The DownlinkSep 03, 2021

For every world, there is a season

Space Snapshot

Mars north polar layered deposites

This image shows large layered deposits of dusty water-ice in the northern polar region of Mars. NASA's Mars Reconnaissance Orbiter, which took this photo, has observed several avalanches in this area, particularly during the northern hemisphere’s springtime when the Sun’s warmth destabilizes the ice. Image credit: NASA/JPL-Caltech/University of Arizona.

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This weekly newsletter is your toolkit to learn more about space, share information with your friends and family, and take direct action to support exploration. Anyone can subscribe at to receive it as a weekly email.

Fact Worth Sharing

Mars illustration

Are you ready for the season to change? If you lived on Mars, you’d have to wait a bit longer. With a longer orbit around the Sun, the four seasons on Mars each last more than twice as long as they do on Earth. On Neptune, each season lasts 40 years.

Mission Briefings

Astro Gene and Carolyn Shoemaker
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Comet hunter Carolyn Shoemaker has died at 92. In a time before the proliferation of digital imaging, Carolyn spent long nights at the telescope taking pictures of the sky with her husband Gene, a pioneering planetary scientist. Despite having no formal academic training, Carolyn became one of the world's foremost comet hunters. Among her contributions was the co-discovery of comet Shoemaker-Levy 9, which impacted Jupiter in 1994. She was also a Planetary Society charter member. The Planetary Society's Shoemaker NEO Grant program is named in honor of Gene, who along with Carolyn worked to raise awareness of the dangers of asteroid impacts. Pictured above: Carolyn and Gene Shoemaker at Palomar Observatory in 1994. Credit: USGS


Want to live on Mars without ever leaving Earth? NASA needs your help. The agency says it’s looking for analog astronauts who will live in a simulated Martian environment where they’ll experience “resource limitations, equipment failure, communication delays, and other environmental stressors” to inform future missions to the Red Planet. The year-long mission is set to kick off in 2022, so if you think you’ve got the right stuff, you can apply here.


SpaceX’s Cargo Dragon successfully sent about 4,800 pounds (roughly 2,200 kilograms) of food and supplies to the International Space Station (ISS). The spacecraft, which docked at the ISS on Monday, Aug. 30, ferried up fresh fruits and vegetables for the crew. Most importantly, the spacecraft brought ice cream.

From The Planetary Society

Iss plant experiments
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Have you ever been asked why we fund space exploration when there are so many problems here on Earth? Here are some of our most convincing talking points to help others understand why space exploration is always worthwhile. Pictured above: An astronaut caring for plants aboard the International Space Station, part of a research program that sheds light on how to grow healthy food in remote communities on Earth. Image credit: CSA/NASA

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Liquid water under the Martian polar ice? Maybe not. It was one of the most exciting planetary science announcements of 2018: Radar from an orbiting spacecraft might have found large pools of liquid water under the Martian south pole. But good science doesn’t end with first conclusions. Mars scientists Jeffrey Plaut and Isaac Smith join this week’s Planetary Radio to discuss why a form of clay may better explain the data.

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Psyche is definitely very metal, and very hardcore. In the literal sense, that is. The metallic asteroid that lies in the main asteroid belt between Mars and Jupiter is thought to be a proto-planet that never got to finish forming. Our newest mission profile looks at NASA’s Psyche spacecraft, launching in 2022, which will visit its namesake to learn about this unique asteroid and help us better understand the interior of our own world.

What's Up

Venus illustration

Take advantage of the new Moon to get your best views of Venus in the west after sunset, as well as Jupiter and Saturn rising in the east and crossing the night sky. Learn more at

Place your bids!

Lightsail 2 northern s america 2020 09 20

Our online auction in support of The Planetary Society’s LightSail 2 extended mission is ending soon! Don’t miss your chance to bid on special limited-edition LightSail swag and unique virtual experiences like a Zoom call with our CEO Bill Nye. Visit our auction site today to check out all the cool packages. Every bid helps us keep LightSail 2 sailing on sunlight!

Wow of the Week

Emerging spring

Artist Cynthia Miller creates artwork inspired by nebulae, including this one titled "Emerging Spring." The piece is made using glass, kiln-fused onto burnished copper. You can find more of Miller's work at Image credit: Cynthia Miller.

Do you have a suggestion for the Wow of the Week? We’re looking for space-related art, music, gadgets, quotes, fashion, burning questions, brief sci-fi passages, or anything else that will make our readers go “Wow!” Send us your idea by replying to any Downlink email or writing to [email protected], and please let us know if you’re a Planetary Society member.