Pratt & Whitney Rocketdyne, Dynetics Propose SLS Boosters Based on F-1 Engines

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WASHINGTON — Propulsion provider Pratt & Whitney Rocketdyne (PWR) of Canoga Park, Calif., and Huntsville, Ala.-based Dynetics submitted a joint proposal to NASA in early April to develop advanced side-mounted boosters for the agency’s Space Launch System (SLS) heavy-lift rocket that would be based on the F-1 engines that powered the giant Saturn 5 launcher of Apollo fame.

NASA plans to use modified space shuttle solid rocket motors supplied by Utah-based ATK Aerospace Systems for the first two SLS flights before switching to a competitively procured Advanced Booster System.

NASA intends to award $200 million in contracts this fall for 30 months’ worth of SLS advanced booster demonstration and risk-reduction efforts meant to set the stage for an eventual flight hardware |procurement.

“NASA is after an affordable booster for SLS that can get them up to at least 130 [metric] tons” of lift capacity to low Earth orbit, said Steve Cook, director of space technologies at Dynetics and NASA’s former lead rocket designer. “Our approach uses two F-1s per booster. That gives us about a 20-metric-ton performance increase over an equivalent solid rocket booster approach.”

The F-1 is a kerosene-fueled engine capable of producing 1.5 million pounds of thrust at sea level, about 75 percent more thrust than the Soviet-heritage RD-180 engines that power United Launch Alliance’s Atlas 5 rocket.

Cook said the Dynetics-PWR proposal involves “taking the best from F-1 and F-1A” — the latter being a lighter, more powerful follow-on engine that never got a chance to fly — and combining it with 40 years of manufacturing advances to produce a high-performance engine that is both reliable and affordable.

“The F-1 is still the most powerful U.S. rocket engine ever flown, but they didn’t worry about cost in the ’60s, not like we have to today,” Cook said.

The Dynetics-PWR team proposed a wide range of demonstration and risk-reduction activities for NASA to fund, the most expensive being a full-scale hot fire test of the F-1 power pack.

John Vilja, vice president of strategy, innovation and growth at PWR, said via email April 24 that there are five F-1 engines from the canceled Apollo 18 mission at NASA’s Marshall Space Flight Center in Huntsville. The agency is disassembling those engines, he said.

In addition, PWR has some F-1 turbopumps that it is disassembling, Vilja said in the email. “The hardware looks really good,” Vilja told reporters in Colorado Springs, Colo., April 16.

In the email, Vilja said PWR’s bid with Dynetics “will be to design an engine to replace the obsolete materials and processes, assemble an F-1A powerpack, and build a modern chamber and nozzle. All that assumes all options of our risk reduction bid are selected.”

During the April 16 press briefing, PWR officials said they also have offered the kerosene-fueled RD-180, which powers the main stage of United Launch Alliance’s Atlas 5 rocket, and an engine dubbed RS-84 for the advanced booster program. The RD-180 is provided by RD-Amross, a joint venture of PWR and Energomash of Russia; the RS-84 is a kerosene-fueled engine designed under NASA’s now defunct Space Launch Initiative, PWR officials said.

In his email, Vilja declined to discuss any advanced booster program teaming arrangements involving the RD-180 and RS-84 engines. He said PWR has discussed large kerosene-fueled boosters with other vehicle prime contractors.

 

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