Three Stellar Years (and Counting) of Precision Photometry by the Brite Astronomy Constellation

The mission of the Bright Target Explorer (BRITE) Constellation, comprised of five nearly identical seven-kilogram nanosatellites, is to study the most luminous stars in the Earth’s sky. Typically massive and short lived, through their turbulent lives and via their especially violent deaths as supernovae, these stars dominate the ecology of the Universe and are responsible for seeding the interstellar medium with elements critical for the formation of planetary systems and organic life. Using 3cm aperture telescopes for photometry, BRITE-Constellation measures stellar brightness variations in two colours, with high cadence over baselines of up to six-months. The milli-magnitude precision it has achieved is at least ten times better than what is currently possible using ground based observatories. These precise measurements of stellar variability are used to probe the internal and surface (sun spot) structures, ages, and potentially even planetary systems (via transit detection) of these massive luminous stars. BRITE-Constellation, which was launched into orbit in 2013 and 2014, was developed by the Space Flight Laboratory (SFL) in collaboration with astronomers and engineers from Canada, Austria and Poland. The constellation is believed to be the first satellite constellation dedicated to astronomy and boasts not just the smallest astronomy satellites ever flown, but also the first spacecraft at this scale to achieve arc-second level pointing. The BRITE-Constellation spacecraft are commissioned, fully-operational, and meeting or exceeding all mission requirements including the instrument’s limiting visual magnitude, attitude pointing & stability, observation time per orbit, and up-time. This paper describes the goals, design, on-orbit performance, and highlights the rich scientific returns of this cutting-edge mission