(8A) Experimental consolidation of design and free-fall performance for the LISA gravitational reference system (Accordo n.2024-36-HH.0, CUP F63C24000390001 “Attività per la fase B2/C della missione LISA”)
Funding institution: Provincia Autonoma di Trento-Atto di indirizzo 2026-2028 & Department of Physics, University of Trento
Doctoral site: University of Trento
Contact: William Joseph Weber [williamjoseph.weber@unitn.it]; Giacomo Ciani [giacomo.ciani@unitn.it]; Rita Dolesi [rita.dolesi@unitn.it]
Funds: Institutional Funds / Project Funds
Mobility abroad: compulsory, minimum 6 months
Periods in companies/research centres/public administrations: optional
The LISA observatory depends on the nearly perfect free-fall of a constellation of free-falling geodesic reference test masses, with stray accelerations limited to the femto-m/s2 level, to trace the gravitational wave tidal deformation from super massive black hole mergers and other signals from the milliHertz gravitational wave sky. This sets the low frequency sensitivity of the observatory and thus the LISA science return. LISA is now in the implementation phase, working towards launch in 2035, and these next several years represent the critical phase of experimental verification of the baseline design for the free-falling test mass system, known as the “Gravitational Reference System” (GRS), that is the Italian (ASI) contribution to the ESA LISA mission. The proposed doctoral research will contribute to this final phase of design optimization and laboratory testing before the flight hardware definition and production, with key analyses and experiments that can impact the last design choices, integration processes, experimental performance model, and in-orbit operations procedures. Specific measurement science objectives can include forces from molecular impacts, stray electrostatic fields, noise in electrostatic force actuation systems, gravitational balancing, photoelectric discharge, and other electromagnetic effects. Laboratory opportunities will include small force (sub-femto-Newton) measurement with torsion pendulums, low noise electronics tests, sub-femtoAmpere photocurrent measurement, and quantitative tests of both secularly decaying and transient desorption phenomena. Dedicated analysis campaigns will support the analysis and interpretation of the laboratory results, with electrostatic modelling, photoelectric charge transfer, molecular flow, and low noise circuitry. As part of the Trento GRS PI team, the doctoral student will have possibilities for intense collaboration with our industrial partner (OHB-Milano), the ESA LISA project team, and partner labs in Europe and in the US.