Yes, walking in space is extremely tiring.
Between the stiff suit resistance and the mental juggling act, astronauts burn serious energy out there. (And that’s before you factor in the temperature swings from “really hot” to “Antarctica in winter.”)
Geographic Context
Outer space isn’t a place you visit—it’s a condition that starts just above Earth’s atmosphere, around 100 km (62 mi) up. The International Space Station (ISS) circles at about 400 km (250 mi), which makes it the only spot where humans regularly pop outside their cozy, pressurized home into the great void. Every spacewalk is like stepping from your climate-controlled house straight into a sauna that flips to a freezer every time you move into shade, all while wearing a suit that weighs 280 pounds on Earth but floats like a feather.
Spacewalks are exhausting because the suit fights every finger bend and demands constant focus.
| Factor | Impact | Data Source |
|---|---|---|
| Suit pressure | Maintains internal pressure at ~4.3 psi; requires extra effort to bend fingers and grip tools | NASA |
| Fatigue timeline | Hand soreness begins after ~2 hours; manual dexterity drops by ~15% after prolonged use | NASA |
| Muscle strength loss in space | ISS crew show 8–17% reduction in isokinetic strength over long missions (mean across 37 astronauts) | NASA Technical Reports |
| Daily exercise routine | Astronauts complete 2-hour exercise blocks to counter muscle atrophy and bone loss | NASA Research Explorer |
| Survival without suit | Consciousness lost in ~15 seconds; death follows within ~3 minutes due to oxygen deprivation | NASA |
Why do astronauts feel so wiped out after EVAs?
Hand fatigue kicks in fast because the gloves resist every motion like a stiff rubber glove stuffed with balloons. After two hours, fingers start to ache, and dexterity drops about 15%. Meanwhile, muscles weaken over time—ISS crews typically lose 8–17% of their strength during long missions. That’s why they spend two hours daily on treadmills and resistance machines just to stay upright.
Spacewalking is officially called an EVA, or Extra-Vehicular Activity.
The first untethered EVA happened on February 7, 1984, when astronaut Bruce McCandless II floated 320 feet (98 m) from shuttle Challenger using only a 50-foot tether. He described it as “an ultimate hotrod ride.” The Manned Maneuvering Unit (MMU) he used got shelved for safety reasons, but the lessons from that wild ride still guide every EVA today—every move is planned, every tool is tethered, and every grip is tested before it’s trusted.
Then there’s the mental marathon. Astronauts juggle oxygen levels, suit integrity, tool placement, and comms while fixing solar arrays or installing new gear. Picture open-heart surgery while dangling from a skyscraper in a hurricane—except the skyscraper is screaming around Earth at 17,500 mph.
How long do spacewalks usually last?
As of 2026, EVAs from the ISS typically run 6 to 8 hours during crew rotations or maintenance windows. NASA and its partners schedule these months ahead, because timing is everything when you’re working in a suit that fights you every inch of the way.
Hand fatigue hits hardest when astronauts wrestle with stiff gloves and tiny fasteners.
Imagine trying to change a lightbulb while wearing ski mittens—except your mittens are made of stiff rubber and fight every twist. That’s the reality inside a spacesuit glove. The fatigue ramps up fast, especially when dealing with small fasteners or delicate tasks.
Can space tourists go on EVAs?
Not anytime soon. Only professional astronauts and cosmonauts with specialized training get clearance for spacewalks. Private crews on Axiom missions do train for weeks in pressure suits and VR simulators, but they stay inside the station during actual EVAs. Still, suit tech is improving—new glove materials like nickel-titanium “memory alloys” could cut hand fatigue by up to 30%, according to 2025 research from MIT’s Aerospace Human Systems Lab MIT Aerospace.
What’s the closest civilians can get to the spacewalk experience?
For most of us, the closest we’ll come is wrestling a frozen lightbulb into a socket after shoveling snow for half an hour—except astronauts do it while circling Earth every 90 minutes. The gloves, the cold, the precision—it’s all eerily similar, just a lot higher and faster.
How do astronauts mentally prepare for EVAs?
They train for years in the Neutral Buoyancy Laboratory’s 6.2-million-gallon pool at Johnson Space Center, where moving in a spacesuit feels like wading through syrup. Every task is drilled until it’s automatic—because once you’re outside, there’s no room for hesitation. You’re not just fighting the suit; you’re managing oxygen, suit pressure, tool tethers, and comms while performing delicate repairs in a vacuum. It’s less “spacewalk” and more “precision demolition derby.”
What happens if an astronaut’s suit fails during an EVA?
Consciousness fades in about 15 seconds without a pressurized suit. Death follows within roughly 3 minutes due to oxygen deprivation. That’s why every suit is packed with backup systems and why astronauts train relentlessly for emergencies—because out there, even a tiny breach can turn deadly fast.
How much do spacesuits weigh?
On Earth, a spacesuit tips the scales at about 280 pounds. In orbit, of course, it feels weightless—but the resistance it creates when you try to move still makes you feel like you’re wrestling a refrigerator in zero-G. That’s why hand fatigue sets in so quickly: your muscles are fighting both the suit’s stiffness and the lack of leverage in microgravity.
What’s the temperature like during a spacewalk?
When sunlight hits, the suit can hit 121°C (250°F). Step into shade, and it plummets to –157°C (–250°F). That’s like moving from a pizza oven to an industrial freezer every time you shift positions. No wonder astronauts say EVAs feel like a workout in a climate that refuses to pick a side.
How do EVAs affect an astronaut’s strength over time?
Long missions on the ISS typically see crews lose 8–17% of their isokinetic strength. That’s why they spend two hours daily on exercise machines—to keep their muscles from wasting away while they’re stuck in microgravity. Without that routine, even simple tasks like gripping tools would become exhausting.
