SpaceX sends first direct-to-cell Starlinks to orbit
- Reference: 1704303913
- News link: https://www.theregister.co.uk/2024/01/03/spacex_sends_directtocell_starlinks_into/
- Source link:
[1]Liftoff , which took place at 0344 UTC today, launched a batch of 21 Starlink satellites to Low Earth Orbit from Space Launch Complex 4 East (SLS-4E) at California's Vandenberg Space Force Base. SpaceX has now notched up 296 launches, 260 landings, and 231 reflights. The launch was the first flight for this particular booster.
While the launch was routine, the most notable part of the payload are the cell-capable sats, which the company says will provide "seamless access to text, voice and data for LTE phones across the globe."
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The mission came weeks after the Federal Communications Commission (FCC) [3]cleared SpaceX to start testing the service. The company told the agency it required "experimental" authority to kick off testing, and has 180 days to do so.
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In its application, SpaceX said the testing would involve around 840 satellites with direct-to-cellular payloads, of which approximately 60 would serve US handsets at any given time.
According to SpaceX, "The enhanced Starlink satellites have an advanced modem that acts as a cellphone tower in space, eliminating deadzones with network integration similar to a standard roaming partner."
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The launch opens up another front in the battle of the billionaire constellations. Jeff Bezos' Project Kuiper is currently testing its first prototype satellites, with production versions set to join them in orbit. SpaceX plans to use cellular spectrum from its mobile partners – T-Mobile in the US – to make the service commercially available.
[7]SpaceX cleared to test satellite phone service via Starlink
[8]FCC really, truly won't give SpaceX nearly a billion bucks for Starlink rural broadband
[9]China's SpaceX wannabe recycles a rocket after just 38 days
[10]NASA pushes back timing of ISS deorbit vehicle contract
However, regulatory approval is required to make that happen. The company also faces criticism from competitors concerned about the potential for interference, and some astronomers might be alarmed to note that, according to SpaceX's webcast, "we do expect these first six Starlink direct-to-cell satellites to be a bit brighter than previous Starlink V2 Minis."
SpaceX has, however, said that after it has measured the effect, it will take steps to make future satellites as dim as possible. "We firmly believe in the importance of a natural night sky for all of us to enjoy."
So that's alright then.
As well as T-Mobile in the US, SpaceX has hooked up with operators in Australia, Canada, New Zealand, Japan, Switzerland, and Chile. A messaging service should come first, followed by voice and data. ®
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[1] https://www.spacex.com/launches/mission/?missionId=sl-7-9
[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/networks&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2ZZXnHUQwggdJBRC2hUAbQgAAAEE&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[3] https://www.theregister.com/2023/12/15/spacex_cleared_to_test_satellite/
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/networks&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44ZZXnHUQwggdJBRC2hUAbQgAAAEE&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[5] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/networks&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33ZZXnHUQwggdJBRC2hUAbQgAAAEE&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[6] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_onprem/networks&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44ZZXnHUQwggdJBRC2hUAbQgAAAEE&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[7] https://www.theregister.com/2023/12/15/spacex_cleared_to_test_satellite/
[8] https://www.theregister.com/2023/12/14/fcc_starlink_spacex/
[9] https://www.theregister.com/2023/12/12/ispace_china_test_success/
[10] https://www.theregister.com/2023/12/10/nasa_pushes_back_iss_deorbit/
[11] https://whitepapers.theregister.com/
Pretty sure they'll stop transmitting the cell signal when they're not over the US. Also, Starlink is noted for beam steering (at least for the terrestrial dishes), so they should be able to only send the signal to where they want.
Just like how they work with getting licensing to provide Internet service in different countries, they should be able to selectively "turn on" cell service in other countries if/as they get licensed.
Likely spectrum will be “shared” by the local mobile operator- for the US it be T mobile, who will carve out a block of their spectrum holdings and switch off the range of frequencies from their terrestrial network. Then SpaceX switch on the matching frequencies on their spaces based transmitters.
SpaceX (along with Lynk and AST) will likely be using software defined radios so they can reconfigure their satellites to match the spectrum bands of countries they are passing over at the time. This will be tricky in places like Switzerland, as cross border issues will arise as the beams from space are very wide and hard to control. Australia and NZ will likely be fine, the secret sauce will have to be added for places like Switzerland to minimise these issues and interfering with neighbouring countries terrestrial cellular networks.
"but presumably the satellite can see a number of different countries from that far up"
The satellites are very low (for a satellite) and are looking down with a restricted cone as well. Over Europe, they'll be able to see several countries, but over the US, China, Russia, etc, they won't. The sats are just a router in space, they must have a ground station to tie into the internet/phone network. Starlink isn't a backbone provider.
Beam forming technology
Even more than traditional geostationary TV/Telecom satellite transponders, LEO satellites antennas like starlink rely heavily on so-called beamforming technologies (increasing and steering gain using massive MIMO antennas, phases, delays and interference) to focus their signal to specific geographical areas. These areas are still too large to be useful in dense, well served, urban settings, but this is not where non terrestrial networks (satellite networks) can claim their best business case.
Beamforming technologies are not only leveraged on satellite side (emission and reception beamforming), but also, in the case of classic rooftop Starlink antennas on the ground to track and to aim at the fast moving LEO satellite, with maximum efficiency. This is possible because rooftop antennas are fixed and can emit much more power than your average 2W smartphone.
In the case of smartphones, uplink beamforming is, best of my knowledge, not an option, simply because smartphones are not fixed (can't track or aim) and have only a few antennas. Therefore, in that case, all the heavy lifting is performed on the satellite side through higher sensitivity and robust protocol (e.g. harq: hybrid automatic repeat request). This is why only SMS is supported for now. Supporting voice will be a remarkable feat of engineering (if it really works).
Genuine (Dopey) question... how do they use T-Mobiles North American spectrum? Presumably that same spectrum is used by other providers in other places? I can get that they might just "turn off the satellite" when it flies over somewhere other than America, but presumably the satellite can see a number of different countries from that far up... So, could it work in Europe, or would there have to be some kind of spectrum harmonisation?