Pantano to improve parachutes for Mars missions


Miranda Holloway, MechSE Communications

When a capsule holding a rover is moving through the Mars atmosphere, it must decelerate considerably before making landfall. There are multiple methods to do this—one of which is a parachute that deploys when the capsule is seven miles from the ground.   
However, as the capsules and similar devices NASA develops get larger, the chance that these parachutes will break upon deployment increases. To help solve this problem, MechSE Associate Professor Carlos Pantano was awarded one of 13 Early Stage Innovation grants from NASA’s Space Technology Research Grants Program. ESI grants are worth as much as $500,000 each, and researchers have two to three years to work on their proposed projects. 
With his proposal, “Adaptive FSI (Fluid-Structure Interaction) of flexible parachutes under strong dynamic loading using strongly coupled shell mechanics and large-eddy simulation with analytical curvilinear hybrid meshing,” Pantano will create better parachutes through computer simulations before NASA conducts expensive experiments. 
“It is in the opening that the parachute immediately feels the flow that is going around the capsule. It is going very fast and breaks because of the large forces,” he said. “So NASA wants to do simulations of this before they do experiments because experiments are very expensive.” 
Pantano works mainly in the field of computational fluid dynamics and turbulent flows. He has been supported with funding from NASA for over a decade. 
About five or six years ago he conducted similar simulations with NASA that illuminated the problem the parachutes were having at such high speeds with big capsules. 
“There is a system of waves that makes the parachute oscillate, forcing it to close up,” Pantano said. “It is not like a low-speed parachute that just stays open.”
Even in instances when it doesn’t break from the forces, a parachute can only effectively aid in deceleration when it stays open to its maximum area. When it oscillates and partially closes, it does not decelerate the payload as effectively. 
Pantano’s goal is to create more accurate simulations using super computers. His previous simulations achieved drag predictions to within a 15 to 20 percent of experiment value, but he aims to lower that to about 5 to 7 percent to make their simulations even more useful in predicting experiment results. 
This all comes from NASA’s desire to send larger and larger missions to Mars. The most recent mission, the Mars Science Laboratory, which held the rover Curiosity, was more than double the weight of their first missions. 
Pantano said that while developing a large mission is expensive, it allows NASA to gain more knowledge and complete more experiments during the mission. Rather than paying for the development of multiple missions, NASA can achieve more in one mission with a larger capsule. 
“If you have the technology to land safely you would like to send the biggest capsule,” Pantano said. “It’s a small increase in cost but it’s a large improvement in the science.”
Pantano was interviewed on the 1400 AM WDWS on December 13. Listen here.
And on December 15, he was interviewed for the WCIA 3 newscast.