The NASA Transition Authorization Act of 2017 mandated that NASA ask an independent organization to study a Mars human spaceflight mission to be launched in 2033, including an evaluation of technologies, schedules, estimated costs, and budget profiles for the mission to Mars and its precursor missions. NASA requested STPI conduct this analysis and base the study's schedule for human spaceflight on NASA's current and notional plans leading to a mission to Mars orbit. STPI found that a 2033 departure date for a Mars orbital mission is infeasible under all budget scenarios and technology development and testing schedules. We found that 2035 may be possible under budgets that match 1.9 percent real growth, but carries high risks of schedule delays due to complex technology development, testing, and fabrication schedules for the Deep Space Transport. 2037 is the earliest the mission could feasibly depart for Mars assuming a small budget increase or smoothing budgets over two time periods in the 2030s, with 2039 being a more realistic timeframe.