WRIGHT-PATTERSON AIR FORCE BASE, Ohio – The United States recently celebrated the 50th anniversary of Neil Armstrong’s historic walk on the moon. Project Apollo, led by NASA in the 1960s and 70s, achieved this feat following years of research, development and precursor missions. While countless individuals and organizations enabled the space program, the Air Force Research Laboratory played a supporting role by making the historic moon landing possible through the marvels of science and engineering.
Kevin Rusnak, AFRL senior historian, explains that, “Apollo built on the tremendous technological organizational base that had been set through the Gemini program, the Mercury program and then going back to the Air Force and other parts of the military.” He asserts that the military’s contributions were instrumental to the success of the U.S. Space Program.
In a recent Lab Life Podcast, Rusnak explains how AFRL technology supported the famed Apollo 11 mission in 1969. As far back as 1920, McCook Field scientists developed systems and pioneered equipment that eventually supported U.S. astronauts.
From the pressurized spacesuits and helmets to the rocket engine that powered the launch and the algorithm that guided the lunar module to the moon's surface, Air Force inventions accompanied astronauts on their journey to space. AFRL and its predecessors also supported NASA missions by developing fuel cell technology, specialized composites and high-speed/heavy-load parachutes. Rusnak says that these contributions ultimately helped the U.S. achieve its goal of putting a man on the moon.
In the 1940s, scientists from the Aero Medical Laboratory at Wright Field (now the 711th Human Performance Wing) developed pressure suits that enabled pilots to survive at high altitudes. When NASA formed in 1958, it relied on the Air Force’s expertise to evaluate its first generation of space suits based on mobility, comfort and inflation.
While the Apollo program required an entirely new type of suit, Rusnak explains that NASA continued to rely on the principles and techniques established by the Aero Medical Laboratory, as well as its experts and industrial partners. Ultimately, NASA incorporated several Air Force principles, including material choice, into the design for the Apollo multi-layered lunar spacesuit.
According to the National Air and Space Museum, Armstrong’s lunar spacesuit featured 21 layers of materials, including rubber and nylon, and provided him with a “life-sustaining environment during periods of extravehicular activity (EVA) or unpressurized spacecraft operation.”
“The suit supported human life in the harshest of environments,” says Ellen Stofan, the director of the Smithsonian museum. “Extreme heat and cold, radiation, micrometeorites and the threat of cuts from sharp rocks all had to be taken into consideration.”
In the 1940s, the Air Force’s Aero Medical Lab also began experimenting with bubble helmet designs. Then, in the late 1960s, scientists from the Air Force Flight Dynamics Lab (now the Aerospace Systems Directorate) improved the optical quality of polycarbonate materials to make them suitable for space helmet transparencies.
According to the National Air and Space Museum, the Apollo pressure helmet featured a transparent bubble made from polycarbonate. The helmet attached to the spacesuit via an aluminum neck ring. Armstrong and Buzz Aldrin wore visor assemblies, also made of polycarbonate, over their pressure helmets when they were outside of the spacecraft.
In the 1950s, the Propulsion Lab (now the Aerospace Systems Directorate) scaled up existing rocket engine technology. The Air Force contracted with Rocketdyne (now Aerojet Rocketdyne) to increase engine thrust by tenfold, thus scaling it from 150,000 to 1.5 million pounds of thrust. Rusnak says this work became the Air Force F-1 engine program, and the effort later transferred to NASA.
The F-1 engine, the first stage of the Saturn V rocket, lifted the astronauts off the ground during the Apollo 11 launch and placed a 50-ton spacecraft in a lunar trajectory. Rusnak explains that the Saturn V incorporates five massive F-1 engines, which equates to 7.5 million pounds of thrust.
“It’s an insane amount [of thrust],” he says. “But that’s what you need to put a man on the moon in the most efficient manner possible.”
The Rocket Propulsion Lab (now the Aerospace Systems Directorate at Edwards Air Force Base, California) also supported the space program with test stands used to evaluate rocket engine performance.
Along with the astronaut equipment and rocket engines, AFRL supported the descent stage of the moon landing. According to AFRL’s History Office, an algorithm known as the Kalman filter guided the Apollo 11 lunar module to the moon's surface.
Starting in 1954, basic research grants from the Air Force Office of Scientific Research (AFOSR) enabled Dr. Rudolph Kalman to transition his theory on guidance, navigation and control into a statistical formula with real-world applications. Bob White, a former AFOSR historian, said that NASA used Kalman’s formula to combine and filter information from multiple sensor sources. Ultimately, this methodology enabled Armstrong to analyze evolving data and make real-time decisions as he piloted the lunar landing module on its descent.
Electricity and water
In the mid-1960s, the Propulsion Laboratory (now the Aerospace Systems Directorate) researched hydrogen-oxygen fuel cells with increased energy power and longer life cycles. The lab also sponsored research with General Electric and Pratt & Whitney to develop this technology. Ultimately, NASA’s manned space program relied on fuel cells to produce electricity and water.
Rusnak explains that, “long-duration space flights required electrical production over a period of two weeks and in the several kilowatt range, clearly outside the realm of battery power.” First, “Gemini proved the technology was viable, and then every Apollo lunar mission used fuel cells derived from the technology developed by AFRL’s predecessors.”
Return to Earth
AFRL also worked on products that helped the Apollo 11 astronauts return safely to Earth. In 1963, the Air Force Materials Lab (now the Materials & Manufacturing Directorate) scaled up silicon carbide coated carbon-carbon composites, later used on the command module’s nose cone.
Prior to this application, the lab evaluated various materials for protective properties. To simulate these conditions, engineers used an Atmospheric Reentry Materials and Structures Evaluation Facility (Arc-Jet) or ground-based simulated environment.
Finally, to land safely, the Apollo 11 crew used a multi-parachute system to slow their rate of descent and reduce the force of impact. McCook Field engineers had perfected the design of free-fall parachutes in the 1920s, while their successors at Wright Field developed high-speed, high-strength parachute systems that fit tightly into small packages. These technologies transferred directly to the Apollo landing system
Ultimately, the Apollo 11 crew successfully traveled to space, walked on the moon and returned to Earth, thanks in part to technologies developed by AFRL and its predecessors.