Considering that SpaceX has started printing *entire* rocket motors - not primary launch motors, to be sure, but rocket motors for production spacecraft nonetheless - I don't think ULA playing "me too" with building a few parts this way is going to make them as cool as SpaceX!

Yep. Some parts of the Merlin 1D are built additively, I think, but the *entire* SuperDraco thruster (which uses Hydrazine rather than cryogenic fuels like RP1/LOX) is printed. http://en.wikipedia.org/wiki/S...

It's really cool to see this technique taking off (pun not initially intended, but let's go with it). People think of 3D printing as making rough plastic parts, but it can be used to create extremely precise parts out of various metals, too.

If they're renting (as most low-income people do), they won't be (directly) paying property tax.

I suspect Lucas doesn't actually expect to turn a profit on doing this, possibly not by a long shot. 200M isn't exactly pocket change, but he can easily afford to write off the whole thing if needed.

It's pretty sad that "rich guy flips the bird to other rich people in revenge for not getting his way" pleases you more than "rich guy helps people get housing in one of the most expensive parts of the world". I mean, I enjoy the feel of a good "fuck you!" too, but if you like that *more* than what's essentially charity, well, that's kind of screwed up of you...

Seems like a reasonable claim to me! Resource supply is one of the key determiners of land value, and always has been. If it rains on my land, and I catch that rain before it wanders onto somebody else's land, how is that not my water?

I mean, there's lots of arguments for (and against) communal ownership of natural resources, but the current (and, for as far back as I'm aware, historical) rule is that they are part of the land value. You're going to have a hell of a time overturning that view. Some things, like rivers, tend to get a bit complicated - it's really awkward if your upstream neighbor feels like using his water (immediately before it ceases to be his) as an arsenic dump - but taking ownership of the water falling from the sky or coming up through the ground has never, so far as I know, *not* been part of land property rights.

I'm not actually sure which of use that tweet backs up; I thought he meant "I estimate we have an 80% chance of at least one landing by year's end, because there are lots of launches between now and then and there's a pretty good chance at least one will succeed." It would be pretty awesome if what he meant was "By the end of the year, we'll have so much more launch practice that, even though each launch has less than 50% chance of recovery right now, by year's end it should be about 80%." I hope the latter is the case, but the two are very different statements and the latter is much more optimistic. I was hoping you could indicate which one was more accurate.

Not clear whether or not you realize this, so to give you the benefit of a doubt:

A) In orbital launch booster rocketry terms, that's a pretty damn small fireball.
B) At the time he sent that tweet, nobody (Musk included) had seen the video from the barge. I doubt he even had the video from the airplane, probably just the telemetry data that showed touchdown followed by a loss of telemetry.

Explode when it crashes, there's a difference. SpaceX has demonstrated powered vertical landings on their test vehicles, there were no explosions.

Hydrazine is nasty stuff, but you don't need very much of it (a few second's worth, maybe) and the *entire point* is to avoid the crash, so what happens in the event of a crash is much less important.

I thought that was him estimating an 80% chance of at least one success by year's end, which (considering that they have a lot of launches this year) is a very different thing. Do you have a source for that?

Nitpick: The first attempt ran out of hydraulic fluid (for the guidance fins), not out of propellant for the RCS thrusters.

The rest of what you say is generally true, although a larger target *would* help. The advantage of a larger target is that, while you still have to zero your horizontal velocity, you don't have to zero it anywhere terribly precise. You can pick an optimal set of thrusts that results in the correct orientation and velocities (horizontal and vertical) without worrying overmuch *where* that series of thrusts has you touching down. Both attempts so far clearly demonstrate the ability to do an excellent good job of targeting a (relatively) tiny barge, but currently, if the rocket would come down even 100' (30m) to one side of its target spot, it needs to induce a horizontal momentum (which requires leaving a vertical attitude as well, it can't just translate sideways) and then null that momentum at the right moment (and fix its attitude). That's hard.

To clarify for the person who keeps misunderstanding my posts: they should, of course, plan for the barge-level of landing precision. They should aim for a precision of inches, and within a year, they may get it... 90% of the time. Stuff goes wrong, though, and (especially early in the testing of such a system) it behooves them to use a larger landing area so that there's some margin for error. I'd say their land attempt (possibly next CRS launch, in a couple months) has a very good chance of being their first success.

The thrusters aren't even supposed to be needed there, actually. They're only supposed to fire in very short bursts, not a continuous stream like in the video. As for the legs holding up, just one of them supported the whole rocket for a few seconds; all four should have had no trouble. We know a hell of a lot more than just that it crashed. To claim otherwise is to embrace ignorance.

There is literally no point at all to living in a world where you are only concerned with the things that you absolutely know. You don't absolutely know *ANYTHING*, you could be a simulation in some advanced being's AI-run world, along with everything the program running you has ever simulated observing. The only way to achieve anything difficult is to analyze the differences between failures and successes, and a part of that analysis is to determine how close you came to success.

But then, you probably already knew that and are just a naysayer...

I'm not trying to fix the wrong problem, I'm trying to add a backup for the fix. Shit happens. Parts will fail, valves will stick, unexpected winds or waves will occur.

I thought the fact that the primary goal was to correct the problem that caused the excessive lateral velocity was so bloody obvious that it didn't need saying, but I guess I forgot I'm on the Internet. The purpose of my idea was not "fuck it, fixing a little problem is hard, let's do something much more complicated", it's "shit happens. What can we do to survive the likely error modes?"

A) You've mastered "dictionary", "bookshelf", and "somewhere", but an eight-letter word is too big for you?

B) Welcome to the Internet. You probably got here using "the blue e", right? Tip: highlight (whoops, big word) the scary word with your mouse, right-click on it, and click the option that will search or define the word for you! No need to go over to your bookshelf at all, and you get to avoid looking like a lazy ignoramus (sorry, is that one too long?) at the same time!

Seriously, I get that you're probably joking, but that is a really stupid thing to complain about. Definitions don't belong in a summary, especially not a summary delivered through the biggest inter-connected information network humanity has ever created.

Agh, bloody autocorrect and stupid failure to proofread. First paragraph:

What would it cost (presumably a matter of weight) to upgrade the nose thrusters?

You saw the part where the reaction control thruster at the top (little white plume) is trying to keep the rocket upright, didn't you? Lasts about four seconds. The rocket had already touched down (on at least one leg, with engines shut off) at that point. If the stage had been even a *little* closer to upright, or the thruster a *bit* more powerful, the rocket would have settled onto all four legs and that would be it.

Also, the stage swings through vertical in the moment before touchdown. It's that half-second of overcorrection that doomed it. It was over the barge and in the correct orientation less than 1000 millisecond before touchdown. I'd say the only reason that "seconds away from what would have been the first successful landing" is wrong is because it was more like *one* second.