Stephen Hawking told a BBC radio audience that if the human race were to survive, it would be necessary to go to another star. Hawking talked about using antimatter powered spaceships to go at about 86% of light speed.
It would take a lot of power to send a space ship with people to another star. Wikipedia discusses the ideas around interstellar travel There are two main ways to make the problem far easier.
1) Some theoretical ships are more achievable if they are far lighter. You make things millions of times easier if you make your ship a million times lighter. I will discuss this option in this article.
2) Another way to go is to go slower. The next article will discuss that option. This option will discuss not going as far, by achieving what we want by staying inside the solar system.
Going to the stars but Go Lighter
Starwisp like concepts could send very light sensor arrays to other stars. The starwisp concept itself has flaws but instead of needing tons of antimatter to move 1000 tons of space ship the energy requirements could be reduced by 1 million to only send 1 kilogram or less of payload.
Frank J. Tipler, Professor of Mathematical Physics at Tulane University, discusses sending quantum computers with uploaded or simulated people around the universe
Wikipedia has information about embryo space colonization as a theoretical interstellar space colonization concept that involves sending a robotic mission to a terrestrial planet (having a biosphere) transporting frozen early-stage embryos. Again the mass of the ship can be small making it a million or more times easier.
Mind uploading has the problem of developing powerful computers and understanding of the brain sufficiently to enable uploading to work. Embryo ships require the development of fully autonomous robots, Artificial Wombs, and computer hardware that can function reliably over long periods of time. Furthermore, a propulsion system would be required that could accelerate the small ship to a fraction of light speed and then slow it down again. Finally this depends on the existence of an exoplanet qualifying for colonization within a few hundred light years of Earth.
Finding exoplanets can be enabled by proceeding with the New worlds imaging project and hypertelescopes.
Magsails can be used to slowdown at the target solar system
There are some recent ideas for being able to generate several grams to kilograms of antimatter
Magnetically inflated structures in space could create kilometer size telescopes are larger within a decade.
Wikipedia has a lot of information about space colonization
new worlds imager
magnetically inflated structure