4 now, though the first one is going on display at their headquarters. I believe the second one is going to be examined and undergo ground testing only (might be wrong on that). So that leaves just the third and now this one as candidates for re-flight.
The high velocity drone ship landing (#3) landed too hard and was deemed unusable for launch duty (Edit 1: https://twitter.com/elonmusk/status/731984739012251648), so realistically, it's likely just two of the four so far.
That's not what he said. He said SpaceX will start testing with the booster that took the most damage, because if it works well then there is high chance that the others will work too.
The problem isn't that it landed hard, it's that it had to slow down very quickly. That's going to be the case for any GTO launch, including today's flight.
From what I understand there was heat damage around the engines.
Edit 2: per user mikeash, it's definitely flyable (i.e. I'm wrong), but it'll still be grounded to aid with testing efforts. Thanks for the kind correction, Mike! https://twitter.com/elonmusk/status/734274360588926976
"Max damage" doesn't imply unflyable. A later tweet clarified that it's capable of flying again. They'd rather keep it for extensive testing, though, as an example of the most extreme conditions. It won't fly again, but not because it's too busted.
I would think if damage was within tolerances (even at the maximum of such), they'd be willing to relaunch. Implications from the tweet and subsequent conversations are that the damage exceeded thresholds to guarantee safe future flight, which is why they'd use it for testing on the ground.
I'd still read his tweet as meaning it's "too busted" to fly, but I suppose it's up to each person's own interpretation. Your point is well received.
Yup, user mikeash linked this soon after and clarified it for me, so I expressed my gratitude for his far more graceful and generally polite correction of the error in my comment. heh
Ah good, thanks. That might have been the one I was thinking of then that was just going to be examined. This flight though was also a high velocity landing so it might have similar issues if that's the case.
