# How fast do they spin astronauts these days? Maximum routine g-training for astronauts in the 21st century?

Comments got me thinking about NASA's 20 g centrifuge. Gemini astronauts pushed to 7 or perhaps 8 g's as discussed in this answer but these days with nicely throttleable engines astronauts going to space experience no more than ballpark 3 g under normal conditions.

The NASA 20 G Centrifuge (also NASA page) potentially goes up to 20 g, but I'm guessing they don't do that so much any more.

Question: How fast (to what g-level) do they spin astronauts these days? Maximum routine g-training for astronauts in the 21st century?

Source

• Tim Peake flew to the ISS in late 2015. There is a video of him experiencing 8g in a centrifuge here: bbc.co.uk/news/av/science-environment-35030406/… In a normal launch the force of a soyuz is less than 4g, but an emergency might subject the crew to higher than that Jan 12 '19 at 10:43
• This 20 g centrifuge was never used to expose astronauts to 20 g. According to this NASA page "additional safety features permit human studies from 1 to 12.5-g"
– Uwe
Jan 12 '19 at 10:53
• From The Pull of HyperGravity "To produce a centrifugal force of 2-g, the centrifuge spins about 15 revolutions a minute." To reach 20 g the centrifuge should spin a 100 times faster, 25 revolutions per second. For 4 g 1 revolution per second, for 5 g 1.5625 revolutions per second.
– Uwe
Jan 12 '19 at 12:07
• @Uwe $\sqrt{10}$ times faster!! $F_C = m v^2/r$
– uhoh
Jan 12 '19 at 12:09
• @uhoh square root of 10 instead of square of 10 is much better. So only 47.4 revolutions a minute for 20 g. I stand corrected.
– Uwe
Jan 12 '19 at 12:16

## 1 Answer

The only centrifuge training received by Shuttle astronauts was a 3g ride in the Brooks Air Force Base facility as new astronauts, followed by optional use of the facility to verify ascent/entry suit fitting.

Description by Clay Anderson from here

Shuttle training sent us to a San Antonio Air Force Base for a single ride in their centrifuge. The Shuttle's ascent and entry profiles were flown, to give us the exposure to what 2-3 g's would feel like. Actually no big deal, and just "checking a box."

Brooks AFB closed in 2011.

Anderson goes on to comment about Soyuz centrifuge training:

In Russia I flew their centrifuge as well. Since I was a ShREC (Shuttle Rotating Expedition Crew Member), I only did the Soyuz re-entry centrifuge profile, in a manner similar to that of the shuttle, pulling the requisite number of g's at the appropriate times. However, we also did some separate runs, which reflected a ballistic Soyuz re-entry profile. This re-entry, a contingency; is extremely dynamic. We pulled 8 and 10 g's for short periods of time, reflecting what would be experienced in the event of a failure driving us into that mode.

(excerpt from Shuttle Crew Training Catalog)