[Starlink] Starlink for Tonga?

Fri Feb 18 05:29:02 EST 2022

I've heard nothing further about teleport establishment in Fiji, but 
that doesn't mean that nothing has happened.

Meanwhile, cable repair has progressed a good bit. The damage was far 
greater than originally envisaged. On the international cable, faults 
(complete cable ruptures and fibre damage) stretched over more than 80 
km. The cable ran entirely SOUTH of the Hunga Tonga Hunga Ha'apai 
volcano (about 60 km away and shielded by a number of submarine mounts 
for at least parts of the damaged section). Yet the Reliance cable ship 
traced one disconnected cable piece end to about 5 km NORTH of its 
nominal route, found various sections had disappeared completely, and 
recovered sections of up to 9 km at a time from the seabed.

A bog standard cable break requires two holding drives (or drags), HD 
for short, to pick up each of the cable endpoints from the seafloor. It 
also requires either an ROV dive to check if the cable has completely 
separated at the fault position, or a cut if the cable is still held 
together by the steel. That cut can be done either by ROV as well, or if 
visibility doesn't permit ROV use, by a cutting drive (CD). Any HD or CD 
requires the cable ship to tow a seafloor grapnel / cutter device 
transversally across the cable, so they're easy to spot on position 
traces. The Reliance did no fewer than seven HD's in its eastern 
operations area near Tongatapu, where it worked first. Visibility there 
was good (so ROV could be used), but damage substantial.

The ship then proceeded to the western end of the fault zone where 
reflectometer measurements from the Suva end had found a fault. Because 
of bad visibility, they did a CD followed by 2 HD's there, then noticed 
that there was fibre damage along the cable to Suva, so reeled that in 
and cut the damaged bit out.

They then proceeded to put a "mini-system" together. Let me explain: 
Enroute to Tonga, the Reliance stopped at Subcom's depot in Apia (Samoa) 
to load whatever cable they had in store there. This included spares not 
only for the Fiji-Tonga cable but also for various other cable systems 
in the wider region. Reliance left Apia with about 80 km of cable in 
total. The amount of cable that will need to be re-laid along the 
damaged international section is 90 km (you need to allow for a bit of 
cable lengthening due to slack being inserted when cable ends are being 
brought up from 2000 m (6000 ft) or so below). This means that the 
Reliance is re-using some of the cable recovered from the damaged 
section, and the whole "mini-system" will be one long stitch job. The 
damaged section also included a repeater worth US$230k, which they were 
trying to recover and which was still missing as of this morning - I've 
yet to hear from my contact as to whether they were successful on the 
last recovery attempt today (they've left the area after three drives 
and are heading West right now. The rest of the mini-system was going to 
be laid after the repeater recovery attempt (the overall success doesn't 
depend on the repeater being found, but the final repair bill does). I 
thus expect the cable repair to be completed in the next few days.

The domestic cable is another story altogether, unfortunately. This has 
a blind stretch of 77 km at present, as measured by optical 
reflectometer from Tongatapu and Ha'apai (there was meant to be a 
measurement from Vava'u yesterday but I haven't heard yet what this 
revealed, the cable from Tongatapu has two fibre pairs, one of which 
heads to each destination from a branching unit west of Ha'apai. That 
said, once the international cable has been fixed, the Reliance won't 
have enough cable left to complete the domestic job, even if some cable 
bits could be recovered there. The next available stock of suitable 
cable is in Europe, around 35-40 days one-way shipping away. They intend 
to bridge this time gap via satellite (and I'm sure would welcome a 
Starlink delegation with a teleport to connect to the international 
cable, too, especially now that the Australian Navy gave them Omicron 
along with their aid deliveries).

I've been in close contact with our volcanology / geophysics community 
here in NZ, who know the area well. The story of damage to the 
international cable is now shaping up to be a pretty complex one. What 
we know thus far is that it was neither the volcano's initial blast nor 
the subsequent tsunami that killed the cable - the outage began only 
well after the tsunami had hit. In all probability, it's been a 
combination of submarine landslides and turbidite waves from a variety 
of sources that hit hours and possibly many days after the eruption. 
Finding that a cable piece has moved 5 km TOWARDS the volcano points at 
an event south of the cable route, and the mix of seafloor visibilities 
encountered by the Reliance points at there having multiple events from 
multiple sources. There have been plenty of quakes upwards of M4 and 
even an M6.2 in the wider area that could have triggered slopes, 
especially with an extra layer of ash on them. Turbidite waves can 
travel up to 1000 km, aren't anywhere near as fast as a tsunami, and 
have long been known to have damaged cables in the past (see B.C. Heezen 
and M. Ewing, Turbidity currents and submarine slumps, and the 1929 
Grand Banks Earthquake, American Journal of Science, v. 250, pp 849-873, 
December 1952. This quake killed 12 submarine cables over more than 18 
hours).

Meanwhile, there's still limited satellite service in and out of Tonga, 
but I can confirm that e-mails (even with attachments) make it in and 
out OK.

On 18/02/2022 8:27 pm, Mike Puchol wrote:
> Hi Daniel,
>
> I added it after there was a confirmation on Twitter that SpaceX 
> people were on the ground to set one up, and also, as two /27 blocks 
> (IPv4) have been assigned to Fiji’s capital, under the Sydney POP, and 
> they can be pinged.
>
> Wether it’s at the teleport or not, unsure, but for simulation, an 
> error of even a few km doesn’t really matter.
>
> Best,
>
> Mike
> On Feb 18, 2022, 06:04 +0100, Daniel AJ Sokolov <daniel at falco.ca>, wrote:
>> On 2022-02-07 at 15:29, Mike Puchol wrote:
>>> As far as placing a gateway in Fiji, it already has a teleport
>>> facility, which will have power and fibre (unless that one has been
>>> taken out too?). Checkhttps://goo.gl/maps/6BYXf4R17yys7zNe9 
>>> <Checkhttps://goo.gl/maps/6BYXf4R17yys7zNe9>
>>
>> Hey Mike, you put a "SUVA (Emergency)" ground station on starlink.sx.
>>
>> Is that for simulation, or has Starlink actually installed a ground
>> station in Fidschi by now? Would you have positive confirmation?
>>
>> Thank you
>> Daniel
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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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