Astronaut VS Cosmonaut

Last updated: 22nd April 2020

Why do we use two different words for people doing essentially the same job? Why are there astronauts on one side and cosmonauts on the other? After all, we don’t call a Spanish doctor or a Mexican chef by a totally different name: they’re just a doctor and a chef.

So what’s different with our beloved space explorers?

Where do the words astronaut and cosmonaut come from?

Well, the answer to this is heavily linked to the early days of space exploration and the politics at play during that time. Back in the days of the space race, it was important for America and Russia to differentiate the people being trained to go on missions in space. After all, they were in a very serious competition with each other and it’s not surprising that they’ve chosen different names despite being the same role, essentially.

This was then quickly picked up by the media and newspapers who would always refer to cosmonauts whenever they were publishing articles about the soviet space program. This never really went away since. 

Other space agencies, like the ESA, the CSA, and JAXA, just call their space travellers “Astronauts.”

However, some new terms have been surfacing those past few years: spationaute in France and Taikonaut in China.

What is the meaning of cosmonaut and astronaut?

Like many of the words used in the scientific world, the name attributed to the brave people sent to space take its root in ancient Greek.

  1. The word Astronaut is made of the prefix “Astro” which means stars and the suffix “naut” which means sailor. An astronaut is essentially a star sailor.
  2. The word Cosmonaut is made of the prefix “Cosmo” which means universe and the same suffix as above “naut”. And so a cosmonaut is a sailor of the universe.

Semantically speaking, the difference between an astronaut and a cosmonaut is not that big in the end, as none of them space explorers are literally navigating the stars nor the universe… for now.

Which one do you think fits the job description better? Personally I think that sailing the universe sounds a little cooler 🙂

So, are there any differences between astronaut and cosmonaut?

There are some differences due to the fact that Americans and Russians follow different space programs. The differences will ultimately lie in the selection criteria to become an astronaut or cosmonaut, the selection process, their training, the spacesuit and equipment used as well as their missions.

Selection Criteria

Becoming an astronaut is an enormous commitment that requires a lot of time, a lot of training and a lot of travelling. You could train for 9 months and not even make it to space. It is indeed a very dangerous job and the selection criteria are strict.

Astronaut Requirements

  1. Be a U.S. citizen
  2. Possess a master’s degree* in a STEM field, including engineering, biological science, physical science, computer science or mathematics, from an accredited institution.
  3. Have at least two years of related professional experience obtained after degree completion or at least 1,000 hours pilot-in-command time on jet aircraft.
  4. Be able to pass the NASA long-duration flight astronaut physical.

Astronaut candidates must also have skills in leadership, teamwork and communications. (source: NASA)

Cosmonaut Requirements

  1.  candidate for cosmonauts of the Russian Federation may be a citizen of the Russian Federation.
  2. Applicants must not exceed 35 years of age.
  3. Applicants must have a university degree in engineering, scientific or flight specialities and have experience. Priority in the selection for people with experience in the aviation, the rocket and space industry for the Russian Federation.
  4. Applicants must meet the following requirements necessary for subsequent preparation for space flight, in particular:
    1. Have the ability to study space technology;
    2. Have knowledge of interaction with computer technology;
    3. Know a foreign language (English) as part of the requirements of programs of non-linguistic universities of the Russian Federation, etc.

(source: Roscosmos)

Selection Process

NASA Astronaut

During the class of 2017, the astronaut selection process took over 18 months in order to select 14 people out of the 18,300 who applied. After a very thorough review of all the applicants, 120 people are selected for in-person interviews, medical test, and psychological evaluation. After that list is further reduced, candidates will go through another round of physical and mental tests, team-building exercises and interviews until a final decision is made.


Russia did their first-ever open (to everyone) selection for cosmonaut in 2012 which lasted a few months. During that time, applicants went through four different stages including initial screening of applications, medical examination, overall credentials reviewed and many tests of various nature. Out of the 420 applicants, 8 made it to the end and joined the Russian space program as cosmonauts.


The selected Russian cosmonauts will be sent to Star City, at the Gagarin Cosmonaut Training Center (GCTC) in Moscow, Russia where they will follow an intensive and long training involving: flight in Mig-29, zero-G flight, wearing Sokol and Orlan spacesuits, spacewalk simulation in the hydro lab, centrifuge, manual docking and much more. 

American astronauts train at Johnson Space Center for hundreds of hours. They learn everything about spaceflight, the ISS (International Space Station), the different equipment needed, basic medical skills and a new language (usually Russian). An astronaut may train for years before even going up to space, and they also have to learn many things besides science: survival skills, public speaking, human relationship and team building.

Space Suits

Space is probably one of the most dangerous places to explore. To survive in space both astronaut and cosmonaut need a suit that protects their body from the heat, the cold, the radiation and provides them with oxygen.

Current Cosmonaut Space Suit

  • Name: Orlan-MKS
  • Manufacturer: NPP Zvezda
  • Missions: Used on ISS. Used from 2017-present
  • Function: Extra-vehicular activity (EVA)
  • Operating pressure: 400 hPa (5.8 psi)
  • Primary life support: 7 hours

Current Astronaut Space Suit

  • Name Baseline EMU (Extravehicular Mobility Unit)
  • Manufacturer: ILC Dover (suit) and Collins Aerospace (primary life support systems)
  • Missions: STS-6 (1983) to STS-110 (2002)
  • Function: orbital extra-vehicular activity
  • Operating pressure: 4.5 psi (29.6 kPa)
  • EVA suit weight: 109 lb (49.4 kg)
  • Total shuttle EVA suit weight: 254 lb (115 kg
  • Primary life support: 8 hours (480 minutes)
  • Backup life support: 30 minutes
Astronaut spacesuit

Further Readings

American or Russian, Astronaut or Cosmonaut, these brave people have been a key part in pushing the human race further into space. Many of the experiments they have conducted are contributing to learning more about space, our place in the universe and our future in the solar system. Below are some of the most famous astronaut and cosmonaut to this day:

Famous Astronauts:
Famous Cosmonauts:

Welcome to

Hey! I’m Tom Urbain, the founder of I have been obsessed with space from a very young age. When I’m not binge-watching space documentaries, movies or TV shows, I can be found in my backyard, carefully collimating my telescope… ready to observe the universe!

More about StarLust

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