PARIS — United Launch Alliance says reuse of its future Vulcan rocket’s first-stage engines — featuring an inflatable hypersonic decelerator to protect the engines on atmospheric reentry, then a parafoil to glide them into position for a mid-air pickup by helicopter — is far more cost-effective than SpaceX’s planned recovery and reuse of the Falcon rocket’s entire first stage.
In a YouTube video demonstrating the technique, which ULA says could begin in 2024, the Centennial, Colorado-based company says SpaceX’s plans would require many more launches to reach economic break-even given the amount of fuel needed to return the first stage to Earth and land it.
“If you work the math, you see that you’re carrying a lot of fuel to be able to bring the booster back and it takes much longer to realize any savings in terms of the number of missions that you have to fly – and they need to be all successful,” says Mohamed Ragab, ULA’s senior staff engineer for advanced programs. “Our focus is on cost and the value of our proposition.”
Ragab says after separating from the lower stage, the engines are enveloped in a Hypersonic Inflatable Aerodynamic Decelerator (HIAD), which NASA developed for atmospheric reentry.
Once in the atmosphere, a parafoil is deployed to await a helicopter pickup. The video does not give the estimated total weight of the engine and HIAD ensemble, but Ragab says the parafoil technology “is well-advanced,” and that parafoils have demonstrated an ability to support masses of 40,000 pounds (18,182 kilograms).
Mid-air pickup has been employed since the 1960s for uses including recovery of spy-satellite film canisters.
Vulcan is scheduled to fly starting in 2019. ULA says the first attempted engine recovery could occur around 2024.
Airbus Defence and Space of Europe, the prime contractor for the Ariane 5 heavy-lift rocket, is working on a reusable design that, similar to ULA’s, focuses on recovery and reuse of only the engines and first-stage avionics suite, not the entire stage. Airbus hopes the technology could be introduced into Europe’s Ariane 6 rocket, to launch starting in 2020, around 2025.
Hawthorne, California-based SpaceX has already begun attempted landings of its Falcon 9 first stage, coming close but not yet achieving the feat on a special barge on which the first stage would land. The company plans to try again on its next Falcon 9 launch, which is scheduled to occur in November.