It’s 1971, and “Stairway to Heaven” blares out of radios across the country. Meanwhile, NASA’s own stairway to heaven, the Saturn V, makes its tenth flight, successfully taking its eighth crew to space and its fourth crew to the lunar surface. Created with slide rules and computers that would be outdone by a modern $15 Casio watch and built with archaic materials and methods, Saturn V was an engineering marvel. Fifty-four years later, and SpaceX Starship’s tenth flight is imminent. Designed by supercomputers and built from cutting-edge materials, it has yet to reach orbit or carry even a fraction of its promised payload and has exploded more times than not… Yeah, Starship isn’t doing that well, is it? But can Flight 10 turn things around?
After the catastrophic failures of both the Super Heavy Booster (SHB) and Starship during Flight 9, and the refuelling failure which destroyed the Starship destined for Flight 10 before it even got to the launch pad, SpaceX has made some changes after investigations finally established what went wrong.
SpaceX and the FAA recently concluded their investigation into Flight 9 and the diagnosis is painfully simple: they were both structurally unsound.
A gas diffuser, a device used to control high-pressure liquid fuel transfers, in the nose of Starship failed under normal conditions, causing a liquid methane leak, which changed its reentry trajectory, causing it to break up during reentry. These are relatively simple devices, so it is surprising that this was a failure point. The Booster was attempting a slightly more exuberant landing procedure during Flight 9, likely in an attempt to reduce its fuel usage. But its fuel tanks, which are structural, couldn’t handle the extra stress, and they failed, causing a huge explosion.
Starship also has its own fuel tank issues. A few weeks ago, a Starship meant to be used for Flight 10 exploded while being refuelled on a test firing rig. The root cause was the failure of its COPV (composite overwrapped pressure vessel) fuel tanks under normal conditions, leading to a huge explosion. So, again, not structurally sound.
But, have no fear, SpaceX has a solution! Sort of…
The gas diffuser has been replaced with one that has been tested under the conditions the previous one failed in. It’s baffling why this wasn’t done earlier. SpaceX are also conducting additional checks to ensure all their COPVs aren’t damaged and are lowering their operating pressure, which has reduced Starship and SHB’s fuel capacity. Likewise, future SHB landings will use a lower angle of attack (i.e., more vertical, using rockets to slow down, rather than aerodynamic resistance), and future iterations will have refined control grid fins.
So, is this enough?
Well, all of these failures and changes are even more evidence for my little theory as to why Starship isn’t moving forward.
You see, I think the concept of Starship is fundamentally flawed, forcing it to carry so much fuel that its payload is functionally zero. Indeed, no Starship has taken any dummy payload to orbit, and they have all failed with payloads less than 10% of the promised specification.
So, SpaceX is building Starships that are lighter in an attempt to increase payload to usable levels but is therefore making them much weaker than they should be. This is causing structural failures, like the COPV failures — which I might add are not normal, given that NASA has used COPVs for decades and never had a single failure. But it is also causing cascading stress failures in the fuel system. For the past handful of flights, there has been a fuel leak caused by stress, which started right by the engines. But when these were rectified, a point further up the fuel system failed on the next flight, and on Flight 9, this had reached all the way to the fuel tanks. This kind of cascading is caused by the entire system being too fragile, but instead of addressing the issue as a whole, SpaceX is only fixing the failure points one at a time.
So, with that in mind, will these changes actually solve Starship’s glaring problems?
I’m not convinced.
SHB being forced to complete more vertical landings, or risk failure, means it can’t use aerodynamic drag to slow down its descent, causing it to rely on its rockets. That means it has to take up significantly more fuel, as it faces the rocket equation twice. In other words, on takeoff, it needs to carry additional fuel it will use during landing. As such, this dramatically increases its weight and eats into Starship’s potential payload capacity. This is exacerbated by the reduction of the COPV pressure, which reduces the fuel that both SBH and Starship can carry but puts much lower limits on the potential payload. It also means future variants of Starship will have to be far larger to carry that additional fuel, meaning they will be heavier, again putting lower limits on the potential payload capacity.
These solutions to the exploding problems make Starship’s fatal payload issue even worse than it already is.
And they don’t even fully solve the explosion problem. Starship exploded during Flight 8, not from a COPV failure or even a fuel system stress failure, but from a flash event in a rocket engine. This is where fuel combusts before reaching the combustion chamber, causing the engine to explode. This happens when the engine is being pushed too hard. Yet Starship was carrying eight tonnes of payload, just 5% of what Musk has promised. The engines should not have been that stressed! And still, I have seen nothing about how they will solve this issue. Even worse, the next version of these engines will remove the heat shields, which will make the problem even worse! Furthermore, just because they have changed these gas diffusers doesn’t mean the cascading stress issue has been figured out. In fact, the fact that they have only changed a single component, and not others, which will be expected to take the additional strain now that this part is stronger, suggests SpaceX hasn’t done enough work to solve that problem.
Flight 10 is scheduled to take place on August 24th. It will have a similar mission as Flight 9. SBH will land more vertically but will test out a backup engine and conduct a soft splashdown at sea. Starship will attempt to deliver a dummy payload equivalent to eight Starlink V3 satellites, totalling 15.2 tonnes, on its suborbital flight and attempt a controlled soft splashdown at sea too.
I will be honest, I can’t see this happening. Don’t get me wrong, I’m happy to be proven wrong. But the improvements SpaceX has implemented don’t actually solve the problem at hand. SHB could complete its mission (though a part of me expects its backup engine to fail, botching the landing), but I fully expect Starship to fail, whether that is the result of an explosion in space or breaking up on reentry.
Even if I am wrong, and Flight 10 is a wild success, with SHB and Starship making pitch-perfect landings, Starship is still far, far, far away from entering operations. This flight’s payload is just 10% of what was promised and is, in fact, smaller than a typical Falcon 9 payload. To take ten times more payload to space and make the entire Starship project worthwhile will require enormous work. The rocket will need more fuel and become far more robust, necessitating a near-total redesign. SpaceX is currently attempting this, with a far larger third generation of Starship in the works. But this kind of redesign doesn’t guarantee success — after all, this larger rocket will face significantly more stress than the current generation. This is, in a way, going back to square one.
So no, even if Flight 10 is a success, which all the evidence suggests it won’t be, it won’t move the needle forward for Starship.
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Sources: Space.com, Space Flight Now, The Register, Will Lockett, Next Bright Future
The Muskrat will be 0 for 11 after this next Starship explosion!!!
Too bad Robert Goddard isn't around to teach the Starship bunch how rockets work!