People don't understand this enough. They took the stage of a rocket from supersonic speeds to a tiny barge in the ocean. Even though they didn't complete the objective, they were successful in showing that the theory holds up.
I saw a really good quote before the attempt:
If they successfully land the rocket, we will learn a lot and advance spaceflight. It will be a good day for mankind.
If they don't successfully land the rocket, we will learn a lot and advance spaceflight. It will be a good day for mankind.
Trying and learning is always infinitely more valuable than sitting around saying i can't be done.
I liked to apply that to the Rosetta mission as well. The happy-path goal was to land a craft on a comet. If everything went 120% better than expected, then we would get a large amount of data about the surface of comets. If things went the way they did in actuality, then we get a large amount of data about comets. In either case, we learn a hell of a lot more than we did having not done the mission, regardless of it's outcome.
Science and knowledge isn't binary. Sure, you can say you either know something or you don't, but knowing something has a range of n through infinity. "Failure" gives you the option to learn more.
I completely agree. I was just confused by the term "hard landing" and the effectiveness of the grid fins at low speed. It didn't make complete sense to me. As for my "stupid mistake" comment, I guess running out of fluid is also as simple as it gets if that's all that went wrong, and they are owning up to that.
That said, this is only a "first attempt" at putting it all together. I had fairly high confidence in them. Remember, they hovered and landed in Texas. Their first controlled re-entry failed, the second made it to the sea with onboad camera, the third was seen hovering at low speed from a plane. They had no reason to think this wouldn't work - which is not the same as having high confidence that it will work ;-) Putting it all together often leads to interesting things...
I'm still impressed and look forward to the next one.
Contrary to popular belief, the fins are _extremely_ effective even at low speeds. First, they have enormous surface area. Secondly, they have huge momentum around the center of mass, which is at the very bottom of the rocket when it's empty. So, even a small force generated by the fins generates huge momentum and can help position the rocket in the desired attitude.
It looks like the control system was commanding the fins to move and was expecting the attitude to change, but they didn't move anymore. Perhaps at the very end of the flight the gimbals on the engine didn't have enough authority to orient the rocket vertically and/or arrest its horizontal speed.
I think it's amazing achievement for the very first attempt. Congrats SpaceX and I'm jealous like hell for what you've been able to achieve.