NASA's primary mission for Mars is the search for life and elements, such as water, that could support life. NASA got its first close-range pictures of Mars in 1965. As of 2015, robot vehicles continue to send valuable information that may one day lead to a manned mission to Mars.
Scientific research has already determined that Mars sits 141,633,260 miles from the Sun and takes 687 days to complete its orbit around the sun. Its days are similar to those on Earth, with Mars taking 24 hours and 37 minutes to make a complete planetary rotation. The temperatures range from minus 125 degrees F to 23 degrees F. Gravity is roughly a third of gravity on Earth. A 100-pound person would weigh only 38 pounds on Mars.
Some of the most effective research missions to Mars involve the rovers Spirit and Opportunity. Both were launched in 2003 and arrived on different ends of Mars in 2004. The robotic vehicles wander about the surface taking pictures, analyzing soil samples and sending periodic reports back to NASA.
These rovers were expected to work for 90 days, but Spirit continued to work until 2011, and Opportunity, as of June 2015, is still sending back information. The latest explorations cover the west rim of Endeavour Crater where it joins the Spirit of St. Louis Crater near Marathon Valley.