The two main advantages of space-based observation of extreme energy
(ā³5Ć1019 eV) cosmic rays (EECRs) over ground based
observatories are the increased field of view and the full-sky coverage with
nearly uniform systematics across the entire sky. The former guarantees
increased statistics, whereas the latter enables a clean partitioning of the
sky into spherical harmonics. The discovery of anisotropies would help to
identify the long sought origin of EECRs. We begin an investigation of the
reach of a full-sky space-based experiment such as EUSO to detect anisotropies
in the extreme-energy cosmic-ray sky compared to ground based partial-sky
experiments such as the Pierre Auger Observatory and Telescope Array. The
technique is explained here, and simulations for a Universe with just two
nonzero multipoles, monopole plus either dipole or quadrupole, are presented.
These simulations quantify the advantages of space-based, all-sky coverage.Comment: 11 pages, 8 figure