On Tuesday, NASA conducted a spin test on its "flying saucer" that will help it bring larger payloads to Mars—and hopefully, in time, humans.
The Low-Density Supersonic Decelerator (LDSD) is a specially-designed decelerator that will be able to put the brakes on spacecrafts bound for Mars and help them gently land on the surface.
The spin test was in preparation for a more elaborate trial run to take place in June, the second of three tests that will bring the LDSD 180,000 feet above the Earth to test its ability to safely land.
But Tuesday's test was just to ensure that the LDSD is able to reach up to 20 rotations per minute, which, as you'll see here, it definitely can:
"It's the same rationale behind by bullets and arrows spin: it stabilizes the object in flight," explained Paul Lytal, the integration and test mechanical lead for LDSD, during the livesteam of the test. "The reason bullets don't tumble when they're flying is really because they're spinning."
That spinning will allow the LDSD to employ its two-part deceleration system, which will allow ships carrying more massive payloads to still gently land on Mars's surface. First, 5-10 psi of pressure inflates airbags all around the rim of the LDSD, a feature called the the supersonic inflatable aerodynamic decelerator (SIAD), which creates more drag. Then, a gigantic parachute, one three times the area of previously used Mars parachutes, is released to further slow the ship even while travelling at supersonic speeds.
Last summer, the first atmospheric test of the LDSD went well, even though the parachute tore up after it was released. That test was mainly to ensure the SIAD functioned properly, but it also gave NASA a lot of data about how to improve the parachute so it can properly deploy at high speed in Mars's thin atmosphere.
NASA is shooting for two complete, successful tests of the LDSD before the administration spends the money to fly it all the way to the red planet. If NASA can get it working reliably, the design would enable ships to carry much more massive payloads than before. Right now, spacecraft can carry only one metric ton of equipment to the surface of Mars and still land safely. If LDSD works, it will be able to increase that to between three and five metric tons, according to James Reuther of NASA's space technology division.
But Reuther explained that a manned mission to Mars—with human beings and all the equipment those high maintenance astronauts need to stay alive—would require the ability to carry 10 to 20 metric tons of payload to the surface of Mars. But we are talking about flying to Mars, after all, and Reuther said we won't get to 10 metric tons without figuring out how to safely land five metric tons first.
"Think of this as a stepping stone," he said during the livestream. "It's still a big step."
We're also going to have to figure out a way to reduce the g-force exerted when hurtling several metric tons of people and equipment to Mars and then trying to hit the brakes. The LDSD will exert 10 to 15 Gs during deceleration, according to Rob Manning, the chief engineer for LDSD.
"That's rough for a human being, but for a robot that's pretty good," Manning said during the livesteam. "The robots don't mind."
For a manned mission, they'd need to reduce that force at least to 6 Gs, or six times the Earth's gravity, Manning said. It would still be a pretty intense force to subject a human to, but it's a lot more manageable than the current conditions.
So while the flying saucer won't be zipping humans to Mars in the next few years, the technology is a significant advancement towards that goal. The team at LDSD said they were hopeful the next two planned tests, scheduled for this summer and the next, will be the two successful runs they need to greenlight the project to actually go to Mars.
In the meantime, we can enjoy the strangely hypnotic spinning the LDSD successfully maintained today: