The Effect of Mission Duration on LISA Science Objectives

TL;DR

This paper evaluates how extending the LISA mission duration from 3 to 6 years enhances its scientific objectives, especially in black hole research, based on performance constraints and observational scenarios.

Contribution

It provides an assessment of the scientific benefits of increasing LISA's mission duration, recommending a 6-year extension to maximize science return.

Findings

Extending to 6 years improves detection of seed black holes.

Longer mission enhances stellar-origin black hole studies.

Mission extension increases overall scientific yield.

Abstract

The science objectives of the LISA mission have been defined under the implicit assumption of a 4 yr continuous data stream. Based on the performance of LISA Pathfinder, it is now expected that LISA will have a duty cycle of $\approx 0.75$, which would reduce the effective span of usable data to 3 yr. This paper reports the results of a study by the LISA Science Group, which was charged with assessing the additional science return of increasing the mission lifetime. We explore various observational scenarios to assess the impact of mission duration on the main science objectives of the mission. We find that the science investigations most affected by mission duration concern the search for seed black holes at cosmic dawn, as well as the study of stellar-origin black holes and of their formation channels via multi-band and multi-messenger observations. We conclude that an extension to 6 yr of mission operations is recommended.