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 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 > 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 > , 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@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink > > > _______________________________________________ > Starlink mailing listStarlink@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@auckland.ac.nz http://www.cs.auckland.ac.nz/~ulrich/ > **************************************************************** > > > > > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink > > > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink >