1. Why Did One Missing Torso Change a Spacewalk Plan?
NASA's spacewalking suit on the ISS is called the Extravehicular Mobility Unit, or EMU. Its hard, shell-like middle section is the Hard Upper Torso, or HUT. NASA's own news release describes it as "essentially the shirt of the spacesuit" [1].
In March 2019, astronaut Anne McClain finished a spacewalk and learned that a medium-size HUT fit her best. Her next spacewalk was meant to be with Christina Koch, which would have been the first spacewalk by an all-woman team of two. But only one medium-size HUT could be made ready in time for that date, so Koch wore it and the assignments were reshuffled. NASA said this was "due in part to spacesuit availability" [1].
Why not just swap in another torso? Space.com reported that changing a HUT on a suit takes about 12 hours of work, so rushing the job would have meant delaying other tasks. At the time, the station had four fully configured suits: one with a medium torso, one with an extra-large and two with large. Medium was the smallest size NASA offered. The report also noted that the suits have no features based on sex; people who are smaller on average simply tend to need the smaller sizes [2]. So the missing piece was a particular size, not a "women's suit." That raises the real question: why does the suit come in so few sizes?
2. Why Isn't Every Spacesuit Made to Fit One Person?
Early in the space program it was possible. A NASA suit engineer told Space.com that when astronaut classes were small, "we could build a custom suit for each person." Once the space shuttle and the ISS arrived, there were too many astronauts for that, "so we started making it modular so we can mix and match" [2]. In a modular suit, the arms, legs, torso and other parts come in sizes, and a technician picks the set that suits one body. It is a bit like choosing a shirt in medium and trousers in large, though a suit has far fewer parts and sizes to pick from.
The torso is where the limit shows. A 2026 NASA abstract explains that the EMU uses "a discrete sizing scheme" for the HUT. Five torso sizes were designed, to cover from a 5th-percentile woman to a 95th-percentile man for key body measurements. Only three of the five were built, so the range actually covered is from about the 40th-percentile woman to the 95th-percentile man [3].
A percentile is a way of placing a measurement in a crowd. If you line up 100 people from smallest to largest, the 5th-percentile person is near the small end and the 95th is near the large end. Percentiles are measured separately for each body part, and one person can be tall in one measurement and small in another. A suit engineer put it this way: "There is no normal person" [2]. The same abstract warns that a poorly fitting torso can lead to fatigue, injury, and less strength and mobility in the suit [3].
3. Why Are Spacesuit Gloves Treated Differently From the Rest of the Suit?
Hands do fine work, and gloves are hard to get right. In a pressurized suit, gas inside the glove makes the fabric stiff, "like putting air into bicycle tires," as one glove designer told National Geographic. Pressure on hard points can also cause blisters, and National Geographic reported that hand injuries, including fingernails lifting away from the nail bed, are a top nuisance for spacewalkers [4].
Fit matters for strength, too. A 1993 NASA report abstract says that if gloves do not fit properly, an astronaut's grip strength can drop by as much as 50 percent [5].
That is why gloves get special treatment. According to the designer National Geographic quoted in 2010, the airtight inner layer of the EMU glove is custom made for each astronaut, using hand casts, laser scanning and computer modeling, while the outer layer comes in set sizes, "small, medium, large." He put the up-front cost of fitting the inner layer at around $100,000. These are one expert's descriptions from 2010, so current practice may differ [4]. Still, the pattern is clear: most of the suit is matched by choosing parts, and the place where a few millimeters matter is made to measure.
4. Can a Suit That Fit on the Ground Stop Fitting in Orbit?
Yes, and measuring on the ground does not settle it. A NASA research summary notes that crew members "often need to adjust their suit sizing once they are in orbit," possibly because microgravity changes body size and posture [6].
The same summary cites a NASA study of spinal elongation in which astronauts grew about 6 percent in seated height and about 3 percent in standing height in microgravity. It adds that not every measurement changes by the same percentage. For someone 170 cm (about 5 ft 7 in) tall, 3 percent is about 5 cm (2 inches). Hands may change too. The 1993 abstract says that in microgravity, fluid moves toward the upper body and some collects in the hands, which then swell, so gloves that fit well on Earth may not fit well in space [5].
The NASA summary does not say how much the suit can be adjusted in orbit, so this article does not claim to know. What it does show is why the size picked on the ground is only a starting point, and why engineers have been collecting measurements from astronauts before, during and after flights [6].
5. How Is NASA Trying to Make Spacesuits Fit More People?
When NASA showed its new moon-walking suit, called xEMU, in 2019, a NASA suit engineer said it was designed for "inclusive sizing" that would fit people from the "first percentile female to the 99th percentile male" [7]. A 2024 NASA abstract confirms the target and explains the thinking: NASA is not using the historical 5th-to-95th cutoffs. A simulation found that if several narrow cutoffs were applied together, less than 68 percent of the population might remain, because body measurements are linked to one another [8].
The 2026 NASA abstract looks even further ahead. It reports a research project that uses 3D body scans and 3D-printed parts to try to design a torso for one person's shape, as a proof of concept, and it says that modern 3D printing and body imaging make custom suits more feasible [3]. It is research, not a suit that exists today. Space.com's 2019 report adds a trade-off: a custom suit could be better for a long stay such as one on Mars, but a modular suit is easier to supply, and NASA had not committed to either approach [2].
So the title's question has no single answer. Spacesuits fit bodies by choosing among a few sizes, by making the most delicate parts to measure, and by testing how bodies change in space. A wider range of sizes helps more people, but it costs more and needs more parts, and "everyone" is hard to reach.
6. Try Measuring Yourself for a Modular Outfit
Ask an adult to help you with a tape measure. Write down your height, the length from shoulder to wrist, the distance around your chest (wrap the tape just under your arms), and the width of your hand across the knuckles. Then look at the size chart on a few of your clothes, or on a store's website.
Do all your measurements land in the same size, such as medium? If one is in a different size from another, you have just seen why a modular system can fit better than a single size, and why even a modular system can fail someone with an unusual mix. Try it again with a friend or family member, and compare which parts match and which do not.