ESA Intended Invitation To Tender

15.164.03


Title: MREP 2 - PHOOTPRINT THRUSTER PLUME AND SURFACE INTERACTION TESTING FACILITY DEVELOPMENT AND THRUSTER CHARACTERIZATION
Program ref.: AURORA MREP-2 S.E.2;TRP;AURORA MREP-2 S.E.2
Tender Type: C
Quarter: 151
Tender Status: INTENDED
Price Range: KEURO
Budget Ref.: E/0432-01 - AURORA MREP-2 S.E.2; E/0901-01 - TRP; E/0432-01 - AURORA MREP-2 S.E.2
Proc. Prop.: DIPC
Special Prov.: AT+CZ+IT+NO+PL+PT+RO+SE+CH+GB
Establishment: ESTEC
Directorate: Directorate of Science
Department: Future Missions Office
Responsible: Safa, Frederic
Publication Date: 18-MAR-16

Plume/Regolith interaction studies are vitally important as the interaction of the hovering and landing plumes with Phobos regolithcan have a severe impact on mission objectives and vehicle/engine performance. Once commissioned, the facility will be in a positionto provide: -assessment of scaling phenomena, vacuum effects and pulsing of rockets; -the erosion effect of the plume impingement onthe Phobos surface; -the lateral extent and depth of regolith contamination due to rocket plumes -the impact of the plume/regolithinteraction on the spacecraft force and torque balance The plume/regolith interaction facility will be defined later based on trade-offs during the design phase of the study. It will be sufficiently sized to study thrusters and is a trade off between the level of vacuum required and the mass flux due to the thruster. The facility will allow the installation of a representative engine nozzleconfiguration vertically. It will be instrumented with fast response pressure transducers, accelerometers and thermocouples. The temperature and pressure of the chamber will be continuously monitored before, during and after the end of a test. An adjustable altitude system will be employed to allow variation of the vertical height of the nozzles inlet above the regolith surface. This activitywill be undertaken in two technical phases. Phase1 will encompass the requirements definition, design and manufacture of the facility.Following the successful acceptance of the facility, Phase 1 will be concluded. Phase 2 covers the validation of the facilityusinghot fire testing and a test matrix that will cover the needs of the Phootprint project. The Phootprint spacecraft will switchoffretro rockets at altitude (baseline 15m) and will have a hard landing. It is therefore assumed that there will be no strong plume surface interaction and therefore no significant site alteration from the thrusters plumes is expected (i.e. no soil blown from the plumes). However, some particles emitted from the thrusters before free-fall are expected to contaminate the landing site. This has science implications as chemical contamination of the sample is not wanted. The current science requirement with that respect is:"Thenumber of contaminating molecules deposited on the asteroid surface by the propulsion system shall be lower than 10^14/cm2". In order toconsolidate the system trade between altitude of free fall and sample contamination by thrusters, characterisation in vacuum of surface contamination from thrusters at several heights is needed, as well as correlation with models, in order to allow making reliable predictions of soil contamination for several thruster and altitude configurations. the outcome will be the appropriate sticking factors (species mass fraction > 5%), force and contamination distribution on the surface. The test will be further supplementedwith numerical tests using DSMC codes to recover the forces and contamination found during experiments.