How Far Away is Mars? | Universe Today

Written by Fraser Cain

How far away is Mars? The minimum distance from Earth to Mars is 55.7 million km, or 34.6 million miles.

But think about the orbit of Earth and Mars around the Sun. This closest point happens when Earth and Mars are lined up on the same side of the Sun (Sun – Earth – Mars). When Mars is at its closest point, astronomers call this opposition. This is when Mars can be only 55.7 million km from Earth. The average Mars opposition distance is 78 million km.

And then when Mars and Earth are on opposite sides of the Sun (Earth – Sun – Mars), Mars can be 401.3 million km from Earth.

A Mars opposition happens every 26 months, when the two planets are lined up together. This is a useful launch windows for sending spacecraft from Earth to Mars. NASA usually launches a spacecraft during each one of these launch windows. The last mission to go to Mars was the Mars Phoenix Lander, and the next one to launch will be the Mars Curiosity Rover in 2011.

We have written many articles about Mars for Universe Today. Here's an article about the gravity on Mars and here's an article about a simulated Mars mission.

If you'd like more info on Mars, check out NASA's Mars Exploration mission page, and here's a link to NASA's World Book on Mars.

We have also recorded several episodes of Astronomy Cast about Mars. Here's a link to Episode 52: Mars.

Filed under: Astronomy