Andrew Ketsdever (Air Force Research Laboratory) expressed support for NASA’s new effort to support advanced, low-TRL concepts. He suggested that investments into advanced concepts should be agile and based on sound physics. He identified three technologies that he believes should be high priority:
• Micropulsion, which Ketsdever said was enabling for small satellites and could be developed at a low cost.
• Beamed energy, which would use ground-based power generation infrastructure to provide power to spacecraft, particularly for EP.
• Advanced high-power EP, including a concept that uses field reverse configurations and rotating magnetic fields.
Robert Frisbee (formerly of JPL) remarked that developing advanced concepts to the point where they can be used by operational systems can take a very long time and a lot of money. He noted the value in looking back at historical developments to avoid reinventing the wheel. He said that the draft roadmap for TA02 did a very good job of covering all the advanced concepts, but it should possibly add advanced tethers such as the “space elevator” concept. He noted that both fusion and advanced fission propulsion technologies would enable astronauts to complete a round trip to Mars in just 3 or 4 months, instead of the multiyear missions envisioned with near-term technology. He went on to state that, except for these advanced concepts, NTP is the only technology that allows for reasonably quick human missions to Mars. Frisbee also pointed out several crosscutting technologies from other roadmaps, such as advanced radiators and lightweight materials and structures, that are vital to advances in in-space power systems.
In the group discussion some speakers suggested making improvement in in-space infrastructure via tethers or beamed energy. Several speakers suggested that a large number of low-TRL technologies and less mature advanced concepts should be investigated at a low level of effort.