Pioneering Space: Langley's Role in Crewed Spaceflight

PIONEERING SPACE

Langley’s Role in Crewed Spaceflight

By Craig Collins

When President John F. Kennedy challenged the nation to send human beings to the Moon on May 25, 1961, he delivered one of the most consequential speeches in U.S. history – and one of the many consequences was the expansion of expertise and capabilities within the new National Aeronautics and Space Administration (NASA). The Space Task Group that had been established at Langley to lead the Mercury program would move to a larger facility, the Manned Spacecraft Center, in Houston, and other specialists would work on the Moon landing from NASA facilities including the Goddard Space Flight Center, the Jet Propulsion Laboratory, the Marshall Space Flight Center, and the three Research Centers: Langley, Ames, and Lewis (now Glenn). The lunar exploration program was a whole-of-NASA movement, involving hundreds of thousands of people and more than 20,000 university and private-sector partners – and the researchers at Langley, where the U.S. space program was born, would play key roles throughout.

What many historians consider NASA Langley’s most important contribution to the Apollo mission happened before the program had fully launched. Kennedy’s goal of landing a man on the Moon “before the decade is out” meant the problems of crewed lunar exploration had to be solved quickly – and the sequence involved in a Moon landing was far more complicated than a Mercury capsule orbit of the Earth: The Apollo spacecraft would launch from Earth, travel 250,000 miles to the Moon, land, take off from the lunar surface, and travel another 250,000 miles home.

NASA considered three options for achieving these steps. The first studied was direct ascent, the method popularized in science fiction novels and movies: A massive rocket that would boost a spaceship large enough to reach the Moon, land, and launch itself from the lunar surface intact. The rocket capable of lifting such a spacecraft would have to be the size of a battleship, however, and a huge amount of fuel would be required to relaunch the entire spacecraft off the lunar surface.

The Gemini VII spacecraft seen from Gemini VI. Walter M. Schirra, Jr. and Thomas P. Stafford on Gemini VI and Frank Borman and James A. Lovell on Gemini VII practiced rendezvous and station-keeping together for one day in orbit. Between Project Mercury and Project Apollo, Project Gemini tested rendezvous in space, longer duration missions, docking two spacecraft, and many other concepts necessary to make Apollo a success.

NASA Photos

The second option, Earth orbit rendezvous (EOR), called for two spacecraft to be launched into orbit, then release payloads that would be assembled into a vehicle that would travel to the Moon and back. EOR’s main drawback, of course, was that it required two multimillion-dollar rockets, each capable of lifting a large payload into Earth orbit.

A third dark-horse option, lunar orbit rendezvous (LOR), was proposed by a vocal minority led by Langley aeronautical engineer John Houbolt. LOR called for three small spacecraft: A command module, a service module (with fuel and control systems), and a small lunar lander would be lifted together into Earth orbit by a three-stage rocket. The third rocket stage would propel the payload to a lunar orbit, where the lunar module (LM) would detach from the mother ship and land on the Moon. After a successful lunar excursion, the top half of the LM would blast off, dock with the Command/Service Module (CSM), and return home.

Langley researchers built the Rendezvous Docking Simulator to give astronauts a routine opportunity to pilot dynamically controlled scale-model vehicles in an environment that closely paralleled that of space.

NASA Photos

LOR seemed a wild idea at first, and was rejected outright by some of the most brilliant minds at NASA, but for two years, Houbolt persisted with facts and figures that supported it as the best option for reaching the Moon by 1970. In time, the advantages of the approach – less fuel, half the payload, and less brand-new technology, among others – couldn’t be denied. Apollo and the Gemini program, conceived primarily to perfect rendezvous and docking procedures, were built around Houbolt’s LOR concept.

Langley’s Applied Materials and Physics Division promptly took charge of the effort to determine the effects of atmospheric entry on the proposed spacecraft – which, in the case of Apollo, would reenter Earth’s atmosphere at a speed of 25,000 miles per hour. Project Flight Investigation Reentry Environment (FIRE) used both ground testing in wind tunnels and flight tests that informed the designs of spacecraft engineers.

Meanwhile, Langley researchers were building simulators that would teach the Gemini and Apollo astronauts what they needed to know. The Rendezvous and Docking Simulator, an ingeniously designed overhead carriage hung from a gantry frame inside the hangar of Langley’s Flight Research Laboratory, became operational in June 1963. From this overhead track, astronauts suspended in gimbal-mounted scale model vehicles practiced docking in an environment that closely resembled space.

Langley’s more conspicuous simulator was completed in 1965: the Lunar Landing Research Facility (LLRF), a 400-foot-long, 240-foot-high A-frame gantry, built over a former cow pasture, from which astronauts could practice “flying” a full-scale LM simulator. The gantry could also be adapted, with the use of slings, cables, and harnesses, into a contraption that came to be known as the Reduced Gravity Walking Simulator, which allowed astronauts to practice walking and working in a simulated Moon environment – down to fake craters; long, dark, painted-on shadows; and powerful floodlights angled to resemble lunar light – while experiencing a gravitational pull 1/6th as powerful as the Earth’s.

By the time the Apollo program had concluded, the LLRF had been used to train 24 astronauts for lunar missions. When Neil Armstrong spotted his shadow on the lunar dust on July 20, 1969, he said, it looked the same as it had while training at the LLRF. Asked what it was like to walk on the Moon, Armstrong replied: “Like Langley.”

In 1985, both the Rendezvous Docking Simulator and Lunar Landing Research Facility were designated National Historic Landmarks, in recognition of their role in the space program.

The Lunar Landing Research Facility (LLRF) was a 400-foot-long, 240-foothigh A-frame gantry from which astronauts could practice flying a full-scale LM simulator.

NASA Photos

“Routine” Spaceflight

In 1972, as Project Apollo began to wind down, President Richard Nixon announced NASA’s next space project. The space shuttle, “an entirely new type of space transportation system,” would be the world’s first reusable spacecraft, capable of leaving the atmosphere, returning, and landing like an airplane, allowing “routine access to space.”

Two dozen astronauts practiced landing on the lunar surface with the LLRF at NASA Langley Research Center. A closer look shows how the LLRF employed floodlights shining down to simulate lunar light and a base modeled to resemble the lunar surface.

NASA Photos

Langley Research Center’s long history of experimentation with winged “spaceplanes” and, during the 1950s and 1960s, “lifting body” spacecraft that allowed for some maneuverability on reentry, ensured that its spaceflight experts played an important role in the design of the new spacecraft. The shuttle’s final shape, in fact, resembled the HL-10 lifting body demonstrator designed by Langley, built by Northrop, and at the time still flying technology demonstrations at the (now Armstrong) Flight Research Center in California.

Early space shuttle concepts included deployable jet engines that could, upon atmospheric reentry, power its descent and maneuvers. Langley engineers, however, pointed out that the shuttle didn’t need to fly – it just needed to glide to a safe landing, as the HL-10 was doing in the desert. The “dead stick” landing, argued Langley’s engineers, would be much simpler and reduce weight. Jet engines were omitted from the final shuttle design, which also featured the modified delta wing recommended by Langley.

Before building flight demonstrators, Langley engineers spent years studying “lifting body” spacecraft concepts. They tested this design in the Langley Full-Scale Tunnel in 1964.

NASA Photo

Before the Space Shuttle Enterprise’s 1977 test flight, scale models endured more than 60,000 hours of testing in Langley’s wind tunnels, verifying the spacecraft’s aerodynamic soundness. Langley’s expertise in entry/descent/landing (EDL) came into play as the agency investigated new heat-shielding technologies. An ablative heat shield, which essentially burned away upon reentry, was a poor choice for a spacecraft that was to be considered “reusable,” so the shuttle design featured a thermal protection system comprised of thick ceramic tiles that would protect the orbiter and its astronauts from the 3,000 degree F heat of atmospheric reentry. After resolving a serious problem with the thermal protection system – the failure of an adhesive to keep tiles bonded to the shuttle’s aluminum skin – Langley researchers investigated and certified the thermal protection system. As they had for the Gemini and Apollo programs, Langley’s researchers also developed simulations of the shuttle’s flight control and guidance systems. The space shuttle was the first spacecraft to need rubber tires to return home, and at Langley’s Aircraft Landing Dynamics Facility, engineers conducted landing tests on tires and braking systems.

A variety of space shuttle designs went through more than 60,000 hours of testing in Langley’s wind tunnels, including this model in the Transonic Dynamics Tunnel in 1972.

NASA Photos

The Space Shuttle Columbia became the first of the five space-worthy orbiters to fly, launching on April 12, 1981. The program flew two dozen successful missions before tragedy struck on Jan. 28, 1986, when the Space Shuttle Challenger and its crew were lost in an explosion shortly after liftoff. After the accident, Langley researchers helped evaluate the components that failed – the O-ring gasket that sealed one of the rocket boosters – and design a new way of joining the shuttle launcher’s solid rocket boosters.

Shuttle Columbia in 2003. Hundreds of Langley’s employees conducted extensive research, analysis and tunnel testing to better understand what happened, which was critical to the accident investigation and successful return to flight.

NASA Photo

In 1984, the Space Shuttle Challenger had placed a Langleydesigned and -built experiment platform, the Long Duration Exposure Facility (LDEF), in low Earth orbit. The LDEF was a school bus-sized satellite designed to provide longterm experimental data on the effects of the space environment – which involved radiation exposure, extreme temperature fluctuations, and collisions with space matter – on man-made materials and systems, as well as on living seeds and spores. The LDEF, originally conceived by Langley engineers in 1970, was the culmination of years of study and interest in the idea of an orbiting laboratory for scientific experiments, communications, and observation, and as an assembly depot and relay station for lunar and planetary missions. NASA approved the LDEF in 1974, shortly after the launch of the first U.S. space station, Skylab.

The LDEF remained in orbit for more than five-and-a-half years – it was retrieved from orbit by the Space Shuttle Columbia in January 1990 – and was home to 57 science and technology experiments by government and academic researchers from around the world.

Around the time of the LDEF’s launch, the idea of an international space station began to gather momentum. President Ronald Reagan gave NASA approval to move forward with the plan to build it – Space Station Freedom, as it was known for a short time – and to invite the participation of international partners. The project that evolved into today’s International Space Station (ISS) met with several obstacles and delays before the launch of its first module, the Russian Zarya Functional Cargo Block, in November 1998. Meanwhile, Langley’s design and construction of the LDEF has evolved into a portfolio of skills, including studies of materials, structures, components, and assembly methods, that allow people to live and work in space.

A team at NASA Langley tests models of the Space Launch System (SLS) – NASA’s heavy-lift launch vehicle – to measure unsteady aerodynamic pressures and forces exerted on the SLS vehicle.

NASA Photo By David C Bowman

Back to the Non-Routine: Toward Mars

The grievous losses of people aboard the Space Shuttles Challenger and Columbia have demonstrated that there’s nothing “routine” about space flight. But before the program ended in 2011, the space shuttle enabled space travel that was, if not routine, reliable and regularly scheduled. The program ushered in the era of on-time deliveries of people and cargo to low Earth orbit, an era that has seen a sustained human presence aboard the ISS for nearly two decades. After achieving such a milestone, many at NASA were understandably itchy. It had always been their job to explore frontiers, but nobody had traveled beyond low Earth orbit since the Apollo 17 mission in 1972.

In a 2004 speech at NASA Headquarters in Washington, D.C., President George W. Bush reminded Americans that their space program hadn’t built a new crewed space vehicle in nearly 25 years, and announced a bold new course for the agency: “… to explore space and extend a human presence across our solar system.” In 2014, then-NASA Administrator Charles Bolden publicly offered a refinement of that objective: NASA’s long-term goal, he said, was to establish a permanent human presence on Mars.

NASA Langley has splash tested the Orion space capsule test article at the historic Landing and Impact Research Facility gantry. These tests simulate water landings and detect forces that the structure and its crew would experience.

NASA Photo

Langley and NASA’s other space flight resources have thrown themselves behind the ambitious goals, both short and long term, of the Mars Exploration Program. In the Langley wind tunnels, structural, aerodynamic, and aerothermal analyses of the launch vehicle designed for future lunar and Mars missions, the heavy-lift Space Launch System (SLS), are underway. “We’re doing a tremendous amount of wind tunnel testing and computational analysis of the aerodynamics to certify that vehicle,” said Walt Engelund, Director of the Space Technology and Exploration Directorate at Langley Research Center. “Langley is probably the biggest provider of that set of technology for SLS development.”

Langley’s EDL expertise, which has enabled several successful robotic landings through the ultra-thin Mars atmosphere, will prove crucial to crewed missions to Mars, which will necessarily require delivery of larger payloads. Langley engineers have developed an ingenious device – the Hypersonic Inflatable Aerodynamic Decelerator (HIAD) – that’s both larger and lighter than a solid heat shield that could be packed into a shroud atop the SLS. The HIAD consists of a series of concentric inflatable rings, resembling huge inner tubes. Packed tightly in the shroud, the rings are designed to self-inflate on deployment and form a single aeroshell, or heat shield. “They have a flexible thermal protection blanket that wraps around them,” explained Engelund. “And that gets inflated into a very rigid structure around the payload. It enables you to package much larger payloads inside a launch vehicle shroud and take bigger things to Mars. Otherwise, you’re going to have to develop bigger rockets and bigger shrouds, and the costs will increase exponentially.” A 10-foot-wide HIAD performed perfectly in a reentry test launched on July 23, 2012, from Wallops Island. The experimental reentry vehicle was shot 290 miles into space and returned at a speed of Mach 10.

Langley Research Center brings several specialized skills to the Mars Exploration Program, including the design and analysis of strong, lightweight materials; in-space assembly of structures; protection from space radiation; and the design of structures and habitation modules that will allow astronauts to live and work comfortably in space.

One of Langley’s most significant responsibilities in the Mars Exploration Program is to lead the development of a system it hopes will never be needed: NASA’s Orion Launch Abort System (LAS), the emergency escape capability that will take astronauts in the Orion crew module away from the rocket if something goes wrong. Designed to ensure astronauts’ safety up to an altitude of 300,000 feet, the system consists of an abort motor, which will separate Orion from the rocket, and a jettison motor that will then separate the LAS from the spacecraft. Engineers at Orbital ATK’s facility in Elkton, Maryland, completed a successful test of the Orion LAS motor in May 2017 – another step toward a crewed flight of the SLS and Orion together.

As it helps NASA chart a course to Mars, Langley Research Center, in its tests of the

Orion spacecraft, evokes memories of its storied past: Langley’s enormous gantry, once used by Apollo astronauts to simulate landing and walking on the Moon, has been transformed into the Landing and Impact Research Facility, featuring a winch system for lifting the Orion spacecraft and a 20-foot-deep basin below the gantry for splashdown simulations. Orion sailed through its first uncrewed suborbital flight in 2014, splashing down in the Pacific Ocean, but future missions will involve both faster reentry and crews of up to four people. In spring 2016, a series of water-impact tests were conducted at Langley, simulating different sets of variables for Orion’s parachute-assisted splashdowns: wind and weather conditions, velocities, and wave heights. Crash-test dummies were fastened securely inside Orion, dressed in modified Advanced Crew Escape Suits.

The Orion drop tests were a reminder of the meticulous matrix of expertise required to conduct such a mission, the culmination of a three-year collaboration between Langley Research Center, Johnson Space Center, Marshall Space Flight Center, Kennedy Space Center, Ames Research Center, and Lockheed Martin, the Orion prime contractor. Each drop, over in a matter of seconds, was preceded by thousands of hours of preparation and study.

To the visionary researchers at Langley Research Center, the sight of Orion at Langley, where America’s crewed space program began, offers a chance to reflect with pride on Langley’s role in both the future and the past of American spaceflight.