Space X’s trials by fire

Dense fog obscured the view. But the explosion on March 30 came through loud and clear on SpaceX’s webcast. About six minutes after launching, the company’s newest Starship prototype exploded mid-air, showering the launch site with metal shards.

“Looks like we’ve had another exciting test,” SpaceX engineer John Insprucker told viewers on the company’s live video feed. The explosion over the Boca Chica, Texas, test site was one in a string of fiery tests for the private rocket company founded by Tesla creator Elon Musk. The last four prototype tests for the ambitious and expensive program have ended in disaster. But the company hopes the explosions are moving it closer to making its largest-ever rocket a reality.

Serial entrepreneur and world’s second-richest person, Musk founded SpaceX in 2002 as a private alternative to national space programs like NASA. The company has completed more than 100 successful launches of its mainstay Falcon 9 and Falcon Heavy rockets, which deliver cargo for NASA. Since 2015, the company has been successfully landing the rocket boosters, typically on the back of a ship, in order to reuse the expensive devices. While national space programs have historically treated rocket boosters as single-use devices, SpaceX has set reusability records. On March 14, the company landed the same Falcon 9 rocket for a record-setting ninth time after delivering its payload of satellites into low Earth orbit.

But to break free from Earth’s gravity and fly to the Moon or Mars, the company needs to build something bigger. While SpaceX officially described most of the March 30 test as a success, the Starship has proved a trickier challenge. The system contains two parts: Super Heavy, a reusable rocket booster powered by three liquid methane and liquid oxygen engines, and Starship, the spacecraft the company hopes will ferry cargo and passengers off the planet.

The 164-foot tall Starship prototype called SN11 successfully blasted off and reached an altitude above 30,000 feet. From there, its three engines began shutting off, allowing the rocket to stall and perform what the company calls a bellyflop. Once the booster tips over on its side, the rocket can use stabilizers to perform a controlled descent. According to the machine’s design, the rockets are supposed to fire back up and tip the booster back to the vertical position once it comes closer to the ground.

In this case, something went wrong when the three engines reignited, causing what SpaceX called euphemistically a “rapid unscheduled disassembly.” Musk blamed a liquid methane leak in one of the three Raptor engines for the mishap. “This is getting fixed six ways to Sunday,” he tweeted on April 5.

Once built, the two-stage rocket will measure nearly 394 feet tall, about 31 feet taller than the mighty Saturn V that powered NASA’s Apollo missions. The company suggests the rocket system could eventually carry more than 100 tons of cargo into low Earth orbit. With roughly three times the payload capacity of the Space Shuttle, Starship could blast a blue whale into orbit.

But all of that must wait until SpaceX engineers can figure out how to land the reusable booster. During a 2018 conference call following a series of successful Falcon 9 missions, Musk commented on the difficulty of landing a rocket booster softly enough to use it again.

From its test site near South Padre Island in far South Texas, SpaceX has been conducting flight tests on Starship since August 2020. The unmanned flight of the prototype SN5 on Aug. 4 lifted off to an altitude of nearly 500 feet before successfully landing 40 seconds later. More recent tests have used larger prototypes and flown to considerably higher altitudes.

The SN8 prototype exploded after touching down too hard at the conclusion of a Dec. 9 test flight. SN9 over-rotated while righting itself and hit the ground at an odd angle. The Feb. 2 test ended in a fireball. The SN10 prototype test appeared to be a success, flying to an altitude above 30,000 feet, bellyflopping into a controlled descent and then righting itself for a soft landing. But some of the craft’s landing legs failed to deploy, causing the booster to lean on the landing pad damaging some components. Just eight minutes after touching down, SN10 exploded on the landing pad.

For SpaceX, that means on to the next prototype. Shortly after SN11 exploded, Musk took to Twitter suggesting that every failed test brings his team of engineers one step closer to success. “A high production rate solves many ills,” he posted. The next prototype, he said, “rolls to the launch pad in a few days.”