A gas analysis system includes a spectroscopy assembly coupled to a vehicle. The spectroscopy assembly includes a multiplexer configured to combine a plurality of light beams into a multiplexed light beam, wherein the multiplexer is configured to direct the multiplexed light beam toward a target surface. Additionally, the spectroscopy assembly includes a collection optic configured to receive a reflected multiplexed light beam from the target surface. Further, the spectroscopy assembly includes a controller configured to de-multiplex the multiplexed light beam into a plurality of reflected light beams and determine a spectral intensity of the plurality of reflected light beams.