For most of the satellite era, if your vessel was required to carry GMDSS — the Global Maritime Distress and Safety System — your choice of satellite provider for that safety service was, in practice, a choice of one. That was simply how the system had grown up. It worked, but a single option is never an ideal position for the buyer, and it left a real gap in coverage at the top and bottom of the world.
In 2018 that changed, and it’s worth understanding what changed and why it matters — whether or not you’re in the market today.
What actually happened in 2018
The International Maritime Organization’s Maritime Safety Committee recognised Iridium as a Recognised Mobile Satellite Service for GMDSS. In plain terms: a second satellite network was formally approved to carry the distress and safety services that SOLAS-class vessels are required to maintain.
This wasn’t a minor administrative tidy-up. GMDSS is the framework that coordinates maritime distress alerting worldwide — the system that ensures a vessel in trouble can raise the alarm and that the right authorities hear it. Approving a second provider, after decades of a single one, opened genuine choice into a part of the vessel where there had never been much.
Why pole-to-pole is the real story
The headline isn’t just “more competition.” It’s coverage.
GMDSS safety services delivered over a geostationary network share the same limitation as any geostationary system: coverage thins toward the high latitudes and runs out near the poles. For a vessel working the far north or deep south, that’s not an abstract concern — it’s a coverage gap in exactly the kind of remote, hostile water where a distress alert is most likely to be needed and help is furthest away.
The Iridium network is a low-Earth-orbit constellation that covers the entire planet, pole to pole. Bringing GMDSS onto that network means distress and safety communication that doesn’t fade as the vessel travels north. For operators on Arctic routes, in the Southern Ocean, or anywhere in the high latitudes, that closes a gap that was simply part of the landscape before.
The system that made it real
Recognition by the IMO is a framework; someone still has to build the terminal that delivers it. The LT-3100S, developed and manufactured by Lars Thrane, was the first Iridium GMDSS terminal brought to market — and remains the system that turned the 2018 decision into equipment a vessel can actually install.
It carries the full GMDSS toolkit a mandated vessel needs: type approval across Sea Areas A1, A2, and A3, with MED and Wheelmark certification; Distress Alert and Distress Call; Safety Calling and Safety Messaging; and Maritime Safety Information. Alongside the safety services, it integrates the Ship Security Alert System (SSAS) and Long Range Identification & Tracking (LRIT) — security alerting and position reporting — into the same certified unit.
The same GMDSS capability now extends across a range. For vessels that want more everyday data capacity alongside the safety services, the LT-4100S and LT-4200S bring GMDSS to the Certus® 100 and Certus® 200 platforms. The safety layer is consistent; the difference is how much commercial connectivity sits beside it.
What it means if you’re not buying today
Even if your next GMDSS decision is years away, the 2018 change matters for two reasons.
First, choice tends to be good for the buyer over time — in service, in airtime options, and in the pace of improvement. A market with a recognised alternative behaves differently from one without.
Second, and more concretely: if your vessel’s operating area includes the high latitudes, the coverage question is now a live one to put on the table. The option to carry GMDSS safety services on a network that genuinely reaches the poles didn’t exist before; now it does, and it’s worth knowing that when the time comes to specify or replace equipment.
The bottom line
GMDSS exists so that a vessel in distress can be heard, wherever it is. For years, “wherever it is” came with an asterisk at the high latitudes. The recognition of Iridium for GMDSS — and the equipment built to deliver it — has gone a long way toward removing that asterisk. For an industry where safety equipment is judged by its worst-case performance, that’s a change worth understanding.