It’s been a few days since the eighth Starship launch and in that time more information has surfaced related to the loss of the ship. Specifically, a possible leaked image inside the aft section, in addition to details on exactly what caused the failure, have been circulating.
While this info is not confirmed by SpaceX, and should be taken with a grain of salt, a lot of it does align with what was shown during the livestream and on Flight 7 as well.
Missing Engines
A supposedly leaked image has been going around inside the aft section of S34 showing a missing Raptor vacuum engine and even one of the sea level Raptors, or at the very least, the engine bell. In theory, this would be taken soon after the explosion that occurred within that section of Starship.
During the official livestream when it happened, we were looking at one of the flaps and only saw a flash of light followed by a loss of attitude control. We got a bit more context in mission control when the video on the monitor was pulled up showing an explosion in the aft section. SpaceX even confirmed in a statement that “Prior to the end of the ascent burn, an energetic event in the aft portion of Starship resulted in the loss of several Raptor engines.”
Focusing back on the image, it makes their statement seem more literal. When overlaying the image with an earlier one during the livestream, it makes it much more clear what’s missing and or damaged. You can now clearly see that besides the Raptor Vacuum engine, the sea-level engine closest to the camera is also gone. In addition, towards the top right, the metal on the engine skirt looks to be torn up quite a bit, which would make sense given there was an explosion right next to it.
As far as exactly when this image would have been taken, it’s not easy to say. You would have to align it based on which engines are still firing. That being said, SpaceX’s in-flight data isn’t always fully accurate, especially after such an energetic event. In other words, the livestream data may have shown certain engines firing when in reality they had already stopped, or vice versa.
In terms of what caused the loss of the ship, not only was the image supposedly leaked, but also initial conclusions regarding what led to the upper stage explosion. As far as the legitimacy of this information, its primary basis is the fact that it had a similar source as the image. With that in mind, some of the points I’m about to mention should be taken with a grain of salt.
They mentioned that data indicates that the problem on S33 during Flight 7 has repeated. “Again, harmonic oscillations in the distribution of vacuum-insulated fuel lines for RVac, which notably was one of the innovations of Starship V2 and the distribution for S34.” They mention that “This crash was more destructive than during Flight 7, and the corrections to the distribution for S34 did not work or turned out to be almost worse.”
For context, after Flight 7 SpaceX concluded that “The most probable root cause for the loss of ship was identified as a harmonic response several times stronger in flight than had been seen during testing, which led to increased stress on hardware in the propulsion system. The subsequent propellant leaks exceeded the venting capability of the ship’s attic area and resulted in sustained fires.”
When they say harmonic response, they are referring to the noise and vibration produced by the rocket. During the official livestream of Flight 8 they were quoted saying, “Flight 7 we saw those vibrations at a specific frequency. They were also at a strong enough amplitude that it was placing a lot of extra stress on some of Starship’s propulsion system. That’s what most likely led to propellant leaks that cascaded into fires and ultimately our loss of contact with the ship.
Importantly, the switch to Starship V2 included some significant changes to the ship including propellant feed lines. After Flight 7, as part of the investigation, an extended duration static fire was completed with the Starship flying on the eighth flight test. SpaceX was quoted saying, “The 60-second firing was used to test multiple engine thrust levels and three separate hardware configurations in the Raptor vacuum engine feedlines to recreate and address the harmonic response seen during Flight 7. Findings from the static fire informed hardware changes to the fuel feedlines to vacuum engines, adjustments to propellant temperatures, and a new operating thrust target that will be used on the upcoming flight test” they said. Granted this all occurred in a relatively short time frame, limiting the ability to truly address the issue.
SpaceX also said, “To address flammability potential in the attic section on Starship, additional vents and a new purge system utilizing gaseous nitrogen are being added to the current generation of ships to make the area more robust to propellant leakage”.
Based on some of the information we are now getting, it’s pointing toward a more serious issue with Starship V2’s design. The leaked information also mentioned that Harmonics cause a break in the lines in the lower part, where the main wiring for the RVac is located. They also caused the engines and regenerative cooling to malfunction, which led to the explosion during the fire in the compartment. They pointed out that the updated nitrogen suppression and compartment purge system would not have been able to cope with such a volume of leakage.
Depending on whether or not this information is true, it’s hard to say the impact on future flights. The best case scenario for SpaceX would likely be an isolated issue or anomaly that they can easily fix and move on to Flight 9. A much worse outcome would be realizing there is a major flaw with part of Starship V2’s design. That would not only impact the next flight but additional V2 variants already built or under construction.
We won’t know for sure until SpaceX provides more info and decides the best course of action going forward. Until then it will mostly be just speculation.
After the flight in a statement the company said, “Starship flew within a designated launch corridor to safeguard the public both on the ground, on water, and in the air. Following the anomaly, SpaceX teams immediately began coordination with the FAA, ATO (air traffic control) and other safety officials to implement pre-planned contingency responses.”
“Any surviving debris would have fallen within the pre-planned Debris Response Area. There are no toxic materials present in the debris and no significant impacts expected to occur to marine species or water quality. If you believe you have identified a piece of debris, please contact your local authorities or the SpaceX Debris Hotline.”
“With a test like this, success comes from what we learn, and today’s flight will help us improve Starship’s reliability. We will conduct a thorough investigation, in coordination with the FAA, and implement corrective actions to make improvements on future Starship flight tests,” they said.
In the near future, the focus will be all around Starship V2. When talking about changes to the ship they said, “Extensive upgrades to Starship’s upper stage debuted on the previous test flight, focused on adding reliability and performance across all phases of flight. Starship’s forward flaps have been upgraded to significantly reduce their exposure to reentry heating while simplifying the underlying mechanisms and protective tiling. Redesigns to the propulsion system, including a 25 percent increase in propellant volume over previous generations, add additional vehicle performance and the ability to fly longer duration missions. And the vehicle’s avionics underwent a complete redesign, adding additional capability and redundancy for increasingly complex missions like propellant transfer and ship return to the launch site” they said.
Interestingly, the plan was to possibly attempt a ship catch as soon as Flight 9. On Flight 8, on the sides of the vehicle, non-structural versions of Starship’s catch fittings were installed to test the fittings’ thermal performance, along with a section of the tile line receiving a smoothed and tapered edge to address hot spots observed during reentry on Starship’s sixth flight test. Starship’s reentry profile for that test was also designed to intentionally stress the structural limits of the upper stage’s rear flaps while at the point of maximum entry dynamic pressure. Something they will now have to try on the next flight.
On the bright side, the booster seems to be operating nearly perfectly. Yesterday, the company released a host of new videos of the third catch. In a statement they said, “The Super Heavy booster then relit 11 of 13 planned Raptor engines and performed a boostback burn to return itself to the launch site. As Super Heavy approached the launch site, it relit 12 of the planned 13 engines at the start of its landing burn to successfully slow the booster down. The three center engines continued running to maneuver the booster to the launch and catch tower arms, resulting in the third successful catch of a Super Heavy booster.”
Conclusion
In the few days since Flight 8, a supposedly leaked image and information has given more insight into what happened to the upper stage. While beneficial, we won’t know for sure until SpaceX provides more info on Flight 8 and the changes being made.