Exploiting orbital dynamics for interstellar separated spacecraft interferometry

Due to the much improved angular resolution achievable with an interferometer, a number of future NASA missions have resorted to using such an imaging system in an attempt to answer fundamental questions posed in the Origins Program. In this paper, the orbit designs of a Sun-synchronous separated spacecraft interferometer operating in the visible spectrum for interstellar imaging are presented. Particularly, the concept of using delay lines to coherently interfered the reflected science light is emphasized. Comparison between the same interferometer placed outside the gravity-well indicates that the use of delay lines becomes viable only when a delay length-mass conversion of 0.006 kg/m is achieved, assuming that a 500 sec specific impulse propulsive system is used.