FutureLiteBIRD: The Lite (Light) satellite for the study of B-mode polarization and Inflation from cosmic background Radiation Detection

LiteBIRD will search for the evidence of cosmic inflation in the early Big Bang universe through high sensitivity measurements of the cosmic microwave background (CMB) polarization signal across the entire sky.

Infrared astrometric observation satellite JASMINE WSO-UV: World Space Observatory UV

The mission of LiteBIRD is to uncover the origins of the universe and how it began. The Big Bang theory of the universe is now widely accepted after the accumulation of empirical evidence from many prior satellite and ground-based experiments. But the Big Bang alone cannot fully explain the evolution of the current universe or what happened in the earliest moments of time. The addition of the theory of cosmic inflation, a short period of rapid exponential expansion of space in the early universe, is the prevailing theory that can explain these shortfalls. The LiteBIRD mission aims to find evidence of cosmic inflation through observations of the cosmic microwave background (CMB).

The CMB radiation is remnant light from when the early universe was still a hot plasma. The CMB is very uniform up to approximately one part in 100,000, but these faint variations or anisotropies allow us to accurately probe the earliest state of the universe. Inflation is theorized to create unique primordial gravitational waves that imprint a distinct pattern in the CMB’s polarization signal called the primordial B-modes. These B-modes are “smoking-gun” evidence of cosmic inflation.

The LiteBIRD mission will aim to detect the primordial B-mode signal through developing a CMB satellite with three millimeter-wave polarization-sensitive telescopes installed. The LiteBIRD satellite will observe the entire sky for 3 years at the Sun-Earth Lagrangian point L2 in space. LiteBIRD will achieve unprecedented sensitivities through implementing in total approximately 4,500 transition edge sensor detectors across 15 observational frequency bands and will be capable of distinguishing between the CMB and foreground (dust, synchrotron radiation, etc.) signals. The telescope will be cryogenically cooled to 5 K low temperatures to reduce thermal noise. LiteBIRD will uniformly observe the entire sky with its wide field-of-view and optimized scan strategy utilizing the satellite’s spin.

LiteBIRD is a JAXA-led international mission in collaboration with various space agencies and research institutions around the world such as CNES, ESA, and CSA. The domestic collaborators include KEK, the University of Tokyo, and Okayama University. LiteBIRD is expected to launch in the late 2020s.