Remote Laser-Evaporative Molecular Absorption (R-LEMA) spectroscopy is a sensor concept for probing molecular composition of asteroids from an orbiting spacecraft. R-LEMA uses a high-power laser aboard the spacecraft which is used to melt and evaporate a spot on the surface of the target; the heated spot is then viewed by a spectrometer through the plume of ejected material. Research supported by the NASA Innovative Advanced Concepts (NIAC) program aims to adapt a laboratory R-LEMA system for operational tests in the space environment. A CubeSat mission is envisioned as a test of the R-LEMA concept in the space environment, with a laser and spectrometer aboard a main craft, and a target craft flying in formation. A systems analysis is presented for the spectrometer and optical subsystem. For typical targets, selected molecular species are deemed to be important resources, e.g. water, hydrocarbons, economic minerals, etc. Infrared spectra of important resources are reviewed for general characteristics, and operational specifications for the spectrometer and optical subsystem are derived from the spectra. Operational and engineering tradeoffs for grating and FT-IR spectrometers are compared. Speed, resolution and wavenumber accuracy of FTIR designs are preferable, but long-motion interferometers become unwieldy in a CubeSat design. Bruker’s patented two-beam interferometer with double pivot scanning mechanism provides a compact FT-IR compatible with CubeSat geometry. Simulation results are presented for detection of important resources under various operational scenarios using the CubeSat design. Even at low concentrations, detectability of water and hydrocarbons is expected.