of the sky. It was installed (with initial configuration) at the pole in January 2015. It was upgraded for the 2015-2016 Austral summer season to a full 2560 detector configuration. BICEP3 is also a prototype for the BICEP Array. BICEP Array The Keck array is being succeeded by the BICEP array, which consists of four BICEP3-like telescopes on a common mount, operating at 30/40, 95, 150 and 220/270 GHz. Installation began between the 2017 and 2018 observing seasons. It is scheduled to be fully installed by the 2020 observing season. According to the project website: "BICEP Array will measure the polarized sky in five frequency bands to reach an ultimate sensitivity to the amplitude of IGW [inflationary gravitational waves] of σ(r) < 0.005" and "This measurement will be a definitive test of slow-roll models of inflation, which generally predict a gravitational-wave signal above approximately 0.01." See also Cosmology Inflation (cosmology) Atacama Cosmology Telescope South Pole Telescope Cosmology Large Angular Scale Surveyor POLARBEAR LiteBIRD, space-based CMB B-mode polarization search project Spider, balloon-based CMB B-mode polarization project References External links BICEP2 winter-over (2009–2012) Steffen Richter (9 winters at the South Pole). Keck winter-over (2010-current) Robert Schwarz (12 winters at the South Pole). Radio telescopes Physics experiments Cosmic microwave background experiments Astronomical experiments in the Antarctic Inflation (cosmology)