Re: [Starlink] Starship's 4th flight test was magnificent

[Ulrich Speidel <u.speidel@auckland.ac.nz>]

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On 10/06/2024 11:50 am, Dave Taht via Starlink wrote:
>
> The second set of questions are that the newer, larger Starlink 
> satellites were designed, oh, 4 years ago? with about 4x the capacity 
> of the existing ones, and I imagine (and hope) that they have been 
> continually redesigned with an eye to latency now, as well as capacity.

What do you actually mean by "capacity" here? We have actual numbers in 
terms of what SpaceX are licensed for for user downlink, and that works 
out to be:

 From a V1 or V1.5:

  * no more than 12 Gb/s into a single cell.
  * no more than 16 Gb/s across all user downlink beams.

 From a V2(mini):

  * no more than 20 Gb/s into a single cell on Ku.
  * no more than 48 Gb/s across all beams licensed for Ku user downlink.
  * no more than 25.2 Gb/s across all beams licensed for Ka user
    downlink into a single cell.
  * no more than 99.2 Gb/s across all beams licensed for Ka user downlink.

Note:

  * The current Dishys don't seem to do Ka, at least going by their FCC
    licenses.
  * In Gen 2 systems, there is no longer an explicit distinction made
    between user and gateway downlinks on at least some beams, so the
    above figures assume that all service downlink beams are carrying
    user traffic.
  * The above figure are before any FEC.
  * The single cell limits are independent of the number of satellites
    you deploy - it's the most a cell can get.

But, like you, I'm somewhat intrigued that we haven't see any follow-up 
applications from SpaceX at the FCC for the 3rd generation. 
SAT-LOA-20200526-00055 is four years old, and its latest amendment from 
March this year (unless something's popped up in the last  few weeks) 
relates to their D2D plans only. The latest amendment pertinent to 
Internet things is from August 2021. The gap between Gen 1 
(SAT-LOA-20170726-00110) and Gen 2 (SAT-LOA-20200526-00055) was just 
over three years - and it took almost that long to get 
SAT-LOA-20170726-00110's last modification SAT-MOD-20200417-00037 filed. 
Maybe now that they know that they can get a lift, they will. Or maybe 
they're going flag of convenience and will launch under the Tongan 
regulator, where they've applied for 29,995 satellites, somewhat more 
recently.

-- 

****************************************************************
Dr. Ulrich Speidel

School of Computer Science

Room 303S.594 (City Campus)

The University of Auckland
u.speidel@auckland.ac.nz  
http://www.cs.auckland.ac.nz/~ulrich/
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