NASA released footage of the first double lunar eclipse viewed from Mars rover Curiosity.
Phobos, the larger of the Martian moons, passes in front of the diminutive Deimos in the sped-up footage of the transit that took about 55 seconds.
While it's easy to imagine a bit of "Hey, check this out!" over at NASA's Jet Propulsion Laboratory, there's serious science behind scanning with the dual-camera Mastcam on the world's coolest and most famous go-cart.
"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," Mark Lemmon of Texas A&M University, one of the investigators of Curiosity's Mastcam, said in a statement. "We may also get data good enough to detect density variations within Phobos and to determine if Deimos' orbit is systematically changing."
Lemmon and fellow researchers figured out that lunar duo would be visible crossing paths Aug. 1, shortly after Curiosity would be transmitting data to NASA’s Mars Reconnaissance Orbiter, for relay to Earth. That meant they could capture the images without using up any un-budgeted power.
The 41 images weren't as high a priority as other data the rover is collecting from Gale Crater, where NASA is investigating whether conditions could have favored microbial life. So it took awhile before they were down-linked to Earth and cobbled together for the time-lapse photo gallery NASA released Thursday.
Phobos, the larger of the two Mars companions, looks to be nearly half the size of our moon viewed from Earth. It's actually a lot smaller, with a diameter about 1% of that of our moon. Phobos is much closer to the Mars surface than the moon is to Earth, though, so it looms large. It's also getting farther away from the Martian surface over time, while Deimos is believed to be coming closer to the Martian surface.