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Curiosity spots clouds drifting across Martian sky

Clouds Sailing Above Martian Horizon, Enhanced

Clouds drift across the sky above a Martian horizon in this accelerated sequence of enhanced images from NASA’s Curiosity Mars rover. Image & Caption Credit: NASA / JPL-Caltech / York University

Wispy clouds resembling Earth’s ice-crystal clouds move across the Martian sky in new images from NASA’s Curiosity Mars rover. The clouds are the most clearly visible so far from Curiosity, which landed on Mars in Gale Crater five years ago this month. Clouds in the Martian sky have been previously observed by Curiosity and other missions to the Martian surface, including NASA’s Phoenix Mars Lander.

Scientists used Curiosity’s Navigation Camera (Navcam) to capture two sets of eight images of the early morning Martian sky last month (July 2017). The camera was pointed nearly straight up for one set of images and pointed just above the southern horizon for the other.

Cloud movement was recorded in both sets of images and was made more visible by image enhancement. A midday observation of the sky with the same camera on the same day showed no clouds.

The elliptical orbit of Mars makes the planet’s distance from the Sun vary more than Earth’s does.

In past Martian years, a belt of clouds has appeared near the equator when Mars was at its farthest from the Sun. The recent images of clouds were taken about two months before that furthermost point in the orbit, somewhat early in the season for the appearance of this cloud belt.

“It is likely that the clouds are composed of crystals of water ice that condense out onto dust grains where it is cold in the atmosphere,” said Curiosity science-team member John Moores of York University, Toronto, Canada via a release issued by the Space Agency. “The wisps are created as those crystals fall and evaporate in patterns known as fall streaks or mare’s tails. While the rover does not have a way to ascertain the altitude of these clouds, on Earth such clouds form at high altitude.”

LEFT: Wispy clouds float across the Martian sky in this accelerated sequence of enhanced images. CENTER: Clouds drift across the sky above a Martian horizon in this accelerated sequence of enhanced images. RIGHT: Wispy clouds float across the Martian sky in this accelerated sequence of early-morning images (unenhanced version of the image sequence on the left). All of the above image sequences were taken on July 17, 2017, by the Navcam on NASA’s Curiosity Mars rover. Credits: NASA / JPL-Caltech / York University

York University’s Charissa Campbell produced the enhanced-image sequences by generating an “average” of all the frames in each sequence, then subtracting that average from each frame, highlighting any frame-to-frame changes. The moving clouds are also visible, but fainter, in a sequence of raw images (shown above right).

Over the course of the past five years, Curiosity has revolutionized our understanding of the Red Planet from its vantage point in Gale Crater. Building upon what prior missions to the dusty planet have gleaned about the past history of Mars (specifically if the planet was ever able to support life), the roughly one-ton rover was sent to seek out evidence of past, and possibly current, signs of microbial life.

NASA’s Mars Science Laboratory rover Curiosity touched down on the flash-frozen plains of the Red Planet after it had lifted off from Cape Canaveral Air Force Station’s Space Launch Complex 41 (SLC-41) located in Florida. It was launched atop a United Launch Alliance Atlas V 541 rocket (AV-028), the second most powerful launch vehicle in the rocket’s family. After a voyage across the void between worlds of slightly more than eight months.

NASA is hoping to follow up on Curiosity’s highly successful mission with a new rover based on Curiosity’s proven design with the planned Mars 2020 rover mission. If everything goes as is currently planned, the Mars 2020 rover should further the space agency’s vision for exploring the Red Planet.

“The Mars 2020 rover is the first step in a potential multi-mission campaign to return carefully selected and sealed samples of Martian rocks and soil to Earth,” said Geoffrey Yoder, acting associate administrator for NASA’s Science Mission Directorate in Washington. “This mission marks a significant milestone in NASA’s Journey to Mars – to determine whether life has ever existed on Mars, and to advance our goal of sending humans to the Red Planet.”



Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.

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