We present a novel micro-interferometer implemented using arrays of single-mode planar optical waveguides. The spatial heterodyne waveguide spectrometer offers high resolution and increased optical throughput (etendue) and is compatible with a microsatellite platform. A stationary Fourier technique is employed to reconstruct the input spectrum from the array of outputs. Calibration mitigates waveguide fabrication errors and input illumination non-uniformities and can be readily implemented in the spectral retrieval algorithm. Signal to noise performance is estimated for a remote sensing application using a classical telescope front end with comparison to classical techniques.