Fortis Stratoliner S-41 review – To infinity and beyond!

Tags: Review | Fortis | Classic

9.12.2025 | 5 MIN

You don’t turn down a chance to review a watch that’s been to space. There’s more to the Fortis Stratoliner S-41 than meets the eye, yet it doesn’t scream that it’s something special. And while you’re not supposed to put the conclusion up front, I’ll say it anyway: even though I found a few things I’d improve, overall this is my top space watch—and one that realistically has a shot at outshining the Speedmaster. But enough spoilers; let’s take a closer look at the Stratoliner.

First impressions

If you’ve been paying even average attention, you’ve probably gathered that I’m excited about the Stratoliner. But why, exactly? I want to highlight the refined indices, the spacing, the details—and really the dial as a whole. Design is subjective, but to me this one is spot on.

That said, the watch is fairly large (41 mm in diameter, 14.5 mm thick) and heavy. While Fortis offsets this “drawback” with a very comfortable bracelet, an exceptionally robust clasp, and overall excellent execution, there will simply be people who won’t like a watch this heavy and tall. In any case, it exudes a very solid, even tool-like character. It’s a true workhorse that won’t shy away from mud, water, shocks, magnetism, or, ultimately, space.

Movement

Although I’m usually not that obsessed with movements, the Stratoliner is something of an exception. While it’s interesting in other ways too, the main selling point will likely be the automatic mechanical movement WERK 17. This isn’t just a stock movement with a swapped rotor and a new name. At the same time, it isn’t a Fortis in-house caliber either. So what is it?

Source: https://chrononautix.com/

In the early 2020s, Fortis was acquired by a new owner, Jupp Philipp—and he really pushed things forward. He approached the legendary movement maker La Joux‑Perret (LJP) and asked them to create a movement that would function in space. LJP said, “Yes, sir. No problem.”—and developed WERK 17, whose final testing phase took place in actual space. Fortis sent a few test movements up to an altitude of 30 km and everyone could only hope the effort wouldn’t go to waste.

As for specifications, the Werk 17 is no slouch. It offers a 60-hour power reserve, 26 synthetic jewels, and a frequency of 28,800 vph. There’s also a shock-resistant construction with a transverse bridge spanning the entire chronograph module, which, in short, increases the rigidity and durability of the whole movement.

As a watch nerd, I’m delighted. Chronographs are often prone to issues and expensive to service, but here I wouldn’t hesitate to wear the watch daily. When a movement is literally developed for space travel, it ought to handle a few knocks.

Dial

All variants are beautiful, minimalist, and finely executed—I honestly wouldn’t know which one to pick.

I have the blue version in for review, so I’ll focus on that one—though much of this applies across the colorways. The dial base has a light-absorbing, dust-like texture. The texture becomes more pronounced in sunlight and there’s plenty to admire.

There are three white sub-dials—one for running seconds, one 30-minute counter, and one hour counter. On the right side of the dial you’ll find the Fortis logo plus day-of-week and date display.

I was pleased to see Fortis use its own typeface, which matches the rest of the watch—and like the rest of the watch, it’s minimalist and highly legible. Finally, there’s a white minute track with very fine red-and-black markers and five-minute numerals.

On the rehaut between the crystal and the dial you’ll find the engraving “DER HIMMEL IST NICHT DAS ENDE DER WELT,” which loosely translates as “The sky is not the end of the world.” What’s truly fascinating on the Stratoliner, though, is the lume.

The lume only glows on highlighted segments that correspond to key phases of a rocket’s flight. There’s 30 seconds, the time needed to ignite the engines. On the minute counter, 15 minutes are marked—the duration of the weightless, i.e., suborbital, phase. And finally, there’s a highlighted 90-minute segment, the interval from mission launch to recovery.

Given that I love good lume—and I really love space and sci‑fi—this is absolutely mind-blowing for me. Five stars out of five to Fortis for this touch.

Case

As mentioned above, the watch is tall, substantial, and heavy. On the steel bracelet it weighs a full 230 grams, which is no featherweight. The dial is protected by a sapphire crystal with anti-reflective coating on both sides. At this price point, anything else would be unacceptable. At the time of writing the watch costs just under 137,000, or a bit over 5,000 euros, which puts it into a more luxurious segment—so I have to look more critically.

The case struck me as quite sharp-edged and, above all, functional, though not outright uncomfortable. At 14.5 mm thick the Stratoliner will struggle to slip under a shirt cuff. I quite like the small detail on the bezel and crown in the form of a black ring, likely made of a material other than steel (I didn’t have a refractometer or spectrometer handy). It neatly divides the watch into sections and visually reduces the perceived case height.

On the underside you’ll find a sapphire display back. The caseback is secured with screws and carries a few inscriptions around the edge, the most interesting being “SPACE RESISTANT 20 ATM,” a nod to resistance to space as well as to 20 ATM water resistance—which, by the way, also makes this an excellent watch for diving. The crown is screw-down, so the weakest link will be the non-screw-down chronograph pushers.

Source: https://chrononautix.com/

Bracelet

I see one blemish with the bracelet: it doesn’t integrate with the case, leaving a gap between the case and bracelet. That’s all. Otherwise, it’s a non-tapering three-link, very solid, with a clasp that features micro-adjustment.

The micro-adjustment is very fine, letting the user size the watch precisely. The clasp is wide and struck me as virtually indestructible—like the rest of the watch. I have no complaints here; on the contrary, although the watch is large and heavy, the bracelet makes it very comfortable for everyday wear. Just be careful when changing straps, because the Stratoliner doesn’t use traditional spring bars but screws, so swaps can be a bit more involved.

Final word

I see competition in the cheaper Bulova Lunar Pilot, which is fairly large and quartz (albeit very precise), and whose mechanical predecessors actually went to the Moon.

8.12.2023
TOP 5 alternatives Omega Speedmaster Moonwatch

Another competitor is the Omega Speedmaster, which is a few tens of thousands more at retail. Its advantage? It’s fantastic and has a fantastic story. The downside? Lots of people have one. The Stratoliner is a very wearable daily alternative which, of these three, is the most functional and most robust in my view—and likely the one I’d choose for a trip to space.

Overall, the target audience for the Stratoliner will be watch enthusiasts and watch nerds—my favorite groups.

Whoever read all of this today can reward themselves by learning Michael Jackson’s Moonwalk.

Photo sources: official manufacturer images, https://chrononautix.com/

You might also be interested in:

7.12.2023
Bulova Lunar Pilot Review – Modern Mission to the Moon