Survey of Software Problems with Impacts to “Campout” Protocol Extravehicular Activity Prebreathe

During International Space Station (ISS) campout protocol extravehicular activity preparations, the crew is isolated overnight in a small airlock volume in a reduced-pressure, oxygen-enriched atmosphere. Special software considerations must therefore be taken into account in terms of air composition, pressure control, and emergency responses. First, the ISS software must monitor and manage two distinct atmospheres. The small airlock volume is also especially sensitive to small environmental changes, so what would be a minor emergency in the larger vehicle volume can have catastrophic results in the isolated airlock. Finally, in cases of emergency, the crew would need to rapidly egress the airlock, which would require an aggressive automatic repressurization to equalize pressure on the hatch.

This paper describes the software that is modified for the airlock campout protocol. The paper also describes the software and hardware problems with software workarounds that have affected campout protocol.