The Astronomy Thread

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Picasso3

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Looka like they had a pretty serios leg system deployed to land, i bet they had something cushy built in.
 
iannis

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I ain't no rocket sciencetist but I don't know if tin has the kind of integrity that you'll require for deceleration from terminal velocity. Maybe they make these things out of some space-age polymer plastic. My guess would be they probably do. Do they use fucking tin?
 
Tuco

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Tolan_sl said:
Expense due to new technology development and (maybe) more on-board components has nothing to do with structural reinforcements, which was my point.

The G forces on that rocket are relatively low compared to many other engineering applications. Except for, perhaps, the shock of landing, which if fine tuned should be very benign, the reverse landing operation exerts similar G's as the launch.
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Tolan, I don't really know what argument you're making here, so let me restate my argument:

Having a smooth landing on the rocket is a massive step toward attaining their goal of an inexpensive refurbish and refuel, but it's just one step. I imagine they have a lot more work to figure out all the ways to prevent damage to the rocket, and those prevention mechanisms will likely add cost and weight to the system, reducing their cost efficacy.

The way I read your posts it makes it sound like you're saying, "No, that will be easy because the landing was soft and aluminum is only 70cents a pound so they can just chuck aluminum bracing wherever they need to.". Which is a retarded position, so help me understand what you're saying here.
 
Tolan

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Tuco_sl said:
Tolan, I don't really know what argument you're making here, so let me restate my argument:

Having a smooth landing on the rocket is a massive step toward attaining their goal of an inexpensive refurbish and refuel, but it's just one step. I imagine they have a lot more work to figure out all the ways to prevent damage to the rocket, and those prevention mechanisms will likely add cost and weight to the system, reducing their cost efficacy.

The way I read your posts it makes it sound like you're saying, "No, that will be easy because the landing was soft and aluminum is only 70cents a pound so they can just chuck aluminum bracing wherever they need to.". Which is a retarded position, so help me understand what you're saying here.
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I probably misunderstood your original post. When you said "minimize weight" and "reinforcements", I was thinking added structure vs. strength/cost of materials. And I'm saying that I don't think that was the engineering battle they had to overcome with this design. The damage reduction mechanism for the landing is much the same as that of the launch, sans some small attitude adjusters, moderate duty legs, and energy absorbers somewhere between the touch-down feet and where the legs attach to the main structure for the relatively soft landing event. The thrust cone reacts 99.999...% of the energy during the decent, as it does during the ascent.

There's one reason they're rewinding the launch to perform the landing: it's efficient and preservative, and provides two main functions for the price of one design.
 
LachiusTZ

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So half a century ago we had tech that was more efficient than what space x is hoping for?

Makes sense.
 
khorum

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I suppose they could've gone the other way and drove down the costs of a real disposable rocket. If they engineered a booster to use the cheapest mass producible materials possible, then it goes back to a sourcing and logistical exercise instead of an ambiguous reusability moonshot project.
 
Tuco

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Tolan_sl said:
I probably misunderstood your original post. When you said "minimize weight" and "reinforcements", I was thinking added structure vs. strength/cost of materials. And I'm saying that I don't think that was the engineering battle they had to overcome with this design. The damage reduction mechanism for the landing is much the same as that of the launch, sans some small attitude adjusters, moderate duty legs, and energy absorbers somewhere between the touch-down feet and where the legs attach to the main structure for the relatively soft landing event. The thrust cone reacts 99.999...% of the energy during the decent, as it does during the ascent.

There's one reason they're rewinding the launch to perform the landing: it's efficient and preservative, and provides two main functions for the price of one design.
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A key component here is that the rocket can be damaged and worn by all stages, not just the touchdown moment. Previous stage 1 rockets aren't re-usable and didn't have to overcome that wear from repeated use. This one does.
 
Tuco

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khorum_sl said:
I suppose they could've gone the other way and drove down the costs of a real disposable rocket. If they engineered a booster to use the cheapest mass producible materials possible, then it goes back to a sourcing and logistical exercise instead of an ambiguous reusability moonshot project.
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I still want to see a good space-rocket launch thing. Maybe using magnetics, maybe using huge bungee-cords!
 
khorum

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Do the math on rubber band tech to get a kilogram into LEO.

They should do an X Prize thing for that.
 
Tuco

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I bet there's some diminishing returns on how fast rubber can contract. We will have to build a series of trampolines to mitigate this issue.

 
iannis

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That shouldn't be a problem. you just make lots of tiny rockets instead of one big one. Then slingshot them into space.
 
LachiusTZ

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Itzena_sl said:
Eh?
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https://en.wikipedia.org/wiki/Sea_Dragon_(rocket)

Space X is barely below $1,000/lb. Sea Dragon's lowest estimate was $63/kg ($600/kg as being the upper limit, estimates were validated[yeah, quoting wikipedia, so what]).

63/kg = 63/2.2lbs
600/kg = 300/2.2lbs

Thats . . . between $28.63 and $136.36, per pound.

And the rocket was reusable (the article reads like it, and since it is using the big dumb booster [iirc was stated as reusable?]) . . .

So . . . yeah, I dunno. Something happened in the 50s and 60s, because we were really ready to make a huge leap forward as a civilization.

So instead of colonies on mars / the moon, and other great achievements, Im able to jerk off in my bathroom using a bluetooth and phone so my wife doesnt know.
 
Mudcrush Durtfeet

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Dunno if inflation is accounted for in that. Anyway, cost estimates for things never even constructed may be wildly different than the end result.
 
Mudcrush Durtfeet

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Big Phoenix_sl said:
Idk, wiki says they had actual working models.
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Upon further research online (about the Sea Bee and Sea Horse rockets), it seems they did not have working models, rather, they tested engines for underwater ignition. Data is sparse.

Sea Dragon itself was a proposal for a rocket that was larger than any ever made (apparently). I am highly skeptical of claims.
 
Tuco

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Mudcrush Durtfeet_sl said:
Upon further research online (about the Sea Bee and Sea Horse rockets), it seems they did not have working models, rather, they tested engines for underwater ignition. Data is sparse.

Sea Dragon itself was a proposal for a rocket that was larger than any ever made (apparently). I am highly skeptical of claims.
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Same here. Not that I know much about rocket science. It just seems like unless there was some new technology enable by the weight, making a very large rocket would not confer cost savings.
 
BrotherWu

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LachiusTZ_sl said:
So instead of colonies on mars / the moon, and other great achievements, Im able to jerk off in my bathroom using a bluetooth and phone so my wife doesnt know.
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Why are you using Bluetooth during porn time? I always turn my Bluetooth off because I don't want to inadvertently connect to a speaker somewhere in the house. Because that would be an awkward conversation with the wife and kids.
 
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