Hmm, You should make the nuclear engine decouple-able and have the probe use two parachutes. It then can land with a higher chance of not blowing up. I suggest not doing a manned mission due to the size of the lander and returner. I suggest duna for another target. Requires more delta-V but is a nice place. If you do a manned mission there in the future maybe it could land by parachutes or glide like a plane. Use areo spikes for the plane idea afor theirs no oxygen. Always do unmanned missions first for two reasons. 1. Check if your idea works. 2. Save a possible life in case it fails. Also remember it takes more fuel to land or take off with a actual capsule because they weigh a lot more. But nice job getting into orbit! Once I was getting a probe into orbit but it was failing, So i improvised and was able to intersect the mun's orbit and now it's a mun orbiter. Remember, If something doesn't go to plan try to improvise. Especially with manned capsules. If it cannot return and is manned, Send a rescue probe or crew with fuel or a habitat module.