The DownlinkNov 19, 2021

Craters are great but we’ve had enough, thank you

Space Snapshot

Manicouagan reservoir crater

Don’t let the lush greenery that surrounds the Manicouagan crater fool you — when the impact that made this crater occurred, nothing nearby would have survived. Around 214 million years ago, an asteroid about 5 kilometers (3 miles) in diameter slammed into what is now Canada, creating a crater about 100 kilometers (60 miles) across. The impact caused a shock wave and air blast that would have killed plants and animals within at least 500 kilometers (310 miles). Pictured: The Manicouagan crater as seen by ESA’s Copernicus Sentinel-2 spacecraft. Image credit: ESA.

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Fact Worth Sharing

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The Moon’s surface has over 100,000 craters from asteroid and meteorite impacts. Tectonic activity and erosion have erased most of Earth's impact craters, which now total fewer than 190. Planetary defense ensures this number won't increase.

Mission Briefings

Kamooalewa artist impression

Scientists may have discovered a fragment of our Moon in disguise as a near-Earth asteroid. A new study says that the wayward chunk in question is a quasi-satellite with a distinctive tilt and reflectiveness, which may be clues that the object comes from our Moon. The satellite was first spotted in 2016 and has been named Kamo'oalewa. Pictured: An artist's impression of Kamo’oalewa near the Earth-Moon system. Image credit: Addy Graham/University of Arizona.


NASA has condemned Russia for performing an anti-satellite test in low-Earth orbit. On Monday, Nov. 15, Russia launched a weapon to destroy one of its older satellites in low-Earth orbit. This anti-satellite (ASAT) test created a cloud of debris that caused astronauts on board the International Space Station to take emergency measures. NASA Administrator Bill Nelson called the move “irresponsible” and “destabilizing,” though Russia’s Defense Ministry has defended the test’s safety.

From The Planetary Society

Dart illustration behind ion engine
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Asteroids beware! We’re coming for you. The launch of the world’s first asteroid deflection mission is coming up on Wednesday, Nov. 24, 2021. The Double Asteroid Redirection Test (DART) mission will arrive at near-Earth asteroid Didymos in September 2022. The spacecraft won't slow down, intentionally crashing into the asteroid's small moon Dimorphos. The crash should change the time it takes Dimorphos to orbit Didymos, proving that this deflection method, called the kinetic impactor technique, works. You can watch the launch live on our website on Nov. 24. Coverage begins at 12:20 a.m. EST. Pictured: This illustration of DART shows a view of the spacecraft approaching the Didymos system. Image credit: NASA/Johns Hopkins APL.

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Want to become the DART expert of your social circle? We’ve got you covered with our comprehensive collection of mission information, from background explainers to videos and infographics, and much more. You can also learn more about DART on this week’s Planetary Radio, which features an in-depth discussion with mission coordination lead Nancy Chabot.

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Cast your vote! It's not too late to weigh in on the Best of 2021: this year’s most exciting moments in space exploration, most jaw-dropping space images, funniest space memes, and more. Vote for your favorites and help us celebrate an eventful year in science and exploration.

What's Up

Jupiter illustration

In the early evening look to the western skies for super-bright Venus, then look a bit to the east to find yellowish Saturn and then bright Jupiter. Learn more at

Celebrate LightSail 2 at the Smithsonian FUTURES Exhibit!

Smithsonian futures

On November 20th, the prestigious Smithsonian Institution in Washington, D.C. will unveil a display of The Planetary Society’s LightSail 2 mission in its FUTURES exhibition, a collection of art and technology that showcases the future of humanity at the Arts and Industries Building. Visitors can see a full-scale engineering model of the CubeSat without its sail, a one-fourth-size model of the spacecraft and sail that uses real sail material left over from construction, and a four-minute video playing highlights from the mission. Planetary Society CEO Bill Nye will be in Washington for the grand opening of the exhibition, and you can catch him at two virtual events on November 19. The LightSail 2 mission was made possible by the support of more than 50,000 people around the world; a great example of the amazing possibilities the future might hold.

Wow of the Week

Roter kamm from endeavour

In another example of the nonexistent boundary between science and art, this radar image shows the Roter Kamm impact crater in southwest Namibia. The 2.5 kilometer-wide (1.6 mile) crater formed when an impactor about the size of an SUV hit the Earth around 5 million years ago. The colors in the image come from different bands of radar used to peer beneath a thick covering of sand to see layers of rock that were ejected during the impact. The image was captured by a radar instrument on the space shuttle Endeavour in 1994. Image credit: NASA.

We love to feature space artwork in the Downlink. If you create any kind of space-related art, we invite you to send it to us by replying to any Downlink email or writing to [email protected]. Please let us know in your email if you’re a Planetary Society member!