The Odyssey orbiter has recorded clouds and dust in the sky of the Red Planet, as well as Phobos, one of the two tiny moons of Mars.
Astronauts often react with awe when they see the curvature of the Earth beneath the International Space Station. Now, Mars scientists are getting a taste of what that’s like, thanks to the Odyssey orbiter, which last month completed its 22nd year on the Red Planet.
Panorama of the Martian horizon
The spacecraft captured a series of panoramic images that show the curved Martian landscape beneath transparent layers of clouds and dust. Stitched together, the 10 images offer not only a fresh and stunning view of Mars. They also help scientists gain new insights into Mars’ atmosphere.
The spacecraft took the images in May from an altitude of about 250 miles, the same height at which the space station flies above the Earth.
“If astronauts were in orbit on Mars, they would have this perspective,” said Jonathon Hill of Arizona State University, who leads Odyssey’s Thermal Emission Imaging System or THEMIS camera. – “No Martian spacecraft has ever gotten a view like this before.
How it was done
The reason why this view is so rare is because of the complexities involved in its creation. Engineers at NASA’s Jet Propulsion Laboratory in Southern California, which manages the mission, and Lockheed Martin Space, which built Odyssey and jointly manages day-to-day operations, spent three months planning THEMIS observations. The infrared camera’s sensitivity to heat makes it possible to map ice, rocks, sand, and dust along with temperature changes on the planet’s surface.
It can also measure the amount of water ice or dust in the atmosphere, but only in a narrow column directly below the spacecraft. That’s because THEMIS is mounted so on the orbiter that it looks straight down.
The mission wanted to get a broader view of the atmosphere. Seeing where these layers of water-ice clouds and dust are in relation to each other – one layer or several layers overlapping – helps scientists improve models of Mars’ atmosphere.
“I think of it as looking at a cross-section, a cross-section of the atmosphere,” said Jeffrey Plaut, Odyssey project scientist at JPL. – “There’s a lot of detail that you can’t see from above, which is how THEMIS typically makes these measurements.
Since THEMIS cannot rotate, adjusting the camera angle requires adjusting the position of the entire spacecraft. In this case, the team needed to rotate the orbiter nearly 90 degrees, making sure the sun still shines on the spacecraft’s solar panels but not on sensitive equipment that could overheat.
The easiest orientation turned out to be the one where the orbiter’s antenna is pointed away from Earth. This meant that the team had no communication with Odyssey for several hours until the operation was complete.
The Odyssey mission hopes to take similar images in the future, recording the Martian atmosphere for several seasons.
A look at Phobos
To maximize its efforts, the mission also captured images of Mars’ small moon Phobos. This is the seventh time in 22 years that the orbiter has pointed THEMIS at the satellite to measure temperature fluctuations on its surface.
“We got a different angle and lighting conditions from Phobos than we’re used to,” said Hill. – “This makes it a unique part of our Phobos data set.
The new images provide insight into the composition and physical properties of the Mars moon. Further research may help resolve the debate over whether Phobos, which is about 25 kilometers in diameter, is a captured asteroid or an ancient piece of Mars that flew off the surface as a result of an impact.
NASA, together with JAXA (Japan Aerospace Exploration Agency), is participating in a sample return mission to Phobos and its satellite Deimos called Mars Moon eXplorer.
