  We construct a kappa-symmetric Green-Schwarz action for type IIA string
theory on AdS_2. As a candidate holographic dual, we consider superconformal
matrix quantum mechanics, given by the Marinari-Parisi model with vanishing or
logarithmic superpotential. We derive that the super-eigenvalues form a
consistent subsector, and that their dynamics reduces to that of the
supersymmetric Calogero-Moser model. The classical string action and the matrix
model both have an infinite set of conserved charges, that include an N=2
target space super-Virasoro symmetry. As a microscopic test of the duality, we
reproduce the exact form of the Calogero interaction via a string worldsheet
calculation.
