The challenge with thinking about space is putting it into terms that we can understand. How far is a light-year? Just how powerful is NASA’s next-generation Space Launch System, which the agency hopes will bring astronauts out into the solar system?
Luckily for us, the comic xkcd is a regular contributor to making space understandable, and the latest comic from Randall Munroe is a gem — explaining launch vehicle capacity and spacecraft mass in terms of horses.
So now comparisons are fairly easy. At the left of the diagram, for example, you can see the Saturn V — that rocket that was the first stage of bringing astronauts to the moon in the 1960s — carried the equivalent of 262 horses. The SLS Block 2, if it is ever developed, will have a slightly larger capacity of 289 horses.
Meanwhile, the spacecraft mass of the International Space Station is an astounding 932 horses, the total shuttle mass was 206 horses, and Apollo was 67 horses. There also are a few robotic spacecraft in there, such as Voyager, Vanguard 1, the Keyhole 3 spy satellite, and the upcoming James Webb Space Telescope.