Thermal Investigation of a Purged Insulation System for a Reusable Cryogenic Tank

To advance reusable space transportation vehicles with cryogenic tanks for future space missions, a reliable thermal management system must be developed. To do so, the challenge of insulating the propellant while at the same time protecting the structure against reentry heat loads needs to be addressed. A possible insulation design including a structural fixation element for the thermal protection system was developed as part of the German Aerospace Center project AKIRA. As a key feature a purged gap was implemented between cryogenic and high-temperature insulation to reduce overall layer thickness. Thermal experiments simulating both steady-state refueling phase and transient reentry phase proved that the defined thermal boundary conditions of the reference configuration could be met. The insulation system design is outlined in brief and both the experimental setup and the test results are presented and discussed.