We have several spacecraft on escape trajectories, meaning they're leaving the solar system and they are never coming back. Which is a sort of success, if you think about it: It's not like our ancestors were able to accomplish such feats as tossing random junk between the stars, but it's probably also not exactly what you imagined interstellar space travel to be like.

^{Image source} At that speed, spacecraft could reach Proxima Centauri in a handful of decades, and send back pictures a few years later, well within a human lifetime. One option is to contain that energy onboard the spacecraft as fuel. Perhaps one of the most promising ideas is to keep the energy source of the spacecraft fixed and somehow transport that energy to the spacecraft as it travels. This is the basic idea behind the Breakthrough Starshot project, which aims to design a spacecraft capable of reaching the nearest stars in a matter of decades. In the simplest outline of this project, a giant laser on the order of 100 gigawatts shoots at an Earth-orbiting spacecraft.

^{Image source} The laser bounces off of that sail, giving momentum to the spacecraft. If we were to shoot this laser at the spacecraft for about 10 minutes, in order to reach one-tenth the speed of light, the spacecraft can weigh no more than a gram. This is where the rubber meets the interstellar road when it comes to making spacecraft travel the required speeds. The laser itself, at 100 gigawatts, is more powerful than any laser we've ever designed by many orders of magnitude. For 40 years, this little spacecraft will have to withstand the trials and travails of interstellar space.

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