We present a novel interpolation technique to improve the small sample support performance of airborne radar space-time adaptive processing (STAP) using bistatic configurations. Bistatic airborne radar operation increases the clutter rank and causes it to be inhomogeneous with range, resulting in the degradation of the output signal to interference plus noise ratio (SINR). Brennan's rule for the space-time clutter covariance matrix rank for monostatic STAP is extended to the bistatic case, which motivates the development of a space-time interpolation (STINT) technique for bistatic clutter compensation. More specifically, we design a linear transformation which maps the bistatic clutter to that which would be received under "virtual" monostatic conditions. Simulation results indicate up to 10 dB SINR improvement can be obtained using STINT with limited sample support.