We humans have certain tendencies toward the eternal. We like to leave our mark by somehow saying “I was here!” or send messages to the future about what we’ve accomplished. We’re also intrigued by things like the Voyager record, the Pioneer plaque, and we all love those “send your name on a spacecraft” opportunities NASA has.

This recent image, above, posted by astronaut Luca Parmitano on Twitter of a message written on a new piece for the International Space Station’s Canadarm 2 is an example of leaving a little message to the future (albeit, one that the majority of us might never get to see) and it prompted me to wonder if there are more “secret messages” like that on the ISS — messages of remembrance or good wishes from the people who built, designed or installed various components, or messages passed down from one crew to the next.

NASA astronaut Tom Marshburn, who returned from a 5-month stint on the ISS in May of 2013, said there are plenty of memorable messages, signatures and objects left by the station’s builders or previous crews.



“We did a lot of maintenance during our flight and rotated out a lot of the experiment racks and we saw many signatures on the internal hull or on the inside parts of the racks,” Marshburn told Universe Today via phone from Johnson Space Center. “Things like ‘Greetings from the Water Recovery team!’ with everyone’s signature. That’s fairly prevalent on the inside, particularly behind the racks, but not in plain view.”

But he’s never seen anything on the external parts of the space station before.

“I have heard that engineers who have built different components and even external structures, like to sign their names to internal pieces that no one can actually see, but the engineers know their name is up in space,” he said. “I’ve done three spacewalks, and I’ve never seen anything like that on the outside — like in the picture from Luca Parmitano — so that’s a rarity to see something like that.”

There are some signatures plainly visible on the interior, however: signed mission stickers from all the visiting Space Shuttle crews and the Expedition crews adorn the walls in certain parts of the ISS.

But how about other messages that crews leave for future inhabitants?

Marshburn said there are several “helpful” notes that are left by former crew members to assist or instruct future crews — important ‘lessons learned’ or little reminders.

“One of the favorite messages left by a former resident of the station is near the resistive exercise machine,” Marshburn said. “This machine allows you to lift the equivalent of 600 pounds, so there is a lot of stored energy there and you have to be careful with it, making sure you follow procedures carefully. There is a placard there that someone just wrote with a Sharpie: ‘Nothing is as important as what you are doing right now.’ That has become a mantra for a lot of people on the ISS, and we quoted quite often. I really like that one.”

There’s also a nice ‘aide-mémoire’ in the space station bathroom.

“Everyone has to urinate into a funnel that goes into a hose,” Marshburn explained. “We are pretty good about cleaning ourselves up in the bathroom, but some crewmembers have not been so good about cleaning up the equipment because written in Sharpie on the wall in the bathroom is, ‘Blessed are those who wipe the funnel.’ That’s just a good little reminder.”

In addition to messages, there are objects left by previous crews that end up as talismans or things that are used over and over.

“There is a four-inch version of Gort, the robot figure from the movie “The Day the Earth Stood Still” stuck on the wall where we gather in the Destiny Lab for our daily planning conferences,” Marshburn said. “He sometimes gets unstuck and floats around the ISS, so whenever we find him wandering around, we stick him back up on the wall. He’s kind of ubiquitous.”

There’s also a little toy astronaut figure that ends up floating around and showing up in different places.

“We don’t know who brought them up, but they have been retained and remain as mascots for the crews,” Marshburn said.

The toy left on the ISS that Marshburn enjoyed the most was a ping pong ball.

“That is a wonderful toy,” he said. “While you are eating, you can bounce it off the wall and figure out the best angles to have it come right back to you. Or you can spin it around a hatch and the centripetal force will just keep it spinning around and around.”

Also on board are musical instruments — an electric piano, guitar and ukulele – that get a lot of use. Additionally, previous astronauts have left reading material, so by now there is a shoebox-sized library of books to read.

“After working on computers most of the day, it’s nice to grab a real book and read during your off time,” Marshburn said.

Since Marshburn and his crewmates — Canadian astronaut Chris Hadfield and Russian cosmonaut Roman Romanenko — launched to the space station on December 19, 2012, they really enjoyed the bag-full of holiday ornaments that are on board. “There’s a 2-foot Christmas tree, stockings, and an elf hat,” he said, “which was nice because it was a tiny piece of home, a little bit of Christmas.”

There’s also Mardi Gras hats, Happy Birthday signs, and flags of each country associated with the International Space Station.

So, any other secret “just between astronauts” messages up on the space station?

“There aren’t any that I saw or even know about that I couldn’t share with you!” Marshburn said with a laugh. “But I don’t know how much mission control even knows about some of these things.”