Frequently there are stories about using suspended animation to send humans to other stars. Across the Universe by Beth Revis is a fun novel about this theme. Sometimes there are science shows talking about how this could be done. It usually involves energies so high that a third of the Solar system (or some such massive energy source) would be needed to make the trip. This is all bogus.
The way I predict inter stellar exploration will occur is through artificial intelligence. We are rapidly approaching the point where machines will be as smart as people (and then quickly much smarter.) Ray Kurzweil said that if Moore’s law holds (computer power doubling every 18 months) then a simple machine would have the equivalent power of a trillion times the consciousness of earth by the year 2099. That’s very profound and a little hard to comprehend. Even if this falls far short of a full run of Moore’s law, it would still mean that artificial life is the future of our planet. I will write more about this later, but the key here is that mankind will be able to send an AI creature to explore in our stead. Just as a simple seed can grow into a 15 ton oak tree, so could an AI creature smaller than a BB, be able to grow into a mighty creature if ever it reaches a suitable environment. A transmission station could then be set-up by our substitute humans and we would know what is out there. The energy needed to send a BB sized “spaceship” to the stars would be very minor and we could send tens of thousands from a station remotely position in the solar system. In a century or two, we would have a vast knowledge of the Milky Way stars that are modestly close.
The only question is that when the signals come back, will there be any humans around to listen to them.
Related / Good Reads:
Ray Kurzweil: The Age of the Spiritual Machine, The Singularity is Near and How to Build a Mind.
Beth Revis: Across the Universe (book 1 of a trilogy)