Arnold Air Force Base, Tenn. -- July 20 marks the 50th anniversary since Neil Armstrong exited the lunar module known as “Eagle” and became the first man to set foot on the surface of the moon.
AEDC played an integral role in this “giant leap for mankind.” In years leading up to the Apollo 11 moon landing, personnel at Arnold Air Force Base were involved in thousands of hours of testing to ensure the success of the NASA Project Apollo program. The aim of this spaceflight program was to accomplish a goal set by President John F. Kennedy in May 1961 – to land a man on the moon and return him to earth by 1970.
NASA designed a test program for AEDC to support the Apollo program. The goal of this program was to obtain data on aerodynamic heating, stability during reentry, reentry ablation, interaction between separating components during escape operations, and aerodynamic loading throughout the flight regime, as well as to help address issues that arose during development.
Getting man to the lunar surface would be no easy feat, and the challenge was not taken lightly by those at AEDC. Approximately 55,000 hours of test work involving more than two dozen of the center’s then-40 test facilities were completed throughout the 1960s in support of the Apollo program.
More than 3,300 hours of wind tunnel tests were conducted at Arnold AFB from 1960 to 1968. This represented well above 30 percent of the total wind tunnel work performed for the Apollo program. Over the same timeframe, more than 1,700 rocket firings were performed at Arnold.
Although Project Apollo had not yet been officially established, tests that would support the development of the Apollo spacecraft began at Arnold in 1960. In June of that year, the first aerodynamic test was conducted on a scale model of a proposed Saturn launch configuration in the 1-foot transonic wind tunnel.
The first propulsion system test on a proposed Saturn launch vehicle configuration occurred in January 1961, the year the Project Apollo was established.
Throughout the testing process, the Saturn rocket, which was developed in support of the Apollo program, went through several configurations. The original Saturn I was upgraded to the Saturn IB. That would eventually be upgraded to the Saturn V, the rocket used to get the manned Apollo spacecraft past earth orbit and to the moon.
Initial activity in support of the propulsion systems for the Apollo spacecraft modules involved an exploratory program using a one-third-scale rocket engine. These tests were run in a simulated space environment for the Apollo service module, which is the spacecraft that remained in orbit around the moon while two astronauts explored the moon’s surface.
By the time the first Saturn was launched from Cape Canaveral in October 1961, more than 600 hours of testing on the Saturn had been completed at Arnold. Additional testing would occur in the years to follow.
In June 1962, the first wind tunnel tests on Apollo spacecraft models were conducted in the AEDC von Kármán Gas Dynamics Facility’s 50-inch Mach 10 wind tunnel. Early efforts included aerodynamic testing on a scale model of the Apollo three-man capsule with its escape tower. These tests established the need for canard control surfaces at the apex of the escape rocket. The escape system, in place in the event of a malfunction during launch, did not have to be used.
In early 1962, the NASA Manned Space Flight Management Council had agreed that the lunar missions would be carried out via a single three-stage rocket carrying a manned capsule. Rather than landing the capsule itself on the moon, the Council further agreed that a smaller, lighter Lunar Excursion Module (LEM) would be used to descend to the moon and return to the larger capsule following exploration of the moon’s surface.
By 1963, tests on the LEM descent engines were underway in the AEDC Engine Test Facility J-2 test cell. Around that same time, the Rocketdyne J-2 engine, used on the Saturn IB and Saturn V launch vehicles, was successfully fired for the first time at AEDC at a simulated altitude of 60,000 feet.
It was around this period that the term “aerospace” would find its way into the AEDC mission statement for the first time. Wording was added to state that AEDC, then known as Arnold Engineering Development Center, would “conduct research, development, evaluations and studies in support of timely acquisition of required aerospace environmental testing facilities.”
In August 1963, a series of tests started using the full-scale service module primary propulsion system to flight-qualify the 21,000-pound-thrust engine for its lunar mission.
Major projects involving the Saturn V bookended 1965. In February of that year, retro rockets, which act as brakes by firing against the direction of flight, developed 100,000 pounds of thrust in the J-5 test cell. This was the highest thrust level ever achieved during testing at AEDC for a solid-fueled motor. That November, a series of tests was conducted in the ETF T-1 cell studying heating around the Saturn V base to ensure no burn through would occur.
From June 1965 to June 1970, 340 rocket engines were fired in the single largest test program ever conducted at the center to human-rate the Saturn V upper stages.
1966 was also a busy year for AEDC in its continued to support the Apollo program. Continuing prior work, tests were conducted in February in the ETF on the LEM ascent engines that would be used to lift astronauts from the surface of the moon and return them to the Apollo capsule in lunar orbit. Testing also continued on the LEM descent engines.
In the early part of 1966, upper-stage configurations for the Saturn IB and Saturn V were tested at AEDC facilities. That June, following work in the J-4 test cell, the 230,000-pound-thrust J-2 rocket engine for the Saturn S-IVB engine, which served the Saturn V third stage, was fired at conditions simulating an altitude of 100,000 feet.
That same year, two major milestones in the development of the Saturn launch vehicle were passed. The first of these was the first launch of the Saturn IB, which would be used to test the Apollo spacecraft in earth orbit while the Saturn V was being completed. The second significant happening was the qualification of Saturn rocket motors for manned space flight.
Tests of scale-model Apollo command modules were also completed in VKF in 1966. Testing on the Apollo service module rocket engine was performed the same year.
Additional Saturn engine tests followed at Arnold. Tests were also conducted on the heat shield designed to protect the Apollo capsule during its reentry into the earth’s atmosphere, as were more aerodynamic tests on the full Saturn-Apollo configuration.
Tests were also conducted at Hypervelocity Ballistic Range G on the Apollo capsule to determine its flight characteristics while traveling thousands of miles per hour. A special test cell was also used to look at the possible effects of small meteorites striking the Saturn during flight.
Eight Apollo missions preceded the Apollo 11 spaceflight. Apollo 1 ended tragically in February 1967 when the crew was killed by a flash fire that occurred in the capsule during a ground training exercise. The first test flight of the Saturn V, designated as the Apollo 4 mission, occurred that November during an unmanned launch. Apollo 7, which took place in October 1968, was the first mission in the Apollo program to take a crew into space. Apollo 8, occurring in December 1968, was the first manned spacecraft to reach the moon. The Apollo 10 flight, which took place in May 1969, served as a practice run for the Apollo 11 mission, as equipment was tested near the lunar surface.
The goal set for Project Apollo was achieved less than five minutes before 11 p.m. Eastern Daylight Time on July 20, 1969. Millions watched as Armstrong exited the Eagle and made “one small step for a man.”
The more-than-200,000-mile voyage to the moon took the Apollo 11 crew four days to complete. The years of testing and development necessary to bring the lunar landing to fruition had paid off.
The Apollo program ran through 1972. Five of the six Apollo missions that followed the Apollo 11 flight resulted in moon landings.