[Starlink] Starlink for Tonga?

Fri Feb 18 10:43:42 EST 2022

Awesome explanation, thanks for sharing!

It looks like 50 Starlink terminals have arrived in Tonga:
https://matangitonga.to/2022/02/18/elon-musk-donates-50-satellite-terminals-tonga

On Fri, Feb 18, 2022 at 4:48 AM Rich Brown <richb.hanover at gmail.com> wrote:

> This is such a cool summary of the current process...
>
> Once I was wasting time in the Dartmouth engineering library (when I was
> supposed to be doing work). I found an older book about the laying of the
> first trans-Atlantic cable. They had terrible problems (their first effort
> failed), for example...
>
> - It was a single strand insulated by gutta-percha (rubber-ish stuff I
> think). They tested for continuity by hourly (?) tests from a team on shore
> sending current one way for a minute, then the other way. They used a
> galvanometer to detect... Talk about low bits/second.
> - When the cable broke, they used the same "back up and drag a grappling
> hook" technique to snag the cable and bring it up
> - It weighed a ton - literally. If I remember correctly, each length from
> the sea floor to the surface weighed 6,000 pounds, so they had to hoist
> 12,000 pounds of cable to begin to find the broken end
>
> Everything's the same... But a lot better :-)
>
> Rich
>
> On Feb 18, 2022, at 5:27 AM, Ulrich Speidel <ulrich at cs.auckland.ac.nz>
> wrote:
>
> 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>
> <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
>
>
> 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
> _______________________________________________
> Starlink mailing list
> Starlink at lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/starlink
>
>
> _______________________________________________
> Starlink mailing listStarlink at lists.bufferbloat.nethttps://lists.bufferbloat.net/listinfo/starlink
>
> --
> ****************************************************************
> Dr. Ulrich Speidel
>
> School of Computer Science
>
> Room 303S.594 (City Campus)
>
> The University of Aucklandu.speidel at auckland.ac.nz http://www.cs.auckland.ac.nz/~ulrich/
> ****************************************************************
>
>
>
>
> _______________________________________________
> Starlink mailing list
> Starlink at lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/starlink
>
>
> _______________________________________________
> Starlink mailing list
> Starlink at lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/starlink
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.bufferbloat.net/pipermail/starlink/attachments/20220218/044f7cd7/attachment.html>