I just finished watching the season five finale of For All Mankind. No spoilers, but the whole show is filled with people in spacecraft stuck, slowly running out of resources of one variety or another. And, shortly after, I happened to catch this video on the World War II buoys anchored out in the English Channel to rescue downed pilots. My brain just decided to staple the two things together and do some napkin math to see if the idea would actually hold up.

It’s the kind of thing I used to do on a Sunday afternoon, sitting around the kitchen table with my father. Unbeknownst to me, but entirely known to him, he was teaching me order-of-magnitude idea testing. So I figured I’d play around with building the equivalent for space.

During WWII, both sides anchored rescue buoys out in the English Channel. A downed pilot could swim to one and find shelter, a bunk, food, water, a radio, dry blankets. You didn’t have to make it all the way home. You just had to make it to the nearest float, and then wait.

So here’s the idea. As we actually start populating the solar system, could you do the same thing? Pre-position emergency caches in known orbits: fuel, water, oxygen, somewhere to shelter, so a ship in trouble has somewhere to go. There’s no port to limp into out there. There’s no chandlery to resupply at. You’re just… out there.

This was a couple of hours doodling in Claude Code, with some real orbital-dynamics Python to back it up. A pile of design notes, a little orbital-mechanics toolkit, a dozen diagrams, and an interactive page:

→ Orbital Lifeboats

The thing that flips the whole idea

In the Channel, the buoy sits still and the swimmer moves. In orbit, it’s backwards. A ship that’s out of fuel can’t move at all. It’s just coasting along its orbital path, forever. And, “distance” in space isn’t measured in meters. It’s measured in delta-v, which is how much you’d have to change your velocity to actually get somewhere. Two ships can pass within meters of each other and still need kilometers per second to meet up.

So we flip the whole picture. In space, the lifeboat usually has to come to you. And, it turns out it’s not even a fuel depot. Most of the ways to die out there aren’t “out of gas.” It’s an air leak, a dead radiator, a medical emergency, or being stuck in an orbit with no way down. The thing worth caching is the stay-alive kit, not the fuel.

A few things that surprised me

Once you actually run the numbers, and it’s all napkin math, but real napkin math with code:

  • Rescue has two budgets, not one. You need enough delta-v and enough time before the air runs out. The clock usually loses, because the cheap maneuvers in space are the slow ones.
  • It becomes a triage problem. Not one big lifeboat, but a wave of them. A fast little one that stops the bleeding and buys time, then bigger ones that resupply and eventually bring everyone home. The first one’s real product isn’t supplies… it’s time.
  • Starship changes the scale, not the physics. One Starship could carry more lifeboat seats home than there are humans in orbit right now, which is a grand total of ten: seven on the ISS and three on China’s Tiangong.

What it actually is

It’s a sketchpad. Order-of-magnitude math, it’s not a mission proposal. But, I built it the way I build everything lately, tools as Lego blocks. The whole toolkit is pure Python standard library with nothing to install, the charts are hand-rolled SVG, and the entire site is one self-contained file. The code is MIT-licensed and the writing and figures are Creative Commons, so the source is all on GitHub if you want to take it apart.

I built this one for myself, just to see if the idea held up. If you know more orbital mechanics than I do, and SOOOO many people do, please poke holes in it. That’s the fun part.