Comment by lxgr
1 year ago
Supposedly they use steering, since the horizontal azimuth to adjacent-plane satellites varies from 0 to 65 degrees across an orbit: https://apps.dtic.mil/sti/tr/pdf/ADA348174.pdf
1 year ago
Supposedly they use steering, since the horizontal azimuth to adjacent-plane satellites varies from 0 to 65 degrees across an orbit: https://apps.dtic.mil/sti/tr/pdf/ADA348174.pdf
It doesn’t get into it too much on pages 14 and 15, but it indeed suggests that they probably exclusively use the “intra-orbital” links closer to the poles to get data to a satellite where the inter-orbital links are more practical.
I believe Iridium had way more downlinks than they used to pre-bankruptcy. I guess volume constraints were less of an issue, so ok to hop around more in space.
This has more details: https://fcc.report/IBFS/SAT-MOD-20131227-00148/1031348.pdf
Apparently it only happens above/below 68 degrees latitude, so the next satellite with a working inter-orbital-plane connection is at most one hop ahead or behind.
https://spaceflight101.com/spacecraft/iridium-next/ has some more photos and diagrams; seems like they're really mechanically steered even on the NEXT constellation.