Analysis Of The Impact Of Major Environmental Disturbances On Space Gravitational Reference Sensor

Laser Interferometer Space Antenna（LISA）is a space-borne gravitational waves observatory,which will study and figure out the entire universe through gravitational waves,and establish a foundation for the creation of gravitational wave astronomy.The design of LISA requires that the non-gravitational acceleration noise of the test mass（TM）at the sensitive axis in each spacecraft is below 3.0×10^-15m/s²/Hz^1/2,ranging from0.1m Hz to 0.1Hz.In order to verify some extremely challenging key technologies of LISA,European Space Agency launched the LISA Pathfinder（LPF）mission,which put the TMs of millions of kilometers apart in LISA into a spacecraft,so it couldn’t detect gravitational waves.Due to the conservative estimation of the environmental disturbances and spacecraft level,the bandwidth of LISA Pathfinder changed slightly.The requirement of non-gravitational acceleration disturbance on the TM was also reduced,which was designed to be lower than 30×10^-15m/s²/Hz^1/2,varying from 3m Hz to0.1Hz.LISA Pathfinder was finally launched on December 3,2015,and all experiments were completed on June 30,2017.The results of it show that the non-gravitational acceleration on the TM is much lower than expected and fully meets the requirements of LISA.The main acceleration noise sources in the gravitational reference sensor in LISA an LISA Pathfinder are summarized here,including circuit noises,stiffness disturbances and environmental disturbances.This paper focuses on the detailed estimation and calculation of various environmental disturbances in LISA Pathfinder,such as the Brownian noise generated by the random collision of residual gas molecules around TM,charge noise caused by the interaction between TM random charging and average stray voltage imbalance,thermal noise raised by temperature gradient fluctuations around the TM.In addition,considering the test results of LISA Pathfinder and some ground torsion pendulum experiments,the various environmental noises are compared here.Brownian noise is mainly related to pressure;the charge management of LPF has basically met the requirements of LISA,the contribution of temperature effects has estimated.The flight test of LPF demonstrates that it has achieved residual acceleration noise levels of（1.74±0.01）×10^-15m/s²/Hz^1/2,from 2m Hz to 30m Hz.A detailed description of whether LISA Pathfinder meets the requirements of LISA,can provide some suggestions for the future space-borne gravitational waves observatory LISA/Tian Qin.