LARGE SCIENTIFIC PROJECT
LISA
Figure 3. LISA satellite and payload critical technologies.
Finally, low noise photoreceivers and their associated readout electronics are required to detect weak heterodyne signals with high linearity and long-term stability. Shot noise, electronic noise, and parasitic couplings must remain below the allocated displacement noise budget, ensuring that they do not limit the GWs measurement sensitivity. Dedicated performance tests of the Optical Metrology System( OMS) will support the qualification of LISA’ s critical interferometric technologies. These tests must confirm that the end-to-end detection noise meets the ~ 10 pm / √Hz requirement. Using specialized optical, electrical and mechanical ground-support equipment under controlled thermal and mechanical conditions, they will characterize optical pathlength stability, readout noise, stray-light mitigation and the tilt-to-length coupling effects. These activities are crucial for consolidating the OMS noise budget, ensuring compliance with mission requirements, and reducing risk before system-level integration.
Conclusions
LISA brings together an unprecedented combination of ultra-stable interferometry, near-ideal inertial references, drag-free spacecraft control, and advanced signal processing to probe the low-frequency GWs Universe. The mission performance emerges from the coherent integration of these technologies, each operating at the edge of what is achievable in space. By successfully
REFERENCES mastering laser stability, precision optics, stray-light control, time-delay interferometry, TM free fall and micro propulsion, LISA opens a new observational window on the Universe, enabling the direct exploration of gravitational phenomena inaccessible by any other means. It is remarkable that this effort, as well as the effort aiming at the processing and interpretation of the future GWs readout data, is indeed pursued by a collaboration of ~ 10 space agencies, ~ 40 nations and ~ 1700 scientists throughout the world.
[ 1 ] A. Einstein, Sitzungsberichte der Königlich Preußischen Akademie der Wissenschaften( Berlin), 7, 154( 1918)
[ 2 ] LVK( LIGO, Virgo, KAGRA collaboration), GWTC-4.0: An Introduction to Version 4.0 of the Gravitational Wave Transient Catalog, LIGO-P2400293-v13,( 2025) https:// dcc. ligo. org / LIGO-P2400293 / public
[ 3 ] P. L. Bender, J. E. Faller, J. L. Hall, D. Hils, R. T. Stebbins and M. A. Vincent, NASA- Optical Interferometer in Space N90-19953 80, 12( 1989)
[ 4 ] M. Armano, H. Audley, G. Auger et al., Phys. Rev. Letters 116, 231101( 2016)
[ 5 ] K. Danzmann et al., LISA- A proposal in response to the ESA call for the L3 mission concepts, European Space Agency( 2017)
[ 6 ] LISA Science Study Team, ESA Study Team, et al., LISA Definition Study Report( Red Book), ESA / NASA LISA Study Report( 2024)
66 www. photoniques. com I Photoniques 137