Despite the fact that the twin robots of the Mars Exploration Rover (MER) mission have advanced our knowledge of Mars so much that we can't really quantify it, engineers at NASA are annoyed by the fact that they can't make the little robots go into steep gullies, or other similar geological formations, for fear that they might not be able to get them out of there safely. The tiny robots, despite having survived for years on the Red Planet – and despite all odds, too – are very fragile, and could not handle a fall. That's why NASA has recently come up with a variety of new rovers, which it says could allow for a number of now-forbidden applications on Mars, Wired reports.

One such instrument is the CliffBot, or the Sample-Return Rover, which is able to escalate slopes of up to 80 degrees in inclination. The way it does that is by setting up two “anchorbots” on top of a ridge, to which it's attached via reels of a high-resistance string. With two such tools to sustain it, the rover can descend along the length of the string, and collect dust and stone samples from the gullies that may have had water flowing through them millions of years ago. These are the most interesting formations on Mars, but, unfortunately, they remain out of Spirit and Opportunity's reach.

Another interesting approach to the whole exploration rover concept is the Lemur (standing for Limbed Excursion Mechanical Utility Robots). Originally designed to help build structures in orbit, it's very handy, if such a term can be assigned to a machine. NASA has shown that the 18-inch-across instrument can escalate the walls of a rock gym with relative ease, without having to be anchored to the top. It can also climb on a segmented mirror, which would definitely be a plus in the event that some space agency builds a permanent human base on the Moon or on the Red Planet.

Based on the Lemur, the larger Athlete (All-Terrain Hex-Legged Extra-Terrestrial Explorer) rover is a heavy-lift robotic vehicle, designed to transport both people and supplies on the hostile surfaces of Mars, the Moon, or anywhere else. With a width of four meters (some 13 feet), its size is its largest advantage in front of almost any kind of obstacle. The most striking feature of the new machine is that it can travel at six miles per hour, which is more than 100 times the speed of the MER mission twin robots. And it does all that while keeping its center perfectly balanced, via the use of gyroscopes.

“It’s like retired people with their big Winnebago and the Jeep behind them. You park your Winnebago [in this case, Athlete] and it stays stationary for a week or two, and you do your little sorties in your Jeep,” Jet Propulsion Laboratory (JPL) Mobility and Robotics Systems Section Manager Richard Volpe said of the rover.