Mars Dazzles in the Eastern Evening Sky

On Tuesday, October 6, Mars will be, closer to the Earth than it has been since 2018.  It won’t be closer until 2035.

The fourth planet from the Sun, Mars is a dusty, cold, desert world with a very thin atmosphere. (Image: NASA/Space Science Telescope Institute

About every 26 months, Earth catches up to and passes Mars.  Tuesday they’ll be rubbing fenders from 38.6 million miles away.  At that distance light, as well as any signals from the fleet of orbiters, a lander, a rover, and another on the way, take nearly 3.5 minutes to reach Earth.  While that may seem like a lot, that distance will increase to nearly 22 light minutes by next September.

The folks that fly and drive these robots on Mars have had 2020, specifically July through September circled on their calendars for a while, as they do every 26 months.  It’s a chance to reach Mars with a minimum of energy.   

When exploring space energy is fuel and fuel is weight, and every gram of fuel you have to add to reach your destination is a gram you cant use for a camera, sensor, or some other science instrument which is why you are going in the first place.

Which is why many plans around Mars, including sending humans there, often mention 2035.  For a couple of reasons, Its far enough in the future that we’ve got a good chance of solving the myriad of technical problems between us and putting boots on Mars.  The other reason is those launch windows.

The summer of 2035 should be a pretty exciting time in Mars exploration because it is ahead of the next perihelic opposition of Mars on September 15, 2035.

Opposition is the point in the orbit of a planet when it is directly opposite the Sun in our sky, which also means it closer and requires the least amount of energy to reach.

We see an example of this monthly in each full Moon, which you could also call a lunar opposition.

2035 is a particularly good year to head to Mars because opposition coincides with Mars perihelion or the closest point in its orbit to the Sun.  That reduces the distance a rocket must travel to the red planet to the lowest point since 2003 and you’ve got to go back to 1971 to find a point closer

In the meantime, Mars is big and bright and just getting brighter ahead of this year’s opposition on Tuesday, October 13, 2020.  Take a moment tonight and look to the east after sunset.  Mars is looking particularly orange right now.

Category: ALL POSTS, Spacey Stuff