Mysteries Of Flight: Fixed-Wing Astronauts

But such wasn't always the case. All of the first astronauts were extremely skilled and accomplished fixed-wing pilots, and they were proud of it, too. The role of astronaut was going to be different from that of pilot, and the question of what makes someone an astronaut, or naut, became a thorny one. 

In The Right Stuff, author Tom Wolfe recounts the pains those early NASA astronaut recruits went through to help the spaceflight agency create the very concept of an astronaut, most importantly by insisting that it include pilot duties as central to being an astronaut. This aviator-centric perspective helped drive the design of the Gemini, and later Apollo, spacecraft.

Even the term "spacecraft" had a backstory. The Gemini astronauts strongly preferred "spacecraft" to "capsule," as the latter term made them out to be, in their vernacular, nothing more than "Spam in a can," a reference to the meat product packed tightly inside a metal container used to ship the inanimate meat-based contents of the can, or capsule, in NASA's case. Thankfully, the astronauts were successful in making their case, and the paradigm of astronaut/pilot carried over to the Space Shuttle, which was a fixed-wing aircraft that didn't fly to space but certainly flew back from it, requiring not just standard pilot skills but exceptional ones.

Our concept of what qualifies one for astronaut status is closely tied to our ideas of what space even is. In the popular imagination, "space" is what's popularly referred to as "deep space," a place far away from Earth and beyond orbit, out of reach of Earth's gravity and completely empty. In fact, no human has ever ventured that far from earth, at least not yet. With the exception of the lunar missions of the 1960s and early 1970s, no human has traveled beyond the highest orbital plane of manmade satellites, which is about 23,000 miles above Earth. The International Space Station (ISS), in fact, is an orbital plane where the earth's gravitational pull is a full 90% of what it is on the surface. The astronauts don't float because of zero gravity but because they're falling, which is essentially what an orbit is.

By definition, space begins way before anything we'd refer to as "deep space," though exactly how far from Earth that point begins depends on who's doing the defining. For the U.S. military, space starts at precisely 50 miles above the Earth because and, this is an important distinction, that's where there's not enough atmosphere for planes to develop aerodynamic lift. Which means they stop being planes. Fair point. 

Others define space as beginning at 62 miles (100 km) above the Earth, and if that sounds like a conveniently round and metric number, well, we agree. Known as the Kármán line, this definition is used by the international organization, the Fédération Aéronautique Internationale (FAI), that certifies aerospace records.

If you're going by when there's no more atmosphere left at all, well, that's around 650 miles up, though even coming up with a definitive boundary for that is dicey. Suffice it to say that if that 650-ish mile distance were the universally accepted definition of space, none of the today's orbital scientists, who do their work at the ISS, would be astronauts because the Space Station orbits at just between 200 and 250 miles up.

But when it comes to determining who gets the astronaut wings, it's the Air Force and NASA and their 50-mile definition (again, the altitude at which wings no longer work) that counts.

So when you think about it, that definition of space requires something that isn't an aircraft, or, to state it differently, a craft that travels through the air by the generation of lift, but NASA (and its precursor, NACA) figured out early on that giving aircraft a boost to altitude would save a lot of fuel and allow for wings that might otherwise be too small for takeoff. The first supersonic aircraft, the Bell X-1, and the first spaceship/plane, the North American X-15, were both launched from mother ships at high altitude.

One of the most fascinating aircraft in the history of flight, the X-15 was designed for more that just going fast, though it was spectacular in that regard. A 1967 flight of the X-15 remains the fastest-powered atmospheric human-carrying craft ever, at Mach 6.7.

The lack of atmosphere at the altitudes to which the X-15 was flown also required rocket motors, as air-breathing engines won't work at very high altitudes. Nor will aerodynamic control surfaces such as rudders, elevators and ailerons, all of which depend on the flow of air over them to function. Instead, the X-15 used rocket thrusters.

Over the course of the X-15 program, which lasted from 1959 to 1968, the ship flew higher than 50 miles 13 times piloted by eight different pilots, all of whom were awarded their astronaut wings. However, only twice, on two flights by Joe Walker in the summer of 1963, did it fly higher than the Kármán line.

In all, only 24 human beings have gone into space beyond a low Earth orbit, and all of those were American NASA astronauts, and all of them have been men.

Being an astronaut is a matter of definition, and those definitions are, for the most part, based on the physical properties of high atmospheric flight, orbital physics and that of space itself. Regardless, flying even into the near reaches of space is a high-risk proposition, as evidenced by the high percentage of astronauts who have died in their pursuit of the heavens. Besides, regardless of what heights they have reached, being an astronaut is an achievement that very few humans can put on their resumes. 

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