The powerful rocket engine developed in the 1960s to launch the first men to the Moon could be reprised in the 2020s as the powerplant for strap-on boosters that NASA hopes to use in heavy-lift human missions to Mars. Under a new NASA risk-reduction project, Dynetics Inc., a relative newcomer to space launch, will explore the idea for the U.S. agency in partnership with Pratt & Whitney Rocketdyne.

Rocketdyne built the 1.5-million-lb.-thrust F-1 engine for NASA, which mounted five of the kerosene-fueled behemoths in the Saturn V first stage to propel the massive Saturn/Apollo stack off the launch pad. The F-1—19 ft. tall, with a nozzle 12.5 ft. across—epitomized the scale of the flight hardware and ground infrastructure NASA used to beat the Soviet Union to the Moon. If NASA decides to fly it again, it probably will be tested in the same stands built for the F-1 at the agency's Marshall and Stennis field centers, stacked in the same 40-story Vehicle Assembly Building at the Kennedy Space Center used for Apollo and the space shuttle, and launched from one of the pads built for the Moon program.

Dynetics scored big in a $200 million NASA effort to reduce the risk on advanced boosters for the planned Space Launch System (SLS) that Congress ordered as a government-owned deep-space alternative to the commercial vehicles the agency wants to use for transport to the International Space Station. Last week NASA selected the company to negotiate for three of six 30-month study contracts designed to reduce risk on the twin boosters that will be needed to raise the SLS capability from an initial 70 metric tons to the 130 metric tons the agency believes will be needed for human missions beyond low Earth orbit.

“With an F-1-based approach, we get significant performance enhancement beyond the 130 [tons], on the order of 20 metric tons,” Steve Cook, Dynetics' director of space technologies and NASA's former Ares program manager, tells Aviation Week's Jefferson Morris.

Headquartered in Huntsville, Ala., near the World War II-vintage U.S. Army arsenal where Wernher von Braun's team developed the Saturn V and its engines, Dynetics was selected for its risk-reduction proposals covering the F-1 engine itself, the main propulsion system for a strap-on booster and the booster structure. For the F-1, Cook says, risk-reduction tasks would include gas generator and powerpack evaluations. The company's main propulsion system proposal would involve cryogenic valve and line-in valve demonstrations, and the structures proposal would demonstrate low-cost cryogenic tank-manufacturing approaches.

“Those risk reductions are focused heavily around affordability . . . because a big deal on the Space Launch System is affordability, while also giving NASA additional performance margin above their 130-metric-ton requirement,” says Cook.

NASA also selected a booster-tank proposal offered by Northrop Grumman's Aerospace Systems unit, which would build a subscale composite tank. Aerojet General Corp. has been working on a larger version of the surplus Soviet NK-33 kerosene-fueled rocket engine it modified for the new Orbital Sciences Corp. Antares, and NASA selected its proposal for a full-scale combustion-stability demonstration. NASA chose ATK Launch Systems—which built the four-segment solid-fuel motors used on the space shuttle and a five-segment version for the defunct Ares I crew launcher—to run an integrated booster static test.

NASA plans to use the five-segment solids with the first version of the SLS, a 70-metric-ton vehicle with a Delta IV upper stage. Later it will add a more powerful upper stage and whatever strap-ons it chooses to begin sending astronauts beyond low Earth orbit.

“We want to build a system that will be upgradable and used for decades,” says William Gerstenmaier, associate administrator for human exploration operations.

If the Dynetics proposal to use the F-1 in the boosters is accepted, all of the engines on the SLS will have heritage in earlier human spaceflight missions, and all will already have been used for decades when deep-space human missions begin. The F-1 ran a full 2.5-min. test at Edwards AFB, Calif., in 1960 (see photo), before the A-1 and A-2 test stands at Stennis were built for it. NASA and Rocketdyne are testing the uprated J-2X variant of the Saturn V J-2 engine to power the SLS upper stage. And the main SLS engine will be a throw-away version of the reusable RS-25D space shuttle main engine, also built by Rocketdyne, once the 15 surplus shuttle engines are used up. Developed in the 1970s, it will be the newest basic engine design for what may one day be NASA's newest human launchers.