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SpaceX Updates (Thread 4): F9, FH & Dragon


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#61 Aheer.R.S.

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Posted 14 December 2013 - 03:58

Almost forgot -

This bay is for the vertical integration of the payload, payload adapter and fairing for some national security payloads.

They need to get it done because the next launcher up to bat at Vandenberg is Falcon Heavy #1.

They're also putting the finishing touches on the *massive* Falcon Heavy test stand at McGregor, which is partially underground to limit the noise townsfolk will have to put up with. That MoFu is gonna be LOUD!

Falcon Heavy: 224 feet tall, 27 Merlin 1D engines, almost 4 million lbf of thrust and able to orbit the mass of a fully loaded Boeing 737. That fairing can hold a city bus.

FHR.jpg

Looks like one of my wife's bedtime toys.... :/




#62 malenfant

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Posted 14 December 2013 - 07:31

@ sarKOY

So your problem is that Musk isn't an obnoxious sneering purist or moral supremacist, that he understands realpolitik?

As for everything else...

#63 SarK0Y

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Posted 14 December 2013 - 18:57

@ sarKOY

So your problem is that Musk isn't an obnoxious sneering purist or moral supremacist, that he understands realpolitik?

As for everything else...

not sure what do you mean :) my point is clear & simple:

 

1. f9 is very limited design: it can't provide the rest of possible orbits.

2. conception of reusability has no serious ground, any normal engineer must avoid such poor schemes.

3. Musk has chased after his ideas for taxpayer's backs. if he is so private company, he has to waste his own monies.



#64 FloatingFatMan

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Posted 14 December 2013 - 19:04

^ Re-usability is the only option moving forward. We can't afford to keep throwing away such expensive resources if we want space exploration to become economically viable.



#65 SarK0Y

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Posted 14 December 2013 - 19:20

^ Re-usability is the only option moving forward. We can't afford to keep throwing away such expensive resources if we want space exploration to become economically viable.

FFM, future spacecraft must be reusable, here doesn't exist other alternatives. But(!) we discuss the conceptions of reusability. Musk's one is very poor.



#66 malenfant

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Posted 14 December 2013 - 19:25

@ sarKOY

Thank You for responding. Where to begin? I don't think I'll bother. So long.

#67 SarK0Y

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Posted 14 December 2013 - 19:41

@ sarKOY

Thank You for responding. Where to begin? I don't think I'll bother. So long.

schemes of reusability have been known for years upon years:

 

1. stage(s) lands as aircraft.

2. spacecraft uses N-dip trajectories for re-entry.

3. orbital tugs.

=========================

it's just short list of possible. :)



#68 OP DocM

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Posted 14 December 2013 - 19:43

As I said on his arrival-

6072c3f98f422cbfe116f89220478223.thumbna

#69 SarK0Y

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Posted 14 December 2013 - 19:53

DocM, perhaps you'd like to ans my question about video of returning stage? ;)



#70 OP DocM

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Posted 14 December 2013 - 20:23

Looks like one of my wife's bedtime toys.... :/

But with a purpose. The side boosters, basically stretched Falcon 9's, used in cross-feed mode both fire and propellants fuel to the center stage preserving it's peopellant loads.

When the side boosters separate the rest of the stack has full tanks, which is essentially like launching a Falcon 9 from 60+ kilometers up and already doing Mach 6. This increases payload mass tremendously - Falcon Heavy will be able to send ~53 metric tons to LEO, 22.5 metric tons to GTO, or almost 13 metric tons to Mars.

The in-development SpaceX Raptor methane engine in a similar (but much larger) stage configuration has been estimated (using Schilling's rocket simulator) to loft almost 200 metric tons to orbit. Perhaps more, depending on assumptions. Raptor components enter testing at NASA Stennis in early 2014.

#71 OP DocM

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Posted 14 December 2013 - 20:25

Accidental dup

#72 SarK0Y

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Posted 14 December 2013 - 20:37

But with a purpose. The side boosters, basically stretched Falcon 9's, used in cross-feed mode both fire and feed fuel to the center stage preserving it's fuel load.

When the side boosters separate the rest of the stack has full tanks, which is essentially like launching a Falcon 9 from 60+ kilometers up and already doing Mach 6. This increases payload tremendously - Falcon Heavy will be able to send ~53 metric tons to LEO, 22.5 metric tons to GTO, or almost 13 metric tons to Mars.

The in-development Raptor methane engine in a similar (much larger) stage configuration has been estimated (using Schilling's rocket simulator) to loft almost 200 metric tons to orbit. Perhaps more, depending on assumptions. Raptor components enter testing at NASA Stennis in early 2014.

just yet another ungrounded claims: cross-feeding, for example, is inefficient scheme -- it makes design more tricky + dry mass gets growing as well :) Methane??? why do you think Methane is more useful than other propellants? :)



#73 ImUtrecht

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Posted 22 December 2013 - 12:28

Methane is more useful because it can be made on Mars, so you do not need to take the return fuel with you.

 

So a 200 tons octaweb that can bring around 65 tonnes to Mars, that could be the mass of the MCT.

The moon could be interesting for resources too. China is going that way.



#74 OP DocM

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Posted 22 December 2013 - 17:12

Cross feeding was actually proposed by both Russia and Boeing, so some pretty smart folks think it's worthwhile. Boeing hasn't used it because Delta IV Heavy can launch current NRO payloads without it. Falcon Heavy brings into play a much larger class of NRO (and science) payloads, or launching 2-3 at once, making cross-feed for these very heavy payloads necessary.

As to cross-feeds complexity and mass, it's (largely hollow) plumbing and vailves (in other words, a manifold) that fit into the existing Falcon Heavy core Octawebs. As a percentage of dry mass it's not much at all. I've also seen cross-feed diagrams for the multi-core versions of Russia's new Angara launcher so they're thinking in that direction too.

Methane is useful because it has a higher specific impulse than keresene but doesn't have the handling, containment degradation and boil-off difficulties of hydrogen - especially long term. It can also be made on Mars from its CO2 atmosphere and hydrogen derived from local water ice via the Sabatier process. This cuts launched mass as you cam refuel locally.

Methane is also useful for reusable rockets, which is a SpaceX priority. Kerosene cokes up the engine (soot deposits) and methane doesn't. Less work during the turnarounds.

BTW, Russia's working on their new RD-162/RD-0164 methane fueled engines, so if it is an insane idea then it's a shared madness. One of these new Russian methane engines is in the same 650,000 klbf class as SpaceX's Raptor.

Where SpaceX has an advantage in a race to methane is manufacturing and engine efficiency. If Raptor can achieve the 150:1 thrust to weight ratio of Merlin 1D (most engines are 30:1 to 80:1) it would mean a much larger than expected payload mass.

Now imagine if they could 3D print most of the engine instead of machining it. They are already 3D printing propellant valves and the Dragon 2's regeneratively cooled SuperDraco abort and landing thruster, at the least - maybe propellant nozzles too, so never say never.

#75 SarK0Y

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Posted 22 December 2013 - 22:44

@DocM

 

Cross feeding was actually proposed by both Russia and Boeing, so some pretty smart folks think it's worthwhile

back then Shuttle was proposed as most cost-efficient way, but ended up as unreliable & crazy expensive. many things were believed as breakthrough, but only a few is living breakthrough. + as i said, scheme to not burn core stage until needful altitude is quite simple alternative. actually, it's just modification of multi-stage design.

 

Methane is useful because it has a higher specific impulse than keresene but doesn't have the handling, containment degradation and boil-off difficulties of hydrogen - especially long term. It can also be made on Mars from its CO2 atmosphere and hydrogen derived from local water ice via the Sabatier process. This cuts launched mass as you cam refuel locally.

  Mars? :) c'mon! Musk's rockets barely get in ordinary orbits. if to say about long-lasting missions, Methane is useless too: it's gas, so boil-off problems shall be as well, leakages are yet another trouble which will not vanish into nowhere too. how weighty hardware you need to mine Methane in the Mars??? :) what about radiation shielding??? what about portable nuke reactors??? And so many others WTFs as well.  & yes, what about oxidizer? :)

 

BTW, Russia's working on their new RD-162/RD-0164 methane fueled engines, so if it is an insane idea then it's a shared madness. One of these new Russian methane engines is in the same 650,000 klbf class as SpaceX's Raptor.

Methane could have some advantages, but for expendable rockets. however, even for expendable ones, it's very unlikely to get significant advance. liquid fuels have better ratio volume to Isp. in short, perhaps Methane will be fruitful for upper stages… but so far it's only theoretical assumption.