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

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

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

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

This episode is sponsored by Brilliant.

The trick to designing any machine, especially a spacecraft, is knowing what its purpose

and mission are.

Unfortunately, science fiction provides us with few ships designed with those concepts in

mind.

So today we'll be looking at spaceship design from modern ships to those of the distant future, to some that might never exist outside of science fiction.

We'll also be deconstructing some sci-fi designs to see if they really make that much sense,

and examining some real-world

design elements that are specific only to modern spacecraft.

Right now, every spacecraft is designed to be as light as possible, because every kilogram

costs a lot of money to get into space.

Also, spacecraft are most commonly lost in the launch phase, so if you want

to assemble a bigger ship or station orbit, you need a lot of launches, each of which might blow

up on the pad or shortly after launch, and even for automated launches, that results

in missions exceeding budgets and introducing big delays.

And so, in modern space exploration, if you can make a hammer that weighs half as much but

costs a hundred times as much, you send that expensive hammer up instead of the cheaper

and heavier one.

...