Eris in a decade

ToughSF points to Edgar A. Bering III and others' "Solar and Hybrid Electric Propulsion to the Kuiper Belt and Beyond". Rather than gravity-assist "slingshots" this one uses a two-stage operation: hard thrust for Crazy Hermann, then a long high-specific-impulse deceleration. They're talking VASIMR ion-drives; close enough to the Sun, energy is sufficient to run the propellant so fast that the Oberth is possible. Two stages... but only one rocket!

Note that by Oberthing the SUN for initial thrust, the launch window is "whenever ya want" - at least for the AU 30 sphere. Okay technically "when the planet is perihelion" but, if they're going to some plutino, that's some time into the future. Otherwise they could use other planets and, for Kuiper missions, they still recommend this. To get to Eris in 9.6 years(!) they propose a Neptune (@3.5y) boost - which is great for other reasons, namely that we've not been there since 1989.

My first quibble would be to boost the thrust which we pay off by boosting I_sp. We can do better than VASIMR, I hope. The solar-Oberth initial thrust is so high that, if this be a manned mission, we might need NERVA. Still one-stage tho'.

Although, keeping it inorganic does lift other constraints - especially if we don't mind returning to some modest launch-windows. For instance the first burst of thrust - to fall sunward - doesn't have to be carried on the craft. That thruster can be set up as a railgun or spinlauncher from Earth high orbit or even from our Moon. The main ship just has to end on a trajectory as falls toward the Sun, that is slower than our own ellipse. There's one engine we don't need to schlep around or jettison. If more savings are desired then how about skating the atmosphere of Venus.

For electronics we do have to shield them near the Sun (ablation?) but, not for long. For orbit-insertion we might propose atmospheric braking at Saturn, Titan, and/or the ice-giants. Titan's probably best.

UPDATE 10/20 Ion propulsion. UPDATE 11/19 Biëlliptic is where it's at, saving delta-V. After this turn we might prefer a sail up to the planet whence we'll borrow momentum; the ion propulsion can then be used to decelerate, as to get into orbit at the final destination. Maybe to Haumea before we ponder distant boring Eris.