Ever since Earth's immediate cosmic neighbourhood, the Solar System, was determined by exceptionally smart humans like Nicolaus Copernicus, Galileo Galilei, Johannes Kepler and Isaac Newton, a big question has pertained - can any other planet sustain life? The Solar System is actually small by factors of millions compared to interstellar distances, but these distances are daunting for man to travel through. To put this distance in perspective - NASA launched a mission called New Horizons in January 2006 and it could reach Pluto, the most distant planetary body in the Solar System, only in summer of 2015. It took about 10 years for New Horizons to be able to see Pluto, the first time mankind saw what it looks like up close. But a planet that isn't as far and is most likely to host life, since it used to have it (well, billions of year's ago), is Mars. NASA has been studying the planet for years now and even sent a rover which collected data from the Red Planet's surface, the Curiosity. Now though, NASA is planning the 2020 Mars Mission and the rover has been updated. So, what does it take for a little man-built machine to take on the unknown surfaces of another planet?
The new rover looks pretty much like the Curiosity Mars rover, but the science machine cum Mars off-roader has seven new instruments, redesigned wheels and more autonomy. This new hardware is being developed at NASA's Jet Propulsion Laboratory, Pasadena, California, which manages the mission for the agency. It includes the Mars 2020 mission's cruise stage, which will fly the rover through space, and the descent stage, a rocket-powered "sky crane" that will lower it to the planet's surface.
The new rover has new goals to achieve and hence is loaded with cutting-edge science instruments. JPL is also developing a crucial new landing technology called terrain-relative navigation. As the descent stage approaches the Martian surface, it will use computer vision to compare the landscape with pre-loaded terrain maps. This technology will guide the descent stage to safe landing sites, correcting its course along the way.
How are they driven?
The rovers were initially designed to move up to 100 metres each sol (Martian day which is about 24 hours and 40 minutes), though they have gone much farther. A hundred metres mat sound less but there are good reasons behind it. While a day lasts quite long on Mars, the Sun can only provide enough power for the rover to drive about in a four-hour window around high noon.
The communication time between Earth and Mars is about 20 minutes, hence moving from rock to rock or location to location can be a challenge. Unlike a remote-controlled car, the controller of a Mars Rover cannot immediately see what is happening and cannot send quick commands to prevent a catastrophe, say if the rover is nearing the edge of a cliff.
NASA boffins will be able to explain all of this a lot better:
During surface operations on Mars, each rover receives a new set of instructions at the beginning of each sol. Sent from the scientists and engineers on Earth, the command sequence tells the rover what targets to go to and what science experiments to perform on Mars.
A drill will capture rock cores, while a caching system with a miniature robotic arm will seal up these samples. Then, they'll be deposited on the Martian surface for possible pickup by a future mission.