Sending things into space is obviously expensive as hell. One of the many, amny reasons why is the manufacturing process: everything that goes in or on a space vehicle has to be built in a clean environment, and there’s more to it than just being generous with the bleach.
Tom Scott took a trip to Innovative Space Logistics, a Cubesat manufacturer based in the Netherlands. It has an ISO level-7 clean room, meaning it has one percent of the particles you’d find in regular air. Cleanliness is achieved through double-walled rooms, plenty of filters, and a lot of special clothing.