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Caitlin: Project Mercury, America’s first human spaceflight program, lasted from 1958 to 1963. And in those few years, NASA went from a rocket that launched half an hour before it was supposed to and blew up on the launch pad, by the way all the way to putting someone in orbit for almost a day and a half. And at every step of the way, they were solving problems that influenced the future of the American space program.

Project Mercury started out with three specific objectives: One, NASA wanted to put a human in orbit around Earth; two, they wanted to see how the human body responded to being in space since no American had ever left Earth before; and three, they wanted to bring the astronaut and their ship back to Earth safely. And yes, it’s a little alarming that putting someone in orbit and bringing them alive back were separate goals.

The first launch of Project Mercury was on August 21, 1959, and it did not go well. The goal of Little Joe 1, as the unmanned booster was called, was to test the escape system you know, that thing that astronauts would need in case something went terribly wrong. About half an hour before the scheduled launch, there was an explosion. When the smoke cleared, the crowd that had gathered to watch the rocket lift off saw that Little Joe had unexpectedly launched. At least, parts of it did.

Other parts were still sitting on the launch pad, waiting to be sent up into the sky. The problem was that a pair of electrical circuits got crossed, which sent mixed signals to the rest of the ship. The next launch, Big Joe 1, successfully tested the heat shields though there were still problems with the actual launching part of things.

Throughout the project, the unmanned missions would continue to be plagued with launch problems. It’s hard to send something into space, and NASA learned that over and over again. But that’s why they were unmanned missions: that’s where the kinks were worked out.

Some of the twenty unmanned missions tested individual components, like the escape system or the heat shields. Others, especially later on in the project, were tests of whole missions a kind of dry run before sending humans along for the ride. There were also six manned missions in Project Mercury.

First came Mercury-Redstone 3, in May 1961, which made Alan Shepard the first American to ever reach space. He was also the first person to ever go to space and then land back on Earth inside the capsule, since the two Soviet cosmonauts who had gone up earlier in 1961 both ejected from their ships and parachuted down to the ground. The third mission was Mercury-Atlas 6, in February 1962. It brought John Glenn into orbit, making him the first American, and the third person in human history, to ever orbit the Earth.

You might have noticed that I skipped the second manned mission the one between Shepard’s and Glenn’s flights. That’s because the second and fourth missions of Project Mercury had a very particular purpose: they were duplicates of the previous missions.

So Mercury-Redstone 4, with Virgil Grissom on board, was pretty much a carbon copy of Shepard’s flight two months earlier. And Mercury-Atlas 7, with Scott Carpenter on board, was pretty much a carbon copy of Glenn’s orbit. Project Mercury had a lot of scientists working on it who knew that there’s no use doing something once if you can’t prove that you can do it again.

And that turned out to be a good idea. After Grissom became the second American in space, his capsule landed in the Atlantic Ocean and pretty much sunk like a rock because the hatch blew open. He got out safely, but the capsule itself wasn’t recovered from the bottom of the ocean until almost forty years later, in 1999.

Now, Project Mercury could have stopped after Carpenter’s orbits, but it had two more manned missions to go: Mercury-Atlas 8 and Mercury-Atlas 9. Each orbited for longer than the previous mission had, with Mercury-Atlas 9 orbiting Earth for almost thirty-four hours. This let NASA really nail down that second objective of Project Mercury, which was to see what happened when humans were in low gravity for a long time.

They were especially interested in seeing if anything happened to the astronauts’ bodies or brains that would’ve made it hard to put together longer missions like the week-long flight to the Moon that was already in the early planning stages. And what they found was encouraging: being in space for a few days didn’t seem to affect an astronaut’s health or brain very much. L. Gordon Cooper, the astronaut on board, was just as good a pilot after a day and a half in space.

Project Mercury also taught NASA how to effectively put together a series of missions that built on one another, and they learned how to train astronauts so that they could succeed in their missions. So not only did America’s first manned space program get us to space it set the stage for all our future space programs, too.

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