The scientists and futurists working on Project Icarus -- a speculative attempt to design a starship capable of reaching the nearest neighboring star system, about 2.35 trillion miles (3.78 trillion kilometers) away -- spent a lot of time thinking about how such a ship might stay in contact with the Earth as it journeyed across the enormity of interstellar space. In the previous item on this list, we mentioned the concept of a bread-crumb-like trail of communications links that the starship would leave in its wake. But back on Earth, those monitoring the mission would still face the challenge of trying to pick up signals from the starship and filter out the ambient electromagnetic noise of space -- a task made even more difficult by the Earth's atmosphere, which would weaken the signals.
To maximize the ability to do that, Project Icarus' planners have suggested building several solar system receiving stations, which would be enormous arrays of antennas stretching for many miles in different locations on Earth. The antennas in such an array would work in synergy to spot and capture the faint signals containing starship messages. (Think of this analogy: If a baseball player hits a home run into the stands at a baseball stadium, it's more likely that the ball will be caught by a fan if the stands are full of people.) Because the Earth rotates, the antennas in a particular SSRS would only be pointing at the distant starship for a small fraction of each day, and the weather in that location on Earth could hinder the reception. For that reason, it might be wise to build multiple arrays of antennas in different locations on Earth, to ensure that we can stay in near-continuous communication [source: Galea].