Ten lunar modules were launched into space. Of these, six landed humans on the Moon from 1969 to 1972. The first two launched were test flights in low Earth orbit—the first without a crew, the second with one. Another was used by Apollo 10 for a dress rehearsal flight in low lunar orbit, without landing. One lunar module functioned as a lifeboat for the crew of Apollo 13, providing life support and propulsion when their CSM was disabled by an oxygen tank explosion en route to the Moon, forcing the crew to abandon plans for landing.