The Mars Explorers are robotic vehicles, known as rovers, that have been sent to the surface of Mars to explore and collect data. They are equipped with cameras, spectrometers, and other instruments to help them analyze the Martian environment. The rovers are designed to travel long distances across the Martian terrain, taking pictures and collecting samples along the way. The data they collect is then sent back to Earth for further analysis. The Mars Explorers have been instrumental in helping scientists understand the geology and climate of the Red Planet.