5.1 Planet finders: Gaia, TESS and PLATO
These latest missions can be split into two categories: planet finders, and characterisation observatories. One planet-finding mission, TESS, launched in March 2018, is already starting to discover new planets. Gaia is also operational, and has been collecting data on over a billion stars since 2014. Another mission, PLATO, is due to launch in 2026.