  We propose that the Antarctic Impulsive Transient Antenna (ANITA) can serve
as a detector for long-lived, charged particles, through its measurement of
extensive air showers from secondary leptons. To test this on an example model,
we simulate the production of staus inside the earth from interactions between
ultra-high energy neutrinos and nuclei. We propose that results of ANITA
searches for upgoing air showers can be interpreted in terms of constraints on
long-lived, charged massive particles (CHAMPs) and consider a supersymmetric
partner of the tau lepton, the stau, as an example of such a particle.
Exploring the parameter space in stau mass and lifetimes, we find that the stau
properties that lead to an observable signal in ANITA are highly energy
dependent. At $10^{18.5}$ eV, we find that the best constraints on the product
of the neutrino flux and the stau production cross section would be placed near
$m_{\tilde{\tau}}=$1 TeV and $\tau_{\tilde{\tau}}=$10 ns. Thus ANITA could be
sensitive to new physics in a region of parameter space that is unconstrained
by experiments at the Large Hadron Collider.
