Working outside a spacecraft in a space suit — or walking on the moon in one — is one of the most dangerous activities an astronaut can participate in. Officially referred to as “EVA” in the abbreviation of the NASA acronym – that’s short for “extravehicular activity” – and commonly referred to as “spacewalking” by the public, leaving the pressurized metal protection of your ship or station and into the Floating emptiness means capturing yourself in a dynamic environment where conditions can change very quickly. EVAs usually last a few hours, but require months of training in the agency’s giant pool to make sure everything goes right.
Apollo’s capstone activities were the surface EVAs, where astronauts planted flags, set up experiments, piloted space cars, and otherwise tried to cram as much activity as possible into very short time windows. It’s hard to make a meaningful estimate of the per-minute cost of each lunar EVA, but estimates in the millions of dollars per minute aren’t far off; with that kind of cost pressure, Apollo astronauts on the lunar surface had to do everything they could to maximize the impact of any trip beyond the lunar module.
We spoke with EVA flight director Grier Wilt, who gave us some interesting information about how EVAs work today and how the Apollo and Gemini programs formed the basis for how EVAs are planned and executed today. She also gave us an excellent historical perspective on NASA today versus NASA in the 1960s – even if we don’t have moon bases in 2017, space continues to inspire.