| It requires the shielding no matter what the transportation method is. If one wanted to build a cycler, conceptually it is somewhat similar to staging a lunar mission with rendezvous in low earth orbit. The construction methodology would be something like the following: 1. Build the base structure of cycler in earth orbit, then transfer it into the orbit you want (i.e. earth-jupiter intersecting). This would be structure, engines, shielding. This might require a couple dozen nuclear thermal boosters, or maybe it has to be phased over two launch periods and assembled in the cycling orbit 2. Assemble in earth orbit everything you want for a manned mission (food, water, landing craft, astronauts) 3. Rendezvouz that material with the cycler on its next orbit (I don't know the timing for earth-jupiter - maybe 12 years after step 1). This is a comparatively small effort, as the shielding and habitable space was already taken care of with step 1 4. live your life for the year or whatever the transfer is 5. Take your landing craft from the cycler to Europa surface Different crews can hop on the original cycler by repeating steps 2 to 5. Conceptually you would want multiple of these cyclers coming and going, so that a crew can arrive on Europa on cycler A and return on Cycler G, only spending 5 years on Europa instead of 12. Their advantage is that the big heavy mass (sheilding) only has to be launched once, and can be used repeatedly, indefinitely. |