Mercury suit The first outfits ever worn into space were high-altitude pressure suits that had been repurposed for more daring missions. Russian cosmonaut Yuri Gagarin took the first flight wearing the SK-1 suit in April 1961, followed by American astronaut Alan Shepard less than a month later. Shepard's outfit (above, worn by astronaut Gordon Cooper) was based off a Navy suit called the Mark IV, and was designed for both wearer comfort and to serve as a backup oxygen source. On later missions, floatation devices were added in case a wearer had to make a water landing.

Gemini suit The second generation of space suits needed to be ready for a much bigger task: spacewalks. Once again, the Russian space program made it up shortly before the Americans, with Alexey Leonov completing a spacewalk wearing the Berkut suit in March of 1965. American Ed White performed the second ever spacewalk in June that year as part of a Gemini mission. The Gemini suit was based off an Air Force pressure suit and added protections for astronauts leaving their ship. In particular, that included insulation from extreme temperatures and protection from micrometeoroids.

AX-3 Part of a prototype series from NASA’s AMES Research Center, the AX-3 was designed in the mid-1970s as an experiment with mobility in high pressure suits. It fell in the middle of AMES’ experimental AX line, which began in the 1960s with a focus on lunar exploration and, two decades later, eventually began exploring how to improve suits for the International Space Station.

AX-5 Developed by NASA in the 1980s, the AX-5 included many of the same design goals as the Mark III. Though it uses a hard, all-aluminum shell, it was actually designed with maneuverability and astronauts’ ease of getting in and out in mind. NASA also says that it offers excellent protection against meteorites.

Mark III One of many experimental suits, the Mark III explored different ways to improve the outfits astronauts wear when on the surface of a planet. Tested in the mid-2000s, the Mark III included a combination of firm and flexible pieces: a pairing that designers hoped would decrease wearers’ fatigue during movement. The suit carries liquid air in a backpack, and it allows its wearer to bend at the knees — a difficult feat in prior moon suits.

Constellation suits After the Shuttle missions, NASA's Constellation program would have taken astronauts back to the moon — but US budget cuts have likely thwarted that goal for the foreseeable future. While NASA was still planning, it hired a contractor to create suits for astronauts both in and out of vehicles. With the looks of an ‘80s action figure, the first suit (left), would have been used for launch and landing, while the second suit (right) was being designed to support extended lunar explorations beyond what the initial Apollo moon suit was capable of.

Z-1 NASA's Z-1 space suit bears an uncanny resemblance to Toy Story's Buzz Lightyear, but it’s an actual prototype meant to test new suit technologies and more maneuverable joints. The Z-1 would also make it much easier for astronauts to get into their suit: unlike the Apollo suits NASA took to the moon, astronauts would enter the Z-1 through an opening on its back, rather than putting separate pieces together as was necessary with the Apollo suits NASA took to the moon. A Z-2 prototype is now in the works with a focus on enhancing efficiency during spacewalks.

Aouda.X Developed by the Austrian Space Forum, the Aouda.X isn’t quite a space suit: it’s more of a space suit simulator. The suit is meant to create a Mars-like environment for its wearer, giving companies down on Earth the ability to test new technologies and see how they’d function for an astronaut up in space. It’s fairly high-tech too, for a simulator: it includes a heads-up display, medical monitoring systems, and a voice recognition system for giving commands. (Image: OEWF / Zanella Kux)

Martianized Orlan suit For Mars500 — a Russian experiment that kept six people in cramped, spacecraft-like living conditions for 520 days — a slightly modified version of Russia’s Orlan spacesuit was used for casually simulated Mars exploration missions. Mars500 says that the Orlan suits have been "Martianized," but considering that they were only meant for use on Earth, the biggest difference may just be that they were colored orange instead of white. (Image: IBMP / Oleg Voloshin)