  This work introduces the problem of initial orbit determination (IOD) from
only heading measurements. Such a problem occurs in practice when estimating
the orbit of a spacecraft using visual odometry measurements from an optical
camera. After reviewing the problem geometry, a simple solution is developed in
the form of an iterative scheme on the parameters describing the orbital
hodograph. Numerical results are presented for an example spacecraft in low
lunar orbit. The principal intent of this brief study is to communicate the
existence of a new class of IOD problem to the community and to encourage the
broader study of hodographs and heading-only IOD.
