[X] My Assistant

[qraal]

Speaking of Mike Brown and his planets, if the proposed Planet IX is confirmed, then it's likely to be about 700 AU away. That's a 200 year journey at "Voyager" speed (~3.5 AU/year), so we'll need to go significantly faster.

For historical precedent there's the Thousand AU mission design from the late 1980s, which used a SNAP powered ion drive to push a probe to ~20 AU/year. Waiting 50 years for major data return seems excessive, so I'd think a 20 year max travel time, and preferably a 10 year travel time, should be in the minimum specifications.

The main propulsion options IMO are an extreme Oberth Maneuver, with a very high thrust system at perihelion; a high performance Solar-Sail; an E-Sail, and - a bit more speculative - a laser-push by the proposed Starshot Array.

Anything missing?

[qraal]

Lorenzo Iorio, the gravitational dynamics researcher, has a melliflous name for the outermost solar planet - Telisto.

Maybe I should have started the thread with that name.

A recent NIAC funded study is of relevance - the Heliopause Electric Rapid Transit System (HERTS) which uses an Electric Sail (E-Sail) to throw a New Horizons class probe into a 10 year trajectory to 100 AU. Of course to reach Telisto a mission time of ~70 years would be required, thus something with a bit more oomph is required. That's the original motivation for the OP.

[mcaplinger]

Lorenzo Iorio, the gravitational dynamics researcher, has a melliflous name for the outermost solar planet - Telisto.

I had to read https://arxiv.org/abs/1512.05288 to understand what this meant, and frankly, I don't think the author has the standing to name this object.

http://knowyourmeme.com/memes/stop-trying-...ke-fetch-happen