No, seriously... why? Because the Chinese are talking about going there? Is it going to be a big busywork project like the space station?
I can think of a half dozen space-related projects that would make more sense to fund, and at a fraction of the cost. This obsession with big vanity projects is crazy in light of the budgetary environment we'll be in for the next few decades.
Still. There's a big difference between the way we all know influence is exerted in Washington and an action that adds up to the legal definition of bribery. As you said, Dodd is an old hand at this from both sides of the table. He knows how far he can go.
I doubt that's true in the strict legal sense, and Dodd certainly isn't the first guy to say something like that - there were similar quotes from Wall St guys as Obama was waxing populist. I don't think it's illegal to say "we can no longer support you if you keep doing this", which isn't the same thing as saying "we'll give you money to change your position".
No, that's not the whole point of a high ISP engine
Sure it is. A high ISP engine is simply more efficient per kg of fuel. If you supply enough fuel to a high mass ratio chemical rocket you can overcome that efficiency advantage. We don't do that today because it's a whole lot cheaper to send a little rocket on a high efficiency trajectory. But since we're talking about sending many extra tons into orbit, including whatever infrastructure needed for construction activities, what we have to compare the NTR to is the best chemical rocket we could have in that mass budget.
Would you have to do a trade study to see if you'd rather do impulsive-ish chemical burns rather than have a fancy, probably much heavier nuclear engine with higher ISP that can do something more akin to a continuous thrust trajectory? Yes, of course, and you'd probably see that it's a huge win for an interplanetary manned craft or anything else with a lot of dry mass.
NASA was never able to do better than 800 seconds with an NTR, which is less than double what you get with a conventional hydrogen/LOX engine, and far less current electric engines. It's definitely not suited to the pie in the sky interstellar probe in the article. Hell, at 800 seconds NTR isn't a good fit for a mars mission. In theory they could get one up to 1000 seconds. So... worth the time and effort? I don't see it, particularly when Ad Astra has already demonstrated an ISP of 4900 seconds in a full-scale test of a VASIMR engine.
In any event, to do such a trade study you'd have to have a working design, something we don't have. Nobody knows exactly how heavy a working NTR would be beyond "pretty damn heavy". I don't see that changing, either, for the same reason Rover and NERVA were eventually abandoned. The concept is just too messy to test. It's unlikely you could ever keep uranium and/or plutonium out of the exhaust stream without physically separating the core from the working fluid. That's going to make it still heavier and probably less efficient. Assuming it could be made to work at all.
All this assumes, of course, a NERVA style solid core engine, which is I think what they're proposing, though it's hard to tell from the article. And the numbers don't pass the laugh test. A liquid or gas core engine would be a real game-changer from the performance perspective and probably a whole lot safer if we could actually build one, but from what I can see we're no closer than we were when the idea was first proposed more than half a century ago. And even the holy grail gas core "nuclear light bulb" engine will only produce an ISP of between 1500 and 2000 seconds (according to the wiki page). Good for an SSTO assuming you weren't worried about spreading nuclear fuel everywhere if it crashed.
Not me. In fact, I think we need a more of it. A whole hell of a lot of people have sold themselves into virtual slavery by borrowing a lot of money without thinking about how they're going to pay it back.
Well, yes, you could. But now you'll have to send up a bunch of extra kg into orbit, and the whole point of having an engine with high ISP is to get really good performance from your fuel because you didn't want to send a bunch of extra kg to orbit.
There's nothing new here. It's another "study" rehashing technology that's been rehashed over and over for at least sixty years. And anyway nuclear thermal rockets don't address the biggest problem we have with space exploration, which is getting to orbit in the first place. Heinlein famously observed "Get to low-Earth orbit and you're halfway to anywhere in the solar system." But the converse is also true - no matter how good your deep space rocket is you're only half way to where you want to be.
Nuclear thermal rockets have a wonderful ISP, but they don't have as much thrust as chemical rockets, and they're heavy. Even assuming you wanted to use one for the first stage it probably wouldn't have enough thrust to do the job. And you wouldn't want to start one up on earth, either. They never did figure out how to keep bits of the radioactive core from breaking off and entering the exhaust stream,
Yeah... gun tolerance approaches Zero and crime drops. Man, it must pain you when the facts run counter to your belief.
There's no actual evidence this is the case. You can find examples of crime rates getting worse as gun laws were tightened, and you can find examples of crime rates getting better.
I dunno, self defense is a pretty legitimate reason. NYC isn't as dangerous as it once was, maybe, but there are still a lot of areas in which I wouldn't feel safe.
Access to health care only matters so much, and from what I understand statistically it's access to a primary care physician that matters. You can catch things like hypertension and diabetes before they become serious.
Rich people die of heart disease all the time. I'm assuming Cheney never goes anywhere without a cardiology team, but that's not enough to explain 34 years. No amount of money would have mattered very much in 1978, and even today doctors can do only so much.
You know, people make jokes, but that dude had his first heart attack (of 5) 34 years ago. Whatever he's done to keep himself alive seems to have worked pretty damn well.
If my employer punished people for taking vacations, I'd find another job. That's what it means to be a professional - your protection as an employee is the threat you'll take your skills somewhere else. If you can't make that threat credibly it means your employer isn't getting his money's worth, and you need to do something about that.
True in theory, but not at all true in practice. An employer who fired someone without giving (and documenting profusely) a reason will almost certainly be sued.
I disagree about conventional warfare - we've never gone twenty years without a war. The situation will change in ways we can't predict, and I don't think we can count on the Europeans to pick up much of the slack - both because they don't always see eye-to-eye with the US and because they're not going to have the money to maintain first-class militaries. Look at what's happening in the UK - they have some kind of financial Zeno's paradox going on, where they cut the military budget in half every year. How much longer do you think they'll be able to project force at all? Could they even retake the Falklands if Argentina attacked today? Seems unlikely. France and Germany have a lot of hardware, but neither can project force very well. They just don't have the logistical support - things like transport aircraft and aerial refueling. They couldn't have maintained the air war in Libya without US intelligence and refueling assets, and Libya was the best case scenario for an air war: close to Europe and without any air defense to speak of.
As Rumsfeld famously said, "You go to war with what you have," and he was absolutely right. Conflicts can arise quickly, and there's no point deciding at the start of the conflict that you should have built a few more of these or refurbished some of those instead of retiring them, Having a few F-35s would be a bit of insurance against unforeseen problems. Ultimately I don't think the program will cost too much because we'll sell thousands to foreign customers, and that keeps assembly lines moving and workers paying taxes.
Having said that, I should say I don't see much use for manned strike aircraft if you have something better for air superiority. We can use drones or heavy bombers to drop bombs, and we have cruise missiles for SEAD. But it's going to be many years before we deploy unmanned fighters, and the linchpin of modern warfare is control of the air. Were it up to me I would have cancelled the F-35, built more F-22s, and put money into developing an unmanned heavy bomber. Nothing fancy, just a big bomb truck.
Slashdot Mirror
No, seriously... why? Because the Chinese are talking about going there? Is it going to be a big busywork project like the space station?
I can think of a half dozen space-related projects that would make more sense to fund, and at a fraction of the cost. This obsession with big vanity projects is crazy in light of the budgetary environment we'll be in for the next few decades.
Still. There's a big difference between the way we all know influence is exerted in Washington and an action that adds up to the legal definition of bribery. As you said, Dodd is an old hand at this from both sides of the table. He knows how far he can go.
I doubt that's true in the strict legal sense, and Dodd certainly isn't the first guy to say something like that - there were similar quotes from Wall St guys as Obama was waxing populist. I don't think it's illegal to say "we can no longer support you if you keep doing this", which isn't the same thing as saying "we'll give you money to change your position".
The question is whether or not what he said amounts to a quit pro quo.
No, that's not the whole point of a high ISP engine
Sure it is. A high ISP engine is simply more efficient per kg of fuel. If you supply enough fuel to a high mass ratio chemical rocket you can overcome that efficiency advantage. We don't do that today because it's a whole lot cheaper to send a little rocket on a high efficiency trajectory. But since we're talking about sending many extra tons into orbit, including whatever infrastructure needed for construction activities, what we have to compare the NTR to is the best chemical rocket we could have in that mass budget.
Would you have to do a trade study to see if you'd rather do impulsive-ish chemical burns rather than have a fancy, probably much heavier nuclear engine with higher ISP that can do something more akin to a continuous thrust trajectory? Yes, of course, and you'd probably see that it's a huge win for an interplanetary manned craft or anything else with a lot of dry mass.
NASA was never able to do better than 800 seconds with an NTR, which is less than double what you get with a conventional hydrogen/LOX engine, and far less current electric engines. It's definitely not suited to the pie in the sky interstellar probe in the article. Hell, at 800 seconds NTR isn't a good fit for a mars mission. In theory they could get one up to 1000 seconds. So... worth the time and effort? I don't see it, particularly when Ad Astra has already demonstrated an ISP of 4900 seconds in a full-scale test of a VASIMR engine.
In any event, to do such a trade study you'd have to have a working design, something we don't have. Nobody knows exactly how heavy a working NTR would be beyond "pretty damn heavy". I don't see that changing, either, for the same reason Rover and NERVA were eventually abandoned. The concept is just too messy to test. It's unlikely you could ever keep uranium and/or plutonium out of the exhaust stream without physically separating the core from the working fluid. That's going to make it still heavier and probably less efficient. Assuming it could be made to work at all.
All this assumes, of course, a NERVA style solid core engine, which is I think what they're proposing, though it's hard to tell from the article. And the numbers don't pass the laugh test. A liquid or gas core engine would be a real game-changer from the performance perspective and probably a whole lot safer if we could actually build one, but from what I can see we're no closer than we were when the idea was first proposed more than half a century ago. And even the holy grail gas core "nuclear light bulb" engine will only produce an ISP of between 1500 and 2000 seconds (according to the wiki page). Good for an SSTO assuming you weren't worried about spreading nuclear fuel everywhere if it crashed.
Not me. In fact, I think we need a more of it. A whole hell of a lot of people have sold themselves into virtual slavery by borrowing a lot of money without thinking about how they're going to pay it back.
Well, yes, you could. But now you'll have to send up a bunch of extra kg into orbit, and the whole point of having an engine with high ISP is to get really good performance from your fuel because you didn't want to send a bunch of extra kg to orbit.
There's nothing new here. It's another "study" rehashing technology that's been rehashed over and over for at least sixty years. And anyway nuclear thermal rockets don't address the biggest problem we have with space exploration, which is getting to orbit in the first place. Heinlein famously observed "Get to low-Earth orbit and you're halfway to anywhere in the solar system." But the converse is also true - no matter how good your deep space rocket is you're only half way to where you want to be.
Nuclear thermal rockets have a wonderful ISP, but they don't have as much thrust as chemical rockets, and they're heavy. Even assuming you wanted to use one for the first stage it probably wouldn't have enough thrust to do the job. And you wouldn't want to start one up on earth, either. They never did figure out how to keep bits of the radioactive core from breaking off and entering the exhaust stream,
Yeah... gun tolerance approaches Zero and crime drops. Man, it must pain you when the facts run counter to your belief.
There's no actual evidence this is the case. You can find examples of crime rates getting worse as gun laws were tightened, and you can find examples of crime rates getting better.
I dunno, self defense is a pretty legitimate reason. NYC isn't as dangerous as it once was, maybe, but there are still a lot of areas in which I wouldn't feel safe.
Well, that's the end of China's economy.
I've always been wont to mete the meat, but to each his own.
Access to health care only matters so much, and from what I understand statistically it's access to a primary care physician that matters. You can catch things like hypertension and diabetes before they become serious.
Rich people die of heart disease all the time. I'm assuming Cheney never goes anywhere without a cardiology team, but that's not enough to explain 34 years. No amount of money would have mattered very much in 1978, and even today doctors can do only so much.
It may just be survivor bias, but still.
It looks like, for once, we could actually see a treatment in a relatively short period of time.
You know, people make jokes, but that dude had his first heart attack (of 5) 34 years ago. Whatever he's done to keep himself alive seems to have worked pretty damn well.
Artificial meet? What, like, a dating site?
Isn't that something Kieth Richards is rumored to have done?
I won't be happy until they're hung, drawn, and quartered, their families are sold into slavery, and their fields are salted.
Proverbially, of course.
Well... yes, of course. They're not charities. Why would you expect them to behave like charities?
Nah, that was a one-off. The normal way is rope.
If my employer punished people for taking vacations, I'd find another job. That's what it means to be a professional - your protection as an employee is the threat you'll take your skills somewhere else. If you can't make that threat credibly it means your employer isn't getting his money's worth, and you need to do something about that.
True in theory, but not at all true in practice. An employer who fired someone without giving (and documenting profusely) a reason will almost certainly be sued.
Oh come on. You have to really stretch to believe this is true. It's way out in conspiracy land.
No, actually.
I disagree about conventional warfare - we've never gone twenty years without a war. The situation will change in ways we can't predict, and I don't think we can count on the Europeans to pick up much of the slack - both because they don't always see eye-to-eye with the US and because they're not going to have the money to maintain first-class militaries. Look at what's happening in the UK - they have some kind of financial Zeno's paradox going on, where they cut the military budget in half every year. How much longer do you think they'll be able to project force at all? Could they even retake the Falklands if Argentina attacked today? Seems unlikely. France and Germany have a lot of hardware, but neither can project force very well. They just don't have the logistical support - things like transport aircraft and aerial refueling. They couldn't have maintained the air war in Libya without US intelligence and refueling assets, and Libya was the best case scenario for an air war: close to Europe and without any air defense to speak of.
As Rumsfeld famously said, "You go to war with what you have," and he was absolutely right. Conflicts can arise quickly, and there's no point deciding at the start of the conflict that you should have built a few more of these or refurbished some of those instead of retiring them, Having a few F-35s would be a bit of insurance against unforeseen problems. Ultimately I don't think the program will cost too much because we'll sell thousands to foreign customers, and that keeps assembly lines moving and workers paying taxes.
Having said that, I should say I don't see much use for manned strike aircraft if you have something better for air superiority. We can use drones or heavy bombers to drop bombs, and we have cruise missiles for SEAD. But it's going to be many years before we deploy unmanned fighters, and the linchpin of modern warfare is control of the air. Were it up to me I would have cancelled the F-35, built more F-22s, and put money into developing an unmanned heavy bomber. Nothing fancy, just a big bomb truck.