Space travel is on everyone’s mind, especially after the successful launch of the Falcon Heavy rocket on February 6, 2018. For the first time since the original space race, we’ve got companies around the world trying to take humanity to the stars.
In an era of reusable rockets and moon tourism, though, there is one thing that’s been left in the technological stone age — space communications. Let’s take a look at the current state of interstellar communication and how it needs to be upgraded before we can head out into the solar system.
Placing an Interstellar Phone Call
If you wanted to place a call to the International Space Station, you could be talking to the astronauts in orbit around our planet in a moment — because the space station is in low earth orbit and our current communication signals travel quickly.
If you wanted to place a call to the Curiosity Rover on Mars, on the other hand, it could take 20 minutes or more for the rover to get your message — and just as long for it to respond. This is because we use radio waves to transmit our messages — and those waves travel slowly, even in the vacuum of space.
In spite of this, we still choose to wait for 20 minutes or more to get information from our more remote rovers, satellites and probes. It seems like we’ve upgraded everything except our communications.
Since we seem to be stuck in the stone age when it comes to communications, what can we do to improve interstellar communications to make becoming a spacefaring species a reality?
One suggestion is to create a series of interstellar communications satellites — like a really advanced string between two incredibly distant tin cans. The satellites would relay the communications more directly, while still allowing us to utilize existing radio technology. While this would work, in theory, building and deploying these remote satellites would be prohibitively expensive, even for NASA. Project Icarus is trying to come up with a way to use satellites both in the solar system and for extra-solar expeditions that will be further than we’ve ever actually traveled before.
Laser transmission is another option that is being considered to transmit both communications and data. Laser light transmission works on a much shorter frequency than radio waves, so it requires less power to send the same amount of data. You also don’t need massive transmitters or receivers on either end. Instead of super-slow data transmission like we have while using radio waves, laser data transmission is fast — roughly the equivalent of a broadband connection here on Earth.
Wi-Fi works great here on Earth, where you’re almost always in range of a Wi-Fi hotspot, but it doesn’t travel far enough in space to work well for interstellar communication. That’s why NASA is looking into a new type of internet. Known as Disruption Tolerant Networking, or DTN, this protocol hangs on to data that is being transmitted until a stable connection can be created. Traditional internet protocols assume that there is always going to be a stable connection, so they don’t store data packets. DTN was successfully tested in 2008 by sending pictures to and from a spacecraft that is currently more than 20 million miles from Earth.
Faster-than-light travel is usually reserved for getting from point A to point B in science fiction novels, but it could provide a way for us to communicate over vast distances. Even if we sent a message to Alpha Centauri, some system a mere 4.2 light years away, it would take 4.2 years to reach it at the speed of light. By transmitting data piggy-backed on a beam of subatomic particles that can travel faster than light, we could cut that time dramatically. Neutrinos were thought to travel faster than light, but they have since been proven to move slower than Einstein’s light speed limit, so we may have to find a different faster-than-light particle to carry those long-distance interstellar phone calls.
Catching up With the Times
For now, we only need to worry about sending messages to Mars, but in the future, we will probably be making some seriously long-distance phone calls as we start to explore the solar system. Our communications methods will have to catch up with the times.