211–220 of 497 posts
Am i missing something, is the need to land vertically a requirement of a fragile fuselage? Seems wasteful to carry extra anything (in this case rocket propellant) to space, just to avoid having to re-right the rocket when you get it back on earth for a subsequent launch. Is extra fuel payload < landing gear or parachutes?
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I attended a conference from the head of the CNES (Centre National d'Etudes Spatiales, ~ French NASA) in Paris a week ago and he talked about that. Ariane 6 is going to be built with a cost effective approach and trying to focus on market needs (3D printing of parts, reusability of the first stage, etc.) At first, concerning SpaceX, his group of experts told him that the design of the rocket wasn't going to work and…
I can't imagine how anyone with the slightest clue could conclude that the first stage would sink the barge. The scales are just too different; the barge outweighs the rocket by orders of magnitude. I hope this is one of those "lost in translation" things, because otherwise I fear for that group of supposed experts.
I remain confused about why SpaceX is getting so much fanfare and praise. What have they accomplished that NASA didn't already accomplish during the Apollo missions? I know SpaceX is doing it all more cost effectively, because we have better technology, but have they actually accomplished anything tangible that NASA didn't a generation ago?
Red Dragon (assuming goes ahead as planned) will be the heaviest payload ever landed on another planet - an incremental improvement to be sure, but a real one. Mars sample return will be a concrete new thing that NASA never managed. Watch this space.
I always try to watch the webcasts and I can't help but cringe so hard when they start chanting 'USA USA USA', every single time. What is up with that?
Maybe they don't know their CEO is South African?
Am i missing something, is the need to land vertically a requirement of a fragile fuselage? Seems wasteful to carry extra anything (in this case rocket propellant) to space, just to avoid having to re-right the rocket when you get it back on earth for a subsequent launch. Is extra fuel payload < landing gear or parachutes?
Parachutes aren't massless. The parachutes you'd need to land a rocket like this are actually comparable in mass to the extra fuel and landing legs needed for the vertical landing approach. You also can't land on a ship with parachutes. You don't have enough control. You can still land at sea, but then you have to actually land in the water, which means getting seawater on all your rocket hardware. That causes lots o…
What's notable about this attempt (as opposed to the last) is that the first stage rocket was traveling twice as fast (4x the energy to overcome on landing), and didn't have enough propellant to do a 'boostback' burn. Instead, coming in very hot, the rocket had to use three engines (instead of one) to slow for landing. The last time this was attempted, the first stage put a nice hole in the deck of the drone ship. Se…
This means that it must slow to a standstill, cut the engines and hit the platform at exactly the same time or it will either start going up again or be dropped onto the platform from a less than ideal height.
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What exactly is wrong with that discussion? I found the level of evangelical, employee circle jerking at these SpaceX events to be nauseating. And that was before they started chanting. Well done guys but it's just not necessary.
Good ol' HN. These folks are pushing the boundaries like nobody else, advancing humanity more than a thousand Facebooks or Snapchats ever could, but if they express pride in their work it's a "circle jerk."
Maybe it's just a cultural difference but there is something unsettling and cringey about seeing those employees act so enthusiastic.
Is it genuine? Maybe for some employees. But the camera setup makes me think there is some expectation placed upon the employees that they will be there to cheer. It's not natural.
Earlier quoted context omitted.
I attended a conference from the head of the CNES (Centre National d'Etudes Spatiales, ~ French NASA) in Paris a week ago and he talked about that. Ariane 6 is going to be built with a cost effective approach and trying to focus on market needs (3D printing of parts, reusability of the first stage, etc.) At first, concerning SpaceX, his group of experts told him that the design of the rocket wasn't going to work and…
I can't imagine how anyone with the slightest clue could conclude that the first stage would sink the barge. The scales are just too different; the barge outweighs the rocket by orders of magnitude. I hope this is one of those "lost in translation" things, because otherwise I fear for that group of supposed experts.
The energy amount the rocket impacts with is dominated by its speed, not its mass. A small, fast-travelling projectile can make a hole in just about any kind of armour. The terminal velocity is quite low, but that's in part because of the way it is engineered — an ICBM would probably be able to put a hole through a ship deck with ease.
There is a lot of reasoning by analogy vs. reasoning from first principles going on, and the latter seems to be winning. But the main driver of the space industry is governmental funding, not commercial. Much of those statements were probably political; SpaceX have prevailed, and indeed found some champions of their own (John McCain is rabidly behind them, and some of the statements he comes up with are ludicrous in their own right, for example), though not before enduring some setbacks.
> P.S. Downvotes for this question? Really? There are always people on HN who love being contrarian and trying to diminish amazing things. It's like they hate seeing people excited for something and want to point out that this isn't that big of a deal. We're literally watching things happen for the first time ever, and this person's response is "what's so great about this?" while implying that people who are excited…
Sorry. We are living in a period where mediocrity and even complete fraudulent stuff is hailed as profound and "amazing". People with differing opinions matter, and I would say they matter more than ever.
And I don't think people love being a contrarian". It is quite easy being a fanboy, but it is hard to go against popular opinion, and be a "contrarian". There is no love in being a contrarian, there is only hate and ridicule.
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I can't imagine how anyone with the slightest clue could conclude that the first stage would sink the barge. The scales are just too different; the barge outweighs the rocket by orders of magnitude. I hope this is one of those "lost in translation" things, because otherwise I fear for that group of supposed experts.
mass != momentum. I'm sure the thinking was that they wouldn't be able to slow the rocket down enough and that the speed of impact would punch through the barge. The autonomous control needed to get the rocket to slow down and stop at just the right time, while accounting for the movement of the barge, the movement of the rocket (eg: unpredictable wind impact), and the difficulty of gathering telemetry through the ro…
Either way, the relative masses matter. It takes a lot more effort to punch a hole through something much more massive than your projectile! It doesn't make much sense that a light, nearly spent rocket stage would punch all the way through a massive barge. And even if it did, the hole still wouldn't be big enough to sink it.