The DownlinkAug 12, 2022

Comets: big, beautiful, and surprisingly smelly

Space Snapshot

Comet swift tuttle

While the comet seen here may not be familiar to most people, its trail of debris certainly is. This is comet 109P/Swift-Tuttle, and as it passes through the Solar System on its 133-year orbit it leaves behind bits of rock and dust. Once a year, the Earth passes through this debris trail, causing the Perseid meteor shower, which peaks over two nights including tonight (Aug. 12-13).

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Fact Worth Sharing

Comet illustration

Comet Swift-Tuttle is the largest near-Earth object to cross Earth's orbit. At 26 kilometers in diameter, it is 260% the width of the asteroid that wiped out the dinosaurs. Luckily, it won’t impact the Earth anytime in the next few thousand years.

Mission Briefings


South Korea launched its first lunar orbiter. The Korea Pathfinder Lunar Orbiter (KPLO), or Danuri in Korean, launched on a SpaceX Falcon 9 rocket from Cape Canaveral in Florida on Aug. 4. Danuri is expected to enter the Moon’s orbit in December to begin a year-long mission. Pictured: An artist’s depiction of Danuri in orbit. Image credit: Korea Aerospace Research Institute.


With the Artemis I launch approaching, NASA is planning for Artemis II. The agency announced that its entire 42-person astronaut corps is eligible for the mission, which will send a four-person crew into lunar orbit as early as 2024. One of those crew members will be a Canadian astronaut, as part of a 2020 agreement between NASA and the Canadian Space Agency. NASA has committed to gender equality in its lunar exploration program and has removed age restrictions from Artemis mission assignments; the astronaut corps includes people with ages ranging from the late 20s to the mid-60s.


The fifth annual Canadian International Rover Challenge is about to begin. From August 12 to 15, thirteen teams of post-secondary students from Canada and the United States will compete in a series of challenges that will test their engineering prowess. The teams have built rovers that will be tested in their ability to collect soil samples, perform dexterous arm operations, navigate challenging terrain, and carry out search and rescue operations.

From The Planetary Society

67p silhouette
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Move over, Io… comets are the new stinkers of the Solar System. The European Space Agency’s Rosetta spacecraft studied Comet 67P (pictured) up close from 2014 until 2016, culminating with a landing on the comet’s surface. The mission provided data that point to an abundance of complex organic molecules on the comet — including some that would be quite stinky to human noses. Three scientists behind this research join this week’s Planetary Radio to discuss this surprisingly smelly little world. Image credit: ESA et al.

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NASA’s plans to return humans to the Moon are about to take a giant leap forward. The Artemis I mission is due to launch on Aug. 29, sending the uncrewed Orion capsule into lunar orbit. Get the full scoop on what to expect from Artemis I, from the launch all the way through the groundbreaking mission.

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For lunar settlements to ever be possible, they'll need water. That’s part of the motivation behind Lunar Trailblazer, a low-cost NASA mission set to launch in 2023. The mission will map the form, abundance, and distribution of water on the Moon. This is important science in its own right, but will also help prepare for longer-term lunar exploration.

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Lori Garver is back for round two. After talking with Planetary Radio host Mat Kaplan about her recent book, the former NASA deputy administrator joins the latest Planetary Radio: Space Policy Edition to take a deeper dive into her struggle to bring change to NASA’s human exploration program.

What's Up

Moon illustration

There’s a lot going on in the night sky this week! We have a beautiful supermoon tonight (Aug. 12-13), although it will compete with the Perseid meteor shower. You’ll still be able to see brighter meteors despite the Moon’s glare, especially if you go to a dark sky site. Saturn is at opposition on Aug. 14, meaning it’s on the opposite side of the Earth from the Sun, rising around sunset, setting around sunrise, and shining particularly bright. You can also spot Jupiter rising a little later, Mars coming up in the middle of the night looking reddish, and Venus super bright low in the east in the pre-dawn. Get the full scoop on what to look for in the August night sky.

Get first dibs on a JWST poster

Chopshop jwst poster

The Planetary Society’s longtime partner ChopShop makes all the awesome merch in our online store, and they’re working on a new series of posters featuring space telescopes, including JWST. To get this series off the ground ChopShop has launched a Kickstarter campaign. Backers can get first access to the poster, as well as other rewards.

Wow of the Week

The comet still

A comet is a dark, distant, cold world, and this has never been more apparent than in this short film by motion designer Christian Stangl and composer Wolfgang Stangl. Made using real images from ESA’s Rosetta spacecraft paired with eerie music, the film presents a haunting look at the beautiful alien world. Pictured: A still from the film. Image credit: Christian Stangl.

Send us your artwork!

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!