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SpaceX lands rocket at sea second time after satellite launch

phys.org

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

#411

Post by grey-area »

SFJulie wrote: post #339
larrydag wrote: post #188

Earlier quoted context omitted.

As an Engineer I might be a little biased but I see this is a massive achievement. We are seeing a paradigm shift in space exploration with the rise of the influence of the private sector. Space exploration used to be the domain of government entities. That is gone now. I believe we are seeing a new age of exploration not seen since the 15th and 16th centuries of discovering the "new" world. These new space companies…

As an idiot, is is less expensive than asking the NASA or the ESA, or any other providers? And well, can the "materials" really be recycled without loss of security/quality? Is the metal more expensive than the carburant/comburant?

Yes, Yes, and Yes.

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

#412

Post by eric_h »

mattmanser wrote: post #233
hoorayimhelping wrote: post #165

> 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…

This is a new thing, 2-3 years ago downvotes were still rare, these days people treat it like reddit where it means disagree rather than inappropriate. The culture's changed.

The karma threshold for downvotes likely means that there are far more people with the ability than there were 3 years ago. Honestly, I only collected enough karma recently to down vote (and it's a privilege I use quite sparingly).

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

#413

Post by jsnider3 »

lostlogin wrote: post #384
CydeWeys wrote: post #277

Earlier quoted context omitted.

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…

A freshwater lake would seem easier

Lake Michigan seems like a pretty easy target and it's 100% American territory.

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

#414

Post by Inconel »

sandworm101 wrote: post #388
elif wrote: post #382

Earlier quoted context omitted.

It is amusing that you insist your speculation about something you've never done is more valuable than the experience of someone that has pioneered it.

Ya, because SpaceX is the only company to have ever transported something on the deck of the ship. It was a rocket until the moment it landed. Now it's cargo.

This isn't my area of expertise and what you've said certainly makes sense, however from my understanding ship-to-ship, or in this case ship-to-barge, boardings at sea aren't without their own inherent risks.

It could be that having the first stage untethered is deemed less risky to personnel than having a team of welders board the barge and tie it down.

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

#415

Post by rfrey »

thrownear wrote: post #392
rfrey wrote: post #370

Earlier quoted context omitted.

Even easier than being a fanboy is to promote one's own superiority via dismissal and sneering at the efforts of others. You probably see yourself as sophisticated, but your remarks are no different than a 7 year old putting down somebody for throwing like a girl. It's adolescent, not contrarian.

>Even easier than being a fanboy is to Easier? How? Because you said so? >promote one's own superiority via dismissal How come I haven't noticed that it isn't working, then? >sneering at the efforts of others.. This is where you show your fanboy colors. The GP said something along the line "I don't think that is as amazing as you say", and you overreact, saying that they are, "sneering at others efforts". Another com…

"Stop for a moment and and think about what exactly in my comment have provoked you to attack me in this fashion"

Flashbacks to middle school.

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

#416

Post by castis »

thrownear wrote: post #334
castis wrote: post #303

Earlier quoted context omitted.

Check out the history of the person you're replying to. That person doesn't get stoked about anything. It's a shame, really.

Getting stoked about trivial stuff and mistaking stunts for real achievements is one of the ways we will end up in Idiocracy. I see here, a whole generation of people reduced to a bunch of stupid cheerleaders... The shame is on you. Not because you play along in this charade. But for how you see and project me for not taking part in it.

That shame is fine with me. My apologies for dragging you back into a thread that is so obviously beneath you.

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

#417

Post by mikeash »

jsnider3 wrote: post #413
lostlogin wrote: post #384

Earlier quoted context omitted.

A freshwater lake would seem easier

Lake Michigan seems like a pretty easy target and it's 100% American territory.

The barge was located about 400 miles downrange of the launch site in this case, so if you're landing in Lake Michigan then you're launching from somewhere around western Iowa/Minnesota or eastern Nebraska/South Dakota. When your rocket goes off course or explodes, you'll rain parts and fuel down on Minneapolis or Chicago or whatever other inconvenient population happens to be in the way.

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

#418

Post by beachstartup »

sandworm101 wrote: post #90
d_theorist wrote: post #88

Earlier quoted context omitted.

Somehow I suspect they have run the numbers.

What numbers? Unsecured cargo is unsecured cargo. A metal object sitting on a flat metal deck gets tied/braced/chained.

how much money and time would a robotic lashing system cost? hint: a shitload.

how much money would a few ditched rockets cost, in comparison? hint: less than a shitload

would a recovery crew approach this platform in rough seas, even if a robotic lash were in place? hint: nope

then what exactly is the point of securing this 'cargo'? hint: there isn't one.

problem solved.

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

#419

Post by lutorm »

mikeash wrote: post #305
grondilu wrote: post #281

This success was unexpected. That means that they can recover a stage from a higher speed than previously thought. Does that mean that the recovery of the second stage from LEO may actually be feasible?

Second stage recovery is a whole different beast. Recovering the first stage on a flight like this is a delicate dance because margins are so small, so everything has to go exactly right. The previous attempt (SES-9) didn't quite go exactly right, and made a big boom, perhaps because the engine burns were slightly mistimed. Recovering the second stage is difficult because it's coming in from a much higher speed. The…

The second stage has a smaller ballistic coefficient than the first one, though. Their cross-sectional areas are the same, but an empty second stage has much less mass. If it could survive entry (and that's a big if), it's terminal velocity would be smaller.

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

#420

Post by nkurz »

Inconel wrote: post #414
sandworm101 wrote: post #388

Earlier quoted context omitted.

Ya, because SpaceX is the only company to have ever transported something on the deck of the ship. It was a rocket until the moment it landed. Now it's cargo.

This isn't my area of expertise and what you've said certainly makes sense, however from my understanding ship-to-ship, or in this case ship-to-barge, boardings at sea aren't without their own inherent risks. It could be that having the first stage untethered is deemed less risky to personnel than having a team of welders board the barge and tie it down.

If they don't need it, they don't need it, but I wonder if there would be any other way do the secure the rocket without requiring welders to board the barge. Coat the deck with solder and put heaters in the feet to attach? A robotic Roomba-style welder? Giant arms that rise up to clasp the rocket regardless of the exact landing position? Fun to think about...
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