It is a common misconception that the first mission to Mars was in 1976, but it actually occurred decades earlier. Mariner 4 flew by Mars and took pictures of its surface on July 15, 1965.
What has been learned about Mars since then? How do we know if life exists there? Read on to learn more!
The History of Mars Missions
Even before the first Mars mission, scientists knew of water ice and carbon dioxide on Mars. However, after these pictures were taken, they realized that Mars had a thin atmosphere with no surface water.
All of this changed when Mariner 9 reached Mars in 1971 and found an enormous canyon system that could only have been created by running water and lots of it.
The Viking Missions
There were two Viking missions, one in 1975 and another in 1976. Much of the controversy about life on Mars stems from these missions. They didn’t find direct evidence of life but did discover that the Martian soil had nutrients that could support life under the right conditions.
The next mission was one such rover, the Sojourner Rover which landed on July 4, 1997. Its main purpose was to show how future missions could live off the Martian land instead of bringing supplies from Earth.
Spirit and Opportunity
The Mars Exploration Rovers, Spirit and Opportunity, landed in 2004 with the goal of looking for signs of water.
These two rovers found evidence that water once existed on Mars. They also discovered sulfates, which form when water evaporates away leaving behind minerals.
These two missions have found plenty of evidence that water used to exist on Mars. They’ve also shown that water is still present in the Martian soil, and there’s a good chance it exists beneath the surface.
The Opportunity rover has found meteorites that formed on Mars and were ejected into space by impacts. This means that Mars was once capable of protecting life from cosmic rays, the main obstacle preventing the evolution of simple life forms elsewhere in the universe.
What the Future Holds
The future of Mars science holds a lot of promises. As human spaceflight continues to advance, we will soon see humans on Mars. It is even possible that we may terraform the planet to make it suitable for human life!