The slender hoses on each side of the Sunrise balloon partially fill the balloon with helium before launch. A large portion of the balloon is left unfilled so it can expand as it ascends into the stratosphere, where air pressure is considerably lower. The launch from Esrange Space Center in Kiruna, Sweden took place in June 2009. The balloon-borne gondola contained a 1-meter solar telescope as well as other instruments on a mission to investigate the structure and dynamics of the Sun's magnetic fields.
