Hello, SFIA audio listeners. In this month's Nebula exclusive, big alien theory,

we're asked at the reason alien civilizations might be rare is because most aliens are huge.

To hear it and every episode early and add free, plus hours of bonus content,

check out go.nebler.tv slash Isaac Arthur and use my code, Isaac Arthur.

This episode is brought to you by NordVPN.

Whether it's real spaceships or those in science fiction, it seems like they are

always breaking down, and barely being held together by duct tape.

So what do we do if our ship breaks down a trillion miles from home?

Whether it's crashing a flying saucer into Roswell or Hans Solo trying to jumpstart the Millennium Falcon,

broken ships are something of a staple of space travel speculation and a regular plot point in science fiction,

but they are very real concern in science and engineering.

Spaceships do break a lot,

even for all the top-notch engineering we put into them, because they are for extreme conditions,

and in many ways nearly every single flight is a test flight or a prototype of something.

We don't have thousands of routine missions to field test some new widget or feature until it is

ultra-reliable. The flip side of that is that we would expect that in the future, and so

it's surprising how often things break on spaceships and sci-fi, or get sabotaged, or

have a backup that's also broken. A quote that comes to mind is for my favorite Starfleet engineer, Chief Myers

O'Brien, when he's explaining why he had to replace a component with a lower capacity one

to make room for a secondary backup, as required by Starfleet specs and codes.

The Cardassian he's explaining this to finds this absurd, asking why you need a backup of the backup,

as it's unlikely both would fail, and he says, that's very unlikely, but in a crunch, I wouldn't

...