A trip to the vacuum chamber today! A big vacuum chamber that contains a replica of a few Russian segment modules, including the Service Module and the Soyuz. As we were inside these module, pressure was dropped in the chamber around us: the chamber technicians had then the possibility of opening one of several valves connected the atmosphere of our module to the rest of the chamber, thus creating “leak” conditions in various modules.
All the hatches are just like the ones in space and the idea is to practice response procedures for the case of a leak, a so called rapid depressurization scenario. We have practiced those procedures many times both in Houston and in Russia, so we know very well how to react if the pressure starts dropping inside the Station, which we could notice because the alarm goes off or simply because our ears start to pop, whichever comes first – unless of course you happened to be staring at a pressure gauge, in which case you would see the needle moving.
The main point of the response procedure is to determine which module is leaking, which involves closing hatches in a specified order. Once you close a hatch you check your pressure gauge: if the needle stops moving, the leak is on the other side and viceversa. And you keep on going until you’ve found the culprit, which then you have to isolate.
Today we practiced again this kind of work, with the difference that we actually had a pressure differential building across the hatches when we had them closed. It was very interesting to see that effect and to realize how hard it can become to open a hatch that, say, swings open towards you, when there is a leak on the other side and you have to pull against a pressure differential. To avoid problems reopening a hatch, we are instructed to leave a hatch closed at most for half the time it takes for the pressure to drop 1 mm.
Unfortunately I was not allowed to take pictures in this facility. I have attached a picture of the regular Russian segment mockup we practice in Star City. Progress, Service Module, FGB, DC1 are all in place. The MRM1 and MRM2 are off to the right and to the left you can see the future modules MLM and UM.
Here you can navigate the panorama if you like:
https://www.dermandar.com/p/eaDoMs/iss-mockup-in-star-city
(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://spacetux.org/cpamoa/category/traductions/logbook-samantha/
11/02/2014