Not very. It's a very mature discipline so most of the difficult stuff is now documented and coded into design software. The action has now shifted to economics, AI, robotics, regulatory crap, material science etc. Design work is now mainly about tedious detail.

We get excited today about what people like Elon Musk and Burt Rutan are doing, but much of the excitement there is not about rocket science per se. Compared to (say) the days of aircraft designers like Clarence "Kelly" Johnson of Lockheed Skunkworks fame (SR-71 blackbird among other things) and the Moon Race, today's stuff seems tame.

For a while formation flight and swarming in air and space promised to make things really exciting again, but that stuff kinda floundered. We can expect a renaissance in flight in a decade or two once today's boring but effective operational UAVs go mainstream and the path is cleared for the really exciting stuff. In space, I don't have much hope that truly hard new problems will relly be tackled. The economics simply don't work out.

If you want the paradigmatic "smart people" applied science of today, it is probably bioinformatics. That's the rocket science of today though it seems to lack a clear moonshot type vision capable of exciting an entire generation or two.