Mars is many millions of miles away, but it’s not always as far away as you think. The powerful scientific instruments we’ve deployed to the Red Planet can occasionally give us a glimpse of our own humble planet from a different perspective. NASA has just released a new image that shows Earth and the Moon as seen from Mars, courtesy of the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter (MRO).
As the name implies, the Mars Reconnaissance Orbiter is in orbit of the Red Planet, and has been since 2006. It was launched in 2005 after being built by Lockheed Martin. This satellite has proven invaluable in analyzing the surface of Mars with visible light cameras, radar, and spectrophotometers. It even snapped a photo of Curiosity parachuting down to Mars in 2012.
This newly released photo of our pale blue dot is a product of the satellite’s HiRISE camera, which is technically a telescope with a 0.5 meter reflecting mirror. This is the largest telescope ever carried on a deep space mission. It has a resolution of 1-foot per pixel at an altitude of 190 miles (300km). That’s even higher than most satellite images of Earth.
HiRISE captures images in three wavelengths: infrared, red, and blue-green. These are shifted down to red, green, and blue in visible light images like the one above. This is actually composed of two separate images acquired on November 20th, 2016. They were processed separately in order to preserve the individual brightness of each body so the details would be visible. The position and size are accurate when viewed from the orbiter’s position at Mars some 127 million miles away at the time of the photo.
The careful processing of the two images into the one at the top of this article makes the details easier to see. The brown shape in the middle of the Earth is Australia, and above that you can see Asia wrapping around the horizon. Asia has a more reddish tone due to the presence of vegetation, which is less prevalent in much of Australia. Down at the bottom you can see the bright white bulk of Antarctica peeking up.
The Mars Reconnaissance Orbiter had an original mission duration of two years, but it’s lasted much longer. NASA doesn’t have a firm end date in mind yet. In fact, MRO was just recently re-positioned into a new orbit to provide support to the InSight lander. That mission should reach Mars by November of 2018.