Quest for circular polarization of a gravitational wave background and orbits of laser interferometers in space

We show that an isotropic component of circular polarization of a stochastic gravitational wave background can be explored by contriving configuration of multiple laser interferometers for correlation analysis. For the proposed BBO mission, the circular polarization degree Pi can be measured down to Pi similar to 0.08(Omega(GW)/10(-15))(-1)(SNR/5) with slightly (similar to 10%) sacrificing the detection limit for the total intensity Omega(GW). This might allow us to detect a signature of parity violation in the very early universe.