[Source] Vacuum bubbles were a starship part available in 20 BBY during the Clone Wars. They were used in Republic bota transport ships where they housed with superconductor couplings. When one of the transports exploded over Republic Mobile Surgical Unit 7 on the planet Drongar during the Battle of Drongar a clone trooper lieutenant theorised it may have been due to the superconductor couplings slipping and causing the ship to go critical. An Ishi Tib technician disputed the claim however stating his crew had checked the couplings housings and that the vacuum bubble seals were tight.