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Is spaceX planning on giving up on reusability?

Posted by: coal_burner - Fri Jan 11, 2013 9:36 pm
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Is spaceX planning on giving up on reusability? 
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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Mon Mar 11, 2013 5:25 pm
There's a new video that shows Grasshopper hovering, and there's a press release on the front page. From that press release:
Quote:
At touchdown, the thrust to weight ratio of the vehicle was greater than one, proving a key landing algorithm for Falcon 9.

So it looks like they are indeed planning to come down in a continuous deceleration, and time it exactly so that they come to a halt just above the pad, then cut the engine and settle down on the legs. That would also explain Elon Musks earlier Twitter comment that this test could have been their first crater: get the thrust level or timing wrong and you're toast, and it comes really really close. Looks like it worked though, even if this was probably a low speed first try at the manoeuvre.

Another thing that I wonder about is that Grasshopper has two flames coming out of it, one out of the main nozzle, and one from a second pipe. You can see that especially well in this video. I wonder if that is some kind of chamber bypass that allows them to throttle deeper than on a normal Merlin. As we discussed above, ordinarily you wouldn't be able to hover an F9 first stage, but in this video Grasshopper does.

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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Sat Apr 27, 2013 8:59 pm
First post :)

The second flame is the output of the turbine exhaust as Merlin engines use a gas-generator power cycle


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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Sun Apr 28, 2013 1:16 pm
harryp wrote:
First post :)

The second flame is the output of the turbine exhaust as Merlin engines use a gas-generator power cycle


That gives me an idea - you could use cows on mars to generate rocket fuel!

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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Sun Apr 28, 2013 5:14 pm
SuperShuki wrote:
harryp wrote:
First post :)

The second flame is the output of the turbine exhaust as Merlin engines use a gas-generator power cycle


That gives me an idea - you could use cows on mars to generate rocket fuel!


Its easier to use CO2, Water, electricity and a zirconium catalyst to make the methane directly its less messy tho does has the disadvantage of no Beefsteak as a by product but IIRC Elon was wanting to keep the Martians vegetarian, tho that might have been a misquote :wink: :twisted:

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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Sun Apr 28, 2013 5:35 pm
How can you keep eating Martians vegetarian? Oh - you meant that the Martians wouldn't eat meat, not that eating the Martians itself would be vegetarian.

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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Sun Apr 28, 2013 5:41 pm
SuperShuki wrote:
How can you keep eating Martians vegetarian? Oh - you meant that the Martians wouldn't eat meat, not that eating the Martians itself would be vegetarian.


Yep I didn't think Elon was planning cannibalism in his retirement tho Big brother may try it to keep the ratings up if they get off the ground :twisted: :wink: :twisted:

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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Sun Apr 28, 2013 6:03 pm
SANEAlex wrote:
SuperShuki wrote:
How can you keep eating Martians vegetarian? Oh - you meant that the Martians wouldn't eat meat, not that eating the Martians itself would be vegetarian.


Yep I didn't think Elon was planning cannibalism in his retirement tho Big brother may try it to keep the ratings up if they get off the ground :twisted: :wink: :twisted:


I wasn't thinking about cannibalism. The martians are those creatures who would have evolved from the bacteria planted by a high school student for a science fair - very cow like, and therefore a great source of rocket fuel.

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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Mon Apr 29, 2013 9:37 am
harryp: Ah right! You just don't notice it so much on the non-hovering version because the flames are much less visible. So it's an ordinary Merlin in that respect. Still wondering how they do it then. Maybe they just added some ballast?

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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Tue Apr 30, 2013 4:17 am
Apparently the grasshopper does carry a lot of ballast in these flights.


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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Tue Apr 30, 2013 11:10 am
Hmm. Well, at some point they're going to have to test it as it will land, without ballast (which will give a very rapid leap into the sky) and with the screech-to-a-halt landing. I see some potential for spectacular Youtube movies yet :-).

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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Tue Apr 30, 2013 4:16 pm
Lourens wrote:
Hmm. Well, at some point they're going to have to test it as it will land, without ballast (which will give a very rapid leap into the sky) and with the screech-to-a-halt landing. I see some potential for spectacular Youtube movies yet :-).


Yeah - this is gonna be fun!

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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Tue Apr 30, 2013 4:17 pm
Lourens wrote:
Hmm. Well, at some point they're going to have to test it as it will land, without ballast (which will give a very rapid leap into the sky) and with the screech-to-a-halt landing. I see some potential for spectacular Youtube movies yet :-).


It'll take off like a rocket!
:lol:

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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Fri May 03, 2013 5:31 am
Recent tweet from Musk seem to indicate, no, they are not giving up on re-usability.

This is a landing leg for the F9-R. It's big, very big.

https://twitter.com/elonmusk/status/330 ... 28/photo/1


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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Fri May 03, 2013 8:02 am
And here are some blurry pictures of how it's supposed to attach. Looks like the cylinder folds up into the aeroshell/support brace to minimise drag on ascent, with the leg pointing upward, and then on landing the whole thing folds out 135 degrees or so and lands.

I wonder if it's attached to the engine's hydraulic system, or has a separate one? How about extending the legs part way early to increase drag and reduce heating at altitude, similarly to Virgin's feathering system? Obviously F9 will re-enter much faster, but perhaps there's still some benefit?

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Post Re: Is spaceX planning on giving up on reusability?   Posted on: Fri May 03, 2013 11:31 am
It looks like it's made out of plastic. Does anyone know what it is made out of?

Tovarich Luorens: It would probably rip off, if it opened up at speed - if it didn't melt. Or are you talking about it slowing the rocket down with the gear closed? Or opening it at "low" speed?

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