by Kelvin F Long
n 2018 I attended an awesome meeting at the Explorers Club in New York. The meeting was to discuss the design of a potential interstellar probe to travel to 1,000 AU, to derive its possible design definition and also the compelling science goals to be achieved. The project was led by scientists at the Johns Hopkins University Applied Physics Laboratory. The main requirement was to develop a probe that could travel at 50 AU per year and therefore reach the distance within around 20 years. Other than the initial meeting in New York, I attended meetings in various other locations around the United States including in New Orleans and California. In those meetings it was insightful to learn how professional spacecraft designers go about designing an interstellar probe and it was a privilege to be involved with the original concept definition as it began to materialise, with one of the earlier goals to generate a 30 W power capability within a 30 kg payload mass. Such a probe would explore the solar heliosphere, Kuiper belt objects and circum-solar dust disk and even a flyby of a Trans-Neptunium object. The interstellar probe would pave the way, scientifically, technically and programmatically, for longer interstellar journeys that would require future propulsion systems. It would go beyond the Grand Tour of the 1970s Voyager probes. It was recognised that a high solar system escape speed would be required, and probably at least twice the asymptotic speeds of Voyager 1 at its ~34 km/s. Two approaches were considered to include a passive one with a C3 launch and unpowered gravity assist, and an active one with a powered gravity assist and the use of in-space propulsion. This might include solar sails, solar electric, radioisotope electric, nuclear electric or nuclear thermal propulsion.
Although I was only involved with the project for the first year or so, I was highly impressed by the professionalism of the scientists involved who led the project. People like Pontus Brandt, Ralph McNutt Jr, Michael Paul and Jim Kinnison. Inspirational leaders reaching for the far frontier in space. The project was initiated in support of the Decadal Surveys of the United States and focussed on the time frame for a possible launch of 2023 – 2032. The final report is listed below and I was honoured to have my name listed as one of the collaborators for such an inspirational study. Below shows a photo from the meeting of the initial team in New York City in October 2018 held at the Explorer's Club.
INTERSTELLAR PROBE, HUMANITY’S JOURNEY TO INTERSTELLAR SPACE, NASA Solar And Space Physics Mission Concept Study for the Solar and Space Physics 2023 - 2032 Decadal Survey, led by Ralph L McNutt Jr, Michael V Paul, Pontus C Brandt, Jim D Kinnison et al., 13 December 2021.
https://interstellarprobe.jhuapl.edu/Interstellar-Probe-MCR.pdf
Inaugural Meeting of Interstellar Probe Working Group