Getting to know the neighbours: Earth analogues in Alpha Centauri with the TOLIMAN space telescope

The TOLIMAN mission will fly a low-cost space telescope designed and led from the University of Sydney. Its primary science targets an audacious outcome in planetary astrophysics: an exhaustive search for temperate-orbit rocky planets around either star in the Alpha Centauri AB binary, our nearest neighbour star system. By performing narrow-angle astrometric monitoring of the binary at extreme precision, any exoplanets betray their presence by gravitationally, engraving a tell-tale perturbation on the orbit. Recovery of this challenging signal, only of order micro-arcseconds of deflection, is normally thought to require a large (meter-class) instrument. By implementing significant innovations optical and signal encoding architecture, the TOLIMAN space telescope aims to recover such signals with a telescope aperture of only a 12.5cm. Here we describe the key features of the mission: its optics, signal encoding and the 16U CubeSat spacecraft bus in which the science payload is housed - all of which are now under construction. With science operations forecast on a timescale of a year, TOLIMAN aims to determine if the Sun’s nearest neighbour hosts a potential planetary stepping stone into the galaxy. Success would lay down a visionary challenge for futuristic high speed probe technologies capable of traversing the interstellar voids.