The radical propulsion needed to catch the solar gravitational lens

Sending a mission to the solar gravitational lens (SGL) is the most effective way of actually directly imaging a potentially habitable planet, as well as its atmosphere, and even possibly some of its cities. But, the SGL is somewhere around 650–900 AU away, making it almost four times farther than even Voyager 1 has traveled—and that’s the farthest anything human has made it so far.