Currently we are vastly limited by our ability to get out of the solar system. It takes decades for us to get a probe out past our solar system. Interplanetary travel should not be affected by universal expansion either. Until we are able to come up with a way to travel more efficiently (I.E. Worm holes or beyond light speed travel) we will not be able to travel interstellar. When we figure that out I don't believe universal expansion is going to stop us.
No, I do not think that the fact that the universe is expanding will make space exploration more difficult, because the universe is already very large such that exploring it is already a very large task. People already have their hands full trying to get all the way to Mars. It's not harder to go much further.
The current technology was built to assist in space exploration and assist those on earth with their heads at the start the power to keep Earths existence. The expansion of the universe could have never been noticed without the programs that assisted in noticing what was noted by one who’s society declared as insane some time ago, we finally found (with technology) what was seen through the highest powered telescopes build centuries ago. There was not an expansion there was a rectification to a family who has been inhibited intellectually and re-noticing what was once noticed in space is not going to inhibit space exploration by any means. The technology and years of experience we now have makes the exploration safer.
I do not believe the expansion of the universe makes it more difficult to explore. I believe our biggest pressing issue right now is speed. The speed we can obtain is far too slow to get anywhere else in the universe in a timely manner, at least with our short life spans.