Hello everybody, now that things have mostly returned to normal on ISS, it’s time to catch up with the logbooks of the week. And what a week it has been!
Looking back to Tuesday, we got to ingress Dragon and unload all the urgent cargo, mainly everything that needed to be in cold stowage. And then on to Wednesday when, as you might have heard, we had quite some excitement here onboard and in the control centers around the world as the ammonia leak alarm went off.
I had just finished a monthly video conference with my ESA management and I was about to start a review of the installation procedure for the Airway Monitoring experiment on the laptop in my crew quarters, when all the speakers throughout the Station started to transmit the one tone sure to catch everybody’s immediate attention: the emergency tone.
I came out of my crew quarters and looked at the Lab aft bulkhead, the closest Caution and Warning Panel I could put my eyes on, and there it was, the third light from the left was lit red: even without reading the label, I know that the third light is the dreaded ammonia leak. Not that I cherish the thought of having a fire or a depressurization (the other two scenario that can trigger an emergency alarm), but ammonia, I am told, can kill you really fast. I couldn’t distinguish any ammonia odor in the cabin, but I certainly didn’t sniff around much: I immediately grabbed an oxygen mask, put it on and headed towards the Russian segment together with Terry, Butch and Sasha. Elena and Anton were in the Russian segment already at the time.
After making sure that nobody was left behind, we closed the hatch isolating the Russian from the American segment of the Station and started to prepare the ammonia measurement equipment and the ammonia respirators. Before I go any further, if you’re interested in some background (like why there is a danger of an ammonia leak, or why the Russian segment is a safe haven or how the ammonia response looks like), you can take a look at my training Logbooks:L-140, L-142
Back to our story… a few minutes after the tone went off, Houston called and declared it a false alarm, so we stood down from the emergency response and came back to the US segment, finding it of course unusually quiet, since the vehicle auto-response had shut down all of the Station’s many fans.
Why a false alarm? Well, looking at the telemetry from Station, the flight controllers couldn’t initially find any confirming cues that there was indeed an ammonia leak and everything pointed instead to a computer malfunction. But that was just the beginning of a long day for everybody…
As we were starting to restow the emergency equipment and get back to normal, we received the unexpected call from CAPCOM: “Ammonia leak. Execute emergency response. Ammonia leak, execute emergency response. Ammonia leak, execute emergency response”.
As we learned later, Houston had in the meantime started to see some signatures in the telemetry that could possibly indicate a real leak of ammonia into the cabin, in particular a slight increase in the cabin pressure: at the very least, a real leak could not be ruled out at that point any more.
So we put on our masks and took refuge in the Russian segment again. Even more than the first time, I believe that the thought did cross everybody’s mind as we closed the hatch: we might never reopen it again.
We went through the full ammonia response procedure and, after swapping the oxygen masks for the respirators with ammonia filters, could confirm with Draeger tubes that the atmosphere in the Russian segment was uncontaminated, hence safe to breath.
We doffed the respirators and eventually we all gathered in the Russian Service Module, eager to hear words from Houston about the suspected leak. We learned that to mitigate the possible leak, the pump in the external cooling loop B had been shut down and that the loop pressure had been reduced, but we were relieved to hear that the ammonia had not been vented from the loop into space: a possible scenario in a situation like this, but also an action that would cripple the Space Station for a long time.
Following the shutdown of the loop, a thermal clock had started for a lot of equipment onboard: if not shut down within a certain time, it would overheat. So control centers in several countries were busy trying to do a powerdown that would have as little impact as possible on Station systems and science.
I think you get the point: the control centers had the hard job from now on. We were safe, doing well and with very little to do, except waiting. Knowing what a stressful time the guys and girls on the ground were having, we tried to keep quiet and never asked for any update, patiently waiting for them to call us, which of course they did periodically.
At every update if became more and more clear that everything pointed to a false alarm, but we were not sure that we would be allowed to leave the Russian segment before the next day.
In all of this time, our Russian colleagues were incredibly hospitable. They even gave us three food containers that we could use for ourselves, so we wouldn’t feel bad about digging into their containers or asking all the time. When the power was restored to the power outlets I could give a quick call to my family to let them know I was OK. And Elena let me borrow her internet-access computer, so I could write a short tweet and make sure everybody knew that we were doing fine.
We didn’t know what information the media were reporting and we were concerned that people might be worried about us.
Eventually, in the early evening, we received instructions to reopen the hatch and go back. To be really safe, we all put on our ammonia respirators. Houston directed us to send two people forward to sample the atmosphere first and Butch decided that he and Terry, as the Soyuz right seaters, would go. After a few minutes they called back declaring that the readings were negative and we had the final confirmation: there had been no ammonia leak!
After a day of waiting, we were ready for action: we quickly gathered all the used emergency equipment, restowing what would be reused, trashing what needed to be discarded. We tagged up with Houston about the oxygen masks: how many had we used and how best to redeploy the remaining masks on Station to make sure we were ready to respond to any other emergency. And we took a few actions that could not be performed remotely by the ground to safe equipment following the powerdowns.
Finally, we got ready for bedtime: since ventilation had not been restored in Node 2, Columbus and JEM, we could not sleep in our crew quarters and had to camp out in the aft modules. I setup my camping spot in the Lab: camping in weightlessness is really easy, you just attach your sleeping bag to a handrail and you’re ready for a good night sleep!
By the next day, we were ready to jump back into the busy science program of the next weeks, thanks to the quick re-planning work done on the ground.
By the way, as unfortunate as this event was, in many ways we were lucky: Dragon was fully berthed, all the urgent cold stowage items had been removed, none of us was working on an experiment that would suffer damage if delayed or left unattended.
That would have been the case, for example for the ESA “T-Cell” experiment, which I performed on Tuesday: had the ammonia alarm gone off on that day, we would have lost the science. So, in the end, we were lucky: must be because, on Expedition 42, we always know where our towel is!
Futura mission website (Italian): Avamposto42
avamposto42.esa.int
(Trad IT) Traduzione in italiano a cura di +AstronautiCAST qui:
https://www.astronautinews.it/tag/logbook
(Trad FR) Traduction en français par +Anne Cpamoa ici:
https://spacetux.org/cpamoa/category/traductions/logbook-samantha
(Trad ES – Currently not updated) Tradducción en español aquí:
https://www.intervidia.com/category/bitacora
17/01/2015