SpaceX after they land their first stage?

[Wingman703]

TBH if SpaceX thinks that they can reuse the stage economically then I trust their judgment over that of random forumers.

I think this pretty much sums up my feelings.

Elon is no fool. If he thinks he can do cheaper, achieve bigger margins, or do something better/faster, then I'm not going to stand in his way.

That being said, he runs a business(several of them actually). There are REASONS that he is doing what he is doing, and he is not the type to foolishly pursue an idea if it doesn't hold any prospect of benefits for his company. He is not going to put into effect one of his ideas unless he has fully vetted and understood its impacts and potential.

Godspeed Elon. The world is watching.

Edited April 17, 2015 by Wingman703

[Kryten]

Who the hell is Enon?

[AngelLestat]

Kryten: The Falcon 1 was an expendable launch system privately developed and manufactured by SpaceX

http://en.wikipedia.org/wiki/Falcon_1

NEWFLASH.. SpaceX only received money from darpa to design the Falcon 1.. it was not develope by them! Sorry, but your news channel does not give accurate info

Is the same that the company Aero (with some others) received money for a darpa program which they need airships able to land and takeoff without external ballasts. But the aeroscraft design was 100% from Aeros.

I guess you misunderstand the word develope with fund.

And the SLS as I said and show in the link, was develope all by NASA, then once they have the design, they can give all the parameters to the contractors to do "some parts" and finish the design of procedures about its contruction.

Or what? You think that each extra contractor will make one part of the rocket as they most want?

[Kryten]

SpaceX needed to develop an LV within certain specifications for the FALCON contract; exactly the same as ULA's predecessors designing Delta IV and Atlas V within certain specifications for the EELV programme. SLS is a red herring, as for the third bloody time, it has nothing to do with ULA and uses a design process that has not been in use for thirty years. A design process which still involves minimal NASA design, as NASA has no capability to design an engine or rocket stage. You might want to look up 'systems integration' and how important it is, probably using something that isn't Wikipedia.

[Rakaydos]

All nasa does is say, "we need a launcher that uses existing shuttle tooling, and can lift xx tons to LEO. Whos the lowest bidder?"

SpaceX is saying "we can lift x tons to space for cheap. Who's buying?"

[GigaG]

Engines in general don't like reusability.

The SSME was built because the Shuttle needed an LH2 engine. I would think they would want a resuably-designed engine for that. If not, then NASA isn't very smart. Or was, anyway.

The Orbiter was designed for reusability,too. It wasn't an engine, and had to survive full on orbital reentry, but it was designed for reusability. It took months to refurbish.

Reusability isn't very viable with current rocket technology. It's just not. Some parts are reusable, sure. But you can't just grab your engine and launch it again. You have to re-certify it. On a per flight basis. Not doing that is an idiotic thing to do.

Plus, restarting =/= reusability. The J-2 could be restarted. The RL-10 can restart. But that doesn't add to their reusability.

Another note - the H-1 engines in the Saturn I/IB could be refired after replacing their single-use igniters, according to Wikipedia. The F-1 might have been like this too, but I don't know.

[Iskierka]

A hull that it basically a very thin aluminium tube that supports multiple tanking/detanking cycles, several tons of vertical load, thermal cycles varying from cryo fuel loading to hypersonic friction, aerodynamic loads, and landing empty at potentially non-vertical angle.

It's much more complex than an airplane's airframe and with much tougher weight constraints.

Tanking providing very little structural requirements other than sealing, vertical load being axial and very steady, no significant fluctuations in load expected, and low-cryo for oxygen to high-supersonic, not hypersonic, at very low q and thus very low heat flux.

Whereas aircraft are designed for tens of thousands of pressure cycles, have to deal with very dynamic bending and torsional loads from five sources (main wings, horizontal tail, vertical tail, main gear, nose gear) which, in heavy landings, can readily double the maximum load per mass on a rocket stack, which have to happily deal with ice formation on aerodynamic surfaces while hot jet exhaust sits nearby, which all has to be done at high q to produce enough lift, and must all be possible in both transonic flight and landing with a 30 kt crosswind with gusts in heavy rain, which may very well end with landing hard on a single gear strut which must not fail, even if this landing might put it through six times the aircraft's weight. It's also a requirement that being struck by lightning must not cause any damage, whereas rockets avoid any kind of cloud whatsoever at all costs.

Yeah, rockets have it easy. They may have more relative effort put into determining exactly how much weight can be saved from the tank structure itself, but that's because they're not spending actual billions on getting the rest of the design to fit huge ranges of design requirements. If planes can be reused, then the biggest reason rockets are having issues is no-one's tried that hard until now.

And most engines could be reused fairly well if they were cleaned of soot and had igniters replaced. All F-1 rocket engines were test fired multiple times before being used. The SSMEs were relatively poor in this regard, even if it's exaggerated that they needed a full rebuild after each flight. Injector failure mentioned isn't likely to be an issue for the Merlin engines, as this was primarily a concern for the SSMEs (which the pdf is specifically about) due to how drastically the mixture ratio could be changed, and just how far from stoichiometric they have to run - pushing closer to stoic results in much, much higher temperatures in a LH2 engine, with far more highly reactive ions in the exhaust ready to mess with any metal nearby. In kerosene engines, they run fairly close to stoichiometric anyway, so any injector failure will result in reduced engine performance and lower temperatures. Highly undesirable, but catastrophic failure unlikely.

[Kryten]

Unfortunately real life is not KSP, so mechanical wear is an actual thing. A thing which has recently been found to have been responsible for the Antares failure, no less.

[magnemoe]

Engines in general don't like reusability.

The SSME was built because the Shuttle needed an LH2 engine. I would think they would want a resuably-designed engine for that. If not, then NASA isn't very smart. Or was, anyway.

The Orbiter was designed for reusability,too. It wasn't an engine, and had to survive full on orbital reentry, but it was designed for reusability. It took months to refurbish.

Reusability isn't very viable with current rocket technology. It's just not. Some parts are reusable, sure. But you can't just grab your engine and launch it again. You have to re-certify it. On a per flight basis. Not doing that is an idiotic thing to do.

Plus, restarting =/= reusability. The J-2 could be restarted. The RL-10 can restart. But that doesn't add to their reusability.

Engines are typically tested multiple times before launch. You however rarely add restart capability on first stage engines as this add some complexity and is pointless so you use an external starter. Top stage have restart capability.

The problem with the shuttle engines is that they had to be used very hard to give enough lift, you used them as hard as engines in an formula 1 car who also need rebuild after each race.

Making an single use engine has a few benefits in that you can design it with ablative parts and you don't have to think of repairing it, however it has to work 100% of its intended lifetime including tests so the benefit is somewhat limited.