---
title: "Astronaut training"
chunk: 1/6
source: "https://en.wikipedia.org/wiki/Astronaut_training"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:47:09.906443+00:00"
instance: "kb-cron"
---

Astronaut training describes the complex process of preparing astronauts in regions around the world for their space missions before, during and after the flight, which includes medical tests, physical training, extra-vehicular activity (EVA) training, wilderness survival training, water survival training, robotics training, procedure training, rehabilitation process, as well as training on experiments they will perform during their stay in space.
Virtual and physical training facilities have been integrated to familiarize astronauts with the conditions they will encounter during all phases of flight and prepare astronauts for a microgravity environment. Special considerations must be made during training to ensure a safe and successful mission, which is why the Apollo astronauts received training for geology field work on the Lunar surface and why research is being conducted on best practices for future extended missions, such as trips to Mars.

== Purpose of training ==

=== Training flow ===
The selection and training of astronauts are integrated processes to ensure the crew members are qualified for space missions. The training is categorized into five objectives to train the astronauts on the general and specific aspects: basic training, advanced training, mission-specific training, onboard training, and proficiency maintenance training. The trainees must learn medicine, language, robotics and piloting, space system engineering, the organization of space systems, and the acronyms in aerospace engineering during the basic training. While 60% to 80% of the astronauts will experience space motion sickness, including pallor, cold sweating, vomiting, and anorexia, the astronaut candidates are expected to overcome the sickness. During the advanced training and the mission specific training, astronauts will learn about the operation of specific systems and skills required associated with their assigned positions in a space mission. The mission specific training typically requires 18 months to complete for Space Shuttle and International Space Station crews. It is important to ensure the astronauts' well-being, physical and mental health prior, during, and after the mission period. Proficiency maintenance aims to help the crew members to maintain a minimum level of performance, including topics such as extravehicular activity, robotics, language, diving, and flight training.

=== Launch and landing ===
The effects of launching and landing have various effects on astronauts, with the most significant effects that occur being space motion sickness, orthostatic intolerance, and cardiovascular events.
Space motion sickness is an event that can occur within minutes of being in changing gravity environments (i.e. from 1g on Earth prior to launch to more than 1g during launch, and then from microgravity in space to hypergravity during re-entry and again to 1g after landing). The symptoms range from drowsiness and headaches, to nausea and vomiting. There are three general categories of space motion sickness:

Mild: One to several transient symptoms, no operational impact
Moderate: Several symptoms of persistent nature, minimal operational impact
Severe: Several symptoms of persistent nature, significant impact on performance
About three-fourths of astronauts experience space motion sickness, with effects rarely exceeding two days. 
There is a risk for post-flight motion sickness, however this is only significant following long-duration space missions. Post-flight, following exposure to microgravity, the vestibular system, located in the inner ear is disrupted because of the microgravity-induced unresponsiveness of the otoliths which are small calcareous concretions that sense body postures and are responsible for ensuring proper balance. In most cases, this leads to some postflight postural illusions.
Cardiovascular events represent important factors during the three phases of a space mission. They can be divided in:

Pre-existing cardiovascular diseases: these are typically selected-out during astronaut selection, but if they are present in an astronaut they can worsen over the course of the spaceflight.
Cardiovascular events and changes occurring during spaceflight: these are due to body fluids shift and redistribution, heart rhythm disturbances and decrease in maximal exercise capacity in the micro gravity environment. These effects can potentially lead the crew to be severely incapacitated upon return to a gravitational environment and thus unable to egress a spacecraft without assistance.
Orthostatic intolerance leading to syncope during post-flight stand test.

=== On-orbit operations ===

Astronauts are trained in preparation for the conditions of launch as well as the harsh environment of space. This training aims to prepare the crew for events falling under two broad categories: events relating to operation of the spacecraft (internal events), and events relating to the space environment (external events)

During training, astronauts are familiarized with the engineering systems of the spacecraft including spacecraft propulsion, spacecraft thermal control, and life support systems. In addition to this, astronauts receive training in orbital mechanics, scientific experimentation, earth observation, and astronomy. This training is particularly important for missions when an astronaut will encounter multiple systems (for example on the International Space Station (ISS)). Training is performed in order to prepare astronauts for events that may pose a hazard to their health, the health of the crew, or the successful completion of the mission. These types of events may be: failure of a critical life support system, capsule depressurization, fire, and other life-threatening events. In addition to the need to train for hazardous events, astronauts will also need to train to ensure the successful completion of their mission. This could be in the form of training for EVA, scientific experimentation, or spacecraft piloting.

==== External events ====
External events refer more broadly to the ability to live and work in the extreme environment of space. This includes adaptation to microgravity (or weightlessness), isolation, confinement, and radiation. The difficulties associated with living and working in microgravity include spatial disorientation, motion sickness, and vertigo. During long-duration missions, astronauts will often experience isolation and confinement. This has been known to limit performance of astronaut crews and hence training aims to prepare astronauts for such challenges. The long-term effects of radiation on crews is still largely unknown. However, it is theorized that astronauts on a trip to Mars will likely receive more than 1000x the radiation dosage of a typical person on Earth. As such, present and future training must incorporate systems and processes for protecting astronauts against radiation.