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?
In:
There are some quality responses here; but a point the other posts dont emphasise is the very narrow specialist nature of the technology.
While there is some overlap with military applications – which have tens of trillions of dollars thrown into them over the last five decades.
Arguably up until recently, **manned space flight is not actually a well funded mainstream industry.** It has a (proportionally) tiny budget, for what is effectively a continued series of research experiments (the launches included).
If major world economies *chose* to throw more time, money, and effort at the technology – you would rapidly see a significant reduction in cost, and an increase in reliability (all the listed problems notwithstanding).
This is what we are finally starting to see with the privatisation of space flight.
Global / planetary entropy means there are always variables independent to the launch parameters, which cannot all fully and explicitly be accounted for ahead of launch.
Because there is so much data available at the time of launch and we only know where to apply human focus when a problem arises.
One of the reason humans consider hindsight 20:20; you only get the complete data set when you are observant
The forces involved are huge, and the machines have to be as light as possible. You can’t “over engineer” due to the weight requirements, and even slightly “under engineered”, or even a tiny flaw in the materials, can cause failure. “Just right” is a thin line.
I feel like most professions are like this. Routine surgeries can go wrong. Hard drive manufacturing still produces defective drives. Database conversion always have some unforeseen error after the fact. Bone grafts by my dentist don’t always work. Etc etc etc…
For a successful rocket launch, a million things have to go right
For it to go wrong, only one thing has to fail
In a rocket you will have a couple of thousand parts that each have to work in order for the whole thing to function.
Now imagine you can achieve a failure rate of only 0.1% through good engineering.
That still means a couple of parts on average will fail per launch.
Of course you can spend a lot of time and money to make everything more reliable on its own, but thats greatly diminished returns at some point.
The better way to solve that is redundant systems, so a single failure will have none/only minor consequences
Read Failure is not an Option. I don’t think there was ever a launch in the Saturn series that didn’t have an issue. There was great Engineering but we got very lucky.
Many people here are talking about the difficulty of rocketry, which is huge, but I think many people are forgetting a big piece: sample size.
There are very very few things in this world that happen as infrequently as a space launch. There have only been ~200 crewed flights by NASA and ~5,000 orbital launches by the world.
Cars produced: over 1 billion
TVs produced each YEAR: ~200 million
Aircraft flights per year: ~10,000
No matter what you are doing, if you don’t do it enough, you’ll never become an expert at it, and until you become an expert at it, you can be rest-assured you will have issues.
Pretty much every rocket launch is it’s maiden voyage. Sure space x can reuse the rocket, but every component has to be inspected, and possibly replaced. Gaskets, pumps, valves, etc.
It’s fairly easy to build a reliable component that never leaves earth. There are many types of rocket fuels, some of them are toxic, corrosive or kept at extremely low temperatures. All of which wreck havoc on seals and gaskets.
Then during the launch, the rocket is exposed to intense forces, near constant acceleration, the vibration and shockwave from both the fuel burning, and supersonic flight.
One big consideration is weight vs fuel. If 90% of a rocket is fuel, just to get to near earth orbit, every pound of structure needs 9 pounds of fuel. So the fuel tank needs to be bigger, etc etc etc. Going to Geostationary orbit? More fuel, so more weight. Moon? Mars? Things get heavy really fast.
You can build a bridge to 150% of strength as a back up for worst case situations and aging, and the bridge won’t be that much bigger. It will be heavier, and a rocket fuel/energy budget can’t afford that. That means everything needs to be built – just strong enough – to do the job, and maybe just a little bit more, but no more.
At that point, then you’re into the weeds of vibration, wind shear, rain, turbulence, and other factors that could go past that little bit more. That’s the engineering challenge.
Latest Answers