“The fan and the water heating unit were on fire.”
The emergency signaling has woken up the ISS crew today at 4.55 Moscow time. In the Russian service module Zvezda, a smoke detector was triggered during automatic battery charging. The smell of burning reached the American segment of the station.
According to RIA Novosti, cosmonaut Oleg Novitsky immediately transmitted a message about the incident to the Mission Control Center (MCC). The instruments confirmed the presence of harmful substances in the station’s atmosphere. The unpleasant smell of burnt plastic or electronics penetrated from the Russian to the American segment of the ISS due to the working ventilation. This was announced by astronaut Tom Pesce.
The place of fire was not found immediately. First, on the recommendations of the MCC specialists, cosmonauts Oleg Novitsky and Petr Dubrov examined the space behind the panel in the Zvezda module, but they did not find a source of ignition. Later, Roskosmos reported that the cause of the smoke detector triggering and the activation of the alarm was a short circuit during recharging of the batteries.
As a source in the space industry told “MK”, in principle, with the rapid detection of smoke by sensors, the spread of harmful combustion products through the ventilation of the space station should have been blocked automatically. The explanation of why the automation did not turn off the ventilation on time looks like this. Most of the smoke detectors are located behind the panel space, where there are many cables hidden from the eyes of astronauts. As a rule, there are not so many smoke detectors near devices that are in plain sight in the residential module. Apparently, the short-circuited charger was located in the living compartment, at a certain distance from the smoke detector, and he could not react in time and give the command to turn off the ventilation. The sensor worked a little later.
Despite this, the fire was liquidated on time. The level of carbon monoxide in the atmosphere, which Pyotr Dubrov checked with a special device, turned out to be not dangerous for the health of the astronauts. However, the atmosphere of the station was nevertheless purified by means of onboard air purification, after which the crew went to bed again.
The fire of the wiring of the devices operating on the space station happened more than once. Over the years, it was caused by the closure of the fan blades, the heating and water supply unit and other devices. Sometimes, according to experts, smoke detectors were triggered by … ordinary dust during cleaning behind the panel space. Therefore, now astronauts temporarily turn them off during such cleaning.
At present, all systems in the Russian segment of the ISS are operating normally. Oleg Novitsky and Petr Dubrov are preparing for a spacewalk, which is to begin at 18.00 Moscow time.
.