It’s been more than 40 years since the first successful space shuttle launch. However, as we saw with the recent NASA launch, we still have launch failures. Why is it so tough to achieve reliability in space shuttle launches? Does this apply to all space technology?
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Rockets are extremely restricted by weight, much more than most other technologies. IIRC the Saturn V was something around 3000tons and only delivered a payload of a few single or double digit tons. If the rocket was 1% more heavy it would have basically lost all its cargo potential.
The result is that rockets operate on much lower safety margins than other means of transport. Everything is designed to be just barely strong enough for the expected loads and redundant systems aren’t always possible or particularly practical. A single sensor failure can lead to the loss of the entire vehicle. IIRC there was a proton rocket that just flipped upside down and exploded because a sensor was mounted the wrong way around.
Another aspect is that there is only limited ways to test your product in realistic scenarios. Rockets are crazy expensive and until recently they were entirely expendable devices. „Test flights“ aren’t really a thing when your vehicle has no way to land. The engineers must rely on in flight telemetry which makes it hard to spot faults unless you have a sensor specifically monitoring that part. There was an arianna rocket which exploded because its control software was partially copied from an earlier generation of the rocket. The newer rocket was faster and as a result a sensor ( I think it was an altimeter) exceeded its range of valid values during the early phases of the launch. This wasn’t an issue on the old slower rocket because the system was shut of before it ever flew that high. It never happened during tests because all tests were performed on the ground.
And lastly rocket failures are always spectacular because rockets are basically a giant fuel tank with some high tech strapped on the top and bottom. If it goes wrong it goes wrong with a big boom. In retrospect it’s often a small „silly“ thing, but every part is critical in the rocket.
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