Ever stared at a photo of Bruce McCandless II? It’s that 1984 shot where he’s just… floating. No tether. No umbilical cord connecting him to the Space Shuttle Challenger. Just a man in a white suit, suspended against a blackness so deep it looks like a glitch in the universe. That’s what NASA folks and space historians talk about when they mention swimming through the void. It isn’t just a poetic phrase for a sci-fi novel; it’s a terrifying, technical reality of Extravehicular Activity (EVA) where the physics of "swimming" don't actually work.
In space, you can’t doggy-paddle. There’s no air to push against. If you’re untethered and your jetpack fails, you are, quite literally, stuck in a state of perpetual falling. It's a psychological weight that every astronaut carries. Even though we’ve been doing spacewalks since Alexei Leonov almost got stuck outside his capsule in 1965, the sensation of being adrift—the void—remains the ultimate nightmare for anyone leaving the airlock.
The Mechanics of Moving When There's Nothing to Push
Let’s get one thing straight: if you try to "swim" in a vacuum, you’re basically a flailing bug on its back. On Earth, we move through fluids or gases. You push water back; you go forward. Newton's Third Law is your best friend at the local pool. In the vacuum of low Earth orbit (LEO), there is no medium.
Astronauts rely on momentum and mechanical leverage. During a standard EVA on the International Space Station (ISS), you’re always "translated" along handrails. You use your arms. It’s more like rock climbing than swimming. But the term swimming through the void gained traction because of the Manned Maneuvering Unit (MMU). This was the gas-powered chair McCandless used. It used nitrogen thrusters to provide the "push" that the vacuum denies you.
Without those thrusters? You’re a statue.
There’s a common misconception that you could throw your glove or a tool to move yourself in the opposite direction. Technically, yes, that works. It’s basic orbital mechanics. But unless you’re throwing a heavy wrench at a significant velocity, you’re only going to drift at a fraction of a millimeter per second. Plus, now you’re down a glove in a minus 250-degree environment. Not a great trade.
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Why the Psychological "Void" is Harder Than the Physics
The physical danger of floating away is actually statistically low. We have Tethers. We have the SAFER (Simplified Aid For EVA Rescue) units, which are like "life jackets" with tiny thrusters.
But the mental part? That’s different.
Psychologists at NASA and the ESA (European Space Agency) have studied the "Overview Effect," which is that life-changing shift in perspective astronauts get when seeing Earth from above. But there’s a darker cousin to that: the feeling of total isolation while swimming through the void. When you turn your head away from the bright, curved limb of the Earth and look out toward the stars, the depth is infinite.
There is no "up." There is no "down." Your inner ear, which relies on gravity to tell your brain which way is which, just gives up. This often leads to Space Adaptation Syndrome. You feel like you’re falling. You feel like the universe is swallowing you.
- The silence is absolute.
- The suit’s cooling fans provide the only heartbeat.
- Your peripheral vision is cut off by the helmet's gold-plated visor.
- The blackness isn't just "dark"—it's a lack of existence.
Astronaut Chris Hadfield has spoken at length about the discipline required to ignore the lizard-brain panic that screams when you realize there’s 250 miles of nothingness between your boots and the ground. You have to focus on the bolt. The wire. The task. If you focus on the void, the void starts focusing on you.
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Real Incidents Where the Void Almost Won
History isn't always as clean as the movies. Take Luca Parmitano’s 2013 spacewalk. He wasn't untethered, but he experienced a terrifying version of swimming through the void inside his own helmet.
Water from the suit's cooling system started leaking. Because of surface tension in microgravity, the water didn't fall to his chest. It migrated. It covered his eyes, filled his ears, and started creeping into his nose. He was effectively drowning while floating in a vacuum. He couldn't see his way back to the airlock. He had to rely on his memory of the handrails—the "braille" of the ISS exterior—to pull himself to safety.
Then there’s the story of Gene Cernan on Gemini 9A. This was back in 1966. He was supposed to test a propulsion pack, but his suit was too stiff. He couldn't get a grip. He was flailing, his heart rate spiked to 155 beats per minute, and his visor fogged up completely. He was blind, exhausted, and drifting at the end of a literal umbilical cord. He described it as a wrestling match with a suit that didn't want him to move.
These aren't just "oops" moments. They are reminders that space doesn't want us there. We are biological entities meant for 1G and a pressurized atmosphere. When we go swimming through the void, we are cheating.
The Gear That Keeps You From Drifting Away
- The D-Ring and Tether: Simple. Effective. A steel cable that keeps you "home."
- The SAFER Unit: A self-rescue device. If a tether snaps (which has never happened, by the way), the astronaut flips a joystick and flies back. It has about 3 pounds of nitrogen fuel. Not much, but enough.
- Magnetic Boots? No. That’s for movies. They’re too heavy and would mess with the station’s electronics. We use foot restraints that look like fancy snowboard bindings.
The Future: AI and Autonomous Rescue
As we look toward Mars and the Lunar Gateway, the "void" gets bigger. If you’re at the ISS, Earth is a giant safety blanket taking up half the sky. If you’re halfway to Mars and you step out for a hull repair, Earth is just a blue speck. The psychological isolation will be ten times worse.
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Engineers are currently working on "automatic return" protocols. Basically, if the suit sensors detect an astronaut is "drifting" (moving away from the craft without a command), the suit’s thrusters will automatically fire to bring them back. No human input needed. This is crucial because if you black out from a CO2 spike or a pressure drop, you can’t fly yourself home.
The void is patient. It doesn't have a "mode." It just is.
Actionable Insights for the Space-Obsessed
If you’re fascinated by the reality of swimming through the void, don’t just watch Gravity (which, honestly, gets the physics mostly wrong). Instead, look into the actual technical manuals and accounts from those who’ve been out there.
- Read "An Astronaut's Guide to Life on Earth" by Chris Hadfield. He breaks down the "power of negative thinking"—preparing for the absolute worst-case scenario so you can stay calm when the void gets scary.
- Watch the raw EVA footage from NASA TV. It’s not edited. It’s slow. It’s silent. It gives you a much better sense of the "translation" movement than any Hollywood film.
- Understand the "Brussels" of the ISS. Astronauts memorize the "pathways" of the station like a map. If you want to understand space travel, stop looking at the engines and start looking at the handrails.
- Track the Artemis Missions. We are going back to deep space soon. The Gateway station will be the first time humans perform spacewalks far outside the protective magnetosphere of Earth. The void there is a whole different beast.
The void isn't something to be conquered. It's something to be respected. Every time an astronaut clips that carabiner onto a rail, they are acknowledging that without that tiny piece of metal, they are just another satellite, orbiting forever in the quiet.