Space Requests allow you to earn Space Coins
You will be presented with three requests for animals to send to space.
When you rescue a maxed out animal you are given the option to either "free" or "prep for space". If you "prep for space" you do not receive any coins.
You can prep any animal for space, but only 10 of each animal can be prepped for space at a time.
If a planet wants the animal you will be given the option to send a prepped animal for the listed amount of space coins.
You are given 3 options, and as you progress it starts to request combinations of animals. Once you complete a request a new one appears, though this can take some time.