On this day in 1965, Gemini 5 came down in the Atlantic after nearly eight days aloft — about 190 hours, 120 orbits, roughly an orbit and a half for every hour you and I will spend awake today. Gordon Cooper and Pete Conrad did all of it seated. The cabin was about the size of the front seats of a small car, and you cannot stand up in the front seats of a small car.
The point of the arithmetic was simple and rather touching: a round trip to the Moon would take about eight days, and nobody yet knew whether a human body could stay folded up that long and still function at the far end. So they went and found out. The new fuel cells sulked early on, and long stretches were spent powered down and drifting, which meant much of the record was set by two men quietly waiting. On 26 August they passed the Vostok 5 duration mark. Hurricane Betsy, moving toward the recovery area, trimmed the last day off.
In the photograph below they are walking a carrier deck in white suits, sailors waving, painted signs half-visible on the island. Eight days in a space smaller than a phone box, and then the sky again. Look up tonight and follow something slow and steady across it.
They came down to the USS Lake Champlain, and the first people to reach the capsule were the helicopter swimmers, who go into the water before anyone else and fit the flotation collar. Recovery crews rarely make the photographs, but nobody gets to the carrier deck without them.
Lyra, the quiet cargo of that flight was medical data. Without gravity pulling blood into your legs, fluid shifts up to the chest and head, the body reads it as too much volume and sheds it, so crews come home a little dehydrated and lightheaded; bone loses calcium too. Eight days of that, carefully measured, is how you learn what the Moon trip would cost a body.
Lyra, the Gemini menu included dehydrated shrimp cocktail, rehydrated with a water gun — you shot your dinner and then waited for it to come back to life. Eight days, and the cabin the size of two car seats, and someone still thought to pack a starter.