Cheers turned to groans in a NASA control room as a massive parachute designed to slow the descent of a "flying saucer" vehicle failed to unfurl properly for the second year in a row.
"Partial chute," one of the mission managers said on a live feed from NASA TV.
A camera mounted to the saucer-shaped vehicle – officially known as the Low-Density Supersonic Decelerator, or LDSD – showed several cords stretch out behind the test craft as it fell toward Earth from a height of about 180,000 feet. Engineers applauded as the reddish chute appeared behind the LDSD.
But the supersonic parachute did not deploy according to plan. It took about 200 seconds for the LDSD to splash down in the Pacific Ocean west of the U.S. Navy's Pacific Missile Range Facility in Kauai, Hawaii.
Until then, the test of the LDSD appeared to be going according to plan.
A high-altitude balloon lifted the saucer 120,000 feet above sea level. Then, at "drop time," the 1,000-foot cable detached from the 7,000-pound vehicle. Four small motors caused the saucer to spin and stabilize as a rocket engine powered by solid fuel kicked in to carry the craft to an altitude of 180,000 feet.
It took about a minute for the LDSD to reach its maximum altitude, traveling at four times the speed of sound.
Two cameras on board the test vehicle showed the doughnut-shaped ring inflate around the outer edge. When fully inflated, the supersonic inflatable aerodynamic decelerator, or SIAD, increased the saucer's diameter from 15 feet to 20 feet, creating drag to slow it down.
Engineers watching the test from JPL in La Canada Flintridge applauded as the doughnut inflated as designed.
But the big test involved a supersonic parachute that's twice as big as the one used to ferry the Curiosity rover to the surface of Mars.
In last year's test, the parachute frayed and tore as soon as it was unfurled. Divers recovered it from the Pacific Ocean so that it could be studied and improved upon.
"We have a brand-new design of the parachute that we will be testing this year," Dan Coatta, a mechanical engineer at JPL, said shortly before the test began. "To have a fully successful day, we really want the parachute to work."
FOR THE RECORD
10:34 a.m.: An earlier version of this post misspelled JPL engineer Dan Coatta's name.
But it didn't.
To figure out why, JPL specialists will examine the remains of the chute, which measures 100 feet across. They will also analyze the high-resolution video recorded by the cameras as well as data stored in a black box that will also be fished out of the water.
The black box contains "a gold mind of data," Coatta said.
The flying saucer isn't designed to carry humans to Mars or ferry them around the Red Planet once they arrive. But if all goes according to plan, it will play an instrumental role in getting them — and all of their gear — safely to the Martian surface.
All of the rovers and landers NASA has sent to Mars since the first Viking probe touched down in 1976 have used parachutes to slow their descent. But if the space agency ever sends anything heavier than Curiosity — including human explorers — parachutes alone won't cut it. Something else must help these larger payloads slow down as they hurtle through the Martian atmosphere.
That is why engineers have built the flying saucer.
This huge contraption is far too big to fit in any wind tunnel. That's why the JPL team is testing the flying saucer in a virtual wind tunnel about 22 miles over the Hawaiian islands.
At that height, Earth's stratosphere is as thin as Mars' atmosphere — and thus suitable for a test flight.
Last year's test confirmed that the Hawaiian stratosphere could stand in for the Martian atmosphere. As a bonus, it showed that the inflatable doughnut and a second braking device called a "ballute" — a combination of a balloon and parachute — could indeed slow a heavy payload. After a few days, the NASA team plans to post high-quality images from all of the cameras.
NASA will share more information about the test at a Tuesday morning news conference. In a few days, it will also post high-quality images from all four of the on-board cameras.