Two more days to go before my stay in space will end. I managed to complete three important tasks before I have to leave. I inspected cooling fluid valves for the Columbus laboratory, fixed an American scientific experiment rack and worked on the Japanese Ryutai rack. We do many maintenance tasks in the ISS. Maintenance must be done in a timely fashion to assure that the Space Station is used optimally for our scientific experiments.

WOOV

In my schedule the Columbus maintenance was marked as WOOV, cooling systems Water On Off Valves. Previous crew had repaired a corroded valve. I had to check if the other valves in the Temperature Control System were corroded. I had to prepare thoroughly. We want to avoid releasing

chemicals so the ventilation was turned off and I had to wear gloves, safety glasses and a mask. The situation was better than expected. The valves were fine.

I also loaded new software in one of the faulty Express racks so that it can be used again. There are five Express racks in three different modules on the Space Station.  Express racks are American racks that can hold many experiments. To conclude the procedure I had to work with three laptops and many cables. I was continuously in contact with NASA’s technical specialists in Huntsville. We went through the complicated procedures without any problems.

False alarm

In between the repair work we had to deal with a number of false alarms. There are three types of alarms on board: a caution, a warning and an emergency. An emergency is the worst type as it means that something is threatening the safety of the crew, for example a hole in the ISS, a fire or ammonium leaking from the cooling system. We had to deal with cautions and warnings this time. A caution means we have to attend to an experiment or hardware or else

data may be lost. A warning means that there is a problem with the station. We might have lost electricity for example, or the attitude control systems might have stopped working.

When an alarm goes off our adrenaline shoots up. The cause of an alarm is unknown and it has to be found quickly. In this case they turned out to be false alarms, caused by a problem in the warning system of the Russian segment. The Russians are working hard to fix the problem. If an alarm sounds several times without a valid reason you start to take it less seriously after a while. And that is not good for safety on board.