LiteBIRD

A JAXA-led satellite to map CMBcosmic microwave backgroundThermal radiation released 380,000 years after the Big Bang, now at 2.7255 K and peaking near 160 GHz. Its temperature and polarisation anisotropies, at the 10⁻⁵ level, constrain the content and geometry of the Universe. polarisationpolarimetryMeasuring the polarisation of incoming radiation. It encodes magnetic-field geometry, scattering and emission mechanisms; in the CMB it separates E- and B-mode patterns. over the whole sky from L2Lagrange pointA point where the gravity of two bodies and the orbital motion balance. Sun–Earth L2, 1.5 million km beyond Earth, keeps Sun, Earth and Moon on one side: a stable thermal environment for passive cooling and an unobstructed view of most of the sky. between 34 and 448 GHz with about 4,000 superconducting detectors (15 bands in the 2023 design; JAXA now lists 12). It searches for primordial B-modesB-modesThe curl-like component of CMB polarisation. On degree scales, primordial gravitational waves from inflation would produce it; its amplitude is quoted as the tensor-to-scalar ratio r., testing the energy scale of inflationinflationA proposed epoch of exponential expansion in the first fraction of a second, which would have seeded the density fluctuations seen in the CMB and galaxy distribution..

Operator

JAXA

Orbit

Sun–Earth L2

Passband

34 GHz – 448 GHz

Launch

2036 (target)