This paper describes the Mars 2001 Miniature Thermal Emission Spectrometer (Mini-TES) being built by Raytheon Santa Barbara Remote Sensing (SBRS) under contract to Arizona State University (ASU). Mini-TES is a point (single-pixel) Fourier Transform Spectrometer (FTS), covering the spectral range 5 - 28 microns (micrometer) at 10 cm-1 spectral resolution. It is part of the Athena Precursor Experiment (APEX) that will fly to Mars on board NASA's Mars 2001 Lander mission. Mini-TES is designed to provide a key mineralogical remote sensing component of the APEX mission, which includes several other science instruments. Even though Mini-TES is a new design, the Athena mission required proven, flight-tested instrumentation to meet a two-year development schedule. Therefore, SBRS designed Mini-TES based on proven heritage from the successful Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES), which was launched in 1996 and is currently providing excellent science data from the MGS, in orbit about Mars. Mini-TES occupies only 15% of the volume and is 83% lighter than MGS TES, yet nearly all the design and technology elements of Mini-TES are direct descendants of proven flight components from MGS TES. Relevance of the Mini- TES to APEX science, overall design, performance, as well as details of the hardware being fabricated at SBRS, are discussed. Possible applications to future missions are also addressed.