Why should I be expected to be the one to find the holes, just because they can't be arsed testing it properly?
Usually you shouldn't, however you will. It doesn't matter if you're creating a web browser that can't display "broken-but-renders-on-IE" webpages, an IDE driver that may corrupt data on "UDMA-compatible-but-not-compliant" hard drives, or a server process that crashes on corrupt or malicious out-of-spec data: as long as your code is what's interfacing more directly with the user, your code will probably be blamed for the problems. In particular, if one of your competitors has found and worked around the holes, your code will definitely be blamed for the problems.
It's not fair, but it's life: from a user's point of view it's easier to get new software than to communicate with a different set of people or buy new hardware.
Two examples from my own experience. We attempted integration with RSA and OpenSSH had significant problems that we had to resolve and in the end we could not resolve the final problem which was a session would hang after exiting the shell if the session was authenticated using the RSA PAM module.
One example from my own experience: I ran ssh-keygen from OpenSSH, copied the RSA public keys around, and it just worked. I do believe you've had different luck, but I suspect my case is more typical.
The other example is related to distribution and configuration managment. We have started using SSH communications central management center to distribute new versions of Tectia server as well as centrally manage the configuration for Tectia/ssh. This has reduced our management overhead considerably. This is an "enterprise" feature.
Ironically, this "enterprise" feature is easily achieved by non-enterprises by putting ssh (Open or not) itself with a 3 line shell script. I install new versions of OpenSSH on a couple dozen computers with "ssh-all smart upgrade", for example.
That's just an example of my point, though: if this really is an enterprise feature, then any enterprise will already have some implementation of this feature, and will want to add new programs to their own central configuration management program rather than running a separate configuration management program for every single program they install. I suspect OpenSSH is easier to package for 3rd party management software - if only because you know you have a licence to redistribute derived versions without breaking copyright law.
The thing is, even if Scaled Composites had 250 billion in one large lump sum, it wouldn't get them very far at first.
If Scaled Composites found 250 billion in the couch cushions, we would have men on Mars in a decade and a permanent research base in two.
If Scaled Composites had 250 billion the way NASA has 250 billion, with 50 states they were required to spread pork around, an army of existing jobs they couldn't afford to cut, and the possiblility of getting that budget cut any time Congress thought they were taking too many risks... well, I'm still sure they'd make orbit, but that's about it.
It's called Safe, Simple and Soon and Griffin is hell bent on building it.
That's the option that the earlier poster called "Kept shooting Apollo capsules up forever more? Built an Apollo 2?" It uses existing infrastructure to prevent job cuts rather than growing a smaller program to enable expense cuts. It predecides a single new launcher on which hundreds of billions of dollars are going to be spent based on projected costs, rather than funding competing launch vehicles and choosing which to use based on actual operational costs. That single launcher uses the old "throw away the vehicle, not just the fuel" philosophy which sets a high lower limit on those operational costs.
Granted, there are a few new ideas (principally attempting to find and mine lunar ice) they're planning to explore, and there are a lot of bad Shuttle ideas (e.g. hoping "refurbishable" would be as good as reuseable, asymmetric staging, tiled TPS) they're getting away from, but this really is called "Safe, Simple and Soon" only because "Apollo 2" would have been political suicide.
On the other hand, the current plan is at least political Russian Roulette. The "cut NASA's budget" reactions I've seen has been astonishing given that they're talking about staying *within* their current budget but sending men a thousand times as far for the same money. From an engineering standpoint it might have been a good idea to abandon Shuttle 20 years ago and learn from the mistakes to design the next generation of launch vehicles. From a political standpoint NASA did just the right thing: tried to keep as low a profile as possible to avoid getting the axe.
Not that I disagree with you, but if you could explain how the consitiution, if enforced, would be adequate (with or without extra "law(s)" or (an) "amendment(s)"
It required amendments to make the Constitution's intent explicit, but fortunately theyboth were passed two centuries ago.
Unfortunately, Amendment IX is practically unenforceable because while everyone can agree that there are human rights not explicitly protected by the Consitution, nobody entirely agrees on which rights those are. Amendment X is theoretically enforceable, but hasn't been enforced in so long that it's probably too late to start now; no Supreme Court Justice wants to be the guy who says "Hey, did you guys notice that most of the federal laws on the books are unconstitutional?"
If these people actually cared about the ELECTORAL PROCESS, they wouldn't have been bringing up Bush every ten seconds, and avoid being labeled kooks.
You fling around derogatory terms pretty freely for someone whose Caps Lock etiquette screams "kook". Unlike your own distracting habits, though, bringing up Bush became relevant once the CEO of the biggest voting machine company promised to deliver Ohio to Bush.
"Watching" doesn't automatically mean physically using ones eyes to monitor the process. They let the machines be used.
Oh, they "let" the machines be used, did they? That's not the fault of people who tried to educate the public and media about the threat that unverfiable voting poses to democratic elections, it's the fault of people like you who scream "Area 51!" at serious concerns. What should people who aren't election supervisors have done to avoid "letting the machines be used", huh? Should people concerned about election fraud have stormed the polling places with guns and sledgehammers to smash the voting machines? Try to think before you reply next time.
If we proposed to count votes in the future by giving all the ballot boxes to a few companies and trusting their counts, even people like you would be able to understand the problem. But no, instead we give all the ballots to computers created by a few companies and so everyone who worships or fears little black boxes just trusts that it'll all come out okay.
What's really sad is that if we gave ballot boxes to a few companies and trusted their counts, the result would be *more secure*, not less. A conspiracy to miscount physical ballots would take lots of manpower, and would really require a conspiracy as everyone involved would be a potential leak. (Of course, despite being more difficult than electronic fraud, non-electronic voting fraud is a regular matter of historical record, and will stay that way no matter how many times you shout "kook!" or "conspiracy theory!") With electronic voting, all you need for a miscount is a security flaw or backdoor anywhere in the chain of responsible software - and that's not a crazy "conspiracy theory", that's something that happens to nearly every program ever written.
Where the hell were you idiots BEFORE the 2004 election?
Trying desperately to get media attention before it was too late. As your ignorance demonstrates, it was a failure.
If it really happened the way you claim, WHY WEREN'T YOU WATCHING?
Because humans have no ability to see software variables without a trusted computer and debugger. The point of moving ballots from macroscopic marks on paper to microscopic electronic states is that watching becomes impossible.
The space elevator seems to be still hovering at that point where it certainly looks to be theoretically feasible, but where no one really has a clear path towards bringing this construct about in reality.
New rockets are engineering work: we have all the materials we need to use, we know all the physics that describes their behavior, and so as you said there's a clear (albeit expensive) path to figuring out how to put it all together.
A space elevator would still require science work, because the central problem is mass production of materials with properties we only know how to produce at microscopic scales. We can try and pour money at that problem, but who's to say how much it will speed up the solution? Scientific breakthroughs don't usually measure in man-hours and aren't easily predictable in dollars.
We probably ought to try pouring money at the problem anyway. We may soon be able to make cheap material that's stronger than diamond but more flexible than rubber. Even if it isn't good enough for a space elevator at first, it'll be in demand for everything from tires to Gibraltar Bridge cables.
We also wouldn't need a heat shield if we could afford to build rockets that landed on a tail of fire like God and Heinlein meant us to.
This is incorrect (although I like that quote too). Even VTOL rocket designs all use aerobraking for reentry on planets where that option is available. It's just a matter of physics: if you need 90% of your gross liftoff weight to be fuel to get up to orbital speed (which makes launch vehicle design hard) then you would need 99% of GLOW to be fuel to get up to orbital speed and down again (which would make launch vehicle design impossible).
Admittedly, you pay a penalty in hauling more tankage and engine mass to orbit than a true second or third stage would. But trading off efficiency for reliability can be a good exchange.
You also avoid a penalty in engine mass: for every "false" second or third stage engine firing at liftoff, there's a reduction in the need for first stage engine thrust and thus in engine weight.
Trading off mass efficiency for reliability is a great exchange. The space program is in trouble because it costs too much money and too many lives, not too much fuel.
Unfortunately mergers keep reducing their numbers - for large payloads it's down to Lockheed and Boeing now, with SpaceX planning to enter the fray soon.
Of course this is a chicken and egg problem: when your largest potential customers swear they're going to create their own product from scratch and have billions of dollars a year to spend on it, investors tend to be wary about jumping into the market.
Getting to LEO is hard, and there are now only three countries who have ever gotten a manned craft into orbit: China (the newest club member), Russia/USSR, and the US. No private venture has gotten even close. Ever.
Private ventures send large payloads into LEO and further all the time. The reason they're all unmanned isn't because life support is an insurmountable problem, it's because comsats are automatable.
It's akin to saying "We need $100B to spend on this, and to do that inside our existing budgets will take a little longer." Having another manned program in the works lets them shut down the Shuttle without saying "We give up now, space is hard!" and "We're firing our army of Shuttle workers now; thanks for the ride!"
I mean, I'd like it to happen, but we all know it won't, right?
It'll happen (the Moon shots, at least), it'll just be "Apollo II: The Unimaginative Sequel". The "Not Invented Here" philosophy means that all our plans will again depend on one huge government cargo rocket, to give Congress a single Saturnesque target for budget cuts when we get bored of flags and footprints and want to stall the space program for another 50 years. The major difference is that this time we don't think we can keep body counts down without putting the crew launches on a separate smaller booster. Fortunately there will be a single government rocket for those, too, so we can keep the market for private launch vehicles starved and stop the evil capitalists from stealing our central planning mojo.
If your problem is so parallelizable that bandwidth isn't a limitation, then you don't need any special clustering software, you just need nfs and ssh: I do all my compiling in a flash with a short script and "make -j 16 CXX=sshcxx".
If your problem isn't that parallelizable and yet you need a whole cluster of computers to run it, odds are you need more efficiency than distributed shared memory can give you. You can access memory on your own node with orders of magnitude more bandwidth and less latency than on other nodes, and if your application doesn't take that into consideration it can run orders of magnitude slower.
Of course, that doesn't apply to every problem, and there are people trying to create exactly the cluster-as-computer architecture you'd like to see for ease of application programming. Check out OpenMosix and MigShm for one example - I haven't used the latter DSM patch myself but I know that for non-shared-memory programs, Mosix has had working process migration code for years.
FWIW, your wife does not, by raising the kids, participate in the economy's production, except as a consumer.
My girlfriend is currently a nanny (yes, paying taxes and everything) - does she count as "employed" because she's raising someone else's children instead of her own? If not, then how about her sister, who worked in day care and raised children en masse? If not, then what about my father, whose job is ostensibly to teach high school math but whose public school position makes him a babysitter for those students who don't want to learn?
I'm not sure how you're defining "the economy's production", but the US hasn't had much of a production-based economy in decades. Service jobs like child rearing don't leave you with a chunk of shaped metal to call your own at the end of the day, but that doesn't mean they aren't employment. In particular, if you're going to bemoan a low "employment participation rate", you should make sure that statistic means "people who want to find paying jobs can't", not "families don't need two incomes to survive".
That's really only useful if you're going to program computers with those new-fangled "math coprocessors". For those of us sticking with our 486SX it's a complete waste of time.
If there's no hostile party on a hop between you and the person you're talking to, you don't need any encryption because nobody is reading your packets.
If there is a hostile party on a hop between you and the person you're talking to, public key encryption is risky unless you already have your correspondent's public key - because if you just ask him for that key over the compromised channel, you can't be sure whether what you get back is really his public key or whether it's the attacker's public key. The attacker can simply decrypt everything you send him and then reencrypt it with your real correspondent's key, and neither of you can tell anything's wrong.
That's why you should have a web of trust (this key is digitally signed by someone whose key was signed by someone whose key was signed by someone I know) or certifying authority (this key is digitally signed by Verisign) or out-of-band (I called my correspondent on the phone last week and verified the hash of the key he'd sent me) means of key verification.
Even without a verified key, though, public key encryption is better than nothing. There are more people who can read your data than people who can rewrite it, so a defense that only works against the former group is still worthwhile. For that matter, even verified keys aren't bulletproof - they only protect against attacks from all the networks bouncing your packets around. If your own computer or your correspondents' have been compromised, you could be using one time pads and it would't matter.
Errrrr..... you seem to be thinking they will be 'landing' in the sense of sitting down on gear gracefully.
This is true, and an assumption I should have stated explicitly. I don't think it's a poor assumption for future vehicles, though. You can land a small capsule with a couple people using a parachute and splashdown, but when you want to to launch that capsule again you either need to build a new launcher to put it on (using expensive materials and machine shops) or you need to refuel an old launcher (using cheap rocket fuel, but requiring that you can safely land a huge launcher at a spaceport first).
I can't help but think there has to be an air breathing way to do the SRB's...
It seems like the easiest part of the system to make reusable, doesn't it? They only need to reach a couple thousand miles an hour, their ISP is already low and has the least impact on total vehicle performance, and they can be resized almost independently of the rest of the stack so long as the (admittedly huge) thrust requirements are met.
That thrust is probably the killer. Each of the 2 SRBs produces nearly 15 meganewtons of thrust; for comparison the concorde's 4 jets each do about 0.17 MN max.
though if you can't shave any weight in the process of providing the same power it is essentially just a lot of work for no gain......says the missile designer at the heart of too many launch vehicle designers. The Shuttle doesn't have to fit in a submarine or be carried under an airplane wing; if a Shuttle replacement weighs five times as much but costs half as much then the replacement will be improvement.
unless the safety margian is greater.... a fly back and fast turnaround would make it worth it though.
Exactly. For reusable vehicles the safety margin is everything - even coldly ignoring the pilots' lives, it's just important to be able to amortize your billion dollar vehicle's construction cost over more than a hundred flights. Fast turnaround should be nearly as important - ideally you want to be able to make those hundred flights with every ship every year, not by divving them up among four ships over a decade.
The SRBs have an excellent safety record (when run within their design parameters...) though, and I don't know how much reducing their turnaround time will help. Shuttle parts from the main engines to the thermal protection aren't so much "reusable" as "refurbishable", and take so long to refurbish that I don't think the SRBs are on the critical path.
We got more done in the 60's with this kind of tech than we do now with our aging shuttle fleet. Also, since the boosters and fuel tanks are based on teh shuttles, we can utilize our current network of contractors to supply parts.
Contradicts this sentence:
I'm tired of spending billions just to get into space.
Those billions of dollars aren't being stuffed in the SRBs and set on fire, they're being spent on the parts and people that make the shuttle run. The equipment costs are likely to increase with less reusable designs, and so the only way to decrease the total costs are to pay fewer people. Unless Shuttle politics now is much better than Shuttle politics decades ago, it will be impossible to pay fewer people - standing between us and every job cut will be a Congressman from that district screaming bloody murder. The only way of shrinking a government program as big as Shuttle is to scrap it entirely and try to start a smaller replacement from scratch.
Spaceflight isn't going to get any cheaper this way. Our best hope now is that the next generation of Shuttle-derived vehicles can be launched more frequently than the dying Shuttles, so that at least we can get more done in space for the same price. That's a much more likely goal, given the increased cargo capacity of the heavy lifter proposals and the increased simplicity of all the proposed replacements.
One: The bigger they are, the easier they fall. No, seriously. Having more surface area during reentry, especially surface area that can provide lift, means that you get to do your deceleration (and more importantly reentry heating) more gradually in thinner atmosphere. This is particularly important for current staged rockets that have to throw away most of their surface area in the form of burnt out stages and empty drop tanks.
Two: Landing by gliding on heavy wings is a well-understood technology. Landing by balancing on rockets with heavy fuel isn't. Until the DC-X flights some people were skeptical that it could be done at all, and some are still skeptical that it can be done as efficiently and safely.
Three: When talking about "spaceplanes" as opposed to just VTHL rockets, you're usually talking about something that uses scramjets or liquid air cycle rockets to pull their oxygen (which makes up most of the gross liftoff weight of conventional rockets) from the atmosphere rather than the fuel tanks for as long as possible. If you're going to be hanging out in the atmosphere for a while anyway, the efficient way to keep yourself aloft is with aerodynamic lift rather than rockets.
Now, I'm not saying that putting wings on a launch vehicle are an obvious design decision - my personal napkin-sketches of the ideal next US launch vehicle wouldn't have wings, in fact. But I hope it's understandable now why wings on a spacecraft aren't as ridiculous as they sound.
Why would you be able to reverse a major plot point just because it's being remade?
Because frankly, it was a pretty stupid plot point. In most other stories the opposite would be true, and dead characters should stay dead, but if I have to grind through 20 hours of Final Fantasy gameplay to see 2 hours of story, they should at least keep the two consistent with each other! I can't be the only one who wanted to yell at the characters:
"Phoenix Down! Use a Phoenix Down! I've got 99 of them! This isn't even the first time Aeris has needed to be resurrected today!!!"
A developer doesn't have 2 weeks to insert new functionality. A developer can work on enhanced performance or new features for 9 months, but there is a 2-week window after each release in which patches will be accepted.
The two things are orthogonal.
We'd better hope everyone's patches are orthogonal too. If five Linux kernel developers all spend 9 months working independently on patches which turn out to make conflicting changes to the same subsystems, then after 2 weeks there will be one happy developer with his patch in the Linux kernel and four unhappy developers deciding whether to fork Linux or switch to FreeBSD.
Of course, to avoid such problems we can assume that those many different kernel developers are not working independently, but are committing changes to a single unstable kernel to share those changes and prevent conflicts. In that case, let's just call the new unstable kernel "2.7" and return to the system that was working so well for years.
If this fails in the next 10 years, we get refunded tax money.
If you want a "tax refund", you can get one right now by taking out an extra $300 on your credit card. Just like the government a few years back, banks will eagerly give you $300 in cash now along with more than $300 in debt you'll be made to pay back later. The only way to cut taxes and keep them cut is to also cut expenditures... and except for Congress' salaries (which come to less than $1 per taxpayer per year), any government expenditures which aren't worth the price ought to be cut whether we're attacked again or not.
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Why should I be expected to be the one to find the holes, just because they can't be arsed testing it properly?
Usually you shouldn't, however you will. It doesn't matter if you're creating a web browser that can't display "broken-but-renders-on-IE" webpages, an IDE driver that may corrupt data on "UDMA-compatible-but-not-compliant" hard drives, or a server process that crashes on corrupt or malicious out-of-spec data: as long as your code is what's interfacing more directly with the user, your code will probably be blamed for the problems. In particular, if one of your competitors has found and worked around the holes, your code will definitely be blamed for the problems.
It's not fair, but it's life: from a user's point of view it's easier to get new software than to communicate with a different set of people or buy new hardware.
Two examples from my own experience. We attempted integration with RSA and OpenSSH had significant problems that we had to resolve and in the end we could not resolve the final problem which was a session would hang after exiting the shell if the session was authenticated using the RSA PAM module.
One example from my own experience: I ran ssh-keygen from OpenSSH, copied the RSA public keys around, and it just worked. I do believe you've had different luck, but I suspect my case is more typical.
The other example is related to distribution and configuration managment. We have started using SSH communications central management center to distribute new versions of Tectia server as well as centrally manage the configuration for Tectia/ssh. This has reduced our management overhead considerably. This is an "enterprise" feature.
Ironically, this "enterprise" feature is easily achieved by non-enterprises by putting ssh (Open or not) itself with a 3 line shell script. I install new versions of OpenSSH on a couple dozen computers with "ssh-all smart upgrade", for example.
That's just an example of my point, though: if this really is an enterprise feature, then any enterprise will already have some implementation of this feature, and will want to add new programs to their own central configuration management program rather than running a separate configuration management program for every single program they install. I suspect OpenSSH is easier to package for 3rd party management software - if only because you know you have a licence to redistribute derived versions without breaking copyright law.
The thing is, even if Scaled Composites had 250 billion in one large lump sum, it wouldn't get them very far at first.
If Scaled Composites found 250 billion in the couch cushions, we would have men on Mars in a decade and a permanent research base in two.
If Scaled Composites had 250 billion the way NASA has 250 billion, with 50 states they were required to spread pork around, an army of existing jobs they couldn't afford to cut, and the possiblility of getting that budget cut any time Congress thought they were taking too many risks... well, I'm still sure they'd make orbit, but that's about it.
It's called Safe, Simple and Soon and Griffin is hell bent on building it.
That's the option that the earlier poster called "Kept shooting Apollo capsules up forever more? Built an Apollo 2?" It uses existing infrastructure to prevent job cuts rather than growing a smaller program to enable expense cuts. It predecides a single new launcher on which hundreds of billions of dollars are going to be spent based on projected costs, rather than funding competing launch vehicles and choosing which to use based on actual operational costs. That single launcher uses the old "throw away the vehicle, not just the fuel" philosophy which sets a high lower limit on those operational costs.
Granted, there are a few new ideas (principally attempting to find and mine lunar ice) they're planning to explore, and there are a lot of bad Shuttle ideas (e.g. hoping "refurbishable" would be as good as reuseable, asymmetric staging, tiled TPS) they're getting away from, but this really is called "Safe, Simple and Soon" only because "Apollo 2" would have been political suicide.
On the other hand, the current plan is at least political Russian Roulette. The "cut NASA's budget" reactions I've seen has been astonishing given that they're talking about staying *within* their current budget but sending men a thousand times as far for the same money. From an engineering standpoint it might have been a good idea to abandon Shuttle 20 years ago and learn from the mistakes to design the next generation of launch vehicles. From a political standpoint NASA did just the right thing: tried to keep as low a profile as possible to avoid getting the axe.
Not that I disagree with you, but if you could explain how the consitiution, if enforced, would be adequate (with or without extra "law(s)" or (an) "amendment(s)"
It required amendments to make the Constitution's intent explicit, but fortunately they both were passed two centuries ago.
Unfortunately, Amendment IX is practically unenforceable because while everyone can agree that there are human rights not explicitly protected by the Consitution, nobody entirely agrees on which rights those are. Amendment X is theoretically enforceable, but hasn't been enforced in so long that it's probably too late to start now; no Supreme Court Justice wants to be the guy who says "Hey, did you guys notice that most of the federal laws on the books are unconstitutional?"
Furthermore, I saw my hairstyle in a cave-painting the other week.
Have you considered getting a haircut?
If these people actually cared about the ELECTORAL PROCESS, they wouldn't have been bringing up Bush every ten seconds, and avoid being labeled kooks.
You fling around derogatory terms pretty freely for someone whose Caps Lock etiquette screams "kook". Unlike your own distracting habits, though, bringing up Bush became relevant once the CEO of the biggest voting machine company promised to deliver Ohio to Bush.
"Watching" doesn't automatically mean physically using ones eyes to monitor the process. They let the machines be used.
Oh, they "let" the machines be used, did they? That's not the fault of people who tried to educate the public and media about the threat that unverfiable voting poses to democratic elections, it's the fault of people like you who scream "Area 51!" at serious concerns. What should people who aren't election supervisors have done to avoid "letting the machines be used", huh? Should people concerned about election fraud have stormed the polling places with guns and sledgehammers to smash the voting machines? Try to think before you reply next time.
If we proposed to count votes in the future by giving all the ballot boxes to a few companies and trusting their counts, even people like you would be able to understand the problem. But no, instead we give all the ballots to computers created by a few companies and so everyone who worships or fears little black boxes just trusts that it'll all come out okay.
What's really sad is that if we gave ballot boxes to a few companies and trusted their counts, the result would be *more secure*, not less. A conspiracy to miscount physical ballots would take lots of manpower, and would really require a conspiracy as everyone involved would be a potential leak. (Of course, despite being more difficult than electronic fraud, non-electronic voting fraud is a regular matter of historical record, and will stay that way no matter how many times you shout "kook!" or "conspiracy theory!") With electronic voting, all you need for a miscount is a security flaw or backdoor anywhere in the chain of responsible software - and that's not a crazy "conspiracy theory", that's something that happens to nearly every program ever written.
Where the hell were you idiots BEFORE the 2004 election?
Trying desperately to get media attention before it was too late. As your ignorance demonstrates, it was a failure.
If it really happened the way you claim, WHY WEREN'T YOU WATCHING?
Because humans have no ability to see software variables without a trusted computer and debugger. The point of moving ballots from macroscopic marks on paper to microscopic electronic states is that watching becomes impossible.
The space elevator seems to be still hovering at that point where it certainly looks to be theoretically feasible, but where no one really has a clear path towards bringing this construct about in reality.
New rockets are engineering work: we have all the materials we need to use, we know all the physics that describes their behavior, and so as you said there's a clear (albeit expensive) path to figuring out how to put it all together.
A space elevator would still require science work, because the central problem is mass production of materials with properties we only know how to produce at microscopic scales. We can try and pour money at that problem, but who's to say how much it will speed up the solution? Scientific breakthroughs don't usually measure in man-hours and aren't easily predictable in dollars.
We probably ought to try pouring money at the problem anyway. We may soon be able to make cheap material that's stronger than diamond but more flexible than rubber. Even if it isn't good enough for a space elevator at first, it'll be in demand for everything from tires to Gibraltar Bridge cables.
We also wouldn't need a heat shield if we could afford to build rockets that landed on a tail of fire like God and Heinlein meant us to.
This is incorrect (although I like that quote too). Even VTOL rocket designs all use aerobraking for reentry on planets where that option is available. It's just a matter of physics: if you need 90% of your gross liftoff weight to be fuel to get up to orbital speed (which makes launch vehicle design hard) then you would need 99% of GLOW to be fuel to get up to orbital speed and down again (which would make launch vehicle design impossible).
Admittedly, you pay a penalty in hauling more tankage and engine mass to orbit than a true second or third stage would. But trading off efficiency for reliability can be a good exchange.
You also avoid a penalty in engine mass: for every "false" second or third stage engine firing at liftoff, there's a reduction in the need for first stage engine thrust and thus in engine weight.
Trading off mass efficiency for reliability is a great exchange. The space program is in trouble because it costs too much money and too many lives, not too much fuel.
Unfortunately mergers keep reducing their numbers - for large payloads it's down to Lockheed and Boeing now, with SpaceX planning to enter the fray soon.
Of course this is a chicken and egg problem: when your largest potential customers swear they're going to create their own product from scratch and have billions of dollars a year to spend on it, investors tend to be wary about jumping into the market.
Getting to LEO is hard, and there are now only three countries who have ever gotten a manned craft into orbit: China (the newest club member), Russia/USSR, and the US. No private venture has gotten even close. Ever.
Private ventures send large payloads into LEO and further all the time. The reason they're all unmanned isn't because life support is an insurmountable problem, it's because comsats are automatable.
It's akin to saying "We need $100B to spend on this, and to do that inside our existing budgets will take a little longer." Having another manned program in the works lets them shut down the Shuttle without saying "We give up now, space is hard!" and "We're firing our army of Shuttle workers now; thanks for the ride!"
I mean, I'd like it to happen, but we all know it won't, right?
It'll happen (the Moon shots, at least), it'll just be "Apollo II: The Unimaginative Sequel". The "Not Invented Here" philosophy means that all our plans will again depend on one huge government cargo rocket, to give Congress a single Saturnesque target for budget cuts when we get bored of flags and footprints and want to stall the space program for another 50 years. The major difference is that this time we don't think we can keep body counts down without putting the crew launches on a separate smaller booster. Fortunately there will be a single government rocket for those, too, so we can keep the market for private launch vehicles starved and stop the evil capitalists from stealing our central planning mojo.
If your problem is so parallelizable that bandwidth isn't a limitation, then you don't need any special clustering software, you just need nfs and ssh: I do all my compiling in a flash with a short script and "make -j 16 CXX=sshcxx".
If your problem isn't that parallelizable and yet you need a whole cluster of computers to run it, odds are you need more efficiency than distributed shared memory can give you. You can access memory on your own node with orders of magnitude more bandwidth and less latency than on other nodes, and if your application doesn't take that into consideration it can run orders of magnitude slower.
Of course, that doesn't apply to every problem, and there are people trying to create exactly the cluster-as-computer architecture you'd like to see for ease of application programming. Check out OpenMosix and MigShm for one example - I haven't used the latter DSM patch myself but I know that for non-shared-memory programs, Mosix has had working process migration code for years.
It's like the Unix philosophy. Each program does one thing and does it well. And it communicates well with other programs.
/usr/bin | wc -l
$ ls
2479
That's fine for software, but hardware? I'm going to need bigger pockets...
FWIW, your wife does not, by raising the kids, participate in the economy's production, except as a consumer.
My girlfriend is currently a nanny (yes, paying taxes and everything) - does she count as "employed" because she's raising someone else's children instead of her own? If not, then how about her sister, who worked in day care and raised children en masse? If not, then what about my father, whose job is ostensibly to teach high school math but whose public school position makes him a babysitter for those students who don't want to learn?
I'm not sure how you're defining "the economy's production", but the US hasn't had much of a production-based economy in decades. Service jobs like child rearing don't leave you with a chunk of shaped metal to call your own at the end of the day, but that doesn't mean they aren't employment. In particular, if you're going to bemoan a low "employment participation rate", you should make sure that statistic means "people who want to find paying jobs can't", not "families don't need two incomes to survive".
That's really only useful if you're going to program computers with those new-fangled "math coprocessors". For those of us sticking with our 486SX it's a complete waste of time.
Do you know how hard it is to find a fiddle on such short notice?
If there's no hostile party on a hop between you and the person you're talking to, you don't need any encryption because nobody is reading your packets.
If there is a hostile party on a hop between you and the person you're talking to, public key encryption is risky unless you already have your correspondent's public key - because if you just ask him for that key over the compromised channel, you can't be sure whether what you get back is really his public key or whether it's the attacker's public key. The attacker can simply decrypt everything you send him and then reencrypt it with your real correspondent's key, and neither of you can tell anything's wrong.
That's why you should have a web of trust (this key is digitally signed by someone whose key was signed by someone whose key was signed by someone I know) or certifying authority (this key is digitally signed by Verisign) or out-of-band (I called my correspondent on the phone last week and verified the hash of the key he'd sent me) means of key verification.
Even without a verified key, though, public key encryption is better than nothing. There are more people who can read your data than people who can rewrite it, so a defense that only works against the former group is still worthwhile. For that matter, even verified keys aren't bulletproof - they only protect against attacks from all the networks bouncing your packets around. If your own computer or your correspondents' have been compromised, you could be using one time pads and it would't matter.
Errrrr..... you seem to be thinking they will be 'landing' in the sense of sitting down on gear gracefully.
...says the missile designer at the heart of too many launch vehicle designers. The Shuttle doesn't have to fit in a submarine or be carried under an airplane wing; if a Shuttle replacement weighs five times as much but costs half as much then the replacement will be improvement.
This is true, and an assumption I should have stated explicitly. I don't think it's a poor assumption for future vehicles, though. You can land a small capsule with a couple people using a parachute and splashdown, but when you want to to launch that capsule again you either need to build a new launcher to put it on (using expensive materials and machine shops) or you need to refuel an old launcher (using cheap rocket fuel, but requiring that you can safely land a huge launcher at a spaceport first).
I can't help but think there has to be an air breathing way to do the SRB's...
It seems like the easiest part of the system to make reusable, doesn't it? They only need to reach a couple thousand miles an hour, their ISP is already low and has the least impact on total vehicle performance, and they can be resized almost independently of the rest of the stack so long as the (admittedly huge) thrust requirements are met.
That thrust is probably the killer. Each of the 2 SRBs produces nearly 15 meganewtons of thrust; for comparison the concorde's 4 jets each do about 0.17 MN max.
though if you can't shave any weight in the process of providing the same power it is essentially just a lot of work for no gain...
unless the safety margian is greater.... a fly back and fast turnaround would make it worth it though.
Exactly. For reusable vehicles the safety margin is everything - even coldly ignoring the pilots' lives, it's just important to be able to amortize your billion dollar vehicle's construction cost over more than a hundred flights. Fast turnaround should be nearly as important - ideally you want to be able to make those hundred flights with every ship every year, not by divving them up among four ships over a decade.
The SRBs have an excellent safety record (when run within their design parameters...) though, and I don't know how much reducing their turnaround time will help. Shuttle parts from the main engines to the thermal protection aren't so much "reusable" as "refurbishable", and take so long to refurbish that I don't think the SRBs are on the critical path.
This sentence:
We got more done in the 60's with this kind of tech than we do now with our aging shuttle fleet. Also, since the boosters and fuel tanks are based on teh shuttles, we can utilize our current network of contractors to supply parts.
Contradicts this sentence:
I'm tired of spending billions just to get into space.
Those billions of dollars aren't being stuffed in the SRBs and set on fire, they're being spent on the parts and people that make the shuttle run. The equipment costs are likely to increase with less reusable designs, and so the only way to decrease the total costs are to pay fewer people. Unless Shuttle politics now is much better than Shuttle politics decades ago, it will be impossible to pay fewer people - standing between us and every job cut will be a Congressman from that district screaming bloody murder. The only way of shrinking a government program as big as Shuttle is to scrap it entirely and try to start a smaller replacement from scratch.
Spaceflight isn't going to get any cheaper this way. Our best hope now is that the next generation of Shuttle-derived vehicles can be launched more frequently than the dying Shuttles, so that at least we can get more done in space for the same price. That's a much more likely goal, given the increased cargo capacity of the heavy lifter proposals and the increased simplicity of all the proposed replacements.
One: The bigger they are, the easier they fall. No, seriously. Having more surface area during reentry, especially surface area that can provide lift, means that you get to do your deceleration (and more importantly reentry heating) more gradually in thinner atmosphere. This is particularly important for current staged rockets that have to throw away most of their surface area in the form of burnt out stages and empty drop tanks.
Two: Landing by gliding on heavy wings is a well-understood technology. Landing by balancing on rockets with heavy fuel isn't. Until the DC-X flights some people were skeptical that it could be done at all, and some are still skeptical that it can be done as efficiently and safely.
Three: When talking about "spaceplanes" as opposed to just VTHL rockets, you're usually talking about something that uses scramjets or liquid air cycle rockets to pull their oxygen (which makes up most of the gross liftoff weight of conventional rockets) from the atmosphere rather than the fuel tanks for as long as possible. If you're going to be hanging out in the atmosphere for a while anyway, the efficient way to keep yourself aloft is with aerodynamic lift rather than rockets.
Now, I'm not saying that putting wings on a launch vehicle are an obvious design decision - my personal napkin-sketches of the ideal next US launch vehicle wouldn't have wings, in fact. But I hope it's understandable now why wings on a spacecraft aren't as ridiculous as they sound.
Why would you be able to reverse a major plot point just because it's being remade?
Because frankly, it was a pretty stupid plot point. In most other stories the opposite would be true, and dead characters should stay dead, but if I have to grind through 20 hours of Final Fantasy gameplay to see 2 hours of story, they should at least keep the two consistent with each other! I can't be the only one who wanted to yell at the characters:
"Phoenix Down! Use a Phoenix Down! I've got 99 of them! This isn't even the first time Aeris has needed to be resurrected today!!!"
A developer doesn't have 2 weeks to insert new functionality. A developer can work on enhanced performance or new features for 9 months, but there is a 2-week window after each release in which patches will be accepted.
The two things are orthogonal.
We'd better hope everyone's patches are orthogonal too. If five Linux kernel developers all spend 9 months working independently on patches which turn out to make conflicting changes to the same subsystems, then after 2 weeks there will be one happy developer with his patch in the Linux kernel and four unhappy developers deciding whether to fork Linux or switch to FreeBSD.
Of course, to avoid such problems we can assume that those many different kernel developers are not working independently, but are committing changes to a single unstable kernel to share those changes and prevent conflicts. In that case, let's just call the new unstable kernel "2.7" and return to the system that was working so well for years.
If this fails in the next 10 years, we get refunded tax money.
If you want a "tax refund", you can get one right now by taking out an extra $300 on your credit card. Just like the government a few years back, banks will eagerly give you $300 in cash now along with more than $300 in debt you'll be made to pay back later. The only way to cut taxes and keep them cut is to also cut expenditures... and except for Congress' salaries (which come to less than $1 per taxpayer per year), any government expenditures which aren't worth the price ought to be cut whether we're attacked again or not.