From enabling astronauts to practice moon landings to aircraft crash testing to drop tests for Orion, NASA's gantry has come full circle.
The gantry, a 240-foot high, 400-foot-long, 265-foot-wide A-frame steel structure located at Langley Research Center in Hampton, Va., was built in 1963 and was used to model lunar gravity. Originally named the Lunar Landing Research Facility (LLRF), the gantry became operational in 1965 and allowed astronauts like Neil Armstrong and Edwin "Buzz" Aldrin to train for Apollo 11's final 150 feet before landing on the moon.
Because the moon's gravity is only 1/6 as strong as Earth's, the gantry had a suspension system that supported 5/6 of the total weight of the Lunar Excursion Module Simulator (LEMS), the device the astronauts used to perform the tests. This supportive suspension system imitated the moon's gravitational environment. Additionally, many of the tests were conducted at night to recreate lighting conditions on the moon.
Image above: NASA's gantry is located at NASA Langley Research Center in Hampton, Va. and was used to help train the original astronauts to land on the moon. Credit: NASA
Aircraft Crash Test Research
After the Apollo program concluded, a new purpose emerged for the gantry – aircraft crash testing. In 1972, the gantry was converted into the Impact Dynamics Research Facility (IDRF) and was used to investigate the crashworthiness of General Aviation (GA) aircraft and rotorcraft. The facility performed full-scale crash tests of GA aircraft and helicopters, system qualification tests of Army helicopters, vertical drop tests of Boeing 707 and composite fuselage sections and drop tests of the F-111 crew escape capsule.
The gantry was even used to complete a number of component tests in support of the Mars Sample Return Earth Entry Vehicle.
Image to right: General aviation airplanes provided crucial information to researchers during aircraft crash testing at the gantry. Credit: NASA
With features including a bridge and a 72-foot vertical drop tower, the gantry was able to support planes that weighed up to 30,000 pounds. Engineers lifted aircraft as high as 200 feet in the air and released them to determine how well the craft endured the crash. Data from the crash tests were used to define a typical acceleration for survivable crashes as well as to establish impact criteria for aircraft seats. The impact criteria are still used today as the Federal Aviation Administration standard for certification.
In 1985, the structure was named a National Historic Landmark based on its considerable contributions to the Apollo program.
Revitalized Space Mission
Recently, the gantry was returned to its work in space exploration: enabling engineers and astronauts to prepare for flight into space and the subsequent return to Earth. Orion, NASA's crew exploration vehicle, is part of the Constellation Program working to send astronauts back to the moon, to Mars and to various other locations in the solar system.
Engineers are currently conducting drop tests at the gantry in preparation for Orion's journey to the International Space Station by 2015 and to the moon by 2020.
Image to left: Engineers and technicians prepare to lift the Orion test article for a pendulum-swing drop test at the gantry. These tests are helping researchers determine the best technology for returning Orion to Earth. Credit: NASA
The gantry provides engineers and astronauts a means to prepare for Orion's return to Earth from such missions. With its new mission, the gantry also received a new name – the Landing and Impact Research (LandIR) Facility.
Although originally capable of supporting only 30,000 pounds, the new bridge can bear up to 64,000 pounds after the summer 2007 renovations. Other renovations include a new elevator, floor repairs and a parallel winch capability that allows an accurate adjustment of the pitch of the test article. The new parallel winch system increases the ability to accurately control impact pitch and pitching rotational rate. The gantry can also perform pendulum swings from as high as 200 feet with resultant velocities of over 70 miles per hour.
The gantry makes researching for the optimal landing alternative for NASA's first attempted, manned dry landing on Earth possible. Orion's return on land rather than water will facilitate reuse of the capsule. A water landing would make reuse difficult due to the corrosiveness of salt water.
The testing process involves lifting the test article by steel cables to a height between 40 and 60 feet and swinging it back to Earth. Although the airbags appear most promising, the gantry has the capability to perform different kinds of tests, including a retro rocket landing system and a scale-model, water landing test using a four-foot-deep circular pool. So far, three types of tests have been conducted in support of the Orion program, each progressing from the previous to more realistic features.
The first test consisted of dropping a boilerplate test article that was half the diameter of what Orion will be. For the second round of testing, engineers added a welded structure to the top, with a shape more comparable to Orion to examine the article's tendency to flip or remain upright.
Image above: The Orion test article lands at the base of the gantry from a pendulum-swing drop test. The test article currently uses airbags from two different vendors. As testing progresses, researchers will down-select to one vendor. Credit: NASA
The third round of testing employed two different sets of airbags to ease the landing of a flat-bottomed test article that was approximately half mass, or 7,000 pounds, with a full-scale 16.5-foot diameter test article.
The future Orion test article will have a curved underside, rather than the current flat one, and will use more lightweight airbags. These new characteristics are more similar to the design of the actual crew exploration vehicle. The testing will also involve more airbags than previous drop tests, which will further provide a more realistic outlook.
With over 41 tests completed in the first year of Orion drop testing and future testing in sight, the gantry is again serving a vital role in space exploration.
Image above: One option for Orion's return to earth involves performing a ground landing using airbags to ease the landing. Engineers at the gantry will next conduct drop tests on articles more similar to Orion's design. Credit: NASA