SpaceX has released a new 4K video that summarizes Starship’s first intact landing after a high-altitude launch as the company prepares the next ship for flight.
On March 3, Starship serial number 10 (SN10) briefly became the first prototype to be successfully launched to 10 km (6.2 mi), ‘skydive’ back to Earth, orbited and landed in one piece. Simply put, Starship SN10 made it unequivocally clear that the exotic, unproven landing method selected by SpaceX could work. Unfortunately, while Starship SN10 did land in one piece, landing was much more difficult than planned.
Due to a combination of that hard landing and an apparent onboard fire that started in the last ~ 20 seconds of the flight, SpaceX only had about six minutes to think about the success before the Starship SN10’s propellant tanks were breached, causing the missile was violently relieved and a major explosion and fire.
Discussed earlier on Teslarati, SpaceX CEO Elon Musk later took to Twitter to provide an educated guess as to why Starship SN10 exploded.
Starship SN9 eventually failed a few seconds earlier than Starship SN8 when one of its Raptor engines failed to ignite, making a true flight test of the helium pressure fixation impossible. As it turns out, Musk believes that same solution may have doomed Starship SN10.
As Starship SN10 drove past the failure points that killed SN8 and SN9, the SpaceX CEO thinks one or more of the vehicle’s three Raptor engines began to take up some of that helium when they emptied the methane supply tank. As a result, the engine thrust fell below expected values, preventing Starship SN10 from decelerating completely for a soft landing. Instead, the spaceship hit the ground at a speed of 25 mph (~ 10 m / s), destroying its small landing legs and damaging the skirt portion. “
Teslarati.com – March 10, 2021
In other words, the Starships SN8, SN9, and SN10 losses all share a relatively common point of failure: propulsion reliability. Technically, only the failure of Starship SN9 can be specifically attributed to Raptor, one of which failed to ignite during its turn and landing maneuver. SN8 and SN10 both failed due to problems in the complex network of plumbing and pressure control systems responsible for feeding Raptors with the correct amount of propellant.
For SN8, the ship’s pressure system failed to deliver the necessary fuel head pressure at the last second, causing the Starship’s Raptors to starve. SN10 ironically failed because the quick fix inspired by the failure of SN8 – partially replacing a methane gas with helium – likely contaminated its methane fuel with helium, effectively diminishing Raptor’s performance. While it’s likely frustrating for SpaceX, the flaws are still extremely valuable, and the loss of hardware remains a routine and deliberate part of the company’s approach to iterative rocket development.
On the plus side, the FAA has already cleared SpaceX’s next spaceship for flight following SN10’s temporary success and subsequent explosion. Spurred on by that brief taste of total success, SpaceX wasted no time preparing that next prototype – Starship SN11 – for flight and the rocket rolled onto the launch pad just days after SN10’s flight on March 3. That same day, SpaceX completed the environmental pressure test – a basic verification that Starship SN11 is leak free.
A few days later, SN11 appeared to pass its first cryogenic test, replacing gas at room temperature with cryogenic liquid nitrogen. Three days later, SpaceX attempted to put the Starship through its first triple Raptor static burn test, but it appeared it failed a millisecond after partial ignition of one or two of its three engines. Starship SN11 caught fire briefly and burned for at least 20-40 seconds after the abortion, unsurprisingly delaying several days. Nevertheless, if SN11 can withstand a second static firing attempt on Thursday or Friday without any problems, the Starship is still well on track to fly weeks earlier than any of its predecessors.