and you'll find that it's still a bit complicated to perform even a lunar swingby mission. One thing, the Soviets sure had a lot of good experience with their launch escape system during the test flights!

The Zond represents a minimalist approach to the lunar swingby mission. The good thing is that the Russians now have decades of experience with both the Proton booster and the Soyuz capsule. They've learned a lot since then. Still, it'd probably cost somewhere around $80-100 million to fly a Zond-style mission today (~$60 million for the Proton and ~$20 million for the Soyuz capsule). That's a pretty expensive joy ride.

If we decided to start from scratch using off-the-shelf technologies to the greatest extent possible, it might be possible to build a vehicle for the job that wouldn't need a Proton-sized booster. On the other hand, if we used the cycler concept, we'd still need to launch the manned capsule on something like the upgraded Soyuz booster being developed (the Aurora) to be able to match the cycler's velocity. A smaller version of the Soyuz capsule like the Soyuz 7K-L1 (mass about 5.7 metric tons) with an enlarged service module could be launched on the Aurora (11 metric ton capacity) booster and accelerate fast enough to catch the cycler. Such a mission might cost somewhere around $20-40 million, minus the cost of developing, launching, and operating the cycler.