Data Combinations Accounting for LISA Spacecraft Motion

TL;DR

This paper introduces generalized data combinations for the LISA gravitational wave detector that effectively cancel laser noise despite spacecraft motion, maintaining sensitivity similar to stationary configurations.

Contribution

It presents new generalized Michelson- and Sagnac-type data combinations that account for spacecraft motion and varying delays, enhancing LISA's noise cancellation capabilities.

Findings

Generalized combinations cancel laser phase noise with moving spacecraft.

Sensitivity remains comparable to stationary configurations.

Diagrammatic method illustrates synthesized equal-arm interferometers.

Abstract

LISA is an array of three spacecraft in an approximately equilateral triangle configuration which will be used as a low-frequency gravitational wave detector. We present here new generalizations of the Michelson- and Sagnac-type time-delay interferometry data combinations. These combinations cancel laser phase noise in the presence of different up and down propagation delays in each arm of the array, and slowly varying systematic motion of the spacecraft. The gravitational wave sensitivities of these generalized combinations are the same as previously computed for the stationary cases, although the combinations are now more complicated. We introduce a diagrammatic representation to illustrate that these combinations are actually synthesized equal-arm interferometers.