When is mars farthest from earth

However, astronomers now calculate the distance to objects in the Solar System using the speed of light. They measure the time it takes for signals to reach spacecraft orbiting other planets. They can bounce powerful radar off planets and measure the time it takes for signals to return. This allows them to measure the distance to planets, like Mars, with incredible accuracy. So, how far away is Mars?

The answer to that question changes from moment to moment because Earth and Mars are orbiting the Sun. It also requires a little explanation about the orbital mechanics of each. Both Earth and Mars are following elliptical orbits around the Sun, like two cars travelling at different speeds on two different racetracks.

And although they get close and far apart, those points depend on where the planets are on their particular orbits. So, the Earth Mars distance is changing from minute to minute. To get the closest point between Earth and Mars, you need to imagine a situation where Earth and Mars are located on the same side of the Sun.

Furthermore, you want a situation where Earth is at aphelion, at its most distant point from the Sun, and Mars is at perihelion, the closest point to the Sun. When Earth and Mars reach their closest point, this is known as opposition. And theoretically at this point, Mars and Earth will be only The last known closest approach was back in , when Earth and Mars were only 56 million km or In the chart the distance data is measured in Astronomical Units and sampled with an interval of 1 day.

The value of the reported distance might be somewhat inaccurate around the times of closest approach for objects passing extremely close to Earth.

The value of the distance of Mars from Earth is also available as a real time updated value in the Live Position and Data Tracker. This site cannot run without your voluntary donations. We don't use Ads. If you find this website useful please consider a small donation, it will help covering hosting costs. Thank you! Engineers must calculate the ideal orbits for sending a spacecraft from Earth to Mars. Their numbers factor in not only distance but also fuel efficiency.

Like throwing a dart at a moving target, they must calculate where the planet will be when the spacecraft arrives, not where it is when it leaves Earth. Spaceships must also decelerate to enter orbit around a new planet to avoid overshooting it.

How long it takes to reach Mars depends on where in their orbits the two planets lie when a mission is launched. It also depends on the technological developments of propulsion systems. The website quotes physics professor Craig C. Patten , of the University of California, San Diego:. The elliptical orbit which carries you from Earth to Mars is longer than Earth's orbit, but shorter than Mars' orbit. Accordingly, we can estimate the time it would take to complete this orbit by averaging the lengths of Earth's orbit and Mars' orbit.

Therefore, it would take about one and a half years to complete the elliptical orbit. You have to plan ahead to make sure that by the time you reach the distance of Mar's orbit, that Mars is where you need it to be! Practically, this means that you can only begin your trip when Earth and Mars are properly lined up. This only happens every 26 months. That is, there is only one launch window every 26 months. The trip could be shortened by burning more fuel — a process not ideal with today's technology, Patten said.

Evolving technology can help to shorten the flight.