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 ad-free, plus hours of bonus content,

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

Rockets and mass drivers each promise to launch humanity into space, but which approach would

take us further, faster, smarter, and cheaper?

Today we'll be comparing not just two types of launch systems, but two fundamental approaches

to space travel, rocketry and mass drivers.

We'll explore the pros and cons of each approach, as both have distinct advantages and

disadvantages.

Most folks are already familiar with rockets, but mass driver is a less commonly known term,

so first let's briefly introduce mass drivers.

Mass drivers can be a fairly broad category, including chemical-powered guns and rare guns,

but for our purpose today, we'll be focused on the category known as a linear motor.

This is an electromagnetic proportion system designed to accelerate objects, or payloads,

to high velocities along a long track. It works by using electricity to generate electromagnetic

forces to propel payloads, launching them into orbit or onto different trajectories. As such,

payloads accelerated with mass drivers don't consume onboard propellant, avoiding

the complexities of the rocket equation.

This payload could be a cargo pod, though we often imagine as a spacecraft, which is

equipped with thrusters and a small onboard fuel supply, to help it reach orbital speed and maneuver

in space, much like the space shuttle had orbital maneuvering engines

...