# New LISA dynamics feedback control scheme: Common-mode isolation of test mass control and probes of test-mass acceleration

**Authors:** Henri Inchauspé, Martin Hewitson, Orion Sauter, Peter Wass  
**arXiv:** [2202.12735](https://arxiv.org/abs/2202.12735)  
**Date:** 2022-02-25  
**Summary page:** https://www.summarizepaper.com/en/paper/2202.12735v2/

## Key points

- The Drag-Free and Attitude Control System is critical for maintaining high dynamic stability of spacecraft and test masses in LISA technology.
- Minimizing electrostatic forces on test masses is crucial for optimal quality of free-fall and system stability.
- Henri Inchauspé, Martin Hewitson, Orion Sauter, and Peter Wass propose a new test-mass suspension scheme that reduces suspension forces and torques by applying proportional forces to observed differential test mass motion.
- A mathematical method introduced by the authors measures differential acceleration of test masses projected on sensitive axes, enhancing data calibration, processing, and analysis for gravitational wave signals detected by the spacecraft.
- The research presents a novel dynamics feedback control scheme that isolates common-mode effects in test mass control and provides valuable insights into probing test-mass acceleration within the LISA system.

## Summary

The Drag-Free and Attitude Control System is a critical component of LISA technology, essential for maintaining the high dynamic stability of spacecraft and test masses. This is necessary to achieve the sensitivity required for gravitational wave astronomy in space. However, minimizing the application of electrostatic forces on test masses is crucial to ensure optimal quality of free-fall while keeping the spacecraft-test masses system in place. In their study, Henri Inchauspé, Martin Hewitson, Orion Sauter, and Peter Wass propose a new test-mass suspension scheme that applies forces and torques proportionally to any observed differential test mass motion. This innovative approach significantly reduces the amount of suspension forces and torques needed to control the entire system, leading to improved efficiency and performance. Additionally, the authors introduce a mathematical method for deriving a new observable that measures the differential acceleration of test masses projected on sensitive axes. This has important implications for LISA data calibration, processing, and analysis as it enhances our understanding of gravitational wave signals detected by the spacecraft. Overall, this research presents a novel dynamics feedback control scheme that isolates common-mode effects in test mass control and provides valuable insights into probing test-mass acceleration within the LISA system. The findings contribute to advancing our capabilities in gravitational wave astronomy and optimizing spacecraft operations in space.