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Space Station Christmas

Santa and his reindeer bring some holiday cheer to the International Space Station.

NASA
Marshall Space Flight Center

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Santa and the International Space Station
December 25 -- Astronaut Cathy Clarke opened her eyes and yawned. Mission Control was playing Jingle Bells over the intercom for about the two hundredth time. "OK," she barked into the microphone. "I'm awake and I know it's Christmas!"

Cathy, one of the crew of the International Space Station (ISS), was feeling homesick.

Back on Earth, she knew, her family was gathered around the Christmas tree, sipping eggnog and opening presents. Later they would radio from Houston, but she yearned to be with them now -- not stuck in an orbiting laboratory, 350 km above Earth, with no Christmas spirit.

Months earlier Mission Control had turned down her request for a tree. "The pine needles would just float around and poke you in the eye," they said. "It's a safety issue."

"Oh, humbug," grumped Cathy. Riippp. She tore open the velcro on her sleeping bag, wriggled out, and pushed herself off the ceiling. That was one thing she enjoyed about life in space: you could sleep anywhere you wanted. As a kid she preferred the top bunk of her and her sister's bed, but the ceiling was even better, she thought.

In fact, she usually loved the station. But today something was missing.

"Time for coffee," she spoke aloud to no one. The rest of the crew was still asleep. They had stayed up later than usual doing a materials science experiment in the Destiny lab module.

picture of a Christmas tree
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"You'd better go to bed," she had playfully reminded them on Christmas Eve. "Santa's coming!"

"We wish!" they replied, ruefully, and returned to work. They were melting metals inside a small zero-G furnace to learn more about industrial alloys. The fumes inside the experiment box were so smelly they had to be purged to space through a "vacuum vent" -- but it was worth it to learn so much.

All of the crew did science experiments of one sort or another. Cathy was in charge of one designed to explore the human immune system. And it was giving puzzling results. She was deep in thought about T-cells and the strange things they did in microgravity when she reached the kitchen and floated inside ...

... right into a thick cloud of cookie crumbs! Cathy gasped in surprise, which was the wrong thing to do. Crumbs went down her windpipe and it was only after a few moments of teary-eyed coughing that she could see again.

And what a sight it was.

Crammed into the tiny kitchen was an 8-ft tree -- its top bent against the low ceiling -- a stack of presents, floating ornaments, and little droplets of milk everywhere. Taped to the food-warmer was a note, from Santa!

Dear Cathy,

Sorry for the mess. Ho, ho! But this was my first experience with microgravity. I knew you would be homesick this year so I brought you and the crew a few things for Christmas.

I must say, though, you could have made it a bit easier to get in. Didn't you know I was coming? There's no handle on the outside of the airlock. I had to squeeze in through the vacuum vent -- tree, presents, and all!

Good thing he's magic, thought Cathy. That vent is only a few inches wide and it leads right to the materials science furnace. The letter continued:

We popped out of a very unusual fireplace -- like a little furnace. It smelled awful! Good thing the reindeer waited outside. Comet was already feeling queasy from the weightlessness. (Poor deer, now the others call him "Vomit Comet." I reminded them it's Christmas, but they just shouted out with glee -- especially Rudolph.)

By the way, you might want to check your solar panels. That's where I landed the sleigh and they gave us a nasty shock. You should have seen Rudolph's nose light up!

Speaking of lights, the ones on the tree won't work. I couldn't plug them in! Your outlets aren't like the ones on Earth. Is that because you use DC power on the space station instead of AC?

I've seen plenty of trees in my time, but nothing like this one. The ornaments don't hang down as they should. I'm not even sure where "down" is.... And the tinsel sticks out in all directions. (Watch out for the pine needles. too. They float around and poke you in the eye. Ho, ho!)

Cathy glanced at the weightless tree. Most of the ornaments had indeed floated off. And the tinsel... well, the scene reminded her of someone sticking their finger in an electrical socket. Her own weightless hair looked much the same every morning -- standing on end before she twisted it into a pony tail.

You'll find a bag of Mrs. Claus's Christmas cookies duct-taped to the counter. I couldn't resist having one myself. But the crumbs ... oh my, they floated everywhere!

The air filters would take care of that in a few hours, Cathy knew. She looked at the swarm of crumbs and saw why NASA packaged crumbly foods in bite-sized morsels -- or avoided them altogether. But, she wondered, where did all the milk droplets come from?

You must be wondering about the milk, his letter continued. I needed some to go with the cookie, of course. Fortunately, I never go anywhere without my thermos; Mrs. Claus insists.

All I can say is this: never unscrew a thermos of warm milk in microgravity. At first it wouldn't pour at all. Then, when I shook it, milk droplets flew everywhere. Ho, ho, what a mess!

I knew then it was time to go. After all, I have to visit another billion or so homes before sunrise. Although, I must say, your home tops them all.

I plan to tour the station on my way out. What a splendid facility! I intend to try that Canadian robotic arm before I leave, too. (Do you really control it with a joystick? Amazing!) I can't wait to see the expression on Donner's snout when I grapple his flank. Ho, ho, ho!

Have a jolly day, dear. And just remember ... the Christmas spirit is in the space station, too.

Sincerely yours, Santa

PS. I noticed your immune system experiment in the lab. Astonishing what we can learn in space! Mrs. Claus is always sneezing and snuffling with some virus or bacteria at the North Pole. She'll be so glad to know you're making progress.

Cathy looked around at the cookie crumbs, the flying milk, the shocking tree ... and felt better. She reached for her stocking, duct-taped "upside down" to a nearby wall. Inside were 38 hair clips and an autographed picture of Comet smiling crookedly.

"Wow," she thought. "It's just what I wanted!"

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Some of this story is fiction, and some of it is real. Here's a guide:

Editor's Note logoCathy Clarke is fiction. There's no astronaut by that name, although one day there might be. In the story, homesick Cathy looked forward to a radio transmission from her family. Real astronauts can communicate with their families on Earth that way -- or via email or private video conferences. Keeping in touch is important!

The vacuum vent Santa entered is real. It's called the "Vacuum Exhaust System." Experiments of all sorts on the ISS use it to vent noxious gases or simply to provide a vacuum within the test chamber. The maximum diameter of the vent pipe is about 5 cm, so Santa would indeed need magical powers to fit through it. The materials science furnace is real, although it hasn't yet flown on the space station. Immune system experiments in space are real, too. They have flown on the space shuttle and will eventually be conducted on the ISS.

If reindeer landed on the station's solar panels, they would feel a real shock, just as Rudolph did, because the arrays carry a strong electric field. The solar arrays provide direct current to outlets throughout the station. Direct current can make Christmas lights shine, but only if you can plug them in. And, as Santa discovered, the power plugs on the space station aren't like power plugs in Earth homes.

There is a robotic arm on the ISS, called "Canadarm 2" -- and it is controlled by a joystick. Lucky Santa! And what of Santa himself? Is he real? That's for readers to decide.

Credits & Contacts
Author: Dr. Tony Phillips
Responsible NASA official: John M. Horack
Production Editor: Dr. Tony Phillips
Curator: Bryan Walls
Media Relations: Steve Roy
The Science and Technology Directorate at NASA's Marshall Space Flight Center sponsors the Science@NASA web sites. The mission of Science@NASA is to help the public understand how exciting NASA research is and to help NASA scientists fulfill their outreach responsibilities.

Web Links

Interplanetary Christmas -- (Science@NASA) In an exclusive interview with Science@NASA, Santa discusses his plans to deliver presents to future space colonies.

see caption'Twas the Night Before Christmas, NASA-Style -- (Thursday's Classroom) A far-out rendition of a Christmas classic, with classroom or home-school lesson plans.

Right: Space Santa and his Rocket Reindeer, by Science@NASA artist Duane Hilton

Christmas Starshine -- (Thursday's Classroom) Christmas vacation is a good time for sky watching, and there are two new things to see in the night sky: the Starshine satellites.

If Santa were a Martian -- (JPL) If Santa Claus were a Martian, he'd be in for one bumpy ride.

Spaceflight.nasa.gov -- (NASA) learn more about humans in space.


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