Nasa tests robot hardware for planet missions
Nasa is testing the next generation of human spaceflight technology in the deserts of Arizona, US.
The Desert RATS (Research and Technology Studies) programme is designed to give advanced equipment a trial run, and to expose any issues before it is used in space.
The dry, dusty, rocky land near the lip of the Grand Canyon provides a good simulation of other planets.
"The terrain is very varied, and is very volcanic in nature, which more or less represents what you would see on the Moon" says Joe Kosmo, Mission Manager for the Desert RATS programme.
"There are also a variety of areas here at the test site which are representative of a Mars environment, from a terrain standpoint.
"So overall it really gives a realistic setting for conducting some of these surface operations."
Nasa's base camp is near Black Point Lava Flow in northern Arizona, and, from there, researchers have spent two weeks conducting a series of tests of hardware, software, and human behaviour.
They are doing trials using a number of concept space vehicles, including two rovers, a six-legged vehicle called ATHLETE, and a pressurised excursion module.
The Space Exploration Vehicle is a rover about the size of a pickup truck, and has a pressurised module that two astronauts can live in for up to 14 days.
In this exercise, two rovers have been working in tandem, meaning they can venture more than 150 miles away from their base. The Apollo-era rover had a range of about six miles.
Each rover uses six sets of wheels, all of which can rotate 360 degrees meaning the rover can go in any direction, including crabbing sideways to get around an obstacle.
Nasa astronaut Mike Gernhardt is project manager of the Space Exploration Vehicle system. He has flown to space on the Shuttle four times, spending over 43 days in orbit.
His duties have included four spacewalks totalling over 23 hours. For him, one of the key developments on the new vehicles is a suit port, that connects spacesuits directly to the outside of the vehicle.
Astronauts can quickly climb into their suits and leave the rover.
"It takes us at least six hours to get out of the space station, and with this, I can be 'boots on the surface' within 10 minutes. The suit is on the outside, it's already powered up, and we only have a few leak checks that we have to do."
That opens up new possibilities for surface exploration at short notice, and also limits the amount of dirt and dust that is brought into the habitable areas.
The Habitat Demonstration Unit provides astronauts with a base to return to, after missions on a rover.
"The crew collects samples, and then they dock with the Habitat Demonstration Unit," says Tracey Gill from Nasa's Kennedy Space Center in Florida.
"Then they come inside, and we have maintenance and science workstations in there where they can examine samples, they can resupply, take care of any medical situations, and we have tools and work benches, where they can do repairs."
It is a reconfigurable unit, and could be expanded with inflatable rooms.
For this field test it consists of a large airlock with room to hang spacesuits, and attached to that, a cylindrical room 5m in diameter.
As well as the maintenance workstations, on this mission botanists on the Habitat Demonstration Unit have produced their own food - lettuce - to simulate having to grow crops to be self sufficient on another planet.
"We actually grew enough lettuce during the mission that we harvested it, and the crew had some with their lunch one day" says Tracey Gill.
If and when Nasa returns to the moon, one of the first missions will be to build a lunar outpost. Lunar landers must land a safe distance from any existing components because their rocket engines kick up dust and gravel.
To collect and deliver their cargo, scientists are working on a transporter called ATHLETE (All-Terrain, Hex-Limbed, Extra-Terrestrial Explorer).
ATHLETE is an imposing sight in the Arizona desert, towering above the other equipment on six legs which can raise it from around one meter above the ground to more than six meters. Each limb is effectively a robotic arm, capable of independent motion.
"We use the robotic arms for our active suspension, but we can also set the vehicle down and pick up one of the wheels with tools on the end of it," says Julie Townsend, an engineer from Nasa JPL, who has been conducting tests on ATHLETE in the Arizona desert.
"The big advantage of being out here is that we are not space constrained, we can do a lot of driving. So on this field test we have been demonstrating that we can traverse this vehicle across long distances."
Nasa is retiring the space shuttle and the US administration has recently proposed that the space agency should focus manned spaceflight efforts on objectives further than the Moon, so the scientists working on these prototypes say they are ready to make changes.
"We're looking at a flexible path, which will take us to the Near Earth Objects," says mission manager Joe Kosmo. That could include missions to Mars, or to asteroids in the Solar System.
"Even though we're roving on a surface here, the habitability studies that are being done within the cabin environment would be directly applicable to doing asteroid activities.
"Sample collection techniques are of interest too, not only on a planetary surface but collecting samples from asteroids. The mission scenarios would be representative of any kind of space exploration activity."