Just wild guesses here but anyone who has played Kerbal Space Program knows that while docking is no piece of cake, it happens slowly and you can back off and try again until you run out of fuel.
Landing on a moving target shouldn't be that hard except you get (almost) zero weight budget, you're relying on atmospheric braking which means intense heat, and at the end you're hoping the engine doesn't malfunction.
In case it wasn't clear there, the real challenge here is using something that wasn't designed for landing - it was designed for liftoff - to do the landing.
Musk is probably just happy it hit the barge, and tried to slow down some. We'll find out later if it:
a) ran out of fuel
b) misjudged the position and velocity of the barge at the moment of impact
c) landed at the intended speed because there were technical concerns that kept it from landing any slower
d) something else entirely
But keep in mind, the stage landed on the barge. That means it can be salvaged! Pretty cool, if you ask me.
In addition, even one engine on the F9 first stage, throttled down to its minimum, generates way too much thrust for the vehicle to do a gentle landing. They have to do a suicide burn --- they fall towards the launchpad unpowered and then at the last possible moment light up the engine, and hope that when they come to a halt they've landed. There is no margin for error.
KSP doesn't really have an equivalent, but you can compare it to trying to land on the moon using a solid rocket fuel engine. (The difference with SpaceX is that at least they can turn it off.)
> KSP doesn't really have an equivalent, but you can compare it to trying to land on the moon using a solid rocket fuel engine. (The difference with SpaceX is that at least they can turn it off.)
Minmus suicide burn with a Mainsail could probably compare.
Landing on a moving target shouldn't be that hard except you get (almost) zero weight budget, you're relying on atmospheric braking which means intense heat, and at the end you're hoping the engine doesn't malfunction.
In case it wasn't clear there, the real challenge here is using something that wasn't designed for landing - it was designed for liftoff - to do the landing.
Musk is probably just happy it hit the barge, and tried to slow down some. We'll find out later if it:
a) ran out of fuel
b) misjudged the position and velocity of the barge at the moment of impact
c) landed at the intended speed because there were technical concerns that kept it from landing any slower
d) something else entirely
But keep in mind, the stage landed on the barge. That means it can be salvaged! Pretty cool, if you ask me.