Cosmic Microwave Background Science at Commercial Airline Altitudes
  Obtaining high-sensitivity measurements of degree-scale cosmic microwave
background (CMB) polarization is the most direct path to detecting primordial
gravitational waves. Robustly recovering any primordial signal from the
dominant foreground emission will require high-fidelity observations at
multiple frequencies, with excellent control of systematics. We explore the
potential for a new platform for CMB observations, the Airlander 10 hybrid air
vehicle, to perform this task. We show that the Airlander 10 platform,
operating at commercial airline altitudes, is well-suited to mapping
frequencies above 220 GHz, which are critical for cleaning CMB maps of dust
emission. Optimizing the distribution of detectors across frequencies, we
forecast the ability of Airlander 10 to clean foregrounds of varying complexity
as a function of altitude, demonstrating its complementarity with both existing
(Planck) and ongoing (C-BASS) foreground observations. This novel platform
could play a key role in defining our ultimate view of the polarized microwave
sky.
