The umbrella-like mechanical ADEPT aeroshell design uses flexible 3D-woven carbon fabric skin stretched over deployable ribs and struts, which become rigid when fully flexed.  (Image source: NASA)

A new expanding NASA aeroshell could mean larger planetary payloads

The Adaptive Deployable Entry Placement Technology uses an umbrella-like, foldable design to expand beyond the diameter of its launch vehicle.
On Sept. 12, NASA will conduct the first test flight of its latest heatshield, the Adaptable Deployable Entry Placement Technology (ADEPT). ADEPT will launch from Spaceport America in New Mexico aboard a suborbital SpaceLoft rocket from Denver-based UP Aerospace. ADEPT is a mechanically deployable semi-rigid aeroshell entry system capable of achieving low ballistic coefficient during entry suitable for a variety of planetary or Earth return missions.

Simply put, ADEPT is an umbrella-like foldable device that opens to make a round, rigid heat shield or “aeroshell.” If this technology proves viable, it could enable engineers to squeeze a larger-diameter heat shield into a rocket with a smaller diameter and safely deliver much larger payloads to planetary surfaces than currently possible – potentially an enabler for long term human exploration.

The 28-inch ADAPT flight unit and a spare are shown fully deployed. This test configuration includes a is sized to approximate a three-unit (3U) CubeSat at approximately 12 by 4 by 4 inches. This design could be adapted to build larger heat shields to support larger payloads. (Image source: NASA Ames Research Center, Dominic Hart)

Spacecraft typically approach planets at speeds tens of thousands of miles per hour, compressing atmospheric gas, creating pressure shock, and generating intense heat in front of the spacecraft. To solve for this, NASA has used aeroshells to slow spacecraft reentry and shield them from heat as early as Project Mercury in the 1950s.

The Mercury, Gemini, and Apollo spacecraft were designed with ablative type of aeroshell with a resin outer surface covering. As the resin sublimated (turned to gas) with the heat of reentry, it carried the atmospheric gas away by convection.

Now, ADEPT could be key to future NASA missions that require extra-large aeroshells to protect spacecraft destined to land on the surface of other planets, all without requiring larger rockets.

(Image source: NASA)

The umbrella-like mechanical aeroshell design uses flexible 3D-woven carbon fabric skin stretched over deployable ribs and struts, which become rigid when fully flexed. This serves the structural purpose of the aeroshell and allows for a large surface skin area to slow entry. The carbon fabric skin that covers the structural surface serves as the primary component of the entry, descent, and thermal protection system.

“Carbon fabric has been the major recent breakthrough enabling this technology, as it utilizes pure carbon yarns that are woven three-dimensionally to give you a very durable surface,” says Paul Wercinski, ADEPT project manager at NASA’s Ames Research Center in California’s Silicon Valley. “Carbon is a wonderful material for high temperature applications.”

Paul Wercinski, ADEPT project manager and Cole Kazemba, ADEPT system engineer, attach the woven carbon fabric skin to the ribs of an early version of ADEPT in the assembly lab at Ames. (Image source: NASA Ames Research Center, Eric James)

During the Sept. 12 test flight, a 28-inch ADEPT aeroshell will launch in a stowed configuration, separate from the SpaceLoft rocket in space, and then unfold 60 miles above Earth. As ADEPT descends toward Earth, NASA engineers expect aeroshell to reach three times the speed of sound, or about 2,300 miles per hour.

While that is not fast enough to generate significant heat during descent, the engineers will observe ADEPT’s initial deployment sequence and assess aerodynamic stability while it enters Earth’s atmosphere and falls to the recovery site.

The entire process will last approximately 15 minutes.

“For a deployable like ADEPT, you can do ground-based testing, but ultimately, a flight test demonstrates end-to-end functionality – surviving launch environments, deploying in zero gravity and the vacuum of space, holding that rigid shape and then entering, in our case, Earth’s atmosphere,” says Wercinski.
The next steps for ADEPT are to develop and conduct a test for an Earth entry at higher “orbital” speeds, roughly 17,000 miles per hour, to support maturing the technology with an eye towards Venus, Mars, or Titan, and also returning lunar samples back to Earth.

Brandon Smith, ADEPT principal investigator, and Joseph William, system engineer, in the entry systems and vehicle development lab at Ames perform final checks to the first ADEPT flight unit prior to a deployment test. (Image source: NASA Ames Research Center, Dominic Hart)

The ADEPT aeroshell heat shield technology was developed at Ames. The center leads the agency in the development and innovation of thermal protection system technologies.

ADEPT was funded by the Space Technology Mission Directorate’s (STMD) Game Changing Development program. The flight test was funded by STMD’s Flight Opportunities program, managed at NASA's Armstrong Flight Research Center in Edwards, Calif. Through both programs, NASA supports promising technologies from government, industry and academia for development and/or testing. UP Aerospace, based in Highlands Ranch, Colorado, is the flight provider.

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William Kucinski is content editor at SAE International, Aerospace Products Group in Warrendale, Pa. Previously, he worked as a writer at the NASA Safety Center in Cleveland, Ohio and was responsible for writing the agency’s System Failure Case Studies. His interests include 'literally anything that has to do with space,' past and present military aircraft, and propulsion technology. And also sportscars.
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