NASA’s attempt to save an aging space telescope from falling back to Earth was delayed Thursday after a launch issue scrubbed the first-of-its-kind rescue mission.

NASA’s Neil Gehrels Swift Observatory, a space telescope launched in 2004 to study gamma-ray bursts and other powerful cosmic explosions, has been slowly losing altitude because of increased solar activity. Unless its orbit is raised, the observatory is expected to re-enter Earth’s atmosphere as early as October.