ORONO, Maine — If NASA successfully builds a spacecraft large enough to carry astronauts to Mars, the ship will need to be able to slow down from 10,000 miles per hour in order enter the planet’s atmosphere and safely land.
Though a manned-mission to the planet may be many years away, NASA is already developing the devices needed for such a trip, and those devices need to be tested.
That’s where University of Maine research engineers come in.
Engineers working the university’s Advanced Structures and Composites Center are currently testing materials and and parts that will be used in the construction of a piece of equipment that may one day be used to help a human-baring ship reach Mars.
The device, called a Hypersonic Inflatable Aerodynamic Decelerator, which the engineers refer to as a HIAD, is made of inflatable tubes of differing sizes stacked one on top of the other to create a cone-shaped structure. The HIAD would be deployed nose first in front of a spacecraft, slowing the entire apparatus down, like a reverse parachute, as it enters Mars’s atmosphere.
The inflatable tubes are made of a firmly woven fabric and strengthened with one inch-wide cords that can carry up to 7,000 pounds of weight.
Everything from the strength of the fibers that make up the fabric, to the angle of the weave, to amount of air used to inflate the tubes must be tested in order to predict how the device will behave once it’s under pressure.
“It’s nice to make a contribution to something of this type,” said Bill Davids, the UMaine engineer who is working on the project.
“It’s a bit intimidating at first,” he added. “You’re working with NASA. With NASA you’re working on a technology that they envisioned and developed some years ago, but there are some holes.”
The engineers take 3-D photographs of the materials they are testing, as they use machinery to stretch, twist, inflate and deflate the parts. They send data back to NASA on how the materials performed.
“We test the little things and then use a model to predict how the big thing behaves,” Davids explained. “It’s really critical to build your knowledge from the ground up, to understand how the individual constituents behave.”
“We don’t have the facilities to test the full size [HIADs] on Earth,” added Josh Clapp, a doctoral student who is working on the project.
Clapp said NASA envisions a spacecraft carrying astronauts would need to be weigh about 40 to 80 tons. The most recent spacecraft to go to Mars weighed less than one ton.
Davids said interest in sending a manned mission to Mars has waxed and waned over the years, but recently it’s become a possibility again.
The data the UMaine engineers are generating will help NASA determine how large and heavy the HIAD should be, which will impact how quickly it will slow the spacecraft down.
UMaine was picked by NASA to work on this project more than a year ago in part because of another project on inflatable structures that the researchers at the Advanced Structures and Composites Center worked on with the U.S. Army.
For that project, which ran from 2005 to 2011, Davids, Clapp and others worked on inflatable tents and storage facilities. That work helped lay the groundwork for the NASA project, Davids said.
“There aren’t that many people in the U.S., or around the world, working on these sorts of things,” he said.
NASA awarded UMaine $750,000 for this project, he said. This summer, three UMaine undergraduate students are working on the project full time and during the year, five to six undergraduates help out.
“It really helps support education as well,” he said.