The type of vehicle that will carry people to the Red Planet is shaping up to be “like a two-story house you’re trying to land on another planet. The heat shield on the front of the vehicle is just over 16 meters in diameter, and the vehicle itself, during landing, weighs tens of metric tons. It’s huge,” said Ashley Korzun, a research aerospace engineer at NASA’s Langley Research Center.
“You can’t use parachutes to land very large payloads on the surface of Mars,” Korzun said. “The physics just breaks down. You have to do something else.”
NASA expects humans to voyage to Mars by the mid- to late 2030s, so engineers have been at the drafting board for some time. Now, they have a promising solution in retropropulsion, or engine-powered deceleration.
“Instead of pushing you forward, retropropulsion engines slow you down, like brakes,” Korzun said.
Led by Eric Nielsen, a senior research scientist at NASA Langley, a team of scientists and engineers including Korzun is using Summit, the world’s fastest supercomputer at the US Department of Energy’s (DOE’s) Oak Ridge National Laboratory (ORNL), to simulate retropropulsion for landing humans on Mars.
“We’re able to demonstrate pretty revolutionary performance on Summit relative to what we were accustomed to with a conventional computing approach,” Nielsen said.
The team uses its computational fluid dynamics (CFD) code called FUN3D to model the vehicle’s Martian descent. CFD applications use large systems of equations to simulate the small-scale interactions of fluids (including gases) during flow and turbulence—in this case, to capture the aerodynamic effects created by the landing vehicle and the atmosphere.
“FUN3D and the computing capability itself have been completely game-changing, allowing us to move forward with technology development for retropropulsion, which has applications on Earth, the moon and Mars,” Korzun said.