While most of the views offered by NASA’s Curiosity Mars rover are of the planet’s surface, the robot pointed its cameras skyward recently and captured video of the Martian moon Phobos eclipsing the planet’s other moon, Deimos.
The telephoto-lens camera of Curiosity's Mast Camera (Mastcam) instrument recorded the images on August 1.
NASA says the video will help them better understand the orbits of the two moons. NASA says the orbit of Phobos is slowly getting closer to Mars, while the orbit of Deimos may be getting farther from the planet.
"The ultimate goal is to improve orbit knowledge enough that we can improve the measurement of the tides Phobos raises on the Martian solid surface, giving knowledge of the Martian interior," said Mark Lemmon of Texas A&M University, College Station in a statement
. He is a co-investigator for use of Curiosity's Mastcam. "We may also get data good enough to detect density variations within Phobos and to determine if Deimos' orbit is systematically changing."
Although Phobos has a diameter less than 1 percent the diameter of Earth's moon, Phobos also orbits much closer to Mars than our moon's distance from Earth. As seen from the surface of Mars, Phobos looks about half as wide as what Earth's moon looks like to viewers on Earth.
Here's a video of the event: