Mea culpa

I made a mistake. There can't be much cargo taken aboard the X 37C. If I am not mistaken again, this craft should be capable of carrying people primarily. In order to take cargo, we'll have to think of something else. For cargo we can consider an expendable craft.

Update:

Another mistake.  It probably won't be useful to use methane in a nuclear thermal rocket.  Better to stick with hydrogen.