Far Infrared (FIR) measurements have many astrophysical applications but are best done from space. Current infrared spectrometers are large so sending them to space is costly. We are currently developing on-chip FIR spectrometers and their spectral response will need to be calibrated. In the FIR, such calibrators are not straight forward and need to be designed to match the wavelength range, resolution, and noise performance of the device under test to achieve satisfactory results. We are building a compact Fourier Transform Spectrometer (FTS) operable at 50 - 500 µm with 1µm resolution. To reduce the photon noise in the system an evacuated cryostat will be employed. In this poster we discuss the initial design and development of this cryogenic FTS and plans for future implementation.