National Aeronautics and Space Administration

Glenn Research Center

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Rocket Engines (1958 – 1966)
Damaged rocket engine outside test chamber
Contour Nozzle

Although NACA Lewis researchers had been working with rocket engines since the mid-1940s, the launch of Sputnik I in October 1957 created a new urgency for rocket research at the laboratory and across the nation. A former employee said that the very night Sputnik began orbiting, PSL ran its final aeronautics test and began switching over to rocket engines. Several small engines were tested during the late 1950s, but major programs such as the Pratt & Whitney RL-10 engine, Contour rocket, and the 260-inch rocket were undertaken at PSL in the mid-1960s.

Pratt & Whitney RL-10
two employees looking at Centaur and Atlas model
Centaur Model

Pratt & Whitney developed its 15,000-pound thrust RL-10 engine to power the Centaur second-stage rocket. Centaur would be responsible for sending the Surveyor spacecraft on its mission to land on the Moon and explore the surface in the early stages of the Apollo Program. The RL-10s and Centaur operated on the high-powered cryogenic liquid-hydrogen propellant. This created increased performance but also caused many early technical problems. The Saturn I, a precursor to the Saturn V that was used for Apollo, also used the RL-10s for its upper stages in the early 1960s. Six RL-10s powered the Saturn-IV second stage and two RL-10s powered the Saturn-V third stage.

PSL was used to throttle and gimbal the engine in simulated altitude conditions. During the tests, the area around PSL was evacuated and the researchers and technicians were locked in the unpressurized control room because of the explosive nature of the liquid-hydrogen. The main problems were combustion instability and low-frequency oscillations in the fuel system. It was found that injecting gaseous helium into the cooling liner stabilized the propellant and reduced chugging. This method reduced the pre-cooling period during a flight and is one of Lewis’ most important modifications to Centaur. The Surveyor, launched by Centaur and its RL-10s, made the first soft landing on the Moon on June 2, 1966.

P&W RL-10 Film
P&W RL-10 Film
RL-10 Firing Footage
RL-10 Firing Footage
Rocket Firing Footage
Rocket Firing Footage

Documents:
     First Decade of Centaur article (1972) (PDF, 1.33MB)
     “Abe’s Baby,” Chapter 3 from Taming Liquid Hydrogen (PDF, 2.16MB)
     Design Report for RL-10-A-3-3 (PDF, 3.46MB)
     ASME Report on RL-10 (PDF, 1.81MB)

Reports:
     Characteristics of Centaur Gimbal System Under Thrust Load (PDF, 1.15MB)
     Effect of Several Injector Face Baffle Configurations on Screech (PDF, 5.96MB)
     Effect of Propellant Injection Velocity on Screech (PDF, 1.60MB)

RL-10 in PSL
RL-10 in PSL
Researchers in PSL
Researchers in PSL
Instrumentation
Instrumentation
Apollo Contour Nozzle Study
Three rocket engine nozzles set on floor
Rocket Engine Nozzles

Storable propellants are fuels that can be stored in a tank without any special pressure or temperature control measures. NASA officials intended to use one of these types of propellants, a nitrogen tetroxide and hydrazine blend, for the upper stages of the Saturn V rocket. NASA had been studying the problems of combustion instability and thrust chamber durability for several years, but the important testing of the overall engine and nozzle efficiency remained a problem because of the lack of altitude chambers. NASA Lewis undertook this task in PSL No. 2 in late 1963 and 1964.

Researchers sought to determine the impulse value of the storable propellant mix, classify the internal engine performance, improve that performance, and compare the results with analytical tools. A special setup was installed in the chamber that included a device to measure the thrust load and a calibration stand. Both cylindrical and conical combustion chambers were examined with the conical large area ratio nozzles. In addition, two contour nozzles were tested, one based on the Apollo Service Propulsion System and the other on the Air Force’s Titan transtage engine. Three types of injectors were investigated, including a Lewis-designed model that produced 98 percent efficiency. It was determined that combustion instability did not affect the nozzle performance. Although much valuable information was obtained during the tests, attempts to improve the engine performance were not successful.

Reports:
     Experimental Rocket Performance of Apollo Storable Propellants (PDF, 2.39MB)

Apollo SPS Nozzle
Apollo SPS Nozzle
Propellant Test
Propellant Test
Control Room
Control Room