NASA Spaceflight As part of NASA’s phased approach to the development of technology and systems needed to carry astronauts on long-duration, deep-space missions, the agency’s Human Exploration Operations Mission Directorate’s (HEOMD’s) Advanced Exploration Systems (AES) division has committed to the “rapid development and testing of prototype systems and validation of operational concepts to reduce risk and cost of future exploration missions.” by Chris Gebhardt
'Part of this initiative includes the development of systems that will aid in the human and robotic exploration of Beyond Earth Orbit targets.
'To do so, however, requires new propulsion systems that have previously been unnecessary for Near Earth Orbit exploration – where traditional chemical-based propulsion works best toward the short duration and relative close proximity of missions and their destinations.
'To support the development of these new systems, a set of three objectives for in-space power and propulsion were developed.
'According to the HEOMD’s AES status update from 4 November 2015, these objectives include the development of a 100 kW class Solar Electric Propulsion (SEP) system, as well as the development of technologies for “nuclear thermal propulsion to enable rapid transport of crew to Mars” and development of “high energy, modular power systems for exploration missions.”'