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SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic

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Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic

#101

Post by syncsynchalt »

redthrowaway wrote: post #16
cloudwalking wrote: post #7

- Successful soft landing in the Atlantic - Seas were too rough for a quick recovery - Rocket subsequently destroyed by wave action - Will attempt recovery of the next Falcon 9 launch - A Falcon 9 recovered on land could be re-used the next day (!) - SpaceX is lobbying to allow private competition for National Security launches (eg GPS satellites)

Is "the ocean was wavy" really a justifiable reason for losing the rocket? Surely sea conditions are something they'd take into account when planning and executing the mission.

Rockets are surprisingly fragile when empty. Most of their strength is compressive, and only in one direction, and only when filled with compressed gas.

Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic

#102

Post by SoftwareMaven »

smackfu wrote: post #78
chidevguy wrote: post #36

Earlier quoted context omitted.

My jaw dropped reading that the rocket could be re-used the next day. That seems like an enormous leap forward for space flight.

I would think inspecting, cleaning, and assembling the stack would take days. So next-day is probably Musk hyperbole.

People constantly say this about him, yet he consistently comes through on what he says. I tend to favor trusting what he says about things like this now.

Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic

#103

Post by 001sky »

(1) Telsa CEO Elon Musk announced a major breakthrough in spaceflight on Friday

(2) Musk revealed the potentially "revolutionary" news on Friday during a hastily organized press conference

(3) "What SpaceX has done thus far is evolutionary, not revolutionary," Musk said.

(4) "If we can recover the booster stage, the chance is there for revolutionary."

What was announded today was a critical first step. But there is nothing seemingly new in the press conference report, beyond what Elon had tweeted on the day of the soft-landing itself. The only new news is that the vehicle was lost, which doesn't really seem to be a "breakthrough" in the context of Musk's own explanation.

The bigger step here will be getting the recovery because the need to confirm empirically what kind of shape the engineered pieces come back in. Many problemes like the icing on the shuttle (which de-laminated and caused projectile damage) are not going to be discovered without such an inspection.

Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic

#104

Post by lotsofmangos »

joyeuse6701 wrote: post #88
lotsofmangos wrote: post #52

Earlier quoted context omitted.

Calling for NASA to stop working with Roscosmos and the ISS over Putin is nuts. Space research and exploration is more than petty flag waving.

Somehow I think taking over Crimea is more than petty flag waving to the people who live there. I'd ask for more empathy for those whose lives may be irrevocably damaged by the actions of the Russian Head of State.

Taking over Crimea is awful and completely predictable, as is the land corridor from Crimea to Russia that will be opened to the north. Russia is scared of losing control of the naval base it has held there for over a century.

However the collaboration with the ISS is something that forces communication and trust on a joint project at a high level. It is not just that it is important for space research, it is even more important for soft diplomacy. It forces the governments into situations where they have to talk about something other than sabre rattling on a regular basis.

Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic

#105

Post by sitkack »

ElComradio wrote: post #81
andrewtbham wrote: post #29

Earlier quoted context omitted.

I watched a senate hearing where Elon Musk squares off with the ULA. It's awesome. One great quote is where the ULA says Space X can't handle the missions. Elon responds. If our rockets are good enough for NASA, they are good enough for the Department of Defense. https://www.youtube.com/watch?v=O_azyt1JhI0

I suspect if you asked a DoD gal if it was more critical that, say, a military commsat got to orbit than something that measures solar flares, she'd beg to differ with Elon.

Yeah we all would expect them to say that. Everyone's baby is the cutest. Everyone's problems are the most important.

Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic

#107

Post by sitkack »

XorNot wrote: post #92
ef4 wrote: post #82

Earlier quoted context omitted.

> you need to strip and re-build the thing That's how politically-designed boondoggles like the shuttle work. It's not inevitable, if you actually spend the engineering effort on reliability and repeatability. If NASA operated an airline, they would probably be tearing down and rebuilding every jet engine after every flight, and a ticket would cost $100,000.

I said this in another thread, but part of the issue is failure intolerance. Sure - for human payloads I'd want to be damn sure my process is good, like, hundreds to thousands of missions deep before I trusted it. But that's totally unnecessary for an unmanned payload! If the cost of launch drops enough, you can fully justify launching 2x the payloads if you expect maybe 1 in 10 failures due to the mode of launch. I…

Teardown and rebuild doesn't increase your safety margins, they reduce it. If I rebuilt my Toyota every 10k miles I'd have a lot more breakdowns.

Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic

#108

Post by lmm »

keehun wrote: post #98
lutusp wrote: post #28

Earlier quoted context omitted.

You clearly have not been at sea, close to the water. A cylindrical object, without a sea anchor, in moderately rough seas, would naturally turn sideways to the waves and be destroyed very quickly in the breaking waves. I don't know whether SpaceX has fitted their boosters with sea anchors yet, but I wouldn't be surprised to see this addition after the present loss. In windy conditions, a sea anchor provides some dra…

How much weight would be such an anchor to hold down something as large as a rocket? Wouldn't you have to launch that into space, too?

Sea anchor, i.e. something like a parachute that drags through the water, so it can be made of light materials.

Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic

#109

Post by lutusp »

keehun wrote: post #98
lutusp wrote: post #28

Earlier quoted context omitted.

You clearly have not been at sea, close to the water. A cylindrical object, without a sea anchor, in moderately rough seas, would naturally turn sideways to the waves and be destroyed very quickly in the breaking waves. I don't know whether SpaceX has fitted their boosters with sea anchors yet, but I wouldn't be surprised to see this addition after the present loss. In windy conditions, a sea anchor provides some dra…

How much weight would be such an anchor to hold down something as large as a rocket? Wouldn't you have to launch that into space, too?

A sea anchor is a pretty lightweight device whose purpose is to create some drag against the water when the wind blows. It can take the shape of a small parachute, but in the water, at the end of a long line. The idea is when the wind blows, endangering the booster, the sea anchor will force the booster to point directly into the wind, thus minimizing wave damage.

> Wouldn't you have to launch that into space, too?

Yes, which is definitely a drawback -- every ounce that isn't payload is regarded as a serious waste, because it all has to be launched at great cost (the ratio of payload to fuel is often greater than ten to one).

On the other hand, the SpaceX people report that the booster was destroyed, so this well-tested idea is very likely in their minds right now.

Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic

#110

Post by robryk »

syncsynchalt wrote: post #101
redthrowaway wrote: post #16

Earlier quoted context omitted.

Is "the ocean was wavy" really a justifiable reason for losing the rocket? Surely sea conditions are something they'd take into account when planning and executing the mission.

Rockets are surprisingly fragile when empty. Most of their strength is compressive, and only in one direction, and only when filled with compressed gas.

I'm not sure about strength being mostly compressive -- for example, Apollo 9's Saturn V withstood a longitudinal oscillation with an amplitude of 12g[1] and it wasn't deemed to be dangerous enough to cause an abort.

I'd expect maintaining pressure in the tanks not to be a significant problem, though it would need to be addressed -- pressure needs to be maintained reasonably constant during the whole burn, and it's done by admitting helium from compressed helium tanks. If the fuel/oxidizer tanks don't leak too much, the same mechanism could be used after the rocket has landed.

[1] http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2008001...

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