During the recent coverage of the Chinese balloon I saw people who should have known better write things similar to: “Why would China use balloons when they can launch satellites”? Here’s the answers.
- The atmosphere is an enemy. It distorts or absorbs radiation. There’s a maximum resolution achievable from orbit, and after that it doesn’t matter how good the satellite camera might be, or the antennae. Having a lot less atmosphere between the sensor and the target helps.
- Satellites move very, very fast. A satellite in low earth orbit will be moving along at 4 or 5 miles a second. Trying to keep the sensor pointed at the target is a challenge, and can introduce vibration (sort of like trying to use a video camera while running — do you remember Blair Witch Project)?
- The revisit time for a satellite is predictable — they call it Orbital Mechanics for a reason. A balloon can show up without much warning. You can at least hope to sneak up on the target.
- Balloons are cheap. If this is the proof of concept balloon, China may try send 100 or 1000 for the cost of one satellite.
So, going forward, don’t dismiss the cheap, lower-tech alternative as obviously inferior. Think balloon:satellite::drone:airplane.