4 ms·

Geosynchronous orbits? You mean, 35,000km away from LEO? Operating in a single orbital plane is really not as hard as you're imagining it to be. We do it all

by mapt 11y ago

Geosynchronous orbits? You mean, 35,000km away from LEO? Operating in a single orbital plane is really not as hard as you're imagining it to be. We do it all the time. And there are tens of thousands of large objects in Earth orbit, but we only detect collisions every several years.

maxerickson 11y ago
Their spectrum license requires that they not create radio interference for geosynchronous satellites. How they plan to accomplish that is not clear to me.
- mapt 11y ago
  I interpreted him to mean physical collision risk. As for interference: They're planning on beaming signal to a wide swath of every plane for full-Earth coverage, not just at a narrow stretch near nadir. That means you'll have users acquiring a fix from a wide swath of sky; Let's say 45 degrees from zenith in various directions. That would make every user below 45 degrees latitude encounter fixes with OneWeb proximate to the geosynchronous belt on a regular basis. If spectral separation alone was insufficient to prevent interference, it's not something that would affect communications when a satellite is near the equator at all, it's something that would affect all the satellites nearly all the time. A 1200km orbit is 30x closer to Earth than the geosynchronous belt.
  - maxerickson 11y ago
    The link I posted has some context that makes it clear that the statement is about radio interference. Various press statements about the system say that the satellites will turn, for example, search "Progressive Pitch" here: http://spacenews.com/virgin-qualcomm-invest-in-global-satellite-internet-plan/ http://spacenews.com/virgin-qualcomm-invest-in-global-satell... (or on my earlier link or Wikipedia) But it must not be thruster based.
- ChuckMcM 11y ago
  This link http://www.oneweb.world/#technologies http://www.oneweb.world/#technologies with the 'learn more' button shows how the satellites beam to the left and then switch to beaming to the right when they cross the equator, presumably they briefly turn off at the equator to avoid anyone try to transmit to them and have the back scatter continue on up into GEO where it might confuse a satellite up there. EDIT: Look for "Progressive Pitch" on the web page.

by mapt 11y ago

maxerickson 11y ago

Their spectrum license requires that they not create radio interference for geosynchronous satellites. How they plan to accomplish that is not clear to me.

mapt 11y ago
I interpreted him to mean physical collision risk. As for interference: They're planning on beaming signal to a wide swath of every plane for full-Earth coverage, not just at a narrow stretch near nadir. That means you'll have users acquiring a fix from a wide swath of sky; Let's say 45 degrees from zenith in various directions. That would make every user below 45 degrees latitude encounter fixes with OneWeb proximate to the geosynchronous belt on a regular basis. If spectral separation alone was insufficient to prevent interference, it's not something that would affect communications when a satellite is near the equator at all, it's something that would affect all the satellites nearly all the time. A 1200km orbit is 30x closer to Earth than the geosynchronous belt.
- maxerickson 11y ago
  The link I posted has some context that makes it clear that the statement is about radio interference. Various press statements about the system say that the satellites will turn, for example, search "Progressive Pitch" here: http://spacenews.com/virgin-qualcomm-invest-in-global-satellite-internet-plan/ http://spacenews.com/virgin-qualcomm-invest-in-global-satell... (or on my earlier link or Wikipedia) But it must not be thruster based.
ChuckMcM 11y ago
This link http://www.oneweb.world/#technologies http://www.oneweb.world/#technologies with the 'learn more' button shows how the satellites beam to the left and then switch to beaming to the right when they cross the equator, presumably they briefly turn off at the equator to avoid anyone try to transmit to them and have the back scatter continue on up into GEO where it might confuse a satellite up there. EDIT: Look for "Progressive Pitch" on the web page.