Designing Spacesuits for The Sojourn

Hey everyone, It’s me Gabriel! Science Advisor for The Sojourn.

Today I was asked to talk a bit more about the EVA Suits of the Sojourn - about our design process, the design itself, and its final depiction in the trailer and other promotional material.

We started designing the EVA Suits proper while we were putting together our Release Trailer for Volume 1, around April 2020. One of the scenes from the episodes in the volume that we chose to depict was that of Cass and Meds walking (though “floating” is more appropriate, I guess...) through the corridors of the decrepit Gatehauler from Inclement Weather. It naturally followed that we’d need to properly figure out what the space suits looked like, and that that’d be a job for me.

Most people don’t give them much thought, but Spacesuits are incredibly complex machines that are essentially miniature spaceships in their own right. Not only do they have to keep a squishy, needy human alive, they also need to be at least vaguely human-shaped and flexible enough to allow said human to operate and do human-things while wearing it.

Keeping all this in mind, the first order of business was figuring out the design requirements of the suit. From talks with Dan, we knew we wanted something that was real-looking, but still much less bulky than modern EVA suits. We also knew we wanted each of the three crewmembers of the Guin to have their own suit. From that I started considering the different kinds of Spacesuits we could chose from.

Spacesuit designs can be generally grouped into three broad categories: Soft Suits, Hardsuits, and Mechanical Counterpressure Suits.

Soft Suits are what most real-life spacesuits to date have been; they’re made of soft, airtight tissues and are internally pressurized. This can lead to some inconvenient problems, however - the first being that by pressurizing it, you’re creating what is essentially a ballon. It gains rigidity, making it hard to articulate the suit. Where this really becomes a serious problem is around the knees and elbows, where we are supposed to bend; as you bend your arm, the internal volume of the spacesuit changes, becoming smaller. As the amount of air in the suit is still the same, this means that by bending your arm, you’re compressing the air inside the suit, and as anyone who has ever played with a syringe knows, trying to compress air takes a lot of effort. To circumvent this issue, Soft Suits use an incredibly clever solution: Constant-Pressure Joints. These are the classic, 50’s looking, Michelin-Man accordion bendy-straw pieces you can see in pulp sci-fi spacesuits. As their name implies, they do not change their internal volume when they bend, and as not work is being applied to compress the air inside the suit, they allow for relatively unimpeded movement. If you’re now thinking “hold on, if that’s true, then why don’t the spacesuits astronauts wear have them”? The fact is, they do - this is what the Apollo EVA suits, the A7L, looks like under the insulation layers:

The second kind of suit is the Hardsuit. In hardsuits, as the name indicates, most of the components in the suit are not made of fabrics, but actual hard components. Instead of relying on constant volume joints, The actual physical shell of the suit articulates on hinges and rotation points, so that the suit does move, but the volume remains constant. They also have the benefit of being very sturdy, as they can be manufactured with rigidity in mind. Their main issues, however, are weight and potential difficulty of articulation.

Finally, Mechanical Counterpressure Suits sidestep the need for pressurization entirely - instead of having a force applied upon the body by the air in a suit, the MCP spacesuit itself squeezes the wearer’s body and prevents it from ballooning towards the vacuum of space. These form-fitting suits would also have the added benefit of having almost no impact on mobility whatsoever, and could potentially be the lightest out of all three kinds of suits. Their drawbacks generally revolve around the necessity for a flawless seal; If any part of the wearer’s body is not properly squeezed by the suit, it will expand to fill that gap (why this might be a problem or otherwise uncomfortable is left as an exercise to the reader). This essentially makes it so MCP suits must be tailor-made to each user.

With all that in mind I went back to our goals and needs for the story: our suits had to be relatively slim, allow for largely unimpeded movement, and be able to be worn by different people. Starting to investigate and iterate upon our options, I immediately tested possibility of Mechanical Counterpressure Suits, toying with the idea of using Dielectric Elastomers Layers to allow the suit to relax and contract to adapt to the wearer, but we eventually abandoned this concept, as it felt both too advanced for our setting and looked too sleek.

Hardsuits were too bulky and gave off too much of a military vibe compared to what we wanted, so we went back to Soft Suits. One recurrent problem with Space Suit designs in the real world is the gauntlets - they tend to be very bulky and hard to move. Given our characters are meant to operate firearms whilst suited up, this would be a thorn on our side. Thinking about this need for manual dexterity and the style we wanted for our suits, we eventually decided to pick the best of all worlds, and go for a hybrid spacesuit. The design we ended up going with is a Softsuit with Mechanical Counterpressure gloves and a detachable helmet. On the shoulders and torso sides of the suit there are hardpoints for connection to a removable Life Support System pack, with the capability of having a cold gas propulsion module attached to it to allow for propulsive zero-g manoeuvring. From this, I made this first drawing to discuss the design with Dan:

Once we felt we were definitely going in the right direction, we set about hammering out the more aesthetic details of the suit, like the different surface materials, the appearance of the LSS Backpack and the layout and accents of the suit. At the end of this process, the preliminary concept above became:

This is the design that was handed to Leon so he could work his magic, and eventually became the suits you can see on the trailer. Personally, I’m quite happy with how this design came out; It looks good, looks functional, and fits both our aesthetic and narrative needs.

The final design consists of a bodysuit, two mechanical counterpressure suits, and the helmet, as well as a detachable life-support pack. The bodysuit is donned by opening an airtight zipper (yes, these are a real thing - I was surprised too) that goes from the base of the neck tunnel, down the back, and all the way to the crotch area - the same scheme used on the Apollo A7L Suits. Once the wearer has put their legs, head, and arms into it, the zipper is closed and the LSS pack is hooked to the four connection points, establishing the linkage to the air supply and water coolant loops, as well as the electrical and avionic subsystems. The wearer can then proceed to put on their mechanical counterpressure gloves, secured by the airtight latch mid-forearms, and then, finally, they can put on their helmet.

An observant reader may have noticed that the final design sketch lacks a helmet - that’s due to the author having been hit by a train-sized artblock at the time, so the only real information on the helmets was that they’d crack open in two with a hinge system, tilting the front half of the helmet forwards - this way, a secure seal can be established with the neck tunnel without the need to constrain the helmet to a big and bulky circular ring seal. With this oh-so-helpful description, Leon went ahead and created the awesome final helmet design we all know and love. (Thanks, Leon!)

So that’s how we’ve made the Sojourn EVA Suits. Some of the details of the drawings haven’t survived or were otherwise changed in the final product, but this trip down memory lane will hopefully give you all a glimpse of how things go from their original idea up to the final product.

And as you’ve gotten this far and are oh most surely not tired of reading about spacesuits already, here’s a drawing I’ve made recently as further reference for Leon, for what we’re currently working on:

And with that massive tease, farewell and until next time!

Fair winds!

- Gab