Despite tentative preservation plans, SpaceX completely scrapped the wreckage of the first prototype high-altitude spacecraft, clearing the landing zone it had touched for the imminent launch of its successor.
Known as serial number 8 or SN8, the Starship prototype was the first of any type to fly beyond 150 meters (~ 500 feet), reaching an altitude of 12.5 km (~ 7.8 mi) on December 9 on its breathtaking debut. In an unexpected twist, SpaceX kept the Starship SN8’s thrust-to-weight ratio as low as possible, turning what could have been a two- or three-minute test into a nearly seven-minute ordeal with three consecutive Raptor engine cuts for the ascent.
At the peak, SN8 used cold gas thrusters to rock into a belly-down orientation and freely fell ~ 95% of the way back to Earth before igniting two of its three Raptor engines, performing a wild return to vertical landing position and almost ensure a soft landing. Unfortunately, about 10 to 20 seconds before this planned landing, what Musk later described as low pressure from the methane tank starved the Starship’s engines of fuel and more or less cut off any appreciable thrust, causing SN8 to hit its full swing. landing zone at about 40 m / s. (~ 90 mph) too fast. The rocket struck the concrete slab, crumpled and exploded.
Obviously, success was one of the less likely outcomes SpaceX expected from SN8’s high-altitude debut, with Musk himself estimating the odds of total success to be only 33%. Additionally, Starship SN8 managed to achieve a low speed landing regime that Starships SN5 and SN6 demonstrated almost perfectly with consecutive 150m jumps and landings in August and September 2020.
In other words, despite the explosive ending, SN8’s high-altitude launch debut was a spectacular success for SpaceX’s Starship program – maybe even. preferable to a perfect landing as he discovered an unexpected fuel tank pressurization problem. Beyond the failed landing, the Starship ticked every box on SpaceX’s test flight list, making its successful debut at multiple Raptors, demonstrating multiple in-flight engine shutdowns and engine re-ignitions; proving that an unprecedented “parachutist” -type landing maneuver is possible and viable; and successfully test Starship’s ability to control himself in that bellyflop orientation with massive thrusters and four flaps.
Speaking in a recent interview with Ars Technica, in the words of SpaceX’s pragmatic COO and Chairman Gwynne Shotwell, The beginnings of the launch of SN8 “risky [the Starship] program quite massively. According to Musk, SpaceX engineers were quickly able to determine why the Starship SN8’s methane tank was unable to maintain the fuel flow (pressure) needed for Raptor’s landing burns and quickly implemented a solution.
Instead of autogenously pressurizing with methane, Starship SN9 will use helium to pressurize its fuel tank, serving as a temporary fix while SpaceX determines what changes need to be made to get rid of that helium kickstand. With the airstrip now cleared of Starship remnants and the more or less repaired SN8 impact crater, the only thing between Starship SN9 and its own 12.5km launch debut is a static fire test triple Raptor. Originally slated as early as Jan.4, SpaceX never succeeded more than a few minutes after the attempt began, while a Jan.5 save window was canceled later that evening. The test could now take place no earlier than Wednesday January 6 (NET).
Fortunately, while SpaceX was unable to save the entire wrecked nose section of the Starship SN8, the company did manage to extract a largely intact nose flap. The rest of the remains were discarded on site and trucked, but it’s possible that some important SN8 components – especially the salvaged shutter – could end up on display at one or more SpaceX facilities.