Application of LISA Gravitational Reference Sensor Hardware to Future Intersatellite Geodesy Missions

Abstract

Like gravitational wave detection, inter-spacecraft geodesy is a measurement of gravitational tidal accelerations deforming a constellation of two or more orbiting reference test masses (TM). The LISA TM system requires TM in free fall with residual stray accelerations approaching the fm/s2/Hz1/2 level in the mHz band, as demonstrated in the LISA Pathfinder “Einstein’s geodesic explorer” mission. Current geodesy missions are limited by accelerometers with 100 pm/s2/Hz1/2 level, due to intrinsic design limitations, as well as the challenging low Earth orbit environment and operating conditions. A reduction in the TM acceleration noise could lead to an important improvement in the scientific return of future geodesy missions focusing on mass change, especially in a scenario with multiple pairs of geodesy satellites. We present here a preliminary assessment of how the LISA TM system, known as the “gravitational reference sensor” (GRS), could be adapted for use in future geodesy missions aiming at residual TM accelerations noise at the pm/s2/Hz1/2 level, addressing the major design issues and performance limitations. We find that such a performance is possible in a geodesy GRS that is simpler and smaller than that used for LISA, with a lighter, sub-kg TM and gaps reduced from 4 mm to less than 1 mm. Acceleration noise performance limitations will likely be closely tied to the required levels of applied actuation forces on the TM.

A single quasi-cubic test mass configuration for space-based gravitational wave detection

“…The configuration of a single quasi-cubic TM is guided by the desire to inherit the already existing and developing technologies of the LISA baseline configuration [1,[15][16][17][18][19][20]. Firstly, considering the triangular satellite configuration in LISA, the single quasi-cubic TM should have two reflecting surfaces (plane or arc) with an angle of about 60 degrees for the OMS.…”

“…The single octagonal prism TM configuration is designed to inherit the LISA existing GRS configuration and control strategy as much as possible [1,15,16]. The TM is made of a Pt-Au alloy in the shape of an octagonal prism with a length and width of about 5 cm, as shown in figure 1.…”

The role of low-energy electrons in the charging process of LISA test masses

“…The present work is also motivated to extend to GEANT4 a simulation work for LISA and, in general, for applications of LISA gravitational reference sensor hardware to geodesy missions [46,47] or for other proposed gravitational wave observatories [9][10][11]. We note that this topic has been considered of great relevance for space mission design by ESA and is the object of a current agency-funded study [48].…”

Robust Control Allocation for Space Inertial Sensor under Test Mass Release Phase with Overcritical Conditions

“…The success of these missions has greatly encouraged more scholars to research drag-free control systems. The space inertial sensor (SIS) [ 8 , 9 , 10 , 11 ] is one of the key payloads of drag-free spacecraft, which consists of a test mass as an inertial reference and a set of electrodes acting as capacitive sensors and electrostatic actuators. During the launch and the following orbital transfer phase, the test mass is locked inside the electrode house by the caging and vent mechanism (CVM).…”