Use the Sun as a Signal Booster
Here's yet another idea hatched by the Project Icarus researchers. According to Einstein's relativity theories, extremely massive objects' gravitational forces can actually deflect light that's passing near them and concentrate it, the way a hand-held magnifying glass does. That gave the Project Icarus think tank the idea of using that effect to focus and boost transmissions from a distant spacecraft. The way they would do it, admittedly, is a little tough for a non-physicist to fathom: A spacecraft capable of receiving communications transmissions would be positioned in interstellar space opposite the direction that the starship is going, about 51 billion miles (82 billion kilometers) away from the sun. That's really, really far -- about 18 times the distance between Pluto and the sun, in fact -- but let's assume that an Earth civilization capable of sending a starship trillions of miles from Earth can do that. The communications craft would then use the sun as a lens to magnify the signals it gets from the distant starship, and then would transmit them back to Earth though some other system, such as a network of satellites with laser links.
"The potential gain from doing this is immense," engineer Pat Galea explained to Discovery News in 2012. "The transmitter power on Icarus could be ramped down to much lower levels without impacting the available data rate, or if the power is kept the same, we could be receiving much more data than a direct link would provide." Ingenious as it might seem, however, the scheme also has some Jupiter-sized complications. It'd be necessary, for example, to keep the receiver spacecraft, the one getting the signals from the starship, pretty close to perfectly aligned at all times, and keeping it that way could prove very, very difficult [source: Galea, Obousy et al].