Here is the full list of all 15 Jettomero: Hero of the Universe achievements.
Collect all parts
Prove you're the best of the best
Find a way to actually save the humans
Chase a storm away
Make a difficult decision
Unlock all back issues
Destroy 25 asteroids
Land on a moon
Fly through all the rings
Catch a comet
Find a helpful lift
Search for survivors in a pile of rubble
Get real warm
Extinguish a forest fire
Find a purpose