G-overload is a term that is known to almost everyone, but beyond the mild G-loads in an accelerating car or passenger airplane, only few experienced it. As a formal term, overload represents the ratio of the force of acceleration to the force produced by terrestrial gravity. During launch, astronauts experience loads of up to 3G. During a descent, passing through the dense layers of the atmosphere is quicker than launching into orbit, so the crew is subjected to loads of up to 5G during a nominal descent and up to 8Gs in a case of ballistic descent.
On April 5, 1975, due to a launch vehicle failure, a Soyuz spacecraft did not reach its target orbit. Later, during re-entry, the crew was subjected to loads of up to 20G and survived.
To prepare the cosmonauts for the anticipated G-loads, the GCTC uses two special Centrifuges -- TsF-7 and TsF-18. Cosmonauts are trained to endure a 5G load while sitting upright and an 8G load while lying flat. They are also trained to operate spacecraft manually during descent.
For beginners, we offer the possibility to experience a 3-minute rotation in a centrifuge with a load of up to 3G. However, for those who wish to test their limits after a successful first session, it is possible to go further and practice higher G-loads, or practice launch and descent training, just like cosmonauts.