Arnold Air Force Base, Tenn. – AEDC’s National Full-Scale Aerodynamic Complex at Moffett Field, Calif., is the site of an ongoing pioneering test campaign supporting NASA’s Hypersonic Inflatable Aerodynamic Decelerator (HIAD) project.
NASA says Hypersonic Inflatable Aerodynamic Decelerator technology could be used to help deliver cargo, or even people, to another planet or return them to Earth.
HIAD, described as a round, stacked series of “high-tech inner tubes,” is under development as a next generation decelerator, which would replace the conventional rigid heat shields currently used for vehicles entering a planetary atmosphere. This advanced entry technology may be used in the future for manned exploration missions.
The objective of the test is to subject a fully-deployed model of the HIAD to simulated planetary atmospheric aerodynamic entry loads, according to Stephen Lee, NFAC’s engineer for the test.
“This is the first time a large scale, mission relevant-sized inflatable will have been tested in a wind tunnel,” he said. “It’s a very neat project.”
The HIAD testing at NFAC has been designed to determine the test article’s structural integrity and ability to withstand tremendous loading.
“We’re assessing the structural response of the inflatable to dynamic load testing for a three-meter and six-meter HIAD so we can compare it to our modeling predictions,” said Anthony Calomino, who serves as the principal investigator for Flexible Systems Development, based at NASA’s Langley Research Center in Hampton, Va. “The test article is a Kevlar fiber reinforced 60 degree sphere cone with an inner polymer liner and it is covered by an insulated high temperature ceramic fabric. Both the three-meter and six-meter HIAD test articles are instrumented so we can monitor overall displacement, vibration, and pressure.”
Inflatable technology could give NASA more options to explore planets on future missions, because it would allow a spacecraft to carry larger, heavier scientific instruments and other tools needed for new discoveries. More near term, the technology could also be used to return payloads to Earth from the International Space Station or other low Earth orbit locations.
NASA Langley’s Keith Johnson, the technical lead for Inflatable Structures and the scheduled tests at NFAC, said, unlike rigid aeroshells that are limited in size by the launch vehicle, an inflatable decelerator can be stowed, much like clothes vacuum packed inside a duffle bag. The inflatable structure, covered by thermal protection system “skin,” is deployed before the spacecraft enters the atmosphere.
“We envision going to a 10, 15 or 20 meter inflatable, the larger we make the inflatable, the higher capacity of payload we can deliver,” he said. “We’ve also got some testing from a materials level and sub-component level. We’re also developing dynamic simulation models that we’re going to correlate to and a key part of that will be anchored with NFAC test results.”
NFAC engineer Lee says the test also has already presented some challenges because of the approximately 250 miles-per-hour airflow the HIAD has encountered in the wind tunnel.
“The flight article generates a lot of load,” Lee said. “The peak loads we’ve been seeing are at the limit of the facility. That’s one thing that we’re keeping our eyes on, because clearly we don’t want to damage the facility – it isn’t very often we get to test these kinds of loads.”
For more information about NASA’s HIAD project, please go to: www.nasa.gov/hiad.