The prospects of detection of SuperGZK neutrinos in the space experiments such as EUSO and OWL is a challenge to theoretical physics. Can particles be accelerated to energies higher than 10²¹ eV to create neutrinos beyond 10²⁰ eV? Are there other mechanisms of production SuperGZK particles? What are fluxes and upper limits?

SuperGZK neutrinos are testing mostly the physics beyond the Standard Model: Topological Defects, Superheavy Dark Matter and Mirror Neutrinos. These sources can provide energies and fluxes detectable by space detectors. The lower limit to SuperGZK neutrino fluxes is given by neutrinos accompaning the GZK cutoff. Their fluxes can be calculated in the models which explain the observed UHECR fluxes. The topics above will be quantitatively discussed.