NASA scientists made history in 1969 when the first men landed on the surface of the moon. So why are they relying on robots like the Mars Pathfinder and Sojourner robotic rovers to explore the surface or Mars? To date, the track record has not been great. Different nations have sent more than 30 probes on missions to Mars, but fewer than one-third have survived the trip.
It is expensive to send people into space. It would take a minimum of 100,000 pounds of vehicle, equipment, food and water for a small team of astronauts to reach Mars. Designing and delivering a robot to Mars doesn't require heavy and complicated life support systems.
Robots also don't have to worry about a return trip back to Earth. It might be possible to produce fuel for a return trip from the Martian atmosphere itself, but many test missions would need to be performed to prove that it can be done.
The Mars Pathfinder and Sojourner rovers were equipped with robotic arms, nine cameras apiece, and all the instruments a human geologist would need to collect samples and seek out indications of water (past or present) on Mars to compile a complete history of the planet's climate. The robots aren't fast -- they typically move just two inches per second -- but they still managed to collect and transmit vital information back to NASA scientists on earth.
Scientists are building robots designed to mimic the movements of snakes. Snakes don't have rigid skeletons, so they can contort their bodies to get into tiny holes and slither over uneven terrain. So-called "snakebots" would be able to dig into the loose soil of Mars to explore where other robots couldn't reach, and slither into cracks in the planet's surface.