NASA’s 2021 Surface Topography and Vegetation (STV) Study Report identified radar technology gaps for sensing vegetation structure and bare Earth surface topography, two key Target Observables identified by the 2017 Decadal Survey. The STV Report identified radar tomography as a candidate observing system to meet STV goals. Single-pass radar tomography requires multi platforms moving in tandem in order to gather additional spatial information about the scene. This allows the system to make measurements as a 3D volume instead of the traditional 2D surface radar image. The main technology challenge multistatic radar faces is the coherent, synchronized operation of multiple platforms to achieve this multistatic radar geometry required for tomography. ESTO IIP 23 project Tomographic Radar Experiment (TREx) aims to close this technology gap by developing a multistatic radar system that meets the needs of STV. TREx is developing a synchronization system and radar processing algorithms for an L-band multistatic, distributed radar. Through ground tests, opportunistic flight tests, and algorithm development, TREx will demonstrate the hardware and single-pass radar tomography to meet the measurement needs of STV. The hardware will also support future formation flights with multiple NASA aircraft and NISAR.