Many times in my life I have misjudged which technologies dominate the future. For example, nuclear power would be THE electricity source in my lifetime. More recently, I have been very skeptical of satellite internet as a viable answer for rural users. I have to reconsidered, and to explain why, we first need to explain what we’re talking about. So, an AgSplainer about how they work.
This superb animation from Wikipedia illustrates the straightforward physics of satellites: the lower the altitude, the faster they must travel to stay up. Most communications, GPS and similar satellites are geo-synchronous, which means they stay directly overhead one spot on the earth. To do that the magic altitude is 22,300 miles and a velocity of about 7000 mph. These work well for TV streaming, so we all have 2-foot dishes on our roofs. But two-way communication like the internet is much harder simply because of the distance. Round trip travel time for a signal means delays from the time your key is pressed to the response. It also means low-power transmitters like TV dishes can’t send much data very fast.
The technological answer was to lower the satellite orbits to 300-500 miles, labeled low-earth orbits, LEOs. But in order for those satellites to stay up, they had to be circling the globe more rapidly, like 17,000 mph. Consequently LEO satellites fly over any given ground location in a few minutes. Which led to the idea, which I formerly thought preposterous – launch thousands of them. This seemed to be an insurmountable hurdle. Oh, and the satellites would need to communicate with each other by laser to hand off your signal to the one following. It’s like using your cell phone in a car while driving and different towers handle the signal as you pass them. Only in reverse – you’re sitting still and the towers are flying by.
As governments began to wind down expensive space programs, commercial enterprises, led by Spacex, stepped into the void. In a series of astonishing engineering advancements, we will soon, as in a few months, be hurling payloads of about 60 LEO satellites every two weeks, thanks to re-usable rockets and economies of scale. The last launch was October 24, and to date about 800 LEOs comprise the Starlink system. Spacex has begun private beta-testing on areas where these first satellites cover nearly all the time. So we are not talking about vaporware here, there are real people using LEO satellite internet right now, and it exceeding my expectations. Next week I’ll talk about the actual results and the exciting possibilities.
