A big, bug-like rover that could one day carry heavy loads on the moon has stretched its six legs in the Arizona desert during NASA field trials.

The All-Terrain Hex-Legged Extra-Terrestrial Explorer (ATHLETE) rover is taking part in NASA's annual Research and Technology Studies demonstration, also known as Desert RATS.

ATHLETE is a 2.5-ton (2,300-kg) rover that NASA envisions ferrying astronaut living quarters and other weighty loads across the moon's surface. ATHLETE is basically a cargo deck on six wheels, each of which sits at the end of a configurable leg.

During Desert RATS, NASA-led teams of scientists and engineers are testing out prototype hardware for future space missions in the desert near Flagstaff, Ariz., for two weeks. The program has been held every year since 1998. This year's program runs from Aug. 31 to Sept. 15.

Engineers at NASA's Jet Propulsion Laboratory have already taken ATHLETE on short jaunts down California dirt roads. They've also shown the rover's flexibility by making a music video in which ATHLETE appears to dance. [Video of the dancing ATHLETE moon rover.]

The Desert RATS tests, however, will really put the rover through its paces. ATHLETE will drive 25 miles (40 km) over rough terrain, encountering rocky slopes, thick underbrush and — since the test site is in cattle country — barbed-wire fences. But the ATHLETE team is confident the slow-moving rover — its top speed is about 1.25 mph (2 kph) — can handle such challenges.

"It has the capability to step over these fences," ATHLETE's test leader Julie Townsend said in a NASA video.

ATHLETE is not the only hardware getting a test drive at Desert RATS. NASA is demonstrating many technologies, including:

Space Exploration Vehicles: rovers in which astronauts could live in for seven days at a time.

Habitat Demonstration Unit/Pressurized Excursion Module: a simulated moon habitat where rovers can dock to give crew enough room to perform experiments or deal with medical issues.

Portable Communications Terminal: a rapidly deployable communications station.

Centaur 2: a four-wheeled possible transportation method for the robot-astronaut concept known as Robonaut 2.

Portable Utility Pallets: mobile charging stations for equipment.

Geology Took Kit: A suite of new geology sample collection tools, including a self-contained GeoLab glove box for conducting in-field analysis of various collected rock samples.

NASA has been staging Desert RATS tests for years, but the space agency took a different approach to this summer's field trials.

In a first, Desert RATS planners opened the project up to the public to allow people outside the agency to help choose which parts of the Arizona desert to explore. NASA posted several choices online and allowed members of the public to vote for their favorite.

Several thousand votes were cast, with 67 percent favoring a spot that appeared to feature several overlapping ancient lava flows, project officials said.