The vibrations that are commonly called 'pogo' in big rockets are caused by a feedback / resonance of thrust oscillations with inlet pressure of the turbopumps
Pogo is any oscillation along the vehicle's longitudinal thrust/flight axis. It's most familiar form is caused by interactions with liquid fuel, but that's a specific case not the general one.
Pogo in solids attracts much less attention because either the solids are attached to a liquid fueled rocket (and the Pogo is damped in the liquid fuel system) or they are part of a big military rocket, which the general public as well as many space experts are largely unfamiliar with.
Ares I, like every big solid, has combustion instabilities that cause thrust oscillations, but there's no feedback like in a liquid rocket.
You might want to read up on the Ares I and note that is has a liquid second stage.
On top of that, vibrations caused by combustion instabilities occur along all vehicle axes - including the longitudinal (I.E. the 'pogo' axis). Which means you can also get feedback by having combustion instability induced vibrations at a frequency that matches a structural resonance frequency - the same failure mode that destroyed the original Tacoma Narrows Bridge.
Even more concerning, was the author's argument that the accuracy of GPS guided autopilot systems also contributed. Historically, even if two planes ended up at the same flight level, headed towards each other, the inherent sloppiness in the autopilot systems would actually increase the chance of a miss. Now, with autopilots capable of keeping planes within very close tolerances of their ideal flightpath, the same two planes accidentally occupying the same flight level may have a much higher chance of colliding.
It's not a new observation - I first saw it bandied about in the RISKS Digest back in the late 90's as GPS was just then starting to come into wide use.
[Side note: I've heard that William Langewiesche wants to be/is thought of as the next John McPhee. If so, he's moving away from the target - the writing in that article was really bad.]
110 miles in a jet? really? big detour? How long does it take a jet to travel 110 miles? This extended the flight what, a whole 15 minutes counting backtrack time? For a jet that's like a bus driver missing an exit and having to drive another 4 miles to the next cloverleaf and do a 180. Though it probably had a few more exaggerated side-effects, like passengers missing connecting flights (which happens too much anyway even when planes are on time) plus the cost of a few hundred pounds of fuel. But still, seems like its being overblown.
Its not about the distance, its about the time.
When the time between life and death (to respond to an emergency communication from ATC) can be measured in as little as seconds... Not listening to ATC for forty five minutes can hardly be overblown.
On top of that, if they were concentrating that hard on their laptops for that long they could easily have missed a minor problem on the aircraft that was trending into a major problem. Etc... etc...
Didn't bother with bots - I concentrated on the steak, not the sizzle, and stayed in software. Their being hardware robots rather than software agents doesn't really change the underlying behavior. My agent's behavior was evolved, though they didn't evolve the same behaviors as those in the experiment, they did evolve unique behaviors of their own.
Which is my point, they discovered specific new behaviors that arose because of the specific features of their environment - something long known to occur. Which is why I asked what was new, because there doesn't seem to be anything.
Ok, what did this study teach us that wasn't learned years ago in (for example) Boids (1987), Core War (1984), and Tierra (1991)? I mean, it's cool having little bots running around a tabletop and all, but I was simulating the same behaviors on my '286 back in the mid 90's.
Dries Buytaert reflected on this, adding: 'this is a clear sign that governments realize that Open Source does not pose additional risks compared to proprietary software, and furthermore, that by moving away from proprietary software, they are not being locked into a particular technology, and that they can benefit from the innovation that is the result of thousands of developers collaborating on Drupal.'"
Or, more likely, the PHB in charge is running with Drupal because it's popular and CMS's are faddish right now, or worse yet maybe Drupal is the favorite one-size-fits-all solution of the head techie at the White House.
Where did I claim that the feature of ballistic reentry "just happens"? That it doesn't require any engineering?
When you stated it was an "inherent bonus of the design".
Also, NASA didn't have other heavy launcher options specifcally because of the fixation on the Shuttle.
You couldn't be much more wrong if you tried. NASA originally proposed flying the Shuttle purely as a passenger and light cargo transport, with the Saturn V being used for the heavy lifting role. The Administration and Congress however shut the door on that plan and refused to fund resumed production of the Saturn V. NASA's 'fixation' on the Shuttle was a cause. Not an effect.
Enlarged abort boundaries never proved usefull (and it's debatable they would help, since even loss of one engine too soon means loss of crew in many cases anyway; certainly it requires no damage). Enlarged landing ooportunities are another backwards argument - they are needed only because Shutle must land on the runway.
You claimed the features had never been used, I showed they they had been used and are being used today. So, having been shown to be wrong in your facts you now attempt to backpedal and claim they didn't matter anyhow.
Not to mention you are wrong on both counts. There is no one-engine-out 'black zone'. Gemini and Apollo both used aerodynamic cross range extension to obtained extended landing opportunities. Soyuz does as well. Orion (it it's ever built) will too.
It's really funny how you accused me of following emotional judgments previously (just...re-read your post)
And here you indulge in them again, making the false claim that my beliefs are based on my childhood experiences. Which is interesting, because during *my* childhood - Apollo was flying. Shuttle didn't fly until just a few weeks before my high school graduation.
As with the technical end of things, you simply don't know what the fuck you are talking about. You're a parrot who repeats what's he heard without the slightest understanding of what the words mean.
Name a mission where the loss of mission was lower than the loss of crew.
The Shuttle has suffered on LOM accident (the ATO flight, the number escapes me now), and Soyuz has has several (mostly caused by inability to dock with their intended destination). Soyuz has also had two LOM accidents due to launch aborts.
The money saved comes from using up the redundant hardware on future missions and from economies of scale in making multiple copies of the same hardware.
That sounds like my wife when she comes home from shopping with more clothes and shoes she'll never wear... "I saved money, it was on sale!".
And please, automotive comparisons?... Also, remember that ballistic reentry is not a safety features that was tackled on. It's an inherent bonus of the design
No it isn't, not one bit. It requires specific attention to aerodynamics and careful control of the center of gravity - it doesn't 'just happen'. (Keep in mind that RV nosecones, which are the same basic shape as capsules, are stable pointy end forward rather than blunt end forward.)
[remainder of handwaving and smokescreens snipped]
Well, once all that is gone... there isn't much substantive left to reply to. Ah, here's one:
It's hard to defend the Shuttle when large part of its design concept was greatly influenced by military requirements...which were never utilised (but caused great waste of resources)
Utter and complete bullshit on both counts. Not only was NASA already moving in the direction of a larger shuttle (needed because of the lack of another booster to launch Shuttle destinations), but the enlarged cross range (oft cited as one of the 'faults' of the 'military influenced' designs) has been routinely used to enlarge abort boundaries and to make available landing opportunities that would would have otherwise been unavailable.
In short, you haven't a clue what you are talking about and don't even have the wit to realize it. You just repeat the bullcrap you've heard elsewhere, and when pointed out that you're wrong - you just repeat it again like a parrot.
Who am I to argue with designers of Shuttle? Space agencies and private ventures all over the world also seem to mostly agree.
Big Macs and Windoze are extremely popular too. They must be (respectively) healthy and tasteful, and secure and viable. After all, the majority agrees.
Historical data are a fact. Soyuz, but also had no fatalities for a long, long time.
Yes, historical data is a fact. And the historical data shows that not only has Soyuz had a higher proportion of fatal flights, it also has had an ongoing pattern of significant failures and near fatal accidents. When NASA continues to fly with known bad SRB joints or known significant damage to the heatshield, they are regarded as villains. When the Russians continue to fly despite repeated problems and accidents, they are regarded as heroes.
This tells me your argument is an emotional one, not an engineering one.
You seem to forget that ballistic reentry is a survivable emergency mode, a very usefull safety feature; being able to deorbit without control; a feature that all capsules share (and early ones were purely ballistic...)
Airbags are useful survival and safety features. So, by your logic, if one out of ten of a given model of car suffers failures that lead to an accident where the airbag saves the lives of the passengers, it's a safe car. Or an aircraft that on one out of ten flights suffers explosive decompression and the lives of the passengers are saved by the emergency oxygen masks is a safe aircraft. (On that note, it's worth pointing out that AFAIK those masks have never saved a passengers life - but they have killed 110 people.)
In other words, if you routinely have to depend on safety features, backups, and luck to save your life - that means something is seriously wrong.
Yes, they were lucky...that the couplings with service module seem to be designed in a way that causes them to break off (soon enough to prevent burning through hatch; the specific contruction of the Soyuz capsule also surely helps) even when the separation fails (I'm NOT claiming that's necesserally a delibarate design decision!)
In other words, because their game of Russian Roulette hasn't yet killed anyone... We should regard the vehicle as safe. I should point out that NASA did the same with the SRB joints and ET foam shedding.
I should also point out that having a spacecraft which sheds sections also has the failure mode of shedding a section too soon... Which has also happened with Soyuz, and again sheer luck prevented the death of a crew.
Another fact/question: why the US is going "back" to capsules?
Because of pressure from fools who value low cost and pander to the public's desire for the illusion of safety over anything else.
It's 'common knowledge' that the Soyuz is safer in the same way that it's 'common knowledge' that eating pop rocks and drinking coke will cause your stomach to rupture.
IOW, just because it's 'common knowledge' doesn't mean it is true.
It's not that the astronauts are saying it...the facts (your quote) simply support that notion.
Actually, the facts don;t support that notion.
The two fatal accidents it had at the beginning were because of a) rushing it into service (first accident) b) disgarding common sense safety (crew not in pressure suits for reentry). Yes, it had a few rough, ballistic reentries, but it survived them.
A few rough ballistic entries? There's been at least five in the last six years, and more before that. (Not to mention that ballistic entries are caused by significant system failures.)
Heck, even reentering the atmosphere with the upper hatch acting as heatshield worked (upside down, basically, due to failure in detaching service module and changed aerodynamics of the spacecraft
No, it didn't work - in both cases where this happened they were lucky (very lucky) in that the service module burned away and detached before the upper hatch burned through.
I still don't understand the seeming obsession with heavy lift. Why develop and fly a new huge expensive rocket, putting all your payload eggs in one basket, rather than use a greater number of smaller, cheaper, existing rockets?
Simple engineering - the more chunks you split your payload into, the more complex the resulting assembly becomes (because now you need interfaces between the chunks), the heavier the resulting assembly becomes (because of the connectors between chunks and docking/berthing assemblies), and the greater the chance of fucking something up during building, testing, and on orbit assembly. Then there's simply math - if your rocket has a 98% chance of flight success (about average nowadays), then each launch you add to the manifest means the greater chance one will go awry.
As far as expense goes, you're way off base - rocket costs scale very weakly with size, and very strongly with complexity and the number of man hours required to prep it for launch. (Which is why the Pegasus, despite it's small size and modest payload, is somewhat above the middle of the pack in $/kg to orbit.)
The more rockets you fly, the more you have to build, and you can begin to take advantage of economies of scale and reduce the dollars per kg cost to orbit.
That's the handwaving-and-smokescreen theory. The reality is that economies of scale in manufacturing don't begin to provide significant advantage until you're talking dozens of launches a year. Costs still really don't drop much until you tackle the problem of the standing army required to integrate, checkout, and launch the vehicle - multiple smaller launches can actually cost more in total than one big launch.
Another advantage is that if your rocket does encounter some calamity, you don't lose your entire (much more expensive than the rocket itself) payload, but rather just a piece of it.
That would be a point in favor of multiple smaller chunks - if space hardware could be bought off the shelf like the load of roof trusses I saw dumped all over the median in an accident the other day. But it can't, and won't be for the foreseeable future. This means that losing a portion of the payload is no different than losing the whole payload, either one is game over.
Are private companies are as concerned about minimizing space debris as NASA and the FKA?
The US is obligated by treaty to minimize space debris, so yes - private industry has been concerned about launch debris and has been for years, lest they not get a launch permit.
The more space flights we have, the greater of a problem it becomes.
You do know that less than half of the launches in the US annually are government launches, and less than half of those are NASA launches?
I wonder whether there is any *original* information that can be found in there. It's not easy to convey a properly argumented original thought in 160 characters...
How long before Twitter becomes a has-been like Everquest, Myspace, Tron Guy, and that rabbit that balances pancakes on its head? Anyone got an estimate on the timeline? Don't these things usually take 18 months to complete?
Email and IM haven't gone away have they? Twitter has been around for three years now, and really growing in mindshare and popularity for two. It's not going anywhere.
Oh yeah, right, twitter is a game-changer that can overthrow governments. Good job they did in Iran, wot?
I predicted the lack of effectiveness back when the story hit Slashdot. I was ignored.
I did recently read two interesting articles; one on the lack of effect from accounts with large numbers of followers, and one speculating that a "tweetbomb" could possibly outshine the impact of the Slashdot Effect.
As I understand it the first astronauts were test pilots, familiar with confined cockpits, long periods of total boredom, and incredible risk of a human roasting giant fireball. Why they ever went away from those men with way too much bravado, I'll never know.
Because it turned out that so long as spacecraft and spaceflight were like the environments test pilots were used to, strapped into a confined cockpit for a few hours, test pilots were good candidates. Unfortunately, once the Mercury program was over, the nature of the flights started to change (and have changed even more radically since then), and test pilots are no longer a good fit.
People act like sticking these people in an isolated chamber for a few hundred days is a new problem, it isn't. Sailors have been doing it for centuries.
And discipline had to be enforced with physical brutality, while those doing the disciplining sought solace in alcohol. To put it mildly, neither is an acceptable course nowadays. (Not to mention that routinely being isolated for hundreds of days vanished well over a century ago with the rise of steam power.)
Put a server on board with some quake and a few other video games. Give them all a bunch of contraceptives.
It will be fine. Trust me.
Trust you? Ok, let's put 'em on the table shipmate. I've got four SSBN deterrent patrols - averaging 90 days each.
My experience is it is very hard to assemble a crew, can be hard to maintain discipline, difficult to maintain motivation, etc... etc... across such a time period. Personal friction rises over time, as does depression at being isolated,
What's your experience that lets you speak with authority?
See: Biodome. The failed movie or the failed experiment.
Biosphere 2 was designed by ecological mystics with a minimum of engineering and scientific support to meet specific environmental, ecological, philosophical, and quasi-religious goals. This lead them to make many costly errors;
They tried to leap from a laboratory bench experiment to a full scale operating facility, which lead to many problems.
They were well along in construction before the discovered the windows wouldn't work - resulting a lengthy and expensive delay to develop new windows.
Late in construction they discovered that they hadn't accounted for changes in atmospheric volume due to temperature changes - resulting in the (expensive) last minute addition of the 'lungs'.
They never ran a small scale simulation with animals and insects, or a small scale simulation long enough to allow plants to spread - resulting in the discovery of multiple nasty interactions between the various ecological elements inside Biosphere.
Because of the lengthy delays in construction and the lack of scientific and engineering rigor in the design of the 'experiment' they rushed to perform the first lockout mission - without properly testing and commissioning the facility.
The 'Bionauts' were chosen on the basis of political and philosophical correctness and acceptability rather than being a properly selected and trained team.
Etc... etc... etc..
In short, Biosphere 2 isn't a valid standard to judge such experiments by. Sadly, it was such a highly visible flop and so few people are aware of the reasons why, they've poisoned the well for decades and rendered it difficult for actual scientists and engineers to gain funding and acceptance for such work. As shown by your comment...
[sigh] Search is a fraction of Google's business and data flow. People really need to stop thinking of Google as a search company. It isn't one, and hasn't been in a very long time.
Why does Google need so much server capacity? YouTube? Command completion? GMail spam filtering? Ad serving?
YouTube, Gmail, Google Maps, Google Earth, Blogger, Google Voice, Orkut, Adsense, Adwords, Google Reader, Feedburner, Google Calendar, Google Docs, Google Groups, Google Directory, Google Wave, Google Talk, Picasa, Panoramio, Sketchup 3D Warehouse, iGoogle (Google Homepage), Google Notebook, Google Sites (Jotspot), Knol...
Google is a very busy brand indeed.
I started to make links out of all those, but I'd have been here an hour. Just google them yourself.
"But remember the cautionary note B&N struck six years back when they got out of the e-book business."
A great deal has changed in six years. Small computing has become more ubiquitous with the arrival of the netbook, high capacity flash devices are a lot more common, low power cpu's more common, wireless hot spots vastly more common...
They had a working prototype, they approached Detroit to get their making-cars expertise... and the project gets quickly scrapped for no apparent reason.
The problem being - your link fails to support your claim. It explains how wonderful the invention could be, but doesn't mention Detroit at all.
A civilized nation should provide free education to the highest level each person wishes to attain, because that's part of believing that the nation's most most important resource is its people.
Your conclusion fails to follow from your premise. Paying for someone's degree in Advanced Featherbedding just because they want on does little for the nation but produce yet another idiot with a meaningless degree and a sense of entitlement.
But when a government just wants dumb consumers, then it's a very different matter.
A nice soundbite, but nothing else.
Personally, I think a system that makes people work to pay for their education works just fine. It sorts out the those with the skills and dedication to obtain an advanced education from those without - the same skills and dedication they will hopefully employ in whatever career that education prepares them for.
And to everyone saying its unsecured debt needs to actually look into their facts.
What then are the secured by?
I'll be graduating next summer with a Masters in IT Management. (Undergrad in Simulation Design Engineering) 75k or so in loans, and the year I went to college they jacked up the interest rate to 6.8%.
Based on your posting, I hope I (the taxpayer) didn't pay for your education. If I did, I want my money back. Your writing is atrocious, your grammar worse than mine, and you can't construct an argument properly.
Slashdot Mirror
Pogo is any oscillation along the vehicle's longitudinal thrust/flight axis. It's most familiar form is caused by interactions with liquid fuel, but that's a specific case not the general one.
Pogo in solids attracts much less attention because either the solids are attached to a liquid fueled rocket (and the Pogo is damped in the liquid fuel system) or they are part of a big military rocket, which the general public as well as many space experts are largely unfamiliar with.
You might want to read up on the Ares I and note that is has a liquid second stage.
On top of that, vibrations caused by combustion instabilities occur along all vehicle axes - including the longitudinal (I.E. the 'pogo' axis). Which means you can also get feedback by having combustion instability induced vibrations at a frequency that matches a structural resonance frequency - the same failure mode that destroyed the original Tacoma Narrows Bridge.
It's not a new observation - I first saw it bandied about in the RISKS Digest back in the late 90's as GPS was just then starting to come into wide use.
[Side note: I've heard that William Langewiesche wants to be/is thought of as the next John McPhee. If so, he's moving away from the target - the writing in that article was really bad.]
Its not about the distance, its about the time.
When the time between life and death (to respond to an emergency communication from ATC) can be measured in as little as seconds... Not listening to ATC for forty five minutes can hardly be overblown.
On top of that, if they were concentrating that hard on their laptops for that long they could easily have missed a minor problem on the aircraft that was trending into a major problem. Etc... etc...
Didn't bother with bots - I concentrated on the steak, not the sizzle, and stayed in software. Their being hardware robots rather than software agents doesn't really change the underlying behavior. My agent's behavior was evolved, though they didn't evolve the same behaviors as those in the experiment, they did evolve unique behaviors of their own.
Which is my point, they discovered specific new behaviors that arose because of the specific features of their environment - something long known to occur. Which is why I asked what was new, because there doesn't seem to be anything.
Ok, what did this study teach us that wasn't learned years ago in (for example) Boids (1987), Core War (1984), and Tierra (1991)? I mean, it's cool having little bots running around a tabletop and all, but I was simulating the same behaviors on my '286 back in the mid 90's.
Dries Buytaert reflected on this, adding: 'this is a clear sign that governments realize that Open Source does not pose additional risks compared to proprietary software, and furthermore, that by moving away from proprietary software, they are not being locked into a particular technology, and that they can benefit from the innovation that is the result of thousands of developers collaborating on Drupal.'"
Or, more likely, the PHB in charge is running with Drupal because it's popular and CMS's are faddish right now, or worse yet maybe Drupal is the favorite one-size-fits-all solution of the head techie at the White House.
When you stated it was an "inherent bonus of the design".
You couldn't be much more wrong if you tried. NASA originally proposed flying the Shuttle purely as a passenger and light cargo transport, with the Saturn V being used for the heavy lifting role. The Administration and Congress however shut the door on that plan and refused to fund resumed production of the Saturn V. NASA's 'fixation' on the Shuttle was a cause. Not an effect.
You claimed the features had never been used, I showed they they had been used and are being used today. So, having been shown to be wrong in your facts you now attempt to backpedal and claim they didn't matter anyhow.
Not to mention you are wrong on both counts. There is no one-engine-out 'black zone'. Gemini and Apollo both used aerodynamic cross range extension to obtained extended landing opportunities. Soyuz does as well. Orion (it it's ever built) will too.
And here you indulge in them again, making the false claim that my beliefs are based on my childhood experiences. Which is interesting, because during *my* childhood - Apollo was flying. Shuttle didn't fly until just a few weeks before my high school graduation.
As with the technical end of things, you simply don't know what the fuck you are talking about. You're a parrot who repeats what's he heard without the slightest understanding of what the words mean.
The Shuttle has suffered on LOM accident (the ATO flight, the number escapes me now), and Soyuz has has several (mostly caused by inability to dock with their intended destination). Soyuz has also had two LOM accidents due to launch aborts.
That sounds like my wife when she comes home from shopping with more clothes and shoes she'll never wear... "I saved money, it was on sale!".
No it isn't, not one bit. It requires specific attention to aerodynamics and careful control of the center of gravity - it doesn't 'just happen'. (Keep in mind that RV nosecones, which are the same basic shape as capsules, are stable pointy end forward rather than blunt end forward.)
[remainder of handwaving and smokescreens snipped]
Well, once all that is gone... there isn't much substantive left to reply to. Ah, here's one:
Utter and complete bullshit on both counts. Not only was NASA already moving in the direction of a larger shuttle (needed because of the lack of another booster to launch Shuttle destinations), but the enlarged cross range (oft cited as one of the 'faults' of the 'military influenced' designs) has been routinely used to enlarge abort boundaries and to make available landing opportunities that would would have otherwise been unavailable.
In short, you haven't a clue what you are talking about and don't even have the wit to realize it. You just repeat the bullcrap you've heard elsewhere, and when pointed out that you're wrong - you just repeat it again like a parrot.
Big Macs and Windoze are extremely popular too. They must be (respectively) healthy and tasteful, and secure and viable. After all, the majority agrees.
Yes, historical data is a fact. And the historical data shows that not only has Soyuz had a higher proportion of fatal flights, it also has had an ongoing pattern of significant failures and near fatal accidents. When NASA continues to fly with known bad SRB joints or known significant damage to the heatshield, they are regarded as villains. When the Russians continue to fly despite repeated problems and accidents, they are regarded as heroes.
This tells me your argument is an emotional one, not an engineering one.
Airbags are useful survival and safety features. So, by your logic, if one out of ten of a given model of car suffers failures that lead to an accident where the airbag saves the lives of the passengers, it's a safe car. Or an aircraft that on one out of ten flights suffers explosive decompression and the lives of the passengers are saved by the emergency oxygen masks is a safe aircraft. (On that note, it's worth pointing out that AFAIK those masks have never saved a passengers life - but they have killed 110 people.)
In other words, if you routinely have to depend on safety features, backups, and luck to save your life - that means something is seriously wrong.
In other words, because their game of Russian Roulette hasn't yet killed anyone... We should regard the vehicle as safe. I should point out that NASA did the same with the SRB joints and ET foam shedding.
I should also point out that having a spacecraft which sheds sections also has the failure mode of shedding a section too soon... Which has also happened with Soyuz, and again sheer luck prevented the death of a crew.
Because of pressure from fools who value low cost and pander to the public's desire for the illusion of safety over anything else.
Hoe exactly do you save money by buying two multi billion dollar pieces of hardware to (maybe) save a few hundred million in launch costs?
It's 'common knowledge' that the Soyuz is safer in the same way that it's 'common knowledge' that eating pop rocks and drinking coke will cause your stomach to rupture.
IOW, just because it's 'common knowledge' doesn't mean it is true.
Actually, the facts don;t support that notion.
A few rough ballistic entries? There's been at least five in the last six years, and more before that. (Not to mention that ballistic entries are caused by significant system failures.)
No, it didn't work - in both cases where this happened they were lucky (very lucky) in that the service module burned away and detached before the upper hatch burned through.
Simple engineering - the more chunks you split your payload into, the more complex the resulting assembly becomes (because now you need interfaces between the chunks), the heavier the resulting assembly becomes (because of the connectors between chunks and docking/berthing assemblies), and the greater the chance of fucking something up during building, testing, and on orbit assembly. Then there's simply math - if your rocket has a 98% chance of flight success (about average nowadays), then each launch you add to the manifest means the greater chance one will go awry.
As far as expense goes, you're way off base - rocket costs scale very weakly with size, and very strongly with complexity and the number of man hours required to prep it for launch. (Which is why the Pegasus, despite it's small size and modest payload, is somewhat above the middle of the pack in $/kg to orbit.)
That's the handwaving-and-smokescreen theory. The reality is that economies of scale in manufacturing don't begin to provide significant advantage until you're talking dozens of launches a year. Costs still really don't drop much until you tackle the problem of the standing army required to integrate, checkout, and launch the vehicle - multiple smaller launches can actually cost more in total than one big launch.
That would be a point in favor of multiple smaller chunks - if space hardware could be bought off the shelf like the load of roof trusses I saw dumped all over the median in an accident the other day. But it can't, and won't be for the foreseeable future. This means that losing a portion of the payload is no different than losing the whole payload, either one is game over.
The US is obligated by treaty to minimize space debris, so yes - private industry has been concerned about launch debris and has been for years, lest they not get a launch permit.
You do know that less than half of the launches in the US annually are government launches, and less than half of those are NASA launches?
I take it then, that you've never heard of a URL?
Email and IM haven't gone away have they? Twitter has been around for three years now, and really growing in mindshare and popularity for two. It's not going anywhere.
I predicted the lack of effectiveness back when the story hit Slashdot. I was ignored.
I did recently read two interesting articles; one on the lack of effect from accounts with large numbers of followers, and one speculating that a "tweetbomb" could possibly outshine the impact of the Slashdot Effect.
Because it turned out that so long as spacecraft and spaceflight were like the environments test pilots were used to, strapped into a confined cockpit for a few hours, test pilots were good candidates. Unfortunately, once the Mercury program was over, the nature of the flights started to change (and have changed even more radically since then), and test pilots are no longer a good fit.
And discipline had to be enforced with physical brutality, while those doing the disciplining sought solace in alcohol. To put it mildly, neither is an acceptable course nowadays. (Not to mention that routinely being isolated for hundreds of days vanished well over a century ago with the rise of steam power.)
Trust you? Ok, let's put 'em on the table shipmate. I've got four SSBN deterrent patrols - averaging 90 days each.
My experience is it is very hard to assemble a crew, can be hard to maintain discipline, difficult to maintain motivation, etc... etc... across such a time period. Personal friction rises over time, as does depression at being isolated,
What's your experience that lets you speak with authority?
Biosphere 2 was designed by ecological mystics with a minimum of engineering and scientific support to meet specific environmental, ecological, philosophical, and quasi-religious goals. This lead them to make many costly errors;
Etc... etc... etc..
In short, Biosphere 2 isn't a valid standard to judge such experiments by. Sadly, it was such a highly visible flop and so few people are aware of the reasons why, they've poisoned the well for decades and rendered it difficult for actual scientists and engineers to gain funding and acceptance for such work. As shown by your comment...
[sigh] Search is a fraction of Google's business and data flow. People really need to stop thinking of Google as a search company. It isn't one, and hasn't been in a very long time.
YouTube, Gmail, Google Maps, Google Earth, Blogger, Google Voice, Orkut, Adsense, Adwords, Google Reader, Feedburner, Google Calendar, Google Docs, Google Groups, Google Directory, Google Wave, Google Talk, Picasa, Panoramio, Sketchup 3D Warehouse, iGoogle (Google Homepage), Google Notebook, Google Sites (Jotspot), Knol...
Google is a very busy brand indeed.
I started to make links out of all those, but I'd have been here an hour. Just google them yourself.
"But remember the cautionary note B&N struck six years back when they got out of the e-book business."
A great deal has changed in six years. Small computing has become more ubiquitous with the arrival of the netbook, high capacity flash devices are a lot more common, low power cpu's more common, wireless hot spots vastly more common...
The problem being - your link fails to support your claim. It explains how wonderful the invention could be, but doesn't mention Detroit at all.
Your conclusion fails to follow from your premise. Paying for someone's degree in Advanced Featherbedding just because they want on does little for the nation but produce yet another idiot with a meaningless degree and a sense of entitlement.
A nice soundbite, but nothing else.
Personally, I think a system that makes people work to pay for their education works just fine. It sorts out the those with the skills and dedication to obtain an advanced education from those without - the same skills and dedication they will hopefully employ in whatever career that education prepares them for.
What then are the secured by?
Based on your posting, I hope I (the taxpayer) didn't pay for your education. If I did, I want my money back. Your writing is atrocious, your grammar worse than mine, and you can't construct an argument properly.