>So other then using the data we have, how are we supposed to compare them?

We can't. We can qualitatively say that all three are essentially 100% reliable launchers, you can't pick a winner with this data because the very few failures they had may very well have been statistical anomalies. Their failure rate is below the margin of error.

Now suppose you multiply everything by 10. For Ariane5 imagine we'd had 20/1150 failures instead of 2/115. And for F9 imagine we'd had 10/1550 failures instead of 1/155. That would give enough margin to safely determine that the difference between the two is statistically significant, i.e. not due to statistical anomalies but rather to an actual better performance for F9.

Yes, I'm aware. JWST used A5 though, a tried and tested launcher with excellent reliability

Why? A5 is an extremely safe launcher

Yep. As long as academia relies on funding from the private sector this will always be the case.

Companies have no interest in funding research unless they get precisely the results they want out of it. A refusal to twist and cherry-pick the results when this isn't the case often leads to the company interrupting any collaboration (and funding) with the research group in favour of more "compliant" ones.

Some fields (and companies) are worse than others in this regard, but generally speaking this is the very sad state of things.

From personal experience as an academic, I'm afraid you have a very optimistic view of science

Bit excessive don't you think?

I'm not debating it, but still for the Starship plan to work there are so many critical points to pass that I simply don't feel we've seen enough at this stage.

Launching and landing the rocket is certainly two of them, which of course they've achieved. But for a Mars mission to work they also need to demonstrate high launch cadence with Starship due to the several orbital refueling launches required for each mission. This in turn means that any reusability strategy (e.g. heat shield, Raptor durability, etc...) and fast construction also need to work as well as envisioned.

And of course landing on Mars on rough terrain, launching from Mars (something which has never been attempted before), habitat and life support for crewed missions on a scale which is simply not required for the ISS and so on.

I'm not saying they won't achieve it, but I find it laughable when people talk about the SpaceX Mars missions as if they were a done deal.

Musk was also envisioning orbital tests of Starship more than 3 years ago. What he thinks he can achieve and what he can actually achieve are two very different things.

Starship is an ambitious and promising concept, but given its highly experimental nature and Musk's tendency to oversell I wouldn't consider it until we find out whether it can live up to expectations.

Essentially, they are saying that the test was successful but it is still only one data point.

The final aim of this research is to be able to know, in case an actually dangerous asteroid were on a collision trajectory with Earth, what kind of impact would be sufficient to knock it onto a safe course.

So we know the mass, trajectory and velocity of DART and soon we'll know the exact effect the impact had on Dimorphos, but what we don't know is the effect of Dimorphos's characteristics. What if DART had struck another asteroid with, for example, the same mass but denser? What if the asteroid had been composed of a different material?

By carefully analysing the impact site and the asteroid itself with follow-up missions (like HERA) we can try to determine the effect of Dimorphos's characteristics so that in the future we may more easily predict the effect of an impact on any asteroid, provided we have some data about it.