How to become an astronaut at NASA and ESA

Who wouldn't want to be an astronaut?

The perks include zero-gravity flight, the ability to conduct unique scientific research and, well, national and international fame.

It even pays well. In the US, job candidates at NASA are offered the curiously specific sums of between $66,026.00 and $144,566.00 per year (roughly 61,000 to 133,000 euros). The European Space Agency (ESA) pays the slightly more democratic spread of between 60,000 and 81,000 euros.

But what, exactly, qualifies you to become an astronaut?

1. A bachelor's degree

Yes, a bachelor's degree is all that's required to become an American astronaut.

But no, yours probably doesn't count.

NASA only accepts bachelor's degrees in engineering, biological science, physical science, computer science or mathematics.

ESA requires master's or doctorate level degrees. Acceptable degrees are in the fields of the natural sciences (physics, biology, chemistry, and earth sciences or related disciplines) as well as medicine, engineering, information technology or mathematics.

ESA is also a touch firmer on real-world experience. It strongly suggests its candidates have three years of related professional experience after they graduate, regardless of other qualifications.

Germany's Alexander Gerst, for example, is a vulcanologist first and an astronaut second. He obtained a master's degree in geophysics in Wellington, New Zealand in 2003, then went on to do volcanic research in Ethiopia, Indonesia, Guatemala and Antarctica, co-developing novel equipment along the way.

So when the then 32-year-old applied to become an astronaut in 2008, ESA would have seen him as a candidate with a master's degree, experience in field research, a knack for tinkering.

When ESA accepted Gerst based on these qualifications in 2009, he was therefore trained to work in an engineering capacity on International Space Station (ISS) missions 40 and 41 - but not as a pilot.

2. For astronaut pilots, 1,000 hours of flight experience

This is true for both NASA and ESA.

To put these numbers in perspective, they equal about four hours of piloting per day for an entire work year.

This is why so many US and EU astronaut pilots have military or aviation backgrounds. Test pilots are also well regarded.

Neil Armstrong, the first man on the moon, piloted planes in the Korean War more than 15 years before he took his "giant leap for mankind."

Samantha Cristoforetti, known the world over as the first person to drink espresso in space, was a captain in the Italian air force before joining ESA and breaking the record for the longest uninterrupted spaceflight by a European astronaut on the ISS.

The current US commander of the ISS, Scott Kelly, began his career flying F-14 fighter planes and has since flown more than 40 different aircraft and spacecraft, logging 8,000 flight hours.

3. Physical challenge

Potential pilots and commanders at NASA must have 20/20 vision (or corrective glasses, or correctable eyes), a blood pressure of 140/90 while sitting, and must be between 5'2'' and 6'3'' tall.

Mission control specialists have roughly an inch of leeway on each side of this height range.

ESA has very nearly the exact same requirements for a candidate's height (between 153 and 190 centimeters).

Beyond that, there are numerous physical challenges. They include stints in centrifuges, rotating chairs, pressure chambers, aircraft and swimming pools.

NASA trains its astronauts in Houston, Texas, at the Johnson Space Center. ESA has its training facility in Cologne, Germany, at the European Astronaut Centre.

Throughout the training, every NASA and ESA astronaut undergoes continuous physical check-ups, along with rigorous investigations into their…

4. Mental health

Being an astronaut means living and working in cramped quarters, bad air, artificial lighting, poor food, strange clothing, sexual frustration, interrupted sleep and, just outside the window, instant death.

It's an emotionally explosive combination. Psychological examinations prior to spaceflight ensure that only the most stable of applicants will ever board a spacecraft.

Those examinations include questionnaires, interviews and live-action "stress tests." Even marital stress is factored in.

Failing any of these tests can torpedo a candidate's chances.

After ESA's last round of hiring closed in June 2008 it took 11 months for the agency to announce the successful candidates.

Roughly 8,400 people applied, and only the best of the best of the best (and the mentally strongest) survived.

5. Citizenship

Finally, NASA requires astronauts to be US citizens. ESA requires astronauts to come from one of its member states, of which there are currently 22.

Full stop… sort of.

If you don't meet this criteria, there is a work-around. If you hold an engineering degree, and you work in the US or one of ESA's member states for five years, you can apply for naturalization.

In summary, America's and Europe's astronaut training programs respectively require a bachelor's or master's degree in the sciences, three years' of related work experience, 1,000 hours of piloting airplanes, psychological stability, and a US passport or one from an ESA member state (not all European Union members are members of ESA).

If obtaining all five criteria by NASA's deadline of February 18, 2016 proves impossible, keep in mind that ESA may provide you another opportunity in the near future.

During the last round of hiring only one of those six astronauts, Thomas Pesquet of France, has yet to visit the ISS. He's scheduled to go there between November 2016 and March 2017, at which point the class of '09 will have presumably finished its collective "mission."

Oh, there is another small thing: be young.

The youngest of ESA's last recruits is now 37. The oldest, UK national and current ISS resident Tim Peake, is 43.

For astronaut applicants, ESA writes, "The preferred age range is 27 to 37."