→ L-142: Ammonia leak

As I told you in the last logbook, this is emergency simulation time for us, with Expedition 42 sim last week and Expedition 43 sim coming up next week. Goal is to practice the emergency responses with our two full crew combinations of 6 people.

More than fire and depressurization, the one scenario that requires a no-kidding immediate response is an ammonia leak into the cabin. If you’re wondering where that ammonia would come from, here’s a little background on ISS design. All the equipment we have onboard generates a lot of heat, that we need somehow to get rid of. That’s why we have cooling lines running throughout Station: via cold plates and the cabin heat exchangers, the water in those lines collects the heat. In the lines we have interface heat exchangers, in which the heat is passed from the internal cooling lines to the external ones. And in those latter ones, you guessed it, we have ammonia. Two external pumps make sure that that ammonia flows from the heat exchangers, where it collects the heat load, to the big Station radiators, where the heat is rejected into space.

So, you now know that there is a interface between the external ammonia lines and the internal water lines. What happens if there is a rupture at that interface, the heat exchanger? Well, since the external lines are at a higher pressure, it’s likely that ammonia would flow into the cabin.

Ammonia is extremely toxic and has a very distinctive smell. However, if the leak is small enough, the vehicle autodetection system or the ground might notice it first, by observing an increase in the fluid quantity in the accumulators of the cooling system: since we’re not adding any water, an increase in quantity must come from ammonia.

This is how our scenario started last week, with a call from the ground repeating this call on all frequencies: “Ammonia leak, execute emergency response! Ammonia leak, execute emergency response!”

I’ll tell you in the next logbook how that response looks like… but it has a lot to do with the two types of masks you see in the picture (Photo:  ESA/S. Corvaja)

Futura mission website (Italian): Avamposto42
avamposto42.esa.int

#SamLogbook  #Futura42

(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/