NASA announced that it was considering spacewalks or a resupply mission to address the failure of one of the two redundant coolant systems on the International Space Station (ISS). There are troubleshooting efforts underway to determine how the valve, believed to be the source of the problem in the pump outside of the $100 billion laboratory on the station, could best be repaired. NASA representatives have stressed that the problem is with one of two redundant systems. All non-essential equipment was shut down, including a few experiments which had to be halted. The ISS crew are reported as being safe and comfortable.
In order to be ready for a Tuesday move to the launching pad, some time-sensitive cargo was put on board the Cygnus rocket potentially being sent on a re-supply mission. The earliest possible launch for the re-supply would be during a five-minute window of opportunity beginning at 9:19 p.m. Eastern Standard Time (EST) Thursday evening, with a number of windows available to them over the next couple of days. If it is determined before that point that spacewalks will suffice to address the problem, they will begin on Thursday in lieu of the re-supply.
Astronauts on board the ISS are beginning preparations now for the possibility of having to conduct spacewalks to repair the damaged pump valve. In 2010, there was a failure of the same pump which was fixed by way of three spacewalks. It is estimated that it would require the same to complete the repairs believed to be needed at this point. NASA is only considering spacewalks if they will be reasonably safe to undertake, and if the equipment and tools needed to do the job are available to them on the ISS.
The external cooling loops are systems that circulate ammonia on the outside of the station in order to keep the electrical equipment, which constantly generates heat, cool enough to operate at peak efficiency. NASA representatives insist that the repair process is one that all of the astronauts have trained for, and that the team on board is more than capable of handling the operation should it be required of them. It has not yet been reported whether or not the experiments which had to be suspended will able to be safely re-started once repairs are made. If they will need to be abandoned, it is not known how much of a financial loss the termination of those projects will represent. Regardless, NASA has not even suggested any course of action which did not have the utmost safety of the six-man crew as first priority.
NASA is expected to post a potential launch schedule at some point on Monday, in case that option is decided upon. While the first window is Thursday night, several more will be available over the days following. NASA will not rush the undertaking unless the safety of the astronauts aboard becomes progressively less safe or secure. Ideally, the situation aboard the ISS can be resolved with the spacewalks, but NASA continues considering all of its options.
By Jim Malone