The High Voltage Hall Accelerator (HiVHAC) development program task, funded by the NASA Science Mission Directorate's In-Space Propulsion Technology Program, is advancing the current state-of-the-art Hall thruste r's performance, life and cost. Its goal is to meet and/or exceed the requirements of Discovery class missions by developing a thruster that operates over a range of input powers from 0.3 to 3.5 kW, that can operate at specific impulses from 1,000 to 2,800 s, and that can proces s 300 kg of propellant while operating at full power. The HiVHAC program is currently building upon a history of design, analysis, fabrication, and test experience gained from a seri es of experimental investigations over the last several years. The latest design is the NASA- 103M.XL (eXtended Life) Hall thruster. This thruster incorporates design features enabling a projected lifetime in excess of 15,000 hours at a power level of 3.5 kW. A laboratory model of the NASA-103M.XL has demonstrated > 4,000 hours of wear testing at a dis charge voltage of 700 V. The next task of the HiVHAC program is to evolve this design into an engineering model thruster capable of demonstrating TRL-6 readiness. This paper will focus on the development status of the engineering model design.