Japan has an orbiter there already (https://en.wikipedia.org/wiki/Akatsuki_(spacecraft) https://en.wikipedia.org/wiki/Akatsuki_(spacecraft) ), though it had a f

Japan has an orbiter there already (https://en.wikipedia.org/wiki/Akatsuki_(spacecraft) https://en.wikipedia.org/wiki/Akatsuki_(spacecraft) ), though it had a few bumps getting into orbit on the way over. However, the environment is very hostile, which makes a rover a much more difficult proposition. Also it's actually more difficult to move towards the inner planets because you can't easily use gravitational slingshots to help save fuel (and for other reasons).