Battle of the Heavy Lift Rockets 211
schwit1 writes: Check out this detailed and informative look at the unspoken competiton between NASA's SLS rocket and SpaceX's planned heavy lift rocket. It's being designed to be even more powerful than the Falcon Heavy. Key quote: "It is clear SpaceX envisions a rocket far more powerful than even the fully evolved Block 2 SLS – a NASA rocket that isn't set to be launched until the 2030s." The SpaceX rocket hinges on whether the company can successfully build its new Raptor engine. If they do, they will have their heavy lift rocket in the air and functioning far sooner than NASA, and for far less money.
Re:Competition is good. (Score:4, Informative)
Re:This is the Congressinal Rocket not NASA. (Score:3, Informative)
No miracles (Score:5, Informative)
There are no miracles in rocket engine design. The RD-180 has pretty much the best performance to be wrung out of a sea-level-to-altitude LOX/RP-1 motor in terms of efficiency. SpaceX is still playing catchup in that area, trading off the lower cost per Merlin motor for a lower Isp from a simpler design.
As for the Raptor the "new" liquid-methane/oxygen fuel mix it will burn has the potential to produce a higher Isp than the current mainstream LOX/RP-1 mix used in motors like the Merlin, the RD-180 etc. but it comes with downsides -- it means a redesign of the rocket structure to support fully cryogenic tankerage (although not requiring the sorts of extreme temps or processing LH needs), launchpad facilities for fuelling and defuelling rockets will need to be revamped, liquid methane is half the density of RP-1 so the tanks and the rocket structure need to be larger and heavier to contain equivalent amounts of fuel and so on.
Re:Competition is good. (Score:4, Informative)
Or maintaining a launch oligopoly funded on the public dollar through to the last decade?
It took two world wars and one cold war to get us to where we are today.
Feel free to complain about the oligopoly, but don't pretend like Boeing, North American, and Douglas were going to build the Saturn V rocket on their own dime.
Or paying a few tens of billions to develop a huge rocket while not paying a few billion to get someone like SpaceX to develop said rocket.
"Or paying a few tens of billions to develop a huge rocket " to who?
Boeing is the prime contractor for the design, development, test and production of the launch vehicle cryogenic stages, as well as development of the avionics suite. [boeing.com]
You had a three sentence post and two of them were full of ignorance.
Re:Why does it take so long? (Score:5, Informative)
For the most part it's a difference in magnitude. The speeds the rockets achieve are much higher than any airplane, let alone car, ever manages. The thrust of the engines is stupendous, the liquid H2 and O2 fuels are cryogenic, the flame temperatures in the engine are extreme. In fact, they're so extreme that the engines use precise control over the flow fuel and oxidizer entering the engine to create a layer of cooler gasses around the inside of the engine nozzle, so that it doesn't melt or ablate entirely away. Everything has to work in vacuum and at ambient air pressure and at max Q during flight.
All of this and more adds up to a much harder design problem, much more stringent test requirements, much tighter manufacturing tolerances, etc. The principle is the same, however; any change to one component of a system may require changes to every other component.
The one thing that all forms of engineering from (whether software, civil, aerospace, or other) have in common is the management of complexity. The automotive engineer designs the engine mounts in your car to accept a wide range of engines, so that they can manufacture several variants of the same car with different engines without having to redesign every component. Similarly, SpaceX has greatly reduced their cost and risk by reducing the complexity of their rockets; one way they did this was to use the same engine for both the first and second stages of their rockets (the first stage simply uses more of them). Another way was to avoid cryogenic fuels; they have a lower specific impulse (fuel efficiency), but a much greater space efficiency (liquid H2 is very light; that orange tank is huge, and 80% of it is for the H2 tank) plus you avoid having to deal with cryogenic fuels, and the complicated materials engineering that goes into designing the tanks to hold them.
If you want to know more, MIT has some great lectures on the subject, even ones suitable for non-engineers. A good one is An Electrical Engineering View of a Mechanical Watch . The description of this lecture only touches on superficial matters; Sussman's real point is that the means of abstraction present in an engineered system can be applied to any other engineered system, and that it's only by designing the right abstractions that engineers make continual progress in designing newer and better systems. He states this directly in the first two minutes, which is quite handy. You might also check out the video lectures for the Structure and Interpretation of Computer Programs , the first lecture of which goes into much the same topics in the realm of software engineering.
Nasaspaceflight.com (Score:3, Informative)
Re:Competition is good. (Score:4, Informative)
Like the US banning private launch vehicles through to 1984?
I'm not allowed to have an unshielded reactor in my backyard either. Fucking liberals.
Yours is just more of the Science as ideology. How about a couple minutes for you to understand exactly why it wasn't allowed.....playing that time passing song....
Times up, BZZZZT! - No it wasn't evul democrats or Beyonce flashing the Illuminati sign at a burning man festival. Not even free birth control for women.
1. Understand that the amount of energy let loose in even a small rocket launch is pretty impressive. So it sort of makes sense to limit especially early private launching, as failure was not only an option, it was pretty likely.
Note of course, if you support second amendment rights to own artillery and hand grenades, you might have an argument there. I mean come on - Just assault rifles does not make for a well armed militia. Sheesh - next thing you know, we won't allow little children to mess with fully automaitic weapons.
Sorry - had one too many cups of coffee this morning. But rocketry is dangerous work, kinda accidentally kills people once in a while. That's no biggie, but it might level a job creator's house, and then the economy will fail , you betchya.
2. There were some hatey people who wanted to kill us, thad they were launching these flamey explodey things. Perhaps we were a little afraid that we might accidentally set off World war 3 when an early private launch of our own, unfettered by government regulations, failed and wiped out a town?
Eventually though, we'd all settle back down and figure out the sticks and stones we were going to fight World War 4 with.
Or maintaining a launch oligopoly funded on the public dollar through to the last decade? Or paying a few tens of billions to develop a huge rocket while not paying a few billion to get someone like SpaceX to develop said rocket.
So what you are telling me is that for some odd reason, despite private rocket launches in their own facilities using their own rockets is now considered okay, and done on a regular basis, you are still in a white hot seething astrorage anger and feeling much butthurt because of the way it used to be a long time ago?
Do you have any newsletters about the evil radical-diabolical Communist Franklin Delano Roosevelt and how he is spreading soclialism from his gravesite? It's important to get that news out.
Think I'm making fun of you? You got that right.
Re:Competition is good. (Score:5, Informative)
How about a couple minutes for you to understand exactly why it wasn't allowed.....playing that time passing song....
It was because NASA needed funding for the Space Shuttle. It had nothing to do with safety. Merely, requiring private companies to post bonds prior to each launch covers your safety concerns without requiring a decade long ban.
Further, it's worth noting that many of the companies which by your reckoning can't be trusted to run a safe commercial launch vehicle are the same ones that were building and running NASA's Space Shuttle (as well as having decades of launch experience under their belts).
Further, it is monumentally stupid to claim that commercial launches can be confused with a nuclear attack. One launch isn't going to take out the USSR. For example, here's a story [heritage.org] written shortly after the fall of the Shuttle monopoly.
Some of the agency's likely tactics are already evident. One strategem, reported by several observers close to the Shuttle/ ELV controversy, has been to apply pressure on contractors sup- plying major components to NASA to keep them from entering the ELV business. Although nothing has appeared in official docu- ments, it is said that NASA officials have suggested to possible private competitors that their contracts for Shuttle components might be endangered if these firms engaged in private launches. Another tactic has been to try to delay implementation of "full cost recovery," so that NASA could charge Shuttle customers less than the full cost of launches for long enough to capture the market, with the cost picked up by the taxpayer. This could close down production lines for a number of the components needed to construct and launch ELVs, making their later development far more expensive than would otherwise be the case.
What is most disturbing is that NASA's anti-competitive activities could undermine the President's broad initiative on space commercialization by undermining private sector efforts before they can acquire a firm financial footing. The agency would thereby undercut a number of key benefits for Americans that the initiative would otherwise yield.
The first thing you should do before writing stupid drivel is ask yourself, "Gee, is there really a problem here?" But no, you just had to get that anti-libertarian straw man in without regard for the history.
So what you are telling me is that for some odd reason, despite private rocket launches in their own facilities using their own rockets is now considered okay, and done on a regular basis, you are still in a white hot seething astrorage anger and feeling much butthurt because of the way it used to be a long time ago?
And you should too. Because history has a habit of repeating itself. What's going to happen when NASA has the SLS supply chain and SpaceX has the Falcon Heavy, a cheaper and more reliable competitor?
Well, that SLS supply chain, being better connected politically, are going to use their connections to sabotage SpaceX, just like Space Shuttle proponents did commercial space launch back in the 70s or the launch oligopoly did to various would-be competitors in the 80s and 90s.
They're already playing games with the Commercial Orbital Transportation Services (COTS) program which was an attempt by NASA to encourage commercial launch services, including SpaceX, to supply ISS with supplies and personnel. The number of competitors was reduced from six competitors to two by interference from Congress [spaceflightnow.com]. There's also fishing expeditions for "anomalies" [spacepolitics.com] from recent Falcon 9 launches. Notice that nobody else was targeted by that demand for info
Re:This is the Congressinal Rocket not NASA. (Score:4, Informative)
And in it's place we got the commercial cargo and commercial crew programs, which have been highly successful so far. So much so that NASA is now looking to duplicate the process in other endeavors: http://spaceflightnow.com/news/n1407/27marstelecom/#.VANoxEi0b0c
Meanwhile the Orion capsule, which was the part of the constellation project that actually put humans on top of those rockets to get them into space, was kept. It's still over budget, under speced and years off from putting anyone in space.