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SpaceX lands rocket at sea second time after satellite launch

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Re: SpaceX lands rocket at sea second time after satellite launch

#271

Post by mikeash »

pilsetnieks wrote: post #268
mikeash wrote: post #195

Earlier quoted context omitted.

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."

If they chanted "SpaceX," or "Falcon 9," or "JCSAT-14" it would signify pride in their work. The "USA" chant glorifies the state/government above all else. It's the same reason why foreigners are baffled by, for example, the Pledge of Allegiance.

The person I'm replying to used "circle jerk" to describe things "before they started chanting."

Re: SpaceX lands rocket at sea second time after satellite launch

#272

Post by pilsetnieks »

mikeash wrote: post #271
pilsetnieks wrote: post #268

Earlier quoted context omitted.

If they chanted "SpaceX," or "Falcon 9," or "JCSAT-14" it would signify pride in their work. The "USA" chant glorifies the state/government above all else. It's the same reason why foreigners are baffled by, for example, the Pledge of Allegiance.

The person I'm replying to used "circle jerk" to describe things "before they started chanting."

Well yeah, that was a dick statement on their part. If I was at SpaceX, I would be proud of my work and the company as well.

Re: SpaceX lands rocket at sea second time after satellite launch

#273

Post by dang »

jklinger410 wrote: post #249

I find the level of criticism for SpaceX on this site to be incredible. I understand this is a place for intelligent discussion, but sometimes I feel like I can't find a single thread on this site without someone in the comments presuming they are smarter than someone else.

I'm pretty sure there's literally no other topic on which the HN community is so overwhelmingly positive.

There are a lot of commenters here, so there will a bell curve (or some distribution) on any topic at all. Picking negative comments from a tail is always possible, but it misrepresents the community, in this case completely. Posting indignant comments about it just adds to the problem and takes the thread off topic.

Re: SpaceX lands rocket at sea second time after satellite launch

#274

Post by grecy »

DougWebb wrote: post #212
mikeash wrote: post #179

Earlier quoted context omitted.

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…

> 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.

Would any "expert" really believe SpaceX didn't run the numbers millions of times, and do millions of simulations to confirm they could slow it down before actually spending the money to buy and outfit drone ships, build landing legs onto their rockets, etc. etc. ?

I mean, honestly, while the devil is in the details for an actual landing, they must have been pretty damn sure they could at least slow the thing down sufficiently.

Re: SpaceX lands rocket at sea second time after satellite launch

#275

Post by grondilu »

stupidcar wrote: post #227
mikeash wrote: post #167

Earlier quoted context omitted.

Airbus is working on Adeline, which would fly back and recover the first-stage engines and avionics (but not the fuel tanks) on an Ariane rocket. The Chinese have mentioned an effort to recover and reuse first stages by landing them with parachutes. So far, the Russians seem to think the effort isn't worthwhile. Closer to home, ULA's new Vulcan rocket is supposed to recover the first stage engines (but again, not the…

Wikipedia says Ariane 6's first test flight is scheduled for 2020, and Adeline will arrive between 2025 and 2030. Meanwhile, SpaceX plans to launch a Mars mission in 2018.

Say what you want about SpaceX's plans for re-usability, nobody can deny they are making progress at an incredible pace. I've just checked on Wikipedia and apparently the first flight of the Falcon was in 2010. That's six years ago.

Compared to that, Arianeespace's target of 2025 (in nine years!) for Adeline is almost ridiculous.

Just checked: Stephane Israël just raised concerned after SpaceX's latest success: http://www.lemonde.fr/economie/article/2016/05/05/face-a-spa...

Re: SpaceX lands rocket at sea second time after satellite launch

#276

Post by grecy »

leecarraher wrote: post #168

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?

Keep in mind everything SpaceX are doing is with the goal of getting to Mars.

They don't want to use cranes, or parachutes or helicopters or complex landing structures, because none of those things will work on Mars in such a way the rocket just needs to be refueled and can fly again.

Re: SpaceX lands rocket at sea second time after satellite launch

#277

Post by CydeWeys »

sevenless wrote: post #215
mikeash wrote: post #191

Earlier quoted context omitted.

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…

If the problem is simply the seawater, you could use a large plastic liner to create a pool of fresh water floating in the sea, and land in that.

This pool of freshwater would need to be many kilometers in diameter to give a high chance of hitting it with an unpowered parachute descent (thanks to unpredictability of the winds). At this point you are talking about doing something that is much, much more expensive than the current approach of a powered landing. How are you going to get so much freshwater out into the sea, anyway? That's way more water than could be carried in the largest cargo ship that exists.

Re: SpaceX lands rocket at sea second time after satellite launch

#278

Post by jacquesm »

lmm wrote: post #234
robszumski wrote: post #232

Earlier quoted context omitted.

While that is true, by the time they rebuilt them, you might as well call them new engines. SpaceX took their landed first stage directly over to the test pad to fire the engines multiple times. It's not really apples to apples.

If SpaceX can deliver what they're claiming in terms of refurb time/cost then that will be something to celebrate. But projects have a way of revealing unexpected challenges right at the last moment. I'm going to hold off the champagne until a refurbished booster actually flies.

That so negative. Of course they don't do this all in one go, it is incremental, step by step to get it to work. And each step is one closer to that goal and something to be happy about. If there are 'unexpected challenges right at the last moment' that's a real pity but those will be met just like all the unexpected challenges along the way. Yes, it's difficult, not it does not seem to be so impossibly difficult or different from what they've done to date that we should assume that it will not work. It will work, the bigger question is when.

Re: SpaceX lands rocket at sea second time after satellite launch

#279

Post by mineshaftgap »

fit2rule wrote: post #242
shiven wrote: post #108

Earlier quoted context omitted.

Yoo.Ess.Ae! Yoo.Ess.Ae! Yoo.Ess.Aeh! There. See. No harm, no foul. Anyways, as a non-American living in the US since 2001, I fail to see an issue with chanting USA, one way or another. It is an American company, with majority US employees, running this project (mainly) for an American entity (NASA), on US sovereign territory (or ocean?), using a significant chunk of US resources. So, it is their company and their cou…

I think its offensive to have nationalistic robot-like-chanting being defended as an okay thing. Its the sort of thing you expect people to do at rallies or cult gatherings, and from an outsider perspective it always tarnishes what is otherwise a very rational event, because its an implied irrational, collective mindset. As a non-American, I wish it'd stop - its a major turnoff for these events, and I switch away whe…

America is growing weary of butt hurt euro-whiners. Soon Europe will pay for its own defense or reap the whirlwind. Also Musk is extremely patriotic so piss off and do something worthy in EU.

Re: SpaceX lands rocket at sea second time after satellite launch

#280

Post by thrownear »

odonnellryan wrote: post #264
thrownear wrote: post #219

Earlier quoted context omitted.

>diminish amazing things.. 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 contrar…

> Sorry. We are living in a period where mediocrity and even complete fraudulent stuff is hailed as profound and "amazing". Like what? Even the transistor is pretty damn amazing. It's fine to be critical, but let yourself get excited sometimes too.

>Like what?

Look around. If you don't see it already, I won't be able to make you see. And what does the transistor has to do with the period we live in? I mean, right now, not 50 years earlier.

>It's fine to be critical, but let yourself get excited sometimes too.

Do you know why landing a rocket in salt water is bad. I mean, do you really, really know?

From Spacex subreddit..

https://www.reddit.com/r/spacex/comments/219sow/how_signific...

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