The astronauts encountered problems when they came to replace the ammonia pump in the broken cooling system of the International Space Station

The astronauts on the space station failed to separate one of the pipes carrying ammonia from the pump to the station's cooling system and an ammonia leak occurred. Today's spacewalk was the first of two. The second is planned for Wednesday, but it may be necessary to reschedule following the malfunctions

The two flight engineers of the 24th crew of the International Space Station, Doug Wilcock and Tracy Caldwell Dyson, returned to the Quest airship around 22:00 PM Israel time, after a partial success in their mission. The two began this morning at 07:20 (14:20 Israel time) the first of two spacewalks during which they will focus on removing the ammonia pump that broke down last Saturday and placing the replacement pump in its place.
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The tasks for today included removing the pump module from component S1 and removing the spare part from the storage facility outside the station. The mission took about seven hours. Installation and commissioning of the new pump is scheduled for the second spacewalk on Wednesday around XNUMX am EST.

After applying more pressure and trying several techniques, Wilcock continued to have trouble trying to disconnect one of the three ammonia lines from the broken pump on the S1 component. Instead he went ahead and disconnected one of the two cooling lines. Two coolant lines must be connected to the rig to maintain the correct coolant pressure in the adjacent ammonia tank during replacement of the correct pump with the replacement pump.

However, as a result of an ammonia leak in the last line that was supposed to be disconnected, the crews decided to connect the line to the pump and install a connection device to maintain normal pressure in the ammonia line. At this point, the control center personnel ordered Wilcock and Caldwell to stop performing the spacewalk missions planned for today and instead "bake" the remaining ammonia flakes that escaped from the leaking lines. They will also use the Quest airlock to clean all the ammonia residue that has stuck to their suits. Crews on the ground will assess today's events and prepare for the second planned spacewalk.

Wilcock, the number one member of the spacewalk crew wears the spacesuit with the red ribbons. This is the fourth spacewalk of his career. Dyson, spacewalker number 2 wears a space suit with no special markings and this is her first spacewalk. Flight engineer Shannon Walker operates the station's robotic arm and transports the spacewalkers out of the station.

The first spacewalk to repair the ammonia pump was planned for Friday, but the mission managers decided that an extra day was needed to finish the work on the details. The extra time allowed NASA to broadcast the planned processes to the station as early as Thursday to give them a full day to review the plans developed by members of the control center, engineers and spacewalk and robotics experts. Administrators also decided to postpone the second spacewalk to Wednesday to give crew members time to rest and prepare.

After the failure of one of the two cooling pumps on July 31, ground controllers turned off non-essential systems to provide sufficient cooling redundancy at the station. The space station is in stable condition and engineers continue to review the data from the malfunctioning pump.