3 ms·
(and too late for an edit) that 1.5M km thing is moderately important when it comes to communication with the JWST. The frequencies that can be used for commun
by shagie 5y ago
(and too late for an edit) that 1.5M km thing is moderately important when it comes to communication with the JWST.
The frequencies that can be used for communicating with a satellite or space probe are governed by how far away it is. The cut off for this is 2.0M km.
https://en.wikipedia.org/wiki/Deep_space_bands https://en.wikipedia.org/wiki/Deep_space_bands
And so, the JWST is still considered near earth and can't use the deep space bands.
https://deepspace.jpl.nasa.gov/dsndocs/810-005/201/201C.pdf https://deepspace.jpl.nasa.gov/dsndocs/810-005/201/201C.pdf
- naikrovek 5y agowhy is the exact frequency used important? what's different about near space bands versus deep space? they look arbitrary to my idiot eyes. (I'm asking why the band used is significant in any way)
- dn3500 5y agoIt's not a technical restriction, it's a regulatory one. Like how parts of the UHF spectrum are allocated to TV and parts to radio. They don't want near earth communication going on in the deep space band because it will swamp the weaker signal.
- naikrovek 5y agoright but the bands are not far apart, and the comment I originally replied to seemed to imply that there was significance that it was in the near space category rather than deep space. like it enabled something or was important in some unmentioned way. it was the whole (unspoken) point of the comment and I'm not "in the know" enough to already know the unspoken part. I'm asking what the unspoken part is.
- jessaustin 5y agoAccording to the wiki link above, the bands are similarly sized and adjacent, so this wouldn't have much to do with "physics". Perhaps the "near" bands are just more congested?