[Starlink] An update on Tonga

[Ulrich Speidel]

Word from Tonga Cable that the break on the domestic cable was fixed on 
Friday. This time, it was a much smaller slip and no significant amount 
of cable was lost, they used about 4 km of spares (owing almost entirely 
to the deployment depth and the need for slack during the repair).

They are currently considering two alternative routes from Tongatapu to 
Ha'apai, but this needs a marine survey, and getting a spur coming in to 
Vava'u from the Hawaiki cable currently has priority. They hope that 
that spur should be in place by about September next year.

On 31/08/2024 7:35 pm, Ulrich Speidel wrote:
> Howdy all,
>
> There were quite a few folk on this list a couple of years back who 
> were interested in what was happening to Internet in Tonga after the 
> big volcanic eruption there. I'm not sure where I left off.
>
> To re-cap, Tonga lost about 90 km of its international connection to 
> Fiji at the time (a few dozen km of that could be recovered), and an 
> amount of cable of similar magnitude on the Tonga Domestic Cable 
> Extension (TDCE) that ran a fibre pair each to both Vava'u and Ha'apai 
> from the main island Tongatapu. The TDCE is one of the longer 
> unrepeatered stretches of submarine cable in the world and runs in a 
> submarine trench just downhill from the Hunga Tonga Hunga Ha'apai 
> volcano and its siblings in the chain. Simulations at the timed showed 
> that this trench likely received a large amount of the material that 
> was ejected from the volcano, likely several cubic kilometres, and 
> acted as a kind of gutter that guided the material away from the 
> volcano in turbidity flows stretching over hundreds of km. At the 
> time, the cable ship sent to repair was unable to repair the TDCE for 
> lack of spare cable - nothing was recoverable from the seafloor, and 
> there was not enough spare cable in the South Pacific to bridge the gap.
>
> Spare cable was ordered from France and was installed middle of 2023, 
> restoring the TDCE to service.
>
> Then, on 29 June 2024, an earthquake near the volcanoes caused yet 
> more debris to descend on the cable, obliterating 13.7 km of it and 
> cutting service to both Vava'u and Ha'apai again. Cable ship MV 
> Lodbrog was brought in from Singapore with 60 km of spares but got 
> delayed in Fiji due to mechanical issues. The cable was repaired on 16 
> August 2024, in the same location. The operators were well aware of 
> the risk, however re-routing the cable would have required it to be 
> lengthened, with the need to insert repeaters, upgrade terminal 
> equipment, and conduct a new marine survey, which would have meant 
> further delays.
>
> On 26 August 2024, 11:29 am, a M6.9 quake struck in the area at a 
> depth of about 106 km. Our Science building in Auckland has a "citizen 
> science" seismograph with a big display in its foyer, and my student 
> and I noticed the very prominent event as we returned from lunch. 
> Little did we know that this wasn't as close to home as we'd thought, 
> but would touch us in other ways that week. You've guessed it: The 
> cable has been cut again, the cable ship's been recalled, and nobody 
> quite knows what they'll find this time.
>
> https://matangitonga.to/2024/08/27/domestic-submarine-cable-out-again-after-haapai-earthquake-yesterday 
>
>
> The latest plan I know of was to repair in the same location again, 
> using armored spares - but they know that this may not prevent further 
> damage. Geological advice is that any decent quake in the area will 
> cause further submarine landslides in the coming years until the area 
> has settled.
>
> Meanwhile, Starlink has been licensed to operate commercially in 
> Tonga. For many Pacific Island countries, this is a double-edged 
> sword: On the one hand, this provides short-term relief, on the other 
> hand, it deprives local ISPs of customers and therefore impacts on 
> aspirations to achieve cable connectivity which could provide more 
> bandwidth in the medium term.
>
> Some island nations have not yet licensed Starlink, but allow Starlink 
> units on regional roaming plans to operate there. In some cases, there 
> are now hundreds of such units operating in individual cells. This 
> appears to be causing Starlink some headaches in terms of capacity - 
> we've seen them being creative when it comes to user density 
> management before. What happens if Starlink are going to be licensed 
> there but can't offer fixed service on the ground because of the large 
> number of roaming subscribers already there? I understand that some of 
> these "roaming" users have been contacted by Starlink with a request 
> to either take these units back to their home location country where 
> they are registered (which isn't likely to happen given the cost 
> involved) or register them in the country they're currently in (not 
> possible in some cases for lack of local fixed service offered).
>
> Ulrich
>
>
-- 
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Dr. Ulrich Speidel

School of Computer Science

Room 303S.594 (City Campus)

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