Objective:The objective is to develop materials and techniques to increase the demisability of high pressure vessels for LEO satcoms.
Targeted Improvements:Reduction by 20% to 30% of the casualty area for LEO Telecommunication satellites.
Description:Since March 2014 (ESA IPOL-2014-002e), all ESA satellites and launcher upper stages which have to be disposed of by atmospheric re-entry atthe end of their operational life must demonstrate that the risk from fragments surviving the re-entry and causing casualties on ground is less than 1 in 10,000.
Surviving tanks can account for up to 30% of the total spacecraft casualty risk so demisable high pressure vessels would facilitate compliance with the requirement.
Within the last five years, several remains of Composite OverwrappedPressure Vessel (COPV) have been found on ground after atmospheric re-entry events, which lead to classify COPV as critical items foratmospheric re-entry events. This classification was further supported by Cleansat studies results and Plasma Wind Tunnel (PWT) tests where composite materials showed complex demise behaviour. In the proposed activity, a high pressure tank used on satcoms will beselected as baseline (Volume 60-120 L, Maximum Expected Operating Pressure 300 bar).
Possible design changes to the high pressure tank with the goal of improving demise behaviour while fulfilling the mission requirements will be proposed. Such techniques could involve different fibre or resin materials, different fiber configurations (e.g. short fibers) with improved thermal conductivity (across the layers and non-metallic liners. Monolithic options in demisable materials could be investigated, but equivalent performance to the baseline would need to be achieved.
Demisability tests at sample level will be used to justify the material and process tradeoff. Re-entry simulations of the various concepts will be performed based on test results (at material level) and material thermo-physical properties.
A breadboard tank shall be designed, manufactured and environmentally tested to ensure compliance with thermal and mechanical requirements.
Future steps for adoption of the new high pressure tank design in future LEO Telecommunication satellitesshall be presented.