Hey, my 1GB Creative Zen Nano cost $89, has a screen, is half the size of a shuffle, and uses standard AAA batteries.
1. The Shuffle is quite a bit smaller than the Zen Nano. The Zen is fat while the Shuffle is elongated. Zen: 1.73 cubic inches. Shuffle: 1.06 cubic inches.
2. The Shuffle has a built-in rechargable battery that charges directly from your computer's USB port. As far as most users are concerned, it really never needs to be charged as it all happens while the music is being swapped.
3. iTunes is an excellent music management program, far superior to the Zen's software.
Each person has their own preference, but you shouldn't feel the need to justify it by spouting nonsense.
The tiny MP3 player, a favorite of gym-goers, is cheap at $129, but lacks a screen.
1. The $129 is for the 1GB version. The 512MB is very popular at $99, a full $100 less than the iPod Nano.
2. While the Nano's screen is very cool (*I* want one!), not everyone needs one. I gave my wife a 512MB Shuffle a little while back, and she couldn't be happier. As far as she's concerned, the screen is just a liability that she would never use anyway. Thus she's in no hurry to upgrade.
In fact, I probably wouldn't have gotten my wife an iPod at all if the 512MB price point wasn't so low. She asked me explicitly not to spend too much money on her (she was afraid I'd go out and get a $300 iPod), so I took the route of saving up a bit of extra spending cash here and there for a few months, and paid cash for the Shuffle. Even at $150, the Nano would be priced a bit too high for such a range.
Total impulse -- thrust times time. Newton-seconds, if you like metric
Gotcha.:-)
"Efficiency" don't enter into it, without defining all your terms. If the Shuttle really had "a far greater efficiency than the Saturn V" (defining "efficiency" as "lift capacity"), it'd be able to put an Apollo CSM/LM combo (or equivalent mass) into trans-Lunar orbit, or a Skylab-equivalent into LEO. It can't do either, although arguably the Orbiter itself, with a Spacelab or Spacehab in the cargo bay, is nearly Skylab-equivalent. (Less roomy and shorter duration, though, although Skylab wasn't designed for reentry.)
You said it yourself. The Space Shuttle's weight has to be taken into consideration of the final payload. Otherwise it looks like the vehicle is far less powerful than the Saturn V, which just isn't the case.
The Space Shuttle is lighter than the Saturn V, but can carry more cargo to orbit. It does this well, but is tied to ensuring that 109 metric tonnes of it is the orbiter itself. If the orbiter were removed from the equation (as the 125 tonne to orbit shuttle-derived HLV is doing), the shuttle could put up Skylab and a lot more.
However, the SRBs propellant is shaped to gradually reduce thrust over time (to compensate for reducing weight of the stack and limit overall acceleration).
Yep. The SRBs could be made to maintain maximum thrust throughout the flight, but doing so would probably result in critical Q. Damned powerful buggers, but also damned uncontrollable.:-/
The center engine on the SatV cuts out for the same reason, but at a later time. The Space Shuttle hits Max Q at about 1 minute into flight whereas the Saturn V hits it at 1 minute and 20 seconds.
The F-1s gain efficiency with altitude and at just before center-engine cutoff
As do the SRBs and SSMEs. In fact, pretty much all engines gain efficiency with altitude. The aerospike engine is an attempt to recoup some of that, but there still hasn't been an actual production design.
BTW, the F-1 has to fire longer for a variety of reasons, the two most important of which are:
1. It's heavier. The thrust from the S-IC has to carry its own weight (greater than a fully loaded Shuttle Stack!) plus the weight of the S-II and S-IVB stages. This gives the Shuttle stack a tremendous thrust to weight advantage over the Saturn V stack.
2. It has less overall thrust. The Space Shuttle has an incredible amount of thrust on lift-off. As I pointed out above, the shuttle hits Max Q significantly before the Saturn V. The Saturn V struggles a lot more than the shuttle, partly for want of more thrust, partly because it is so much heavier.
Funny, I coulda sworn I saw some Zenits and Atlas Vs flying.
The Energia is far from "as dead as the Saturn V". Most of the technology is still in place, and much of it is still in use. As far as rockets go, it was one of the best pieces of engineering that Russia ever produced.
Which is precisely what NASA isn't doing. The current scheme, just like Apollo, will end up providing expensive white elephants. Too expensive to keep us on the moon.
You keep telling yourself that. I, on the other hand, will be gleefully awaiting the launch of the Earth Departure Vehicle and the Lunar Surface Access Module. Reusable components that will take us to the moon the same way we should have gone the first time. Not the mention the wonderous joy of having a superbooster back on the payroll that isn't attached to a 109 metric tonne pair of wings. Can you say, "Space Station Freedom in 2 flights?" (Yep, 250 tonnes in two goes. So much better than dozens of Shuttle flights.)
Expensive new launchers with virtually zero use beyond the moon mission isn't the right way - but it is how NASA is doing it.
Pardon me, sir, but you don't know what the hell you're talking about. There is absolutely nothing mission specific about the "Porklauncher V" (like the name, BTW). The "Porklauncher Ib" as you call it, is mission specific, but that's not a big deal. It's the HLV that's interesting. Just as the Saturn V boosted Skylab in a single launch, and was going to boost the mini-Orion in a single launch, so will the Shuttle Derived HLV be able to launch extensive, and useful payloads.
Would you rather NASA followed the original "Orbital Space Plane" plan? (Now THAT was stupid.)
It's not so much the release process, as the development process, which still requires the distinct build and compilation stages.
As I said, you can automate it with ANT or Maven.:-)
Or making changes to a bean and needing to restart java.
Don't use Tomcat. Seriously. Use Orion or something. With hotdeploy enabled, you can deploy an EAR file just by copying it to a directory. Everything will reload automatically. You said you use JRun? It has that feature as well.
And I can't (as far as I know) make a separate bean class (component) as a jsp file that can be treated as a bean by the rest of the system.
You can, and you can't. You can create a include JSP with an anonymous inner class, but it's really kind of dirty. You're much better off using an automated build and hotdeploy.
Just so you're aware, the Energia was designed to carry the Russian Space Shuttle Buran. While no manned flights were ever accomplished (just a single, computer controlled flight), the rocket was ready for prime time.
But yeah, the RD-170 is an incredible engine. That's why they reworked it to create the RD-180 for the Atlas V.:-)
That's why I said thrust to weight ratio, i.e. thrust divided by weight. For the SRBs, it's enormous.
Just some numbers to help you out:
SRB Liftoff: 14,700 kN / (590,000 kg * 9.807) * 1000 = 2.5:1 ratio SI-C Liftoff: 33,400 kN / (2,280,000 kg * 9.807) * 1000 = 1.5:1 ratio
Of course, there's a huge curve in thrust-to-weight between the full and empty rockets (with the S-IC actually coming out ahead at empty), but I'm willing to bet that the plotted curves would show the overall power output of the SRB to be far superior. (If someone has too much time on their hands, they can plot these curves in excel by computing several data point between full and empty. Wikipedia and Astronautix both contain fuel burn rates for the rockets.)
Where do you think he gets this nonsense about a 1.1:1 ratio? A rocket would never make orbit with that kind of performance! (Putting aside the fact that it would topple over and blow up on launch.)
Initial thrust of the 2 SRBs is about 5 million pounds
Where do you get 5 million pounds? I have 3.3 million pounds of force per SRB, giving a combined total of 6.6 million pounds of force, or 29.4 kN. That's pretty darn close to the 33.4 MN of the S-IC.
Shuttle launch is also augmented by the thrust of the 3 SSMEs
This is where we start getting into the fact that the Shuttle is just different. The total STS power on liftoff is OVER the standard 34.8 MN of all the engines combined (the SSMEs are overthrottled at liftoff), the acceleration curves are different, the F-1s need more fuel to compensate for lower thrust, the entire shuttle stack is lighter than the S-IC, so on and so forth.
The comparison is fair, but the two total designs aren't really 1:1 comparable.
the whole thing puts about 65,000 pounds in orbit.
The STS has a theoretical maximum of 137.8 metric tonnes to orbit. Of that, 109 metric tonnes is the orbiter itself. The maximum theoretical payload of the Saturn V is 118 metric tonnes to orbit, of which none of it is lost through integration with a vehicle.
The 2 SRBs don't have quite the same thrust as the 5 F-1s of the S1C, and don't have nearly the total impulse.
I'm not sure what you mean by "nearly the total impulse". The SRBs fired in conjunction with the SSMEs gives the shuttle a far greater efficiency than the Saturn V.
What are you talking about? The shuttle flew 12 times a year at it's peak? The CEV will fly maybe that many?
And the Atlas V has flown only 7 times in the past 3.5 years it's been in operation. Plus it's not even NASA's rocket. They've flown it twice, with the other flights being entirely commercial. The future planned flights will be mostly military and will attempt to move the launch to Vandenberg.
I also do not believe that the F1+Fuel is much heavier then an SRB.
Saturn 1C Empty: 135,218 kg SRBx2 Empty: 174,000 kg Saturn 1C Fueled: 2,286,217 kg SRBx2 Fueled: 1,180,000 kg
What a difference of a kiloton in mass between rockets, eh?:-P
In short, the SRBs weight half as much to get nearly the same performance as the 5 F-1s that the Saturn V did.
The difference in the specific impulse means close to 10% less fuel mass for the F1 than the SRB.
Wrong. You've got to be careful with those Isp figures. They're very misleading.
The expendable portion of a lunar mission isn't necessarily waste. You took a bunch of survey equipment (including a golf cart) to the moon.
It wasn't really cargo, though, because we had to send up one with each mission. If the rovers were reusable, I would concede the point. Same with the lunar lander. (14 metric tonnes) The RTG generators used for lunar experiments have been in continual usage, however, and meet the critera of cargo.
Unfortunately, even if you didn't count all of this as direct waste, the Saturn V rocket itself easily eclipsed any amount of hardware that actually made it to the moon.
Besides, bringing back used equipment is usually pointless.
Not true. If you can reuse a rover, you can bring something else next time. If you can reuse a LEO to LMO shuttle, then you don't have to relaunch another craft. If you can reuse a pair of SRBs, you can save money by not manufacturing new ones. That is the infrastructure the CEV will put in place. The Saturn V program never had such an infrastructure, nor did it intend to. It was a simple, "Get up and get the hell back down" mission.
They don't. Or more precisely, the Soyuz doesn't. It's not even in the same class. Here you go:
RD-117 - First Stage (4 Engines) - 838 kN RD-118 - Second Stage (1 Engine) - 792 kN RD-0124 - Third Stage (1 Engine) - 294 kN
You probably don't even want to see the Isp figures on those.
The four RD-117s in the first stage produce a total of 3.3 MN, or less than 1/4 of a single SRB. The second stage engine is about 100 kN less powerful than the J-2, and the third stage is about 1/3 as powerful as a J-2. In comparison, the Saturn V carried 5 J-2s on its second stage, and the space shuttle carries 3 SSMEs throughout its entire trip.
There was only a single J-2 for the third stage of the Saturn V, but like I said, it was about three times more powerful than the Soyuz third stage. More info on the Soyuz launch vehicle can be found on Wikipedia.
If you want a real comparison (and a look at one of the odder designs in rocket engines), take a look at the Energia.
I can understand your point (all too well I'm afraid), but you do have to admit that the CEV plan has really been shaping up. While just about every STS replacement technology before it tried to go for pie-in-the-sky technology, at least the CEV is mostly a matter of plumbing existing components together and certifying the sucker. It's not exactly a bold plan (any schoolchild could have come up with the idea of using the shuttle without the shuttle), but it at least is a good plan.
Erm... at least in comparison to the X-33 plan. (Let's see, take a dozen or so unproven technologies, mash them together into a vehicle, don't plan in any contingency for failed tech branches, and then expect the thing to fly right the first time? Good one!)
The Saturn 1B flew an addition 10 flights on the J-2s, which was based on the Saturn 1 that flew 10 flights on the RL-10s, which was based on the Jupiter IRBM that flew about 17 flights. Each Saturn 1B had 1 J-2 while each Saturn V had 6 J-2 engines.
Or in other words, the J-2 engine has a long history and has proven itself highly reliable. Its reliability isn't really in question.
"In addition, NASA has no infrastructure for Kerosene fuels,"
There have been a handful of Atlas V launches. Nothing near the scale of what the Shuttle flys today, and what the CEV *will* fly.
Yes the SRB has more static thrust but I think the F1 is equal to it in specific impulse.
Static thrust is what you want. The point of the F-1s and SRBs was to get the rocket off the pad, up to Max Q, and out of the thickest part of the atmosphere. From there the more efficient LHOx engines provide more than enough thrust to carry the weight into orbit. The plain and simple fact is that the F-1 is MUCH heavier, reducing the overall efficiency of the entire rocket. Thus the SSME/SRB combination will continue to be used for the liftoff phase. The J-2 will be used in orbit where its reliability and restart advantages make it a better choice than the SSME, and the F-1/SRB argument doesn't even enter.
Using modern AlLi alloys for the tanks an F1 powered first stage might still be a good option.
Then the program would be held up for years why they certify a new engine. That defeats the point of the entire CEV exercise. (i.e. Build an infrastructure quickly.)
The real reason is cost. The SRBs are cheaper short term.
The SRBs are always cheaper. Not to mention reused.
Did you see those differences in performance on those engines? The SSME is about twice as powerful as the J-2, but it also weighs twice as much. Thus it makes sense to use two J-2s. The SRBs OTOH, get over twice the power of the F-1 for far less weight. Since they're almost entirely fuel (not much engine, just light 'em up), they have an incredible thrust to weight ratio.
In addition, NASA has no infrastructure for Kerosine fuels, making the switch from the SRBs to the F-1 more difficult. They *do* have an infrastructure for LHOx fuels, so the change from the SSME to J-2 is a fairly easy one.
I'm a bit confused as to how it takes us longer to get to the moon now than it did in the 60s.
1. Money. If we spent as much today as we did on the Apollo program, we'd be able to get a craft ready in a very short period of time. (Note that while NASA receives more than enough money, most of it goes toward the Space Shuttle's maintenece and other projects.)
2. Technology. The industry that produced the Saturn V doesn't exist anymore, so it is not really possible to produce it again. We can produce a new rocket like the Saturn V (or buy off the Energia, take your pick), but that would just give us another moonshot rocket. What we want to build this time is an infrastructure that will keep us on the moon instead of merely sending up a few tons there and back.
If there was an emergency, I imagine we could get to the moon inside two years. Most of the lander equipment can be remanufactured and lifted by the Space Shuttle, and strap-on boosters could be lifted to propell the module. But that's not the point. That's why we're doing this the right way this time. Or to put it in perspective, the Apollo missions started out with 2,900 tons of hardware. They came back with about 6 tons. That means that they expended 2,300 tons of hardware to get 3 people to the moon and back. That's a hell of a lot of waste!:-)
Note that this isn't really a surprise to those who have been following the CEV development. The original plan called for a modification to the SSMEs for multiple restarts as the J-2 (the upper stage engine for the Saturn V) is no longer in production. However, there was a lot of discussion inside NASA that restarting production on the less powerful J-2 would be cheaper, faster, and easier than trying to modify the more powerful (but far more complex) SSME to do the job.
All that hassle is there for a reason. As someone who has to support various CFMX applications (*shudder* What a mess.) I can testify that poor release process is a guaranteed way to create a maintenece nightmare. Java's packaging scheme is easy to automate and provides a guaranteed release methodology that will get you a complete application every time.
Now you don't have to use it (JSPs can be referenced directly, and reloaded on the fly), but it does make things work so much better.
All I have to do there is create my component (CFC) and save the text file to the server using RDS.
This is effectively the same thing as creating a JSP include file with embedded Java. Same results.:-)
If you can catch the damn things at apogee, they're going to be largely in space and relatively few in numbers- well placed low-yield warheads might do the trick; but you've still got fallout issue
There's relatively little fallout with an airburst. Since most of the materials are destroyed at detonation, most fallout problems occur due to irradiated soil. No soil to irradiate == fairly clean detonation.
The shockwave will disrupt things, the EMP probably won't
It's is just a syntax specification. The rest of that stuff you're complaining about are called libraries. Repeat it with me class, llllliiiiiibrrraaaaarrriiiess.
The REAL solution is not to put everything and the kitchen sink in the language itself.
I'm thinking that's why the language doesn't have a lot. It's got WAY fewer features than even C.
The language should be a syntax specification,
It's not. Those are called libraries. Repeat it with me class, llllliiiiiibrrraaaaarrriiiess.
not an implementation of every obscure library you could ever think of.
So Linux shouldn't follow the POSIX specification, GNOME shouldn't standardize APIs, and Apple should drop the NeXTStep APIs? Why, you're right! Everyone should revert to rolling their own solution for EVERYTHING! WHAHAHAHAA! Chaos is where it's at! </sarcasm>
Outside methods similar to CPAN and BOOST do a far better job of being library repositories.
CPAN and BOOST are library repositories. That doesn't stop PERL or C++ from having a base library set. Nor do the large number of third party libraries stop Java.
To get back to the point that went WHOOOSH over your head, the Java VM is the part that needs to be an OS component to completely elminate the perceived "bloat" problem by moving it to the best location for it to do its job. This is already common in cell phones and many other portable devices.
Make no mistake, the Java platform is very much a super Operating System on top of the host system. There's no other way to completely abstract code from an OS. All other cross-platform implementations at some point reference back to the parent system. In many cases, the portability of code is based on the portability of the native libraries it interfaces with. Java doesn't have that problem. In fact, you'll find that most Java libraries are written in Java. (Unlike most of CPAN.)
Java does its job well. Recognizing its design can only improve the situation further.
If you ever break your atomic battery, you'll never need the light of day again, as you'll glow in the dark rather spectacularly.
And this, my friends, is why we don't have laptop batteries that last 10+ years. Because of a hick-town sherrif who's afraid to glow in the dark.:-P
BTW, visit your eye doctor sometime. They've got this cool phosphorus solution that they put in your eyes to check your vision. It works great for Halloween parties as you can make your eyes glow in the dark. I think I should go as a Go'uld next year.:-)
Since they are typically used in spacecraft, I guess waste heat and leaked radiation isn't usually much of a problem in their design.
1) If it's leaking radiation, then it's not a very good design. The entire point of an RTG is to convert radiation to electricity. If you're letting it escape, you're letting your power escape.
2) Waste heat is already a huge problem. You're going to have that problem whether you use a 65Watt battery or a 65Watt RTG.
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Hey, my 1GB Creative Zen Nano cost $89, has a screen, is half the size of a shuffle, and uses standard AAA batteries.
1. The Shuffle is quite a bit smaller than the Zen Nano. The Zen is fat while the Shuffle is elongated. Zen: 1.73 cubic inches. Shuffle: 1.06 cubic inches.
2. The Shuffle has a built-in rechargable battery that charges directly from your computer's USB port. As far as most users are concerned, it really never needs to be charged as it all happens while the music is being swapped.
3. iTunes is an excellent music management program, far superior to the Zen's software.
Each person has their own preference, but you shouldn't feel the need to justify it by spouting nonsense.
The tiny MP3 player, a favorite of gym-goers, is cheap at $129, but lacks a screen.
1. The $129 is for the 1GB version. The 512MB is very popular at $99, a full $100 less than the iPod Nano.
2. While the Nano's screen is very cool (*I* want one!), not everyone needs one. I gave my wife a 512MB Shuffle a little while back, and she couldn't be happier. As far as she's concerned, the screen is just a liability that she would never use anyway. Thus she's in no hurry to upgrade.
In fact, I probably wouldn't have gotten my wife an iPod at all if the 512MB price point wasn't so low. She asked me explicitly not to spend too much money on her (she was afraid I'd go out and get a $300 iPod), so I took the route of saving up a bit of extra spending cash here and there for a few months, and paid cash for the Shuffle. Even at $150, the Nano would be priced a bit too high for such a range.
Total impulse -- thrust times time. Newton-seconds, if you like metric
:-)
:-/
Gotcha.
"Efficiency" don't enter into it, without defining all your terms. If the Shuttle really had "a far greater efficiency than the Saturn V" (defining "efficiency" as "lift capacity"), it'd be able to put an Apollo CSM/LM combo (or equivalent mass) into trans-Lunar orbit, or a Skylab-equivalent into LEO. It can't do either, although arguably the Orbiter itself, with a Spacelab or Spacehab in the cargo bay, is nearly Skylab-equivalent. (Less roomy and shorter duration, though, although Skylab wasn't designed for reentry.)
You said it yourself. The Space Shuttle's weight has to be taken into consideration of the final payload. Otherwise it looks like the vehicle is far less powerful than the Saturn V, which just isn't the case.
The Space Shuttle is lighter than the Saturn V, but can carry more cargo to orbit. It does this well, but is tied to ensuring that 109 metric tonnes of it is the orbiter itself. If the orbiter were removed from the equation (as the 125 tonne to orbit shuttle-derived HLV is doing), the shuttle could put up Skylab and a lot more.
However, the SRBs propellant is shaped to gradually reduce thrust over time (to compensate for reducing weight of the stack and limit overall acceleration).
Yep. The SRBs could be made to maintain maximum thrust throughout the flight, but doing so would probably result in critical Q. Damned powerful buggers, but also damned uncontrollable.
The center engine on the SatV cuts out for the same reason, but at a later time. The Space Shuttle hits Max Q at about 1 minute into flight whereas the Saturn V hits it at 1 minute and 20 seconds.
The F-1s gain efficiency with altitude and at just before center-engine cutoff
As do the SRBs and SSMEs. In fact, pretty much all engines gain efficiency with altitude. The aerospike engine is an attempt to recoup some of that, but there still hasn't been an actual production design.
BTW, the F-1 has to fire longer for a variety of reasons, the two most important of which are:
1. It's heavier. The thrust from the S-IC has to carry its own weight (greater than a fully loaded Shuttle Stack!) plus the weight of the S-II and S-IVB stages. This gives the Shuttle stack a tremendous thrust to weight advantage over the Saturn V stack.
2. It has less overall thrust. The Space Shuttle has an incredible amount of thrust on lift-off. As I pointed out above, the shuttle hits Max Q significantly before the Saturn V. The Saturn V struggles a lot more than the shuttle, partly for want of more thrust, partly because it is so much heavier.
Thank you Scotty, that was downright hilarious! I don't think I've had that good of a laugh in a long time.
:-P
Here's hoping you get +5 Funny.
The Energia is just as dead as the Saturn V.
Funny, I coulda sworn I saw some Zenits and Atlas Vs flying.
The Energia is far from "as dead as the Saturn V". Most of the technology is still in place, and much of it is still in use. As far as rockets go, it was one of the best pieces of engineering that Russia ever produced.
Which is precisely what NASA isn't doing. The current scheme, just like Apollo, will end up providing expensive white elephants. Too expensive to keep us on the moon.
You keep telling yourself that. I, on the other hand, will be gleefully awaiting the launch of the Earth Departure Vehicle and the Lunar Surface Access Module. Reusable components that will take us to the moon the same way we should have gone the first time. Not the mention the wonderous joy of having a superbooster back on the payroll that isn't attached to a 109 metric tonne pair of wings. Can you say, "Space Station Freedom in 2 flights?" (Yep, 250 tonnes in two goes. So much better than dozens of Shuttle flights.)
Expensive new launchers with virtually zero use beyond the moon mission isn't the right way - but it is how NASA is doing it.
Pardon me, sir, but you don't know what the hell you're talking about. There is absolutely nothing mission specific about the "Porklauncher V" (like the name, BTW). The "Porklauncher Ib" as you call it, is mission specific, but that's not a big deal. It's the HLV that's interesting. Just as the Saturn V boosted Skylab in a single launch, and was going to boost the mini-Orion in a single launch, so will the Shuttle Derived HLV be able to launch extensive, and useful payloads.
Would you rather NASA followed the original "Orbital Space Plane" plan? (Now THAT was stupid.)
It's not so much the release process, as the development process, which still requires the distinct build and compilation stages.
:-)
As I said, you can automate it with ANT or Maven.
Or making changes to a bean and needing to restart java.
Don't use Tomcat. Seriously. Use Orion or something. With hotdeploy enabled, you can deploy an EAR file just by copying it to a directory. Everything will reload automatically. You said you use JRun? It has that feature as well.
And I can't (as far as I know) make a separate bean class (component) as a jsp file that can be treated as a bean by the rest of the system.
You can, and you can't. You can create a include JSP with an anonymous inner class, but it's really kind of dirty. You're much better off using an automated build and hotdeploy.
Admittedly, I doubt they're man-rated
:-)
You're sure about that?
Just so you're aware, the Energia was designed to carry the Russian Space Shuttle Buran. While no manned flights were ever accomplished (just a single, computer controlled flight), the rocket was ready for prime time.
But yeah, the RD-170 is an incredible engine. That's why they reworked it to create the RD-180 for the Atlas V.
That's why I said thrust to weight ratio, i.e. thrust divided by weight. For the SRBs, it's enormous.
Just some numbers to help you out:
SRB Liftoff: 14,700 kN / (590,000 kg * 9.807) * 1000 = 2.5:1 ratio
SI-C Liftoff: 33,400 kN / (2,280,000 kg * 9.807) * 1000 = 1.5:1 ratio
Of course, there's a huge curve in thrust-to-weight between the full and empty rockets (with the S-IC actually coming out ahead at empty), but I'm willing to bet that the plotted curves would show the overall power output of the SRB to be far superior. (If someone has too much time on their hands, they can plot these curves in excel by computing several data point between full and empty. Wikipedia and Astronautix both contain fuel burn rates for the rockets.)
Where do you think he gets this nonsense about a 1.1:1 ratio? A rocket would never make orbit with that kind of performance! (Putting aside the fact that it would topple over and blow up on launch.)
Initial thrust of the 2 SRBs is about 5 million pounds
Where do you get 5 million pounds? I have 3.3 million pounds of force per SRB, giving a combined total of 6.6 million pounds of force, or 29.4 kN. That's pretty darn close to the 33.4 MN of the S-IC.
Shuttle launch is also augmented by the thrust of the 3 SSMEs
This is where we start getting into the fact that the Shuttle is just different. The total STS power on liftoff is OVER the standard 34.8 MN of all the engines combined (the SSMEs are overthrottled at liftoff), the acceleration curves are different, the F-1s need more fuel to compensate for lower thrust, the entire shuttle stack is lighter than the S-IC, so on and so forth.
The comparison is fair, but the two total designs aren't really 1:1 comparable.
the whole thing puts about 65,000 pounds in orbit.
The STS has a theoretical maximum of 137.8 metric tonnes to orbit. Of that, 109 metric tonnes is the orbiter itself. The maximum theoretical payload of the Saturn V is 118 metric tonnes to orbit, of which none of it is lost through integration with a vehicle.
The 2 SRBs don't have quite the same thrust as the 5 F-1s of the S1C, and don't have nearly the total impulse.
I'm not sure what you mean by "nearly the total impulse". The SRBs fired in conjunction with the SSMEs gives the shuttle a far greater efficiency than the Saturn V.
What are you talking about? The shuttle flew 12 times a year at it's peak? The CEV will fly maybe that many?
:-P
And the Atlas V has flown only 7 times in the past 3.5 years it's been in operation. Plus it's not even NASA's rocket. They've flown it twice, with the other flights being entirely commercial. The future planned flights will be mostly military and will attempt to move the launch to Vandenberg.
I also do not believe that the F1+Fuel is much heavier then an SRB.
Saturn 1C Empty: 135,218 kg
SRBx2 Empty: 174,000 kg
Saturn 1C Fueled: 2,286,217 kg
SRBx2 Fueled: 1,180,000 kg
What a difference of a kiloton in mass between rockets, eh?
In short, the SRBs weight half as much to get nearly the same performance as the 5 F-1s that the Saturn V did.
The difference in the specific impulse means close to 10% less fuel mass for the F1 than the SRB.
Wrong. You've got to be careful with those Isp figures. They're very misleading.
The expendable portion of a lunar mission isn't necessarily waste. You took a bunch of survey equipment (including a golf cart) to the moon.
It wasn't really cargo, though, because we had to send up one with each mission. If the rovers were reusable, I would concede the point. Same with the lunar lander. (14 metric tonnes) The RTG generators used for lunar experiments have been in continual usage, however, and meet the critera of cargo.
Unfortunately, even if you didn't count all of this as direct waste, the Saturn V rocket itself easily eclipsed any amount of hardware that actually made it to the moon.
Besides, bringing back used equipment is usually pointless.
Not true. If you can reuse a rover, you can bring something else next time. If you can reuse a LEO to LMO shuttle, then you don't have to relaunch another craft. If you can reuse a pair of SRBs, you can save money by not manufacturing new ones. That is the infrastructure the CEV will put in place. The Saturn V program never had such an infrastructure, nor did it intend to. It was a simple, "Get up and get the hell back down" mission.
They don't. Or more precisely, the Soyuz doesn't. It's not even in the same class. Here you go:
RD-117 - First Stage (4 Engines) - 838 kN
RD-118 - Second Stage (1 Engine) - 792 kN
RD-0124 - Third Stage (1 Engine) - 294 kN
You probably don't even want to see the Isp figures on those.
The four RD-117s in the first stage produce a total of 3.3 MN, or less than 1/4 of a single SRB. The second stage engine is about 100 kN less powerful than the J-2, and the third stage is about 1/3 as powerful as a J-2. In comparison, the Saturn V carried 5 J-2s on its second stage, and the space shuttle carries 3 SSMEs throughout its entire trip.
There was only a single J-2 for the third stage of the Saturn V, but like I said, it was about three times more powerful than the Soyuz third stage. More info on the Soyuz launch vehicle can be found on Wikipedia.
If you want a real comparison (and a look at one of the odder designs in rocket engines), take a look at the Energia.
Just a bit cynical, are we? :-)
I can understand your point (all too well I'm afraid), but you do have to admit that the CEV plan has really been shaping up. While just about every STS replacement technology before it tried to go for pie-in-the-sky technology, at least the CEV is mostly a matter of plumbing existing components together and certifying the sucker. It's not exactly a bold plan (any schoolchild could have come up with the idea of using the shuttle without the shuttle), but it at least is a good plan.
Erm... at least in comparison to the X-33 plan. (Let's see, take a dozen or so unproven technologies, mash them together into a vehicle, don't plan in any contingency for failed tech branches, and then expect the thing to fly right the first time? Good one!)
The Saturn 1B flew an addition 10 flights on the J-2s, which was based on the Saturn 1 that flew 10 flights on the RL-10s, which was based on the Jupiter IRBM that flew about 17 flights. Each Saturn 1B had 1 J-2 while each Saturn V had 6 J-2 engines.
Or in other words, the J-2 engine has a long history and has proven itself highly reliable. Its reliability isn't really in question.
"In addition, NASA has no infrastructure for Kerosene fuels,"
There have been a handful of Atlas V launches. Nothing near the scale of what the Shuttle flys today, and what the CEV *will* fly.
Yes the SRB has more static thrust but I think the F1 is equal to it in specific impulse.
Static thrust is what you want. The point of the F-1s and SRBs was to get the rocket off the pad, up to Max Q, and out of the thickest part of the atmosphere. From there the more efficient LHOx engines provide more than enough thrust to carry the weight into orbit. The plain and simple fact is that the F-1 is MUCH heavier, reducing the overall efficiency of the entire rocket. Thus the SSME/SRB combination will continue to be used for the liftoff phase. The J-2 will be used in orbit where its reliability and restart advantages make it a better choice than the SSME, and the F-1/SRB argument doesn't even enter.
Using modern AlLi alloys for the tanks an F1 powered first stage might still be a good option.
Then the program would be held up for years why they certify a new engine. That defeats the point of the entire CEV exercise. (i.e. Build an infrastructure quickly.)
The real reason is cost. The SRBs are cheaper short term.
The SRBs are always cheaper. Not to mention reused.
You can't throttle the SRBs either, so that's sort of a moot point.
:-)
The throttling on the STS (and presumably the CEV) design is handled by the SSMEs. The SRBs always put out their 3.3 million pounds of thrust.
Did you see those differences in performance on those engines? The SSME is about twice as powerful as the J-2, but it also weighs twice as much. Thus it makes sense to use two J-2s. The SRBs OTOH, get over twice the power of the F-1 for far less weight. Since they're almost entirely fuel (not much engine, just light 'em up), they have an incredible thrust to weight ratio.
In addition, NASA has no infrastructure for Kerosine fuels, making the switch from the SRBs to the F-1 more difficult. They *do* have an infrastructure for LHOx fuels, so the change from the SSME to J-2 is a fairly easy one.
I'm a bit confused as to how it takes us longer to get to the moon now than it did in the 60s.
:-)
1. Money. If we spent as much today as we did on the Apollo program, we'd be able to get a craft ready in a very short period of time. (Note that while NASA receives more than enough money, most of it goes toward the Space Shuttle's maintenece and other projects.)
2. Technology. The industry that produced the Saturn V doesn't exist anymore, so it is not really possible to produce it again. We can produce a new rocket like the Saturn V (or buy off the Energia, take your pick), but that would just give us another moonshot rocket. What we want to build this time is an infrastructure that will keep us on the moon instead of merely sending up a few tons there and back.
If there was an emergency, I imagine we could get to the moon inside two years. Most of the lander equipment can be remanufactured and lifted by the Space Shuttle, and strap-on boosters could be lifted to propell the module. But that's not the point. That's why we're doing this the right way this time. Or to put it in perspective, the Apollo missions started out with 2,900 tons of hardware. They came back with about 6 tons. That means that they expended 2,300 tons of hardware to get 3 people to the moon and back. That's a hell of a lot of waste!
Note that this isn't really a surprise to those who have been following the CEV development. The original plan called for a modification to the SSMEs for multiple restarts as the J-2 (the upper stage engine for the Saturn V) is no longer in production. However, there was a lot of discussion inside NASA that restarting production on the less powerful J-2 would be cheaper, faster, and easier than trying to modify the more powerful (but far more complex) SSME to do the job.
To give quick rundown on which engines are which:
SSME (Space Shuttle Main Engines) - LHOx Fuel - 1.8 MN
SRB (Solid Rocket Booster) - Solid Fuel - 14.7 MN
J-2 (2nd and 3rd stage Saturn V) - LHOx - 890 kN
F-1 (1st stage Saturn V) - Kerosine - 6.7 MN
The SSME and J-2 are directly comparable, and the SRB and F-1 are directly comparable.
All that hassle is there for a reason. As someone who has to support various CFMX applications (*shudder* What a mess.) I can testify that poor release process is a guaranteed way to create a maintenece nightmare. Java's packaging scheme is easy to automate and provides a guaranteed release methodology that will get you a complete application every time.
:-)
Now you don't have to use it (JSPs can be referenced directly, and reloaded on the fly), but it does make things work so much better.
All I have to do there is create my component (CFC) and save the text file to the server using RDS.
This is effectively the same thing as creating a JSP include file with embedded Java. Same results.
If you can catch the damn things at apogee, they're going to be largely in space and relatively few in numbers- well placed low-yield warheads might do the trick; but you've still got fallout issue
:-)
There's relatively little fallout with an airburst. Since most of the materials are destroyed at detonation, most fallout problems occur due to irradiated soil. No soil to irradiate == fairly clean detonation.
The shockwave will disrupt things, the EMP probably won't
As I said.
Slight correction:
The language should be a syntax specification,
It's is just a syntax specification. The rest of that stuff you're complaining about are called libraries. Repeat it with me class, llllliiiiiibrrraaaaarrriiiess.
The REAL solution is not to put everything and the kitchen sink in the language itself.
I'm thinking that's why the language doesn't have a lot. It's got WAY fewer features than even C.
The language should be a syntax specification,
It's not. Those are called libraries. Repeat it with me class, llllliiiiiibrrraaaaarrriiiess.
not an implementation of every obscure library you could ever think of.
So Linux shouldn't follow the POSIX specification, GNOME shouldn't standardize APIs, and Apple should drop the NeXTStep APIs? Why, you're right! Everyone should revert to rolling their own solution for EVERYTHING! WHAHAHAHAA! Chaos is where it's at! </sarcasm>
Outside methods similar to CPAN and BOOST do a far better job of being library repositories.
CPAN and BOOST are library repositories. That doesn't stop PERL or C++ from having a base library set. Nor do the large number of third party libraries stop Java.
To get back to the point that went WHOOOSH over your head, the Java VM is the part that needs to be an OS component to completely elminate the perceived "bloat" problem by moving it to the best location for it to do its job. This is already common in cell phones and many other portable devices.
Make no mistake, the Java platform is very much a super Operating System on top of the host system. There's no other way to completely abstract code from an OS. All other cross-platform implementations at some point reference back to the parent system. In many cases, the portability of code is based on the portability of the native libraries it interfaces with. Java doesn't have that problem. In fact, you'll find that most Java libraries are written in Java. (Unlike most of CPAN.)
Java does its job well. Recognizing its design can only improve the situation further.
If you ever break your atomic battery, you'll never need the light of day again, as you'll glow in the dark rather spectacularly.
:-P
:-)
And this, my friends, is why we don't have laptop batteries that last 10+ years. Because of a hick-town sherrif who's afraid to glow in the dark.
BTW, visit your eye doctor sometime. They've got this cool phosphorus solution that they put in your eyes to check your vision. It works great for Halloween parties as you can make your eyes glow in the dark. I think I should go as a Go'uld next year.
Since they are typically used in spacecraft, I guess waste heat and leaked radiation isn't usually much of a problem in their design.
1) If it's leaking radiation, then it's not a very good design. The entire point of an RTG is to convert radiation to electricity. If you're letting it escape, you're letting your power escape.
2) Waste heat is already a huge problem. You're going to have that problem whether you use a 65Watt battery or a 65Watt RTG.