Telescope jitters and phase noise in the LISA interferometer.

Area of Science:

• Astrophysics
• Space Science
• Gravitational Wave Detection

Background:

• The Laser Interferometer Space Antenna (LISA) is a planned space-based observatory designed to detect gravitational waves.
• LISA will consist of a constellation of three spacecraft forming a giant interferometer with 2.5 million km arm lengths.
• Precise measurement of these arm lengths is crucial for detecting minute gravitational wave-induced changes.

Purpose of the Study:

• To investigate the end-to-end measurement noise in the LISA constellation.
• To quantify the impact of telescope jitters and wavefront aberrations on measurement sensitivity.
• To establish critical requirements for optical performance to achieve LISA's scientific goals.

Main Methods:

• Simulated end-to-end analysis of the LISA measurement system.
• Modeling the interaction between telescope pointing errors (jitters) and optical wavefront distortions (aberrations).
• Heterodyning of received laser wavefronts with local references for arm length measurement.

Main Results:

• Telescope jitters and wavefront aberrations are significant sources of measurement noise for LISA.
• To meet the mission's picometer-level sensitivity requirement, root-mean-square wavefront aberrations must be controlled to less than λ/65.
• This finding highlights the critical importance of high-precision optical systems and stable spacecraft pointing.

Conclusions:

• The study provides essential insights into the optical noise budget for the Laser Interferometer Space Antenna.
• Maintaining wavefront quality below λ/65 is a key requirement for achieving LISA's gravitational wave detection objectives.
• The results inform the design and engineering of LISA's optical payload and spacecraft control systems.