I am working on YouTube videos about the search for life on Venus. The Venus Life Finder team had hoped to launch their first probe this month, but it has been delayed. Their next launch window is over a year away. Rather than creating videos on a system that might be changing I’ll do more general videos on spacecraft. My next video is on how we communicate with spacecraft.
If you’re not a spacecraft engineer you might think you don’t know anything how we communicate with them. That sounds reasonable but it isn’t true. I think you know a lot about technologies and difficulties around communicating across a distance. And what you already know explains how we communicate with spacecraft.
We’re all intimately familiar with cell phones, all the features and foibles. Your cell phone is battery powered, two-way wireless communication device. It provides communication by sending signals to distant antennas on cell phone towers. The towers connect to the internet and other networks over fiber optic cables. Your cell phone has a battery that needs to be charged. It can send and receive many kinds of data like voice, music, images, videos, maps, basically anything we can think of. As you drive away from a nearby cell tower your cell phone will eventually switch to a different antenna on a different tower. The fact that this happens without interrupting a phone call shows how well the underlying technology works. But if you’re driving where there aren’t enough towers you could go out of range and lose your connection. Or maybe the the tower isn’t that far way but it’s on the other side of a big hill, then you can still lose your connection. When you have a weak signal and only one bar is showing you may not have the bandwidth to stream video. If you’re in a really crowded space like a stadium maybe the nearby cell towers are full and you can’t get a connection.
Clearly you know a lot about wireless communication systems. And I haven’t even mentioned wifi. Everything you know about cell phone networks applies to wifi networks. Only the details change. Household wifi networks have a much smaller range, a higher bandwidth and maybe less latency. Any kind of data can be sent over either network. A phone call can be switched to a different network. If you start a phone call at home it may connect over your home wifi. Then if you walk away from wifi router it can seamlessly transfer to the cell network. One difference you see with wifi networks is you have to initially select the wifi network by its name and probably enter a password. But actually the exact same thing happens on the cell phone network when your phone is activated.
What you know about one of these networks is true for the other one. And what you know about both networks applies to networks between us and our spacecrafts. In my next post I’ll talk about the details of spacecraft communication. Don’t worry. It won’t sound abstract or complicated. It will all be grounded in your experience with devices on cell networks and wifi networks.