Elon Musk’s space company has taken another key step toward re-using its most expensive vehicle, the Falcon 9 rocket, by test-firing a previously-used first stage. In May, the rocket containing nine engines and their fuel tanks stage sent a Japanese communication satellite nearly 37,000 km (22,990 miles) into space, before flying back down to land gently on a robotic platform at sea. Yesterday, the 40-meter rocket was clamped to a test stand in McGregor, Texas, and fired through the simulation of an entire flight into space. The rocket did fine: Nine Merlin engines combined rocket fuel and super-chilled liquid oxygen to produce 1.8 million lbs (800,000 kg) of fiery, smoky force, leaving the rocket straining to take off and producing a pretty dramatic show. According to company officials, no problems were found during the 2:30 test run. With that test complete, SpaceX is checking off the items needed to actually fly the rocket on a real mission. Luxembourg satellite giant SES is expected to be the first customer to put one of its products on top of a previously-used rocket, perhaps as soon as this autumn. Should all go well, SpaceX officials believe that they will be able to cut prices by 30% by using recycled rockets. So far, SpaceX has recovered five Falcon 9 first-stages.