A quick guide to getting the Alpaca Space Program achievement.
Alpaca Space Program Achievement Guide
All You Need to Know
After the dialogue that can be seen in the image below, you need to win the battle with the alpaca (this battle is in the history of Arizona).
After the battle the alpaca will lie on the ground, you will have to press the interaction until the phrases about the lying alpaca run out.
And then stomp around the lying alpaca.
The alpaca will bounce higher and higher from the stomp and fly away and you will get this achievement.