015 when the company announced its plans to introduce a new launch vehicle. The original design for the second stage involved using the current Centaur III and later upgrading to the Advanced Cryogenic Evolved Stage (ACES). However, the ACES concept was shelved, and ULA decided to incorporate design elements from both Centaur III and ACES into a single second stage. The first flight was initially planned for July 2021 but faced delays due to the delivery of BE-4 engines and the impact of the COVID-19 pandemic.

The payload for the inaugural Vulcan launch includes Astrobotic’s Peregrine lunar lander, which will be one of the first US landers on the Moon since Apollo 17 in 1972. Peregrine is scheduled to land in February 2024 at Sinus Viscositatis, a lunar feature near the largest dark spot on the near side of the Moon. The lander will carry five NASA payloads aimed at collecting data on water molecules, solar radiation interaction with the lunar surface, and other scientific experiments. Additionally, a secondary payload from Celestis Memorial Spaceflights, known as the Enterprise flight, will include capsules with cremated remains and DNA samples of notable individuals.

The flight profile for the Vulcan’s inaugural launch, known as VC2S, involves various stages of propellant loading, engine ignition, and stage separation. The BE-4 engines will ignite at T-5 seconds, followed by liftoff at T+1 second. The SRBs will finish their portion of the flight at T+1 minute 50 seconds, followed by their jettison. The first stage booster will continue burning until T+4 minutes 59 seconds, after which it will separate from the second stage. The Centaur second stage will continue firing until its first main engine cutoff at T+15 minutes 45 seconds. There will be subsequent burns and separations before the mission concludes at T+4 hours 24 minutes 44 seconds.

The inaugural flight of the Vulcan rocket marks an important milestone for ULA, as it becomes the company’s first new launch vehicle since its formation in 2006. With its advanced features and capabilities, the Vulcan will play an important role in future space missions and the Artemis program’s objective of returning astronauts to the Moon.