OTD In Space - July 4: Mars Pathfinder Arrives On Mars

On July 4, 1997, NASA's Mars Pathfinder mission arrived on Mars and began transmitting images from the surface of the Red Planet.

The rover, named Sojourner, was the first rover to successfully land on Mars. Sojourner was accompanied by a lander named the Carl Sagan Memorial Station. The mission used an innovative landing system to touch down on the surface. NASA cocooned the rover with airbags to cushion the impact after a parachute slowed down the fall. Pathfinder touched down in a region of Mars called Ares Vallis — an ancient flood plain that NASA chose because it was relatively safe but still had plenty of rocks to study. While the Pathfinder lander took pictures of the Martian sky and collected meteorological data, the Sojourner rover studied Martian rocks and soil with its three cameras and an Alpha Proton X-ray Spectrometer, which allowed it to analyze the chemical composition of samples from the surface.