Click here to enlarge. (Photo Credit: xkcd)
If you've ever wondered how the size of Apollo spacecraft compared to, say, the space shuttles or the Mir space station, XKCD cartoonist Randall Munroe decided to make it easy for you with today's cartoon, which displays the mass and payload of spacecraft and launch vehicles in an easy-to-understand unit of measurement: the horse.
Sputnik 2, once in orbit with just orphan dog Laika in tow, it weighed less than a single horse. Russian probe Venera 1 was the first probe to weigh a full horse. The Apollo spacecraft weighed 67 horses. If the duration of the program were included, Munroe would have to add in 842 pounds of moon rocks brought back across the duration, which would have added another equine unit (an average horse weighs a little less than 1,000 pounds).
While the space shuttle weighed 206 horses, with 54 horses of cargo capacity, the Voyager 2 probe is a measly two horses. By contrast, the International Space Station has a mass about about 932 horses. No wonder they had to assemble it in orbit piece by piece.
As part of his plan to reduce the cost of reaching orbit, SpaceX CEO Elon Musk set a goal of $500 per pound of space cargo capacity. At that rate it would cost $500,000 to launch a single horse, though that doesn't count the cost of developing an equine spacesuit. Perhaps it's best if we just take horses up on a future space elevator.
Via xkcd.
