Shuttle Water Spray Boiler Flight Performance

The Water Spray Boiler (WSB) is a completely self-contained system which provides an expendable heat sink for each Shuttle Orbiter Hydraulic System and Auxiliary Power Unit (APU). At the heart of the system is the tube-bundle boiler which rejects heat by pool boiling on the ground and by impingement spray boiling in space. This paper describes the system and addresses flight performance during STS-1, STS-2, and STS-3.