NASA’s ASPIRE project (Advanced Supersonic Parachute Inflation Research Experiment) was tasked with developing a parachute that could open extremely quickly, at very high speeds, in a very diffuse atmosphere.
In a series of three high-speed, high-altitude tests, which concluded on Sept. 7, scientists at NASA’s Jet Propulsion Lab (JPL) gathered data.
On Oct. 3, they announced the results: They had developed the strongest, fastest-opening parachute ever deployed. Their parachute is ready for its mission to Mars.
“Mars 2020 will be carrying the heaviest payload yet to the surface of Mars, and like all our prior Mars missions, we only have one parachute and it has to work,” said John McNamee, project manager of Mars 2020 at JPL.
“The ASPIRE tests have shown in remarkable detail how our parachute will react when it is first deployed into a supersonic flow high above Mars. And let me tell you, it looks beautiful.”
Tough Test Mirrors Harsh Martian Conditions
A parachute deployed over Mars faces challenges a terrestrial chute would never face. The atmosphere around Mars is far less dense than Earth’s—about 1 percent of the Earth’s—meaning the chute develops less drag per square unit of surface area.
Even with two-thirds less gravity, parachutes don’t work nearly as well on Mars as on Earth.
Further, since the Mars Lander will be falling at more than 900 miles per hour, the chute has to open fully extremely quickly, despite having less atmospheric drag, which is the driving force behind the process with terrestrial parachute.
The ASPIRE chute worked remarkably well—better than it will need to.
The tests took place high in Earth’s atmosphere, where conditions mimic those over Mars. The payload was launched using a 58-foot-tall Black Brant IX sounding rocket. The payload was ejected, and when it reached the proper speed and altitude (23.6 miles high, traveling at Mach 1.8) the parachute deployed.
“Earth’s atmosphere near the surface is much denser than that near the Martian surface, by about 100 times,” said Ian Clark, the test’s technical lead from JPL.
“But high up—around 23 miles—the atmospheric density on Earth is very similar to 6 miles above Mars, which happens to be the altitude that Mars 2020 will deploy its parachute.”
The parachute was deployed at nearly twice the speed of sound. It took less than half a second for the barrel-sized bundle of nylon, Kevlar, and Technora to expand to the volume of a large house, generating more than 67,000 pounds of drag. That’s about 85 percent higher drag than NASA scientists think the chute will ever have to face on Mars.
More importantly, the chute has successfully deployed and safely lowered loads 40 percent higher than anything expected to be used during the actual 2020 Mars mission.
Now that the parachute has passed its tests, Clark and his crew will focus on the rest of the landing.
“We are all about helping 2020 stick its landing 28 months from now,” said Clark. “I may not get to shoot rockets to the edge of space for a while, but when it comes to Mars—and when it comes to getting there and getting down there safely—there are always exciting challenges to work on around here.”