The Evolution Of Space Suits Explained

Technically speaking, the MMU (short for Manned Maneuvering Unit) is not a space suit, but we’d be remiss in talking about the evolution of suits without mentioning it. The MMU was an accessory attachment first deployed during the Space Shuttle era, in 1984. It allowed an astronaut on a spacewalk to freely maneuver in space, detached from any spacecraft.

It was designed with satellite rescue missions in mind, (via NASA) but was only ever flown three times, during the tenth, eleventh, and fourteenth shuttle missions. Bruce McCandless had the honor of that first flight.

The MMU took inspiration from previous devices like the M509 backpack which had been tested in Skylab. It was, for all intents and purposes, a very small spacecraft lacking any enclosure or pressure, more akin to a space motorcycle than a car, which an astronaut could strap into and fly around untethered in space.

The MMU achieved propulsion from two tanks of nitrogen gas which could be released from various outlets via hand controls. Despite it being among the coolest things we’ve ever done in space, it was ultimately retired. Today, astronauts wear the SAFER unit (Simplified Aid For EVA Rescue), which pairs down the MMU’s capabilities to a small backpack worn during EVAs (via NASA).