  Supernovae are important probes of the properties of stars at high redshifts
because they can be detected at early epochs and their masses can be inferred
from their light curves. Direct detection of the first cosmic explosions in the
universe will only be possible with JWST, WFIRST and the next generation of
extremely large telescopes. But strong gravitational lensing by massive
clusters, like those in the Frontier Fields, could reveal supernovae at
slightly lower redshifts now by magnifying their flux by factors of 10 or more.
We find that Frontier Fields will likely discover dozens of core-collapse
supernovae at 5 $ < z <$ 12. Future surveys of cluster lenses similar in scope
to Frontier Fields by JWST might find hundreds of these events out to $z \sim$
15 - 17. Besides revealing the masses of early stars, these ancient supernovae
could also constrain cosmic star formation rates in the era of first galaxy
formation.
