In yesterday’s logbook we were discussing an emergency scenario, in which we received this call from a simulated Mission Control “Ammonia leak, execute emergency response! Ammonia leak, execute emergency response!”
Since ammonia is highly toxic, the first action is to put on an oxygen mask. Throughout the ISS we have at least one mask, often two, in each module, ready to be used. US segment masks come with a bottle containing a 7-min supply of oxygen. That might not sound like a lot, but these masks are only used for initial response, as you’ll see.
With the mask on, those of us who were in the USOS segment (US modules plus Columbus and JEM) quickly move aft to the Russian segment – that’s not only because our Soyuz vehicles are docked there, but also because of one important design difference: there are no ammonia lines in the Russian segment.
Making sure that all six crewmembers are accounted for, we close the Node 1 hatch, thereby isolating ourselves from the USOS segment and the source of the leak. At that point we get rid of the external layers of clothes, potentially contaminated, and leave them in the PMA, the small adapter element between USOS and Russian segment, closing the PMA aft hatch as we retract into the Russian FGB module.
Time to retrieve our respirator masks and install on them the pink ammonia filter cartridges. Swapping from the O2 mask to the ammonia respirators must be done quickly and carefully, since we don’t know what the ammonia concentration in the Russian segment atmosphere is. Assuming a contaminated atmosphere, we keep eyes closed and hold our breath while coming off the O2 mask. Once we have the respirators on, we go through a number of purging breaths to get rid of any ammonia inside the hood. Only then do we open our eyes.
Once everybody is safely on respirators, it’s time to understand how much ammonia we have in the Russian segment atmosphere. For that we have a dedicated chip measurement system. In the worst case scenario, the Russian segment is contaminated to such a level that we need to evacuate Station. If the ammonia concentration is not so high, we can filter the air through our respirator cartridges via our breathing. We then stay for several hours, until the measurements show a safe atmosphere. In the lucky case that the air in the Russian segment was not contaminated, we could come off masks and breath normally. Safe, for sure, but with a lost USOS segment, at least for the moment.
Picture: going through the purging procedure (ESA/S.Corvaja)
Futura mission website (Italian): Avamposto42
avamposto42.esa.int
(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/
07/07/2014