Concept for Space-Based Dual-Spacecraft Astrometry to Detect Low-Frequency Gravitational Waves

This innovative approach involves quantum two-photon interference between two spacecraft operating without optical links, simplifying mission design compared to traditional interferometry. The technique aims to detect gravitational waves in the micro- to nano-Hertz band by measuring correlated apparent motions of celestial objects as the waves pass Earth.

Such detection would fill a current observational gap in gravitational wave astronomy, offering insight into galaxy formation and supermassive black hole physics. Conceptual mission designs suggest feasibility using two modest spacecraft in free-fall orbits achieving astronomically interesting sensitivity levels.