You tap creatures, and their total power adds that many charge counters to the Spacecraft
(Additionally, some of these effects are often built into tribal rewards on creatures for the tribe, such as Heron's Grace Champion being a combat trick in addition to also being a creature.) Additionally, there are cards that want your deck to have a higher overall count of a creature type to make sure they work more often
When I build decks that win by dealing damage, I always make sure to include a few cards specifically to deal with Glacial Chasm
Requiem Monolith This is a very strange design with a lot of play to it
It means [Cost], Exile this permanent, Exile [materials] from among permanents you control and/or cards in your graveyard: Return this card to the battlefield transformed under its owners control
It also puts a veritable kick me sign on your deck for the next six turns, which isnt for everyone