Stick a little 12-inch sattelite dish on your roof and you can watch any one of hundreds of crystal-clear television channels, broadcast from satellites in way high orbits.
So how come audio and video signals from manned spacecraft in low earth orbit are so terrible?
Hmm. I’m not quite sure what you’re talking about. One of my cable channels is, ostensibly, the NASA channel. Occasionally, when there’s a shuttle up, late at night the channel will show views of Earth taken from the shuttle. Absolutely breathtaking stuff, and of good quality.
Are you talking about EVA images? I can’t recall seeing any that are subpar in quality, although I would imagine that image quality is not the top priority during those shots.
Audio is another matter, however.
There are lots of places in the chain where the quality can degrade, starting from the microphones, the transmitter, the amount of bandwidth used, the receivers and antennas on earth, etc.
I can’t remember the exact bandwidth, but the shuttle uses different channels for things like voice communication, telemetry, video, etc. And they use as little bandwidth as possible, because you need less power, and therefore less weight and size for all the equipment.
Most of the really breathtaking shuttle pictures you see are video or film that is recorded in space and brought back to earth. Although they’ve got some pretty good live video feeds now.
I was thinking mostly of the orbital interviews we always see with the crews. Fuzzy picture, terrible audio, etc. Come on, how much bandwidth and power does it take to broadcast a simple audio signal?
These are done with simple handheld CCD cameras that have been subjected to extreme vibration and 9Gs of acceleration. For a practical experiment in the effects of a shuttle launch on video cameras, get some duct tape and attach a your video camera to the wheel of your car, and then drive a few blocks at high speed over a bumpy road. See if the camera’s picture quality degrades.
The average TV show you see is either filmed on 35mm film, or in front of massive studio cameras. Even your local news crew uses BetaCams, which are massively higher quality than NASA’s equipment, and very bulky.
Thanks for the answer, Chas, but I’m a bit skeptical of that explanation. In my limited experience, mistreating a Handycam results in one of two things: nothing at all or total inoperability. Frankly, the signals always look to me like broadcast signal deterioration, not crummy equipment. And as P.R. obsessed Daniel Goldin is, you’d figure they’d budget a few mil for a camera that would handle lift-off.
Besides, what about the crummy audio? Are the microphones just getting jostled around too?
I don’t think they’re so bad. It’s just that those interviews are informal, and not some elaborate TV/movie production with specialized lighting and pre-broadcast editing, etc. They’re about the quality of a home video.