Open Sky was a terrorist organization dedicated to liberating the Akritirian people from an undemocratic regime. Its members were hunted by authorities on Akritiri and had scant resources with which to work.
Two members of Open Sky synthesized paralithium into a trilithium explosive in 2373. They used it to bomb the Laktivia recreational facility on Akritiri, killing 47 off-duty patrollers. The USS Voyager, which was powered by dilithium, was subsequently blamed for the explosion because there was no natural source of trilithium in the sector. (VOY: "The Chute")