Towards a nonsingular tachyonic big crunch

We discuss an effective field theory background containing the gravitational field, the dilaton, and a closed string tachyon, and couple this background to a gas of fundamental strings and D strings. Allowing for the possibility of a nonvanishing dilaton potential of Casimir type, we demonstrate the possibility of obtaining a nonsingular, static tachyon condensate phase with fixed dilaton. The time reversal of our solution provides a candidate effective field theory description of a Hagedorn phase of string gas cosmology with fixed dilaton.