NASA’s InSight Lander Spots The Shadow Of An Eclipse On Mars

NASA / JPL-Caltech

Witnessing a solar eclipse on Earth is a wondrous thing, but have you ever seen an eclipse on Mars? NASA’s InSight lander has, and the mission’s team wanted to share the glorious sight with all of the space enthusiasts out there.

On Tuesday, the InSight team took to the mission’s Twitter account to post brief footage of a Martian eclipse, as spotted by the lander from its location on Mars’ Elysium Planitia.

According to the mission scientists, InSight captured the shadowy eclipse just as Mars’ larger moon, Phobos, passed in front of the sun. This caused a tiny dip in the brightness of the star and sent shadows moving across the red Martian terrain.

To illustrate what InSight saw on Mars, the team shared a GIF of the eclipse, which CNET describes as “a delight.” The footage shows the lander’s shadow slowly crawling across the dusty ground as the sunlight flickers “like someone just leaned on a light switch.”

The short clip gives an ample view of InSight’s SEIS seismometer resting on the dust-covered terrain under the comfy protection of its Wind and Thermal shield. Deployed in early February, or about two months after the seismometer, the shield protects the supersensitive instrument “from being shaken by passing winds, which can add ‘noise’ to its data,” explained NASA.

The entire eclipse only lasted for about 27 seconds, the InSight team detailed in a comment to their post. Meanwhile, the photo sequence showed in the GIF covers around 14 minutes and was shot right around noon, the team explained via Twitter.

Judging by the angle from which the footage was captured, it seems that InSight documented the Martian eclipse with the help of its Instrument Context Camera, or ICC, which is mounted on the body of the lander. The ICC sits just below the deck, on the edge of the lander facing the so-called “workspace,” and has a “fisheye” field of view of 120 degrees, notes NASA.

The Moons Of Mars

Mars boasts two moons, Phobos and Deimos, but they are far smaller than Earth’s natural satellite. In fact, Earth’s moon is more than 100 times wider than Phobos, the bigger of Mars’ two moons.

Color image of Phobos, imaged by the Mars Reconnaissance Orbiter on 23 March 2008.Featured image credit: NASA/JPL-Caltech/University of ArizonaWikimedia Commons/Resized

“Mars’ moons are among the smallest in the solar system,” shows NASA. Phobos has a diameter of about 14 miles, while Deimos is about 7.8 miles wide. By comparison, Earth’s moon measures 2,159.2 miles in diameter, notes Space.

Illustration comparing the size of Earth’s and Mars’ moons.
Illustration comparing the size of Deimos and Phobos to that of Earth's moon.Featured image credit: NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M Univ.

However, the Martian moons orbit a lot closer to their planet. For instance, Phobos whips around Mars three times a day, whereas the more distant Deimos circles the planet once every 30 hours. No known moon orbits closer to its planet than Phobos orbits Mars.

InSight is not the first NASA robotic Mars mission to spot Phobos eclipsing the sun. In 2013, the space agency unveiled spectacular footage of a Martian eclipse captured by the Curiosity rover. In the clip, which you can watch below, Phobos is seen passing directly in front of the sun as photographed from Curiosity’s vantage point in the Gale Crater.