Starship Launch 13 Exposed Its Fatal Achilles Heel
Delays are more than an annoyance - they are potentially mission-ending.
I have already covered how Starship’s flight test 13 wasn’t the huge leap forward SpaceX needed. But this launch demonstrated something crucial that the media has barely even noticed, let alone discussed: a major flaw with Starship’s promised future. A fundamental problem so catastrophic, we will look back and wonder why anyone thought this launch vehicle would ever work. It isn’t just me who has spotted this, though; industry insiders, including ex-Space Shuttle engineers, have too. The issue at hand is boil-off and delayed launches, and while that might sound trivial, the impact is devastating.
Delays
Starship is no stranger to delays. An entire upper stage exploded before it even reached the launch pad, the FAA have grounded it numerous times for months on end, and SpaceX has had to conduct considerable design overhauls to fix Starship’s stark underperformance, delaying launches by over six months, just to name a few. Quite frankly, Starship makes England’s woeful train system look like the pinnacle of punctuality.
Launch 13 demonstrated that, even when all of these critical issues have been dealt with and the rocket is ready and waiting to go, major delays can still happen. The flight was originally scheduled for July 16th, but the launch was aborted immediately after ignition, as four of the Super Heavy Booster’s engines failed to ignite, thanks to LOX (liquid oxygen) fuelling issues, leaving the rocket with insufficient lift. SpaceX had to replace these engines, before testing them on July 22nd, and then attempted another launch on July 23rd. But, it was too cloudy that day, so SpaceX delayed the launch by another 24 hours. To be clear, Starship can launch through clouds, but SpaceX wanted to be able to observe the rocket during the launch. So, while this incident caused an actual delay of eight days, we can ignore this 24-hour delay, as it wasn’t caused by technical issues, meaning four failed engines caused a week-long launch delay!
Why is this a problem?
Well, for pretty much the entire history of space launches, delays like these haven’t been an issue at all. You see, most missions rely on a single launch, and the few that have relied on multiple launches (such as the ISS) are explicitly designed to cope with extensive launch delays.
But this is simply not the case for Starship.
To reach the Moon or Mars (which is Starship’s intended purpose), Starship needs to be entirely refuelled in LEO (Low Earth Orbit), and thanks to the kind of propellant Starship uses, such refuelling is a frantic race against time, making delays like this insanely costly and potentially mission-ending.
Let me explain why.
Mission Profile
In order to land on the Moon or Mars, SpaceX plans to use three different variants of Starship. The first to launch is the depot variant. This will be placed into LEO and will be used to store propellant in orbit. Then, there is the tanker variety, which will launch into orbit, dock with the depot Starship, transfer propellant to it, and then land back on Earth. Starship supposedly has a 100-ton payload to LEO, meaning the tanker variety can only transfer 100 tons of propellant per launch to the depot. This is a problem, as our final variant, the Moon/Mars-bound Starship, has a propellant capacity of 1,600 tons and requires its tanks to be fully topped up to make the journey.
So, you might think that such a mission would require at least 17 launches (i.e., 16 tanker launches and one outbound Starship). Indeed, on the rare occasion SpaceX addresses this refuelling process, they hint that it will require a little over a dozen launches.
But, this is neglecting one major factor: boil-off.
Boil-Off
Ultimately, the propellant Starship uses is a mixture of cryogenic liquid oxygen (LOX) and liquid methane. Both are normally gases, but storing them as a gas takes up far too much room. However, when placed under immense pressure and cryogenically chilled to -183°C (-297.3°F) for oxygen and -162 °C (-259.6°F) for methane, they turn into liquids, which makes them energy dense enough to be used as rocket fuel.
It’s no mystery as to why Starship uses cryogenic LOX and methane — together, they are an incredibly efficient and powerful rocket fuel mixture. There is just one problem, though: they aren’t exactly what you would call shelf-stable.
If the fuels’ temperature creeps above that cryogenic mark, then they start to turn back into gas (boil) and increase the already extreme pressure in their tanks. This is called boil-off, and to prevent these tanks from reaching unsafe pressures and risking catastrophic explosive failure, fuel has to be vented out. In other words, over time, these cryogenic fuels evaporate away.
This is where I think Musk has made a rather rookie mistake. He seems to believe that space is cold, and so it makes sense to store cryogenic fuels and AI data centres there. But that isn’t true. In space, you are exposed to the raw, unfiltered radiation of the Sun.
Take the ISS; it operates in the same orbit as the Starship depot, and its exterior facing the Sun routinely reaches temperatures of 121°C (250°F), which is hotter than a slow cooker (crockpot) turned all the way up.
So, Musk is effectively taking this highly temperature-sensitive, and arguably most mission-critical, component, and storing it at a temperature hot enough to make a hotpot in record time.
Now, yes, insulation can slow down boil-off, and the square cube law is in Starship’s favour here. But, even if SpaceX stuffed the Starship depot with all the insulation in the world, it wouldn’t stop this loss of fuel. That is why, despite trying to find a way to make zero-boil-off cryogenic fuel tanks for a while now, NASA has found it simply impossible to store cryogenic fuels in space for more than a few days.
So, can you see why Starship having even small launch delays can quickly become a catastrophic problem?
