This makes little sense. The benefits of things like weather, communication, and other satellites vastly outweighs the costs of getting them into orbit. If it cost 2.4 times as much on Earth to get payloads into space it might have slowed space exploration some, but certainly wouldn't have prevented it. As for star travel, .2c seems feasible with current technology, bringing flight times down to decades for nearby stars. Humans started buildimg cathedrals they knew wouldn't be finished for centuries. Star travel might be slow, but that wouldn't stop humans or aliens.