One final Soyuz sim today with Terry and Anton before Terry and I leave Russia for the Christmas holidays.
Our scenario started today just prior to undocking for reentry to Earth. Before we could open the hooks and release the Soyuz from Station, we had to perform a suit leak check, to make sure that our pressure suits would save our lives in case of depressurization.
In the picture, just left of my left elbow, you can see our pneumatic connections to Station. The big line is ventilation, meaning that it’s just cabin air circulated in our suits. The smaller one is the supply of pure oxygen.
For a leak check we close the blue regulator just below the helmet and start supplying oxygen into the suit by opening the valve next to the window. On the arm we have a pressure gauge: if the suit reaches 0.1 atm and then from there 0.35 atm of overpressure within 90 seconds, the leak check is passed! We reopen the regulator and relief the extra pressure into the cabin.
The regulator then remains at the setting 0,4 atm throughout the flight. In a normal day, the suit is simply connected to the outside, but should the pressure in the cabin drop, the regulator will not allow the pressure in the suit to decrease below 0.4 atm.
It’s not easy to work in the suit at that pressure: freedom of movement and dexterity are very limited. That’s why for a maximum of 5 min we are allowed to change the setting to 0,27 atm if there’s a need to work demanding procedures. This pressure makes the suit softer and less bulky, but it’s also unfortunately too low to ensure that we’ll have no issues with decompression sickness, hence the time limit.
As always in spaceflight, and maybe in life in general, it’s a compromise!
(Trad IT) Traduzione in italiano a cura di +AstronautiNEWS qui:
https://www.astronautinews.it/tag/logbook/
(Trad ES) Tradducción en español aquí:
https://www.intervidia.com/category/bitacora/
(Trad FR) Traduction en français par +Anne Cpamoa ici:
https://anne.cpamoa.free.fr/blog/index.php/category/logbook-samantha
18/12/2013