Watch 9 awesome moments with NASA astronauts in space in 2021

The International Space Station is a state-of-the-art laboratory where astronauts perform hundreds of important experiments every year — but that does not mean that life on orbit is all work and no play for the outpost's crews.

In between their other assignments, NASA astronauts take part in in-flight educational downlinks with schools around the country, answering students' questions about science, technology, engineering and mathematics (STEM) topics. Some of those exchanges are a source of fun, too!

"For the first time I am going to attempt a triple, so here we go," said Mark Vande Hei, before performing three zero-g somersaults in a row. Currently a member of the Expedition 66 crew, Vande Hei is set to spend a full year, 365 days, aboard the space station.

Vande Hei's orbital acrobats kicks off NASA's list of "The 9 Most Memorable Downlink Moments of 2021," as posted to the agency's STEM YouTube channel.

Related: 7 things the International Space Station taught us in 2021

NASA astronaut Mark Vandei Hei demonstrates orbital acrobatics as his Expedition 65 crewmate Shane Kimbrough looks on during an educational downlink from the International Space Station.

NASA astronaut Mark Vande Hei demonstrates orbital acrobatics as his Expedition 65 crewmate Shane Kimbrough looks on during an educational downlink from the International Space Station. (Image credit: NASA TV)

Not to be outdone — and actually ranking a step ahead — Expedition 65 crewmates Shannon Walker of NASA and Soichi Noguchi of the Japan Aerospace Exploration Agency (JAXA) replied to a young girl's query about whether you can arm wrestle in space by demonstrating just that.

"That's a great question!" said Noguchi. "I am ready to fight today with Shannon, so I give you the arm wresting in space!" 

Guess who won? 

Not all of the moments on NASA's list were feats of physical prowess. SpaceX Crew-1 pilot Victor Glover shared his thoughts on extraterrestrial gardening to rank sixth, while Crew-2 crewmates Shane Kimbrough and Megan McArthur likened the smell of space to a popular fast food sandwich to come in fifth.

"Maybe we're just really hungry…" said Kimbrough with a laugh.

Kimbrough and McArthur reunite for spot number 4, this time joined by Thomas Pesquet of the European Space Agency (ESA) for a bit of space food show and tell. 

Number 3 involves Expedition 64 crewmates Walker and Kate Rubins sharing hair care tips, while the penultimate place goes to Vande Hei (joined by Pesquet) for account of the strange-but-sparkly weather on Jupiter.

So who and what ranks number 1? You will have to watch the video to find out, but suffice to say they have a ball (or two) when answering!

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Robert Z. Pearlman Editor, Contributor

Robert Pearlman is a space historian, journalist and the founder and editor of, an online publication and community devoted to space history with a particular focus on how and where space exploration intersects with pop culture. Pearlman is also a contributing writer for and co-author of "Space Stations: The Art, Science, and Reality of Working in Space” published by Smithsonian Books in 2018. He previously developed online content for the National Space Society and Apollo 11 moonwalker Buzz Aldrin, helped establish the space tourism company Space Adventures and currently serves on the History Committee of the American Astronautical Society, the advisory committee for The Mars Generation and leadership board of For All Moonkind. In 2009, he was inducted into the U.S. Space Camp Hall of Fame in Huntsville, Alabama. In 2021, he was honored by the American Astronautical Society with the Ordway Award for Sustained Excellence in Spaceflight History.