What Do the Space Shuttle and Two Horses Have in Common?

Pair of horses harnessed to a carriage

Sometimes, historical influence doesn’t look like a revolution - but rather… like a horse’s rear end.

Yes, really - at least according to a beloved myth that connects horses, the Roman Empire, steam trains, and space shuttles in one breath. The story goes like this:

In the 8th century BCE, the Romans paved their empire with new roads and two-horse chariots. Their width? About 143.5 cm - just enough for two horse behinds to move side by side.

Centuries later, when the British built the first railways, they used the same standard - simply because that was the width of the old wagon roads in England. That width remained to this day: 143.5 cm, or 4 feet 8½ inches - the standard gauge for most railways in the world.

So far, a cute story. But here’s the fun part.

In the 1970s, NASA engineers were designing the Space Shuttle. Its side boosters - the Solid Rocket Boosters (SRBs) - were manufactured in Utah but had to be transported to the launch site in Florida. How? By train. Through tunnels. The width of those tunnels? Determined, of course, by the width of the railway. And the railway? Built according to that same 143.5 cm - the width of two horse’s rear ends.

And so, according to the legend, the design of one of the critical propulsion components of one of humanity’s most advanced technologies was shaped by the width of two Roman horses.

So… Did It Really Happen?

Not exactly.

Like every good urban legend, this story contains a few grains of truth and a lot of imagination. The railway gauge was indeed inherited from the Victorian era, and train standards can affect transport. But the shuttle boosters weren’t actually limited by that width - there were plenty of workarounds, and their diameter was much larger than the train gauge.

Still, the story feels true. Maybe because it sounds so familiar.

Horse-drawn railway carriage from the early 19th century (the carriage runs on railway tracks)

Why Do We Love This Story So Much?

Because it speaks to something deeper than history or engineering.

It tells of the way habits, conventions, and standards set long ago - sometimes without much thought - continue to shape our thinking and behavior long after their original context has vanished.

It points to that moment when we design something new, bold, and groundbreaking - only to discover we’re constrained. Sometimes physically. Sometimes mentally. A limitation we don’t even know the origin of.

We move forward - yet narrow our own path, because “that’s how it’s always been.”

It’s not just trains and spacecraft. It’s culture.

Think of some of the assumptions we all live by: what counts as a “legitimate life path,” what a workday should look like, or big abstract ideas like success, authority, intelligence, beauty.

Many of these foundations were laid centuries ago - sometimes for practical reasons, sometimes for control, sometimes simply because there was no alternative. Even when new possibilities opened, we kept moving along the same track.

And the Horses?

Well, they’ve had a similar journey.

Once - a source of transportation, agriculture, and warfare. Later - a symbol of luxury, power, freedom, or nobility. And in recent years - quiet partners in deep processes of personal change.

What’s fascinating is that their essence didn’t change - we changed the way we see them.

And maybe it’s time we do the same for ourselves.

Because if a horse, once a kind of “armored combat vehicle,” can become a partner in healing, presence, trust, and emotional life - then maybe we, too, can break free from the track that dictates how we act, think, or live.

Maybe we, too, can release our own “143.5 cm” - the invisible limits that define how things should be - and choose again.

The story of the space shuttle and the horses may not be historically accurate, but it’s emotionally precise.

It reminds us that sometimes, an old habit or a small mental fixation can limit even the greatest things we try to build.

And it invites us to ask:Where am I still riding on a track I didn’t choose?And where might an open field be waiting - one that demands courage, yet finally allows me to gallop?