ApolloHoax.net
Off Topic => General Discussion => Topic started by: Peter B on February 13, 2014, 06:00:48 AM
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http://www.space.com/24628-will-spacex-kill-nasa-sls.html
The private spaceflight company Space X plans to build a rocket so big it would "make the Apollo moon rocket look small,"the company's CEO, Elon Musk, announced on "CBS This Morning"on Feb. 3.
The huge rocket would ultimately send colonists to Mars, but what would SpaceX do in the meantime? The company's primary focus right now is giving NASA astronauts access to the International Space Station (ISS) on American vehicles, drastically lowering prices to Earth orbit versus what the Russians are charging, Musk said.
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This all begs the question: If SpaceX is going to build this gargantuan rocket on its own dime, anyway, why is the U.S. Congress forcing NASA to develop the less capable Space Launch System (SLS) for many billions of dollars more?
Earlier, SpaceX stated it could develop a rocket that would launch 150 metric tons of payload,or 20 metric tons more than the most powerful version of SLS at a fixed price development cost of $2.5 billion (an amount that comes to roughly 1.25 years of SLS's funding).
I was wondering if the subject-matter experts on this board would care to comment on this article. I have my own non-expert opinion, but I'd prefer to keep it to myself until I hear what people more knowledgeable than me think.
Thank you!
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SLS is really all about pork, right? The big concern for SpaceX is that while they may be able to develop the capability faster and cheaper, would the government bar them from the market in order to protect their the image of SLS?
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SLS is really all about pork, right?
Yep, Senate Launch System.
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SLS is being built. After all of the false starts over the years, there had better be a damn good reason to cancel it.
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SLS is being built. After all of the false starts over the years, there had better be a damn good reason to cancel it.
Well, I suppose the question is why the SLS is being built? If it's simply to provide the US Govt with a heavy lift rocket, why not instead help fund SpaceX's Falcon X Heavy production line and buy the rockets they build? The article I linked above would appear to indicate that would be a lot cheaper than the SLS. But if, as the article suggests, the SLS is a high-tech piece of pork, wouldn't cancellation be justified?
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SLS is being built. After all of the false starts over the years, there had better be a damn good reason to cancel it.
- The costs of development and launch for the 13 SLS launches, ending in 2032, work out to as much as 122 Falcon Heavy launches. Assuming no overruns.
- Assuming no delays, the first launch of the fully capable SLS won't happen until 2022. The Falcon Heavy is scheduled to launch this year.
- SpaceX is willing to develop an even larger rocket on a similar timeframe to the SLS and for far less money.
- With the costs of development of the SLS, there's no funding to develop a mission to use it on.
These seem like excellent reasons to cancel it.
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SLS is being built. After all of the false starts over the years, there had better be a damn good reason to cancel it.
Well, I suppose the question is why the SLS is being built? If it's simply to provide the US Govt with a heavy lift rocket, why not instead help fund SpaceX's Falcon X Heavy production line and buy the rockets they build? The article I linked above would appear to indicate that would be a lot cheaper than the SLS. But if, as the article suggests, the SLS is a high-tech piece of pork, wouldn't cancellation be justified?
I am a fan of Elon Musk. I intend for my next car to be a Tesla. But I am wary of throwing away billions of dollars and years of work AGAIN on a promise.
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SLS is being built. After all of the false starts over the years, there had better be a damn good reason to cancel it.
Well, I suppose the question is why the SLS is being built? If it's simply to provide the US Govt with a heavy lift rocket, why not instead help fund SpaceX's Falcon X Heavy production line and buy the rockets they build? The article I linked above would appear to indicate that would be a lot cheaper than the SLS. But if, as the article suggests, the SLS is a high-tech piece of pork, wouldn't cancellation be justified?
I am a fan of Elon Musk. I intend for my next car to be a Tesla. But I am wary of throwing away billions of dollars and years of work AGAIN on a promise.
Even if it produces a rocket which is grossly more expensive than the Falcon (based on cjameshuff's post)?
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Looks like a test on the SRB. Jay how far are you from Promontory?
http://www.nasa.gov/press-release/update-nasa-to-discuss-broadcast-booster-test-for-space-launch-system-rocket
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Looks like a test on the SRB. Jay how far are you from Promontory?
http://www.nasa.gov/press-release/update-nasa-to-discuss-broadcast-booster-test-for-space-launch-system-rocket
Right now, about a quarter mile.
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Looks like a test on the SRB. Jay how far are you from Promontory?
http://www.nasa.gov/press-release/update-nasa-to-discuss-broadcast-booster-test-for-space-launch-system-rocket
Right now, about a quarter mile.
If you able to hear the test, on a scale from the SRB's of the Shuttle(assuming you heard any of those tests) what was the noise level of this booster?
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If you able to hear the test, on a scale from the SRB's of the Shuttle(assuming you heard any of those tests) what was the noise level of this booster?
I can't hear anything very well right now. ;D
All seriousness aside, it's no louder than a shuttle SRB from the viewing area.
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If you able to hear the test, on a scale from the SRB's of the Shuttle(assuming you heard any of those tests) what was the noise level of this booster?
I can't hear anything very well right now. ;D
All seriousness aside, it's no louder than a shuttle SRB from the viewing area.
Thanks
I have never been around any and was wondering if it were louder than previous SRB's.
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If so, then only marginally.
OrbitalATK is my customer, so I generally have to say nice things about what they do. But SLS isn't all they do. I agree with many who offer the opinion that SLS not the way to go. It's big, outdated, and expensive -- a Cadillac rocket to nowhere. I'll let others more versed than I in economics explain the sunken-cost fallacy.
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If so, then only marginally.
OrbitalATK is my customer, so I generally have to say nice things about what they do. But SLS isn't all they do. I agree with many who offer the opinion that SLS not the way to go. It's big, outdated, and expensive -- a Cadillac rocket to nowhere. I'll let others more versed than I in economics explain the sunken-cost fallacy.
What is or will be the thrust for each SRB?
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Designing for 3.6 million pounds each.
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Designing for 3.6 million pounds each.
Ok, slightly more than the Shuttle SRB's at 3.1 million pounds.
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I watched the test firing
I didn't see you in the crowd :(
I did see the engine gimballing. :)
I do have a couple of questions
Beside the engine there was a small building with what looked like air conditioning vent lines connected toward the base of the sections slightly forward of the nozzle. What are they and there function?
There was also a fire extinguisher rotated into the nozzle at the end of the test, what was burning at that time?
For those that want to watch the firing but not all the discussion fast forward to around the 33 minute mark in the video.
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I watched the test firing
I didn't see you in the crowd :(
Well, there were about 10,000 people there. :D
Beside the engine there was a small building with what looked like air conditioning vent lines connected toward the base of the sections slightly forward of the nozzle. What are they and there function?
I don't know, because I've never actually been on the test stand when all the equipment is there. (Nearly all of Orbital ATK's facility is strictly off-limits to anyone but employees at all times.) But I'm pretty sure those are standard portable air-conditioning units. The temperature of various components in the test is a crucial variable, and sitting out in the desert sun will make it hotter than allowed. I don't recall those units being there fore QM-1, which was a hot-temperature test. QM-2 was a cold-temperature test, so they actually cold-soaked the entire booster on the test stand. I'm betting those were there to maintain 40 F temperatures inside the booster after the cold-soak housing was rolled back.
There was also a fire extinguisher rotated into the nozzle at the end of the test, what was burning at that time?
Mostly the remainder of the rocket fuel, but also other materials. Keep in mind that a solid rocket works essentially the same as a liquid-fueled rocket in that it produces Newtonian thrust by constraining an energetic thermodynamic reaction to expand only through a relatively small opening. The solid fuel lines the walls of the steel tube, with a cavity in the middle extending the length of the fuel load -- the "grain."
At ignition, a flamethrower shoots a flame down the entire length of the grain cavity, igniting it all at once. It burns from the center outward, along the length of the grain. In the first few microseconds the expanding gases can just pass easily out the nozzle if they need to without hindrance, but at a certain point a nonlinear response happens when the pressure from burning gases rises produces a gas velocity that makes the flow viscid with respect to the nozzle opening. At that instant the pressure in the casing rises dramatically and within another few milliseconds you have the customary convergent-divergent flow. All that happens in a handful of milliseconds, and during that time all the booster seals must activate.
Okay, so now it's at steady-state, which lasts two minutes. But when happens when the combustion front reaches the casing walls? Ideally the grain burns so evenly that the flame front reaches the casing at exactly the same instant all over the casing. In that case, combustion would abruptly cease. Instead what happens is that some areas of the grain are exhausted first, and combustion peters off gradually. At a certain point the flow once again becomes inviscid; hot gases are still being produced, but they have the huge empty casing to expand into and thus do not create enough pressure and resulting flow to be propulsive.
At this point in the test the quencher moves in and extinguishes the remainder of the fuel. In space, the SRBs will be jettisoned as soon as their thrust decays to the point where the structure can separate safely, and the non-propulsive afterburn happens after staging. You can see this happening in videos of STS staging.
But the smoke that you see at the end is black, indicating that something besides the normal propellant is burning. The propellent isn't filled right up to the steel casing. There's a layer of insulation between the propellant and the casing. So naturally when the propellant is nearly exhausted, the insulation will finally decompose and combust, having served its purpose. But for the test we don't want that stuff burning any longer than necessary in an Earth environment. Especially a Utah environment. Because of some of our unique geology, we often have poor air quality due to a mixture of aerosolized particulates and vehicle exhausts. If you'll pardon a bit of vulgar Western U.S. slang, the past week or so has been "hot as balls," and the ground is very dry. I'd estimate at least half the plume generated by the test was dust blown into the air. (The test stands (https://www.google.com/maps/place/Orbital+ATK+Aerospace+Systems/@41.6509328,-112.3992345,3345m/data=!3m1!1e3!4m12!1m6!3m5!1s0x8753600f58990353:0x7fe5d3fd145c71bd!2sOrbital+ATK+Aerospace+Systems!8m2!3d41.6597255!4d-112.4410442!3m4!1s0x8753600f58990353:0x7fe5d3fd145c71bd!8m2!3d41.6597255!4d-112.4410442) aim the plumes against mountainsides.)
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I didn't realize that there was insulation inside the casing. and that was probably producing the black smoke. I had never seen that burn in the shuttle launches, but then the cameras were normally pointed at the shuttle not the SRB's. I hope it was fun.
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I didn't realize that there was insulation inside the casing. and that was probably producing the black smoke. I had never seen that burn in the shuttle launches, but then the cameras were normally pointed at the shuttle not the SRB's. I hope it was fun.
Keep poking around YouTube. A lot of people have published some very high quality video of the STS ascent as seen by the various onboard data collection cameras. You probably won't see the black smoke at altitude for a variety of reasons. First, the combustion products will disperse rapidly. Second, the insulation is probably burning in the test burn using ambient oxygen, of which there isn't a lot inside the casing after the cutoff. So it will be oxygen-starved incomplete combustion.