Mars has fascinated humanity for centuries. The Red Planet has long been a source of study and speculation. Science fiction stories have inspired scientists and the general public to learn more about the world. Recently, Elon Musk, founder of the private space exploration firm SpaceX, has proposed an ambitious manned mission to Mars that could depart as early as 2022 though he has not fully explained overcoming the technical and financial obstacles.

The need-to-know facts about Mars exploration:

1. In the late 1960s and into the early 1970s, NASA studied possible manned missions to Mars and even proposed manned missions that would have taken place possibly between 1981 and 1986. Funding cuts, however, cancelled the plans in favor of the space shuttle and space station programs.

2. NASA projects that it could take astronauts more than a year to even reach Mars and as long to return and would be prone to problems due to long-term weightlessness and threats from solar radiation.

3. The first satellite to reach Mars was the NASA probe Mariner 4, which was launched in 1974 and flew by the planet in July 1965, taking the first pictures of another planet from space.

4. Mariner 9 was the first satellite to orbit Mars, arriving in November 1971 and sending information back to Earth until October 1972.

5. The first craft to land on Mars was the Soviet probe Mars 3 in December 1971, but it failed seconds after landing.

6. The first American landers on Mars were the Viking 1 and Viking 2 probes, both arriving in 1976. The Viking lander experiments searching for signs of life displayed unusual results but no clear signs of life, either present or past.

7. NASA robotic rovers first landed on Mars in 1997 (four altogether: Sojourner (1997), Spirit (2004), Opportunity (2004), and Curiosity (2011)) and have discovered that water ice exists beneath the Martian surface and that the planet could have supported some form of life many millions of years ago.

8. NASA has proposed future missions to Mars that include a possible sample-return mission in the late 2020s and even a possible manned mission sometime in the 2030s, pending spacecraft design studies and funding.

9. For amateur astronomers, the most popular form of the exploration of space, Mars will be visible in the night sky in October, appearing in the northern hemisphere as a bright red star in the southwest in the early nighttime hours.

— Dr. Bridges is a professor of history and geography living in Arkansas. He can be contacted at drkenbridges@gmail.com.