United launch alliance (ULA)
Who is ULA?
United Launch Alliance, more commonly known as ULA, is a provider of space launch services to the US government that was formed by Lockheed Martin and Boeing. ULA typically launches payloads for the Department of Defense (DoD) and NASA. They held a monopoly on military and defense launches before SpaceX was awarded a GPS contract by the US Air Force in 2016.
“ULA is harnessing the potential of space for humanity. We are dreamers inspired by possibilities not yet imagined, believers driven to broaden horizons, and doers combining technology, innovation, expertise, ingenuity and a commitment to the extraordinary.”
ULA currently utilizes two launch systems, the Delta IV and the Atlas V, both having multiple configurations to accommodate various mission requirements — with the Delta IV Heavy being the most powerful launch vehicle in their arsenal, for now. ULA and SpaceX are currently the only providers launching out of the Space Coast.
ULA’s Delta IV is a two stage, completely expendable launch system that is currently available in three configurations: the Delta IV Medium+, with either two (M+ 5,2) or four (M+ 5,4) solid rocket motors (SRM), and the Delta IV Heavy (DIVH) with three common booster cores (CBC). The Delta IV was designed to launch payloads for the US government and all Delta IV launches, with the exception of its maiden launch, have been paid for by the government. All Delta IV variants are powered by Aerojet Rocketdyne RS-68A engines, the world’s most powerful hydrogen-fueled rocket engine, capable of up to 705,000 pounds of thrust. In its Medium+ configuration, the first stage consists of one RS-68A engine and up to four GEM 60 SRMs. In its Heavy configuration, which is currently the most powerful vehicle that ULA launches, the first stage consists of three CBCs — with each powered by one RS-68A engine. Delta IV’s upper stage, known as the Delta Cryogenic Second Stage (DCSS), is powered by an Aerojet Rocketdyne RL10B2 engine which is fueled by liquid hydrogen and uses the “world’s largest carbon-carbon extendable nozzle for increased performance.” The Delta IV has launched 37 times all of which successful, other than one partial failure during the the demo flight of DIVH where a premature engine shutdown led to the DCSS needing to make up for the under-burn. ULA CEO, Tory Bruno, has described the Delta IV as the world’s “most metal rocket” since it creates a large fireball, that typically engulfs the rocket in flames, during the beginning stages of engine startup as it burns off excess gas in the immediate environment caused by premature hydrogen fuel flow that’s used protect the vehicle’s interior components from the more reactive oxygen. ULA is slowly phasing out the Delta IV, which only a few launches left on its manifest.
ULA’s Atlas V is a two stage, completely expendable launch system that is currently available in a number of configurations, with its 551 configuration being the most powerful. All Atlas V variants are powered by a Russian-built RD-180 engine capable of up to 860,000 pounds of thrust as well as AJ-60A SRM boosters, each providing 379,600 pounds of thrust. Atlas V’s upper stage, known as Centaur, is powered by an Aerojet Rocketdyne RL10 engine. Atlas V has launched 79 times all of which successful, other than one partial failure that was declared successful by the customer.
The Vulcan Centaur is a new heavy-payload rocket being developed that, like ULA’s other launch vehicles, will be available in a number of configurations — including a planned Vulcan Centaur Heavy variation. Vulcan’s first stage will be powered by two of Blue Origin’s methane-fueled BE-4 engines, which are expected to be capable of 495,000 pounds of thrust, as well as a number of GEM-63XL SRM boosters. The second stage, known as the Advanced Cryogenic Evolved Stage (ACES), is an upgraded variant of Centaur and will either be powered by four RL10-C engines or a single BE-3 engine. Both Vulcan and its ACES second stage are planned to undergo the human-rating process to allow for manned missions. When completed, Vulcan will be the most powerful launch vehicle in ULA’s arsenal. ULA is currently targeting NET April 2021 for Vulcan’s maiden flight.