So, an interesting thing about high eccentricity orbits like 2014 UN271 has, is that they have a much higher ratio of energy (kinetic and potential) to momentum

So, an interesting thing about high eccentricity orbits like 2014 UN271 has, is that they have a much higher ratio of energy (kinetic and potential) to momentum around the sun than a nearly circular orbit like say, Earth has. One can think of an orbit as being a superposition of a purely circular orbit and a purely radial one, with all the momentum around the sun being in the circular one. Any leftover energy above what is needed for the circular component goes into the radial component. In this case, almost all the energy is in the radial component. What this means is that if do you have a way to move it into a circular orbit around the sun, you could gain energy from the process, rather than having it cost energy. Maybe the best way to gather that energy, and possibly to move it as well, would be through gravitational assists, since they are lossless kinematic interactions. The energy gathered could then be used to build more of whatever is doing the interaction, exponentially speeding up the process.