Extrasolar Object Intercept and Sample Return Mission Using Ultra Power Dense Radioisotope Electric Propulsion

Author: Christopher Morrison

Background:  In the past three years, we have detected the first two known interstellar objects passing through our solar system: Oumuamua in 2017 and C/2019 Q4 (Borisov)in 2019. Both interstellar objects contain a wealth of undiscovered information about what the universe is like outside our solar system. Being able to visit, take a sample from these extrasolar objects, and return them to Earth for study has the potential to fundamentally change our view of the universe and its evolution. This study is the subject of an ongoing Phase I NIAC. 

Objective: Intercepting and returning from an extrasolar object requires an extremely high ∆V on the order of 100 km/s. Currently chemical propulsion cannot feasibly achieve a Δ𝑉 exceeding 20. Electric propulsion can achieve Δ𝑉on the order of 100 km/s but requires a power source that can operate at vast distances from the sun and with a low mass.  

 Methods: USNC-Tech is proposing a power source technology called a Chargeable Atomic Battery (CAB). The key innovation is a novel manufacturing process for radioisotope power systems that unlocks the ability to produce high performing non-traditional radioisotope materials that can be produced cheaply and quickly compared to traditional Pu-238 radioisotope systems. The CAB batteries are manufactured using natural non-radioactive feedstock material and then be activated or “charged” inside of a fission reactor to the desired power. They can then be packaged without the need for chemistry or separation. 

Results: When combined with other state-of-the-art and near-term technologies, this architecture can achieve this ambitious mission. The proposed technology is a radioisotope electric power system capable of achieving a specific mass of 5-10kg/kWe. The CAB sources scale well to low mass and a 1-metric ton wet mass vehicle which can be delivered using a single ground launch vehicle. The spacecraft would be capable of delivering a 50 kg payload with a 100 km/s Δ𝑉 over a 5-to-10-year timeline. 

Conclusions: Radioisotope electric propulsion combined with CAB technology can enable sample return missions from extra solar objects.