Next summer, NASA plans to send a saucer-shaped Mars entry vehicle aloft by balloon from Kauai, boost it from 120,000 feet to as high as 180,000 feet by rocket, then, as it hurtles through the thin air at 2,600 mph, deploy a speed-reducing inflatable doughnut around the craft, followed by a big parachute, until it plops into the water for pickup.
It will be refitted and re-fired three more times through the summer of 2015.
That’s the National Aeronautics and Space Administration formula to test new arresting capabilities for increasing payloads to be sent to the red planet in years to come — some of the first steps on the technology path to potentially landing humans, habitats and return rockets in the 2030s.
NASA officials said the Kauai flights will represent the first supersonic parachute tests for NASA re-entry missions in more than 40 years.
The technology that was developed put two Viking landers on Mars in 1976. It was used again in 2012 to deliver the Curiosity rover to Mars.
“So even before we actually landed the Curiosity rover on Mars, we started realizing, you know what, we’ve taken that technology set as far as we can,” said Ian Clark, NASA’s principal investigator for the Low Density Supersonic Decelerator project.
For NASA to land bigger payloads to elevations and regions of Mars that haven’t been accessible — such as mountainous areas and the high-altitude southern plains — and to land them more accurately, the space agency has to develop new technology sets, which is what it will be testing at the Navy’s Pacific Missile Range Facility, said Clark, who works at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
“Part of that technology set is a new type of parachute, a new configuration of parachute, a much, much larger parachute than we’ve ever flown before, deployed at Mach numbers, at speeds much higher than we’ve ever deployed before,” Clark said.
That means a “ringsail” parachute 99 feet in diameter — more than twice the area of the most recent Viking-based parachute used to land Curiosity.
Also to be tested are two doughnutlike pressure vessels, called Supersonic Inflatable Aerodynamic Decelerators, designed to create drag and slow the re-entry vehicle.
One is 20 feet in diameter and sized for future robotic missions. The other is 26 feet in diameter and related to manned missions to Mars.
NASA said the new designs, never used before on a Mars mission, borrow from the same technique used by the Hawaiian puffer fish — the oopu hue — to increase size without adding mass through rapid inflation.
The $189.6 million Low Density Supersonic Decelerator project included wind-tunnel tests of parachute designs and rocket sled tests at the Navy’s China Lake Naval Air Weapons Station in California.
Parachutes for Mars landing craft must be enormous because the atmosphere is too thin to fill a parachute like those used on Earth, NASA said. Even with large parachutes, powerful retro-rockets or airbags have been necessary to make successful landings.
NASA intends to use the very thin air high in the atmosphere above Kauai to duplicate Mars’ low-density conditions.
Mark Adler, project manager for the decelerator project at the Jet Propulsion Laboratory, said NASA did supersonic parachute testing in the early 1970s at Roswell and near White Sands in New Mexico with rockets launched by balloon.
“But it turns out, we can’t do it there anymore,” Adler said. “There are populations and roads and other things that prevent that now. So now we’re looking to do it at PMRF.”
NASA examined locations in New Mexico, Utah and Alaska before deciding on the Kauai missile range.
“It’s mainly overflight of population,” Adler said of mainland limitations. “And so the nice thing about PMRF is we can just go out over the water.”
Australia also was considered, but there were no services and it would have cost a lot more to build up needed logistics, he said.
NASA released a “finding of no significant impact” for the project May 29 after conducting an environmental assessment. One flight test is planned for June to July 2014, and up to three more tests are expected June to August 2015.
Adler said a group got together in 2005 to start to figure out how the United States would land people on Mars. President Barack Obama, meanwhile, has called for a manned mission to Mars by the 2030s.
NASA realized that putting down a habitat for humans on Mars, a return rocket and other equipment would require the capability to land 20- to 40-ton payloads, Adler said.
The space agency reached about a ton with Curiosity, he said.
“The leap from one ton to 20 to 40 tons is enormous — so this (PMRF testing) is beginning along that path towards increasing the masses.” Adler said. “Maybe we’ll get up to two tons or so, or more, with the kind of technology that we’re developing here.”
This is “just technology development No. 1 out of several” that will be required to get a 20- to 40-ton payload on Mars, he added.
The full-scale 15-foot diameter test vehicle is about the size of robotic entry vehicles for Mars, including Curiosity, NASA said. Officials said it will be constructed of carbon composite, titanium and aluminum for the Kauai test.
The environmental assessment says the test vehicle will weight 7,000 pounds, but Clark said once the rockets have been expended, it will weigh about 2,500 pounds.
“So dimensionally, we’re actually testing full-scale articles,” he said. “The scale that we’re not matching is the mass of the vehicle that we’re testing.”
When it comes time for the first test, an 800-foot-long scientific balloon will be laid out on the ground at missile range. Helium will be pumped into the balloon, and as it expands high in the atmosphere, the balloon will reach 440 feet in diameter.
At 120,000 feet the 7,000-pound test vehicle will be cut from the balloon, and within a few tenths of a second, rockets will fire to spin the vehicle and stabilize it, Adler said.
A solid rocket motor then will accelerate the craft up to or past 160,000 feet at Mach 4, or about 3,045 mph.
“So it goes up to very high altitude to try to get to very thin air, which simulates the density of the air that this thing would be operating at on Mars when it deploys above the surface of Mars,” Adler said.
As the vehicle slows to Mach 3.5, or 2,664 mph, one of the Supersonic Inflatable Aerodynamic Decelerators will be deployed around the craft, which is expected to slow it to Mach 2.5, he said. One of the doughnutlike decelerators has a skin made of Kevlar coated with silicone.
The parachute, which will deploy at about Mach 2.4, or 1,827 mph, is made of nylon. Clark said NASA can use the material because it slows the vehicle so quickly, it never sees appreciable heating.
Cameras, accelerometers and inertia measurement devices will monitor the flights.
A separate Mars experiment is being carried out on Hawaii island with the Hawaii Space Exploration Analog and Simulation, or HI-SEAS, testing a Mars-style diet on six people living in a domed habitat at 8,000 feet on Mauna Loa.
Adler said he expects that before NASA sends people to Mars, there will be a series of robotic precursor missions to land payloads larger than Curiosity to test technologies, put down a power plant or start producing fuel for a return rocket.
“There are many possible things, and so these technologies (to be tested in Hawaii) could be used to put down those large precursor payloads in the 2.5-ton range,” he said.
