Chances are that you’ve seen images of Earth from space, thanks to the astronauts aboard the International Space Station (ISS), who regularly share stunning photos of our planet. These images provide us regularly with breathtaking views of cities, oceans, storms, eruptions, clouds, the curvature of the planet, and the way the atmosphere glows against the horizon. Thanks to NASA’s Mars Odyssey Orbiter, which has been in orbit for over 22 years, we now have an equally breathtaking view of Mars from orbit that captured what its curvature and atmosphere look like from space.
The images were taken back in May when the orbiter was at an altitude of 400 km (250 mi) above the surface, the same altitude that the ISS orbits Earth. The spacecraft took ten pictures in total, which were stitched together to create a panoramic image showing the curving Martian landscape below a hazy layer of dust and clouds, as well as Mars’ smaller satellite Phobos. The THEMIS camera is ideally suited to capturing what’s happening in Mars’ atmosphere, as its sensitivity to infrared (heat) enables it to map ice, rock, sand, dust, and temperature changes on the planet’s surface.
Because THEMIS is fixed to the bottom of the orbiter, adjusting the camera’s angle requires that the entire spacecraft be reoriented. In this case, the team needed to rotate the orbiter about 90 degrees while making sure the solar panels were still pointed at the right angle so they could continue to draw power from the Sun. At the same time, they had to ensure that the orbiter’s sensitive instruments would not overheat. This included the THEMIS camera itself since external heat would cause extreme interference with its readings.
This required that the orbiter’s antenna be pointed away from Earth, which meant that the mission team could not communicate with Earth until the operation was complete. Preparing for this maneuver took three months and involved engineers at NASA’s Jet Propulsion Laboratory and Lockheed Martin Space, which together manage the mission and lead its day-to-day operations. Jonathon Hill, Arizona State University, is the operations lead for Odyssey’s camera, the Thermal Emission Imaging System (THEMIS). As he explained in a NASA press release, the image is reminiscent of what astronauts may see someday:
“If there were astronauts in orbit over Mars, this is the perspective they would have. No Mars spacecraft has ever had this kind of view before. We got a different angle and lighting conditions of Phobos than we’re used to. That makes it a unique part of our Phobos dataset,” he said. “I think of it as viewing a cross-section, a slice through the atmosphere,” added Jeffrey Plaut, Odyssey’s project scientist at JPL. “There’s a lot of detail you can’t see from above, which is how THEMIS normally makes these measurements.”
The resulting panorama is not only impressive to look at but will provide scientists with new insights into the composition and dynamics of the Martian atmosphere. Seeing where layers of water-ice clouds and dust are (and how they are stacked) in relation to each other is essential to improving models of Mars’ atmosphere. The mission team hopes to take similar images in the future that capture seasonal changes in the Martian atmosphere. The spacecraft also captured images of Phobos, which is the seventh time the mission has pointed THEMIS towards Phobos in the 22 years it has been orbiting Mars.
The latest imagery shows temperature variations across the moon’s surface and provides insight into the composition and physical properties of the moon. These images will also be helpful to the Odyssey scientists who are also working on the joint NASA-JAXA sample-return mission to Phobos and Deimos – the Mars Moon eXplorer (MMX). It is hoped this mission will finally settle the long-standing debate about whether Phobos is a captured asteroid or a chunk of Mars that was blasted into orbit by a past impact.
Further Reading: NASA