Technology Requirements of Exploration Beyond Neptune by Solar Sail Propulsion

This paper provides a set of requirements for the technology development of a solar-sail-propelled Interstellar Heliopause Probe mission. The mission is placed in the context of other outer solar system missions, ranging from a Kuiper belt mission to an Oort cloud mission. Mission requirements are defined and a detailed parametric trajectory analysis and launch-date scan are performed. Through analysis of the complete mission trade space, a set of critical technology development requirements are identified that include an advanced lightweight composite high-gain antenna, a high-efficiency Ka-band traveling-wave tube amplifier, and a radioisotope thermoelectric generator with power density of approximately 12 W/kg. It is also shown that the Interstellar Heliopause Probe mission necessitates the use of a spinning sail, limiting the direct application of current hardware development activities. A Kuiper belt mission is then considered as a precursor to the Interstellar Heliopause Probe, and it is also shown through study of an Oort cloud mission that the Interstellar Heliopause Probe mission is the likely end goal of any future solar sail technology development program. As such, the technology requirements identified to enable the Interstellar Heliopause Probe must be enabled through all prior missions, with each mission acting as an enabling facilitator toward the next.