Planned CMB Satellite Mission Overview

I will summarize space missions that are in the planning stage to measure the polarized spatial fluctuations of the cosmic microwave background (CMB). Space missions are complementary to ground-based observatories. First, the absence of atmospheric emission results in a wider range of frequencies that can be observed, which in turn improves removal of galactic foreground emission. Second, the stable observations possible from space give high-fidelity measurements at angular scales of tens of degrees where inflation theory predicts a peak in the B-mode angular power spectrum. Robust detection of both this ``reionization" peak and the ``recombination" peak at degree angular scales will give the most convincing case that the fingerprints of inflation have been detected. CMB polarization space missions in the planning stage include CORE+, LiteBIRD, and PIXIE. Science goals for all these missions include the detection and characterization of inflation and the characterization of the reionization epoch. CORE+ and LiteBIRD are imaging telescopes with sub-Kelvin superconducting focal-plane detector arrays with several thousand detectors. PIXIE is a two-beam differential spectrometer that will measure the Planck spectrum of the CMB in addition to searching for inflation.