Civilian planes don't have military power; a likely aircraft for this would be an older Boeing 7x7.
The article said that the rocket would be ejected by compressed air. This means that gravity doesn't have to do the job, and the spacecraft and carrier plane will have what is known as "positive separation".
A shift in attitude at such altitudes wouldn't be a big deal; there is plenty of airspeed and time to recover even if the wing is stalled. The two things that have to be respected are maneuvering speed (the indicated airspeed below which the wing will stall before the airframe is overloaded), and that the worst-case upset doesn't move the aircraft to an attitude from which it cannot be recovered.
Ejecting a center-mounted load directly rearward isn't going to apply a yaw torque, so a spin is extremely unlikely (a spin requires an asymmetrical stall condition in the first place).
Just some questionable wisdom from a pleasure pilot.
The change in CG is temporary. If the rocket is ejected by compressed air at 1 G, it will be 145 feet behind its starting point in 3 seconds. The pilot can apply down-elevator to compensate for this, but it's probably not necessary. It may not even be desirable, as you want the rocket sliding out the back of the aircraft smoothly and not hanging up due to torque forces. For that scenario you could begin by flying a small arc with the nose pitching downward just as ejection begins, reverse the pitch change during ejection, and then pitch down again after ejection. Really figuring this out needs a bunch of aircraft experts with a good computer simulation, not a single-engine-land guy with a physics habit doing hand-waving on Slashdot.
It's been done many times; it's called a "rockoon". It doesn't work so well for heavier rockets, though; high-altitude balloons can't support very much weight per unit volume. Launching the balloons can be a real challenge too.
Larger than the current birds which can be sent up by Pegasus, for sure.
A Pegasus is carried under one wing, where it presents an asymmetrical load. There is only so much that an aircraft can carry that way. Its drag is also asymmetrical, and there are ground-clearance and interference drag issues. This limits how fast the carrier aircraft can fly, how high it can go before launch, and even if it can get off the ground with a heavier load (if it can't rotate to takeoff attitude without scraping the rocket's tail on the ground, you can't take off).
Putting the rocket inside the aircraft creates one problem, which is a mechanism to extend the wing; there may also be some issues with drag from the modified cargo doors. Other than that it's all positive:
The weight is carried in the center, where it is symmetrical.
Nothing extends beyond the aircraft; there are no new difficulties with ground clearance.
Drag isn't changed much, so the aircraft can launch the spacecraft from a greater speed and altitude. This improves the spacecraft's performance and carrying capacity to orbit.
While the price drop probably isn't enough to create much new market for launch services, it's a good start.
I guesstimated based on 8 pounds/ft^3, forgetting that it should be 8 lb/gallon and roughly 62 lbs/ft^3. I almost posted a correction, but I figured that someone would do it for me.
Let's see. If you live in a nice, wet place where you get 30 inches of rainfall per year, and 1000 square feet of roof, that's 2500 cubic feet of water. Call it 20,000 pounds. If the roof is 20 feet above the ground, that makes 400,000 foot-pounds of work per year. I make that out to be about 540 kJ/year, or about 150 watt-hours; over the course of a year you'd be able to run a 20-watt compact fluorescent for a bit less than 8 hours (assuming no losses in conversion).
A 40 watt-peak solar panel on the roof would be able to run the same light for 8 hours a day, most days. The roof would accomodate quite a few of those panels. You can build your gutter-micro-hydro systems. Please do, I can always use a good laugh!
... sez the guy who assumes the nome de plume of a group known for singing songs about Star Trek. Come set foot in the real world for a while, willya?
Solar and wind energy should be a bigger focus, but we lack an efficient transport and storage mechanism. We obviously don't have enough of an incentive to develop these technologies. dino-oil is cheap.
Not so obviously (you have to know what you're talking about), you're wrong. There is a huge market for energy-storage technologies which are lighter, cheaper, longer-lived and more compact than what we have now. There's a host of devices, from computers to phones to PDAs, which would benefit from these things. So far we are still stuck with prices where a little Li-ion battery holding ten watt-hours or so costs tens of dollars. Lifespan is a few years or a few thousand charges. Charging takes a large fraction of an hour, at best.
I thought we'd finally broken that barrier when NEC announced the proton polymer battery last year; with its power density, freedom from heavy metals, 5-minute charge time and a lifespan in the tens of thousands of cycles, it was a dream come true. Unfortunately, that may have been a flash in the pan. I have been looking for more news about this thing, and found nothing. It just goes to prove that transporting and storing electricity efficiently is hard.
Someday when we have a global power grid that efficiently moves energy between the continents, we will be able to produce peak-time energy for the other side of the globe and vice versa. for now i'm happily releasing nasty hydrocarbons to power my computer
And you're not going to change your habits in case that never comes about. I believe that makes you part of the problem. Quelle surprise.
If planning permission is granted Britain will more than double its renewable energy capacity. Environmental campaigners say a new generation of nuclear power stations may not then need to be built.
Why not eliminate an older generation of coal-fired plants instead, and eliminate their carbon emissions? Wind cannot replace nuclear by itself, because there is no cheap way to store wind power. There will remain a need for constant supplies of power to feed the base load, and that power will have to come from some kind of energy store such as fossil fuel or nuclear. The only one of these which doesn't emit CO2 is, of course, nuclear. Given the concern over global warming I am amazed that elimination of nuclear power is still a Green priority; it is vastly easier to sequester a few thousand tons of spent fuel every year than billions of tons of diffuse gas.
...put Oil and Gas fired plants on current offshore drilling platforms so the energy is being transported not the oil and we won't have to worry about another Exxon Valdez disaster.
The problem with that is that you are throwing a lot of the energy away. If you need space heat instead of light, converting the fuel to electricity on a platform loses 50% or more; you can't use cogeneration to improve your return on a given amount of fuel, either.
The real penalty would be in transport energy. We currently use oil because it makes fuels which are compact and easily transported. If you convert the fuel to electricity on the platform you have to convert the entire vehicle fleet to batteries, with all the range limitations this implies. You also lose all the flexibility you get with pipelines and storage tanks; if you lose one cable, you can wipe out a large part of the transport network as well as the industry and whatnot. Storable fuels provide a valuable buffer against supply and transport disruptions, and any nation which ignores this in a push to go "green" is risking trouble on a scale which would make California's blackouts look trivial.
You do realize that beer is made by other microorganisms (yeast), so the consumption of beer by bacteria is just making things a little more equal between the producers and consumers?
You imply that the author is somehow stealing from society by extracting monopoly rents. Firstly, individuals in society purchase the author's creation of their own free will. One must conclude that these individuals are extracting more value from the creation they borrow than what they pay, for if it were not so they wouldn't purchase the invention. Hence, I don't think anyone is being exploited.
Aside from noting that you're confusing physical property (which exists in reality; only one person can have or use it at a time) and "intellectual property" (which is a legal construct, as it has no such limitations), I'll ask you if you're also demanding that society provide its courts and police to IP owners for free in perpetuity, if society is allowed to demand property taxes on the value of the IP in return for these services, and exactly how it benefits society to allow such monopoly rents to go on to the Nth generation of heirs to the creator while the rest of society pays the on-going costs of making certain that they aren't infringing and the opportunity costs of avoiding the use of such items which they cannot justify the cost of researching and paying for.
I'd also like you to say what the incentive would be to make new inventions, when one could live off the old ones in perpetuity. Whither progress?
My argument is that all copyright should be strictly enforced because it is the creation of another individual that is not your slave. I wouldn't even have expiration limits on copyright or patents. Think about the incentives that creates in a marketplace.
In your personal opinion, who should be receiving royalties from sales of the Iliad and wheels? How about screws, gears, nails, the gasoline carburetor?
At what point, if ever, does society have a right to say that the author/inventor has received enough and no longer has the right to use the police and courts to extract monopoly rents from the rest of society?
I hate to make "me too" posts, but that was very much worth reading and I'd like to thank Zeio for the effort. (This is posted without a +1 bonus to keep it under the radar of people reading at +2, and anyone reading at +1 probably doesn't mind a little fluff.)
DeCSS is a somewhat more gray area, but it still basically allowed people to steal.
I have hands. Hands allow me to pick pockets. Should possession of hands be grounds for prosecution, or should liability only extend to the actual crime?
We would not so glorify those who would publish plans for robbing bank vaults, and yet we take men like Sklyarov who delight in playing a sort of twisted Robin Hood and turn them into our heroes.
Bad analogy, faulty reasoning. Consider it a "weapon control" issue, where a manufacturer of kitchen knives tries to prevent violent people from carving up their family members by making the knife work only on a special cutting board, and only when they are on the specific kitchen counter to which they are registered. No more stabbing-kiddies-in-their-beds crimes in the newspapers, yay!
Then the cheaply-made cutting board breaks. Or you move. Suddenly your knife doesn't work, and you have to buy all-new cutlery so you can do your basic cooking tasks. Not so good any more, is it? Thing is, if you had $200 invested in a good set of knives, wouldn't it be worth $99 to get a gadget that would let you use the knives as you want to? Aren't the people really bent on mayhem (or theft) going to find a way to do their dirty work no matter how many silly legal obstacles you put in their way?
People, the capitalism that it seems the majority of people here are trying to undermine is the same system which produced all this high-quality content in the first place.
I know you're playing Devil's Advocate, but I'd take issue with this. I subscribe to Sturgeon's Law, with Spamalamadingdong's corollary: Sturgeon was an optimist (an hour listening to Top 40 radio will confirm this to any open-minded person). I don't see that the work of Mozart, or Beethoven, or Debussie, or Ellington was impaired in the slightest by the lack of the DMCA, and I don't think we need such absurd hoarding of authority by publishers today any more than we did then.
... why not drive them down to the karate school instead?
Maybe it would be good for the kids to be able to have fun with their favorite games and get exercise at the same time, while saving gasoline and wear and tear on the parental units. Class a few times a week isn't enough exercise for most people. --
The poster mentioned nothing about cleaning up Earth before going to space. It would be nice if you could keep your responses pertinent to the parent.
This Pluto mission is beginning to look a lot like our Halley mission: underfunded, behind the schedule set by Nature, and fated to be cancelled instead of launched. At that, the poster has a decent argument: research dollars are scarce enough that we should spend them on missions which will actually fly.
Not that I agree that this means we should bypass Pluto. On the contrary, I think we should gear up to go ASAP. Something like the DS-1 propulsion system, perhaps with improved concentrators, might do the trick; while nuclear is the natural choice for anything going that far from old Sol, I don't think we're going to see it. Heck, if these things can be done cheap enough we should launch two, or even three; redundancy never hurt anyone's chances. --
The Long-EZ has a Vne (never-exceed speed) far below Mach 1, and no thermal protection system. Even if you can keep the speed down on the way up through the atmosphere (losing velocity to gravity every second), once you have boosted to space you are coming down again on a ballistic trajectory until there's enough air to make your aerodynamic devices effective again. It only takes a drop of about 3 miles to break Mach 1; the edge of space is considered to be at 50 miles. The Long-EZ airframe isn't going to cut it for that trip. --
be nicer to have the starving suffering people fed first, but hey....
Maybe we need to hook at least some of the governments, business and schools up to the global information network so that they can communicate well enough to feed the starving (meaning, hook the starving up with the opportunities they need to feed themselves). The world grows enough food to feed everyone, but enough is lost due to failure to store and transport it that people suffer. Information is a big part of fixing that particular problem. --
You can't use HTML tags in Slashdot subject lines. I assume this means you can't use the < and > characters, either. If you want to use either character, you have to write it as < or >. --
I was just listening to the CBC today and they were going on about how the effects of Toronto's urban sprawl (the second fastest growing city in N-A) should be asssisted by having better transit systems in place.
That's when this discussion came back to me and it occured to me that if nothing else, N.A. governments should be subsidising mass transit a lot more than they do.
The problem with mass-transit is that it is rightfully perceived as inconvenient, time-consuming, and oftimes dangerous. Rail is horribly expensive to buy right of way, and the planning is usually ten years out of date at best; buses move no faster than the rest of the traffic on the road, and you have to accept whatever route they run whether it goes where you need to or not. Then there's crime.
People prefer private automobiles for a reason. Unless the mass transit offers a large advantage (or loses some of its disadvantages), people will still prefer to use private automobiles. Given that preference, changing the automobile will probably do more to eliminate greenhouse emissions than changing the subsidies for buses and trains (except at the very bottom end of the economic spectrum, where people can't afford a great deal of anything). At the very least you won't be trying to fight people's desire for independence and a personal "cocoon" against unpleasant or even hostile elements and/or people.
(This is one of my complaints about the "watermelons", who are green on the outside and red on the inside. They claim to be concerned about the environment, but their proposals for addressing environmental issues all involve re-shaping society in their preferred image - and that in turn causes the environmental message to be resisted, even rejected outright.)
Consider the effects if major urban centres in North America had fast and efficient mass transit service to and from the surrounding areas...
Consider the population density and pedestrian-unfriendliness of most suburbs, plus the increasing change of commuting patterns from suburb-downtown to suburb-suburb. Now ask yourself if people will need to use their cars anyway, and once in them if they will get out of them before they've arrived where they want to go. --
But he also implies that protecting children from say pornography is bad.
"Protecting" them, as if looking at pictures of people without any clothes on will hurt them.
American society (especially the so-called Christians who haven't figured out that the gospels are about love and tolerance) needs to figure out that if we were meant to run around naked we would have been born that way. On the other hand, I haven't seen any society which has been improved by the elevation of casual violence to a public spectacle, and the desensitization to death by showing people tens of thousands of simulated killings before the age of 18. If you asked me if Big Brother or a standard fsck-and-suck porn flick were more likely to mess up a kid, I'd have to review them both but I bet I'd vote for Big Brother... and I'll bet a majority of psych professionals would agree with my appraisal. --
It is quite possible, and even likely, that the right solution to any given problem won't be necessarily profitable.
That's why I said "make it pay", not "it pays".
This is usually fixed by giving tax credits to those who do what the populace considers to be the 'right things' and heavily tax those who do the 'wrong things' to give a money incentive.
I have long been a fan of carbon taxes for exactly this reason. CO2 is fungible; there is no difference between a pound of CO2 emitted in India from a coal fire and a pound of CO2 from a natural-gas-fired turbine in California, so far as the environment is concerned. Tax the release of fixed carbon and you've taken care of that.
It would be nice, of course, if companies and individuals operated for the common good inherently, but we don't:-(
Individuals and companies can't, if the rules of the game ignore the external costs; if doing the right thing is suicide, people and companies will do the wrong thing out of necessity. As I said, make it pay and people will automatically choose the right thing. --
Wouldn't be too hard to write something that automatically finds and interpolates over them.
... because that's what the plain-Jane CD players do, and usually in hardware. Doing it with software should be a piece of cake.
The biggest problem is probably going to be modding rippers like CD Paranoia to give up on the deliberate errors and continue with the rest of the rip. --
Slashdot Mirror
Not when it was flown by a B-52, it wasn't. I see that that's changed.
- Civilian planes don't have military power; a likely aircraft for this would be an older Boeing 7x7.
- The article said that the rocket would be ejected by compressed air. This means that gravity doesn't have to do the job, and the spacecraft and carrier plane will have what is known as "positive separation".
- A shift in attitude at such altitudes wouldn't be a big deal; there is plenty of airspeed and time to recover even if the wing is stalled. The two things that have to be respected are maneuvering speed (the indicated airspeed below which the wing will stall before the airframe is overloaded), and that the worst-case upset doesn't move the aircraft to an attitude from which it cannot be recovered.
- Ejecting a center-mounted load directly rearward isn't going to apply a yaw torque, so a spin is extremely unlikely (a spin requires an asymmetrical stall condition in the first place).
Just some questionable wisdom from a pleasure pilot.The change in CG is temporary. If the rocket is ejected by compressed air at 1 G, it will be 145 feet behind its starting point in 3 seconds. The pilot can apply down-elevator to compensate for this, but it's probably not necessary. It may not even be desirable, as you want the rocket sliding out the back of the aircraft smoothly and not hanging up due to torque forces. For that scenario you could begin by flying a small arc with the nose pitching downward just as ejection begins, reverse the pitch change during ejection, and then pitch down again after ejection. Really figuring this out needs a bunch of aircraft experts with a good computer simulation, not a single-engine-land guy with a physics habit doing hand-waving on Slashdot.
It's been done many times; it's called a "rockoon". It doesn't work so well for heavier rockets, though; high-altitude balloons can't support very much weight per unit volume. Launching the balloons can be a real challenge too.
A Pegasus is carried under one wing, where it presents an asymmetrical load. There is only so much that an aircraft can carry that way. Its drag is also asymmetrical, and there are ground-clearance and interference drag issues. This limits how fast the carrier aircraft can fly, how high it can go before launch, and even if it can get off the ground with a heavier load (if it can't rotate to takeoff attitude without scraping the rocket's tail on the ground, you can't take off).
Putting the rocket inside the aircraft creates one problem, which is a mechanism to extend the wing; there may also be some issues with drag from the modified cargo doors. Other than that it's all positive:
- The weight is carried in the center, where it is symmetrical.
- Nothing extends beyond the aircraft; there are no new difficulties with ground clearance.
- Drag isn't changed much, so the aircraft can launch the spacecraft from a greater speed and altitude. This improves the spacecraft's performance and carrying capacity to orbit.
While the price drop probably isn't enough to create much new market for launch services, it's a good start.I guesstimated based on 8 pounds/ft^3, forgetting that it should be 8 lb/gallon and roughly 62 lbs/ft^3. I almost posted a correction, but I figured that someone would do it for me.
A 40 watt-peak solar panel on the roof would be able to run the same light for 8 hours a day, most days. The roof would accomodate quite a few of those panels. You can build your gutter-micro-hydro systems. Please do, I can always use a good laugh!
I thought we'd finally broken that barrier when NEC announced the proton polymer battery last year; with its power density, freedom from heavy metals, 5-minute charge time and a lifespan in the tens of thousands of cycles, it was a dream come true. Unfortunately, that may have been a flash in the pan. I have been looking for more news about this thing, and found nothing. It just goes to prove that transporting and storing electricity efficiently is hard.
And you're not going to change your habits in case that never comes about. I believe that makes you part of the problem. Quelle surprise.The real penalty would be in transport energy. We currently use oil because it makes fuels which are compact and easily transported. If you convert the fuel to electricity on the platform you have to convert the entire vehicle fleet to batteries, with all the range limitations this implies. You also lose all the flexibility you get with pipelines and storage tanks; if you lose one cable, you can wipe out a large part of the transport network as well as the industry and whatnot. Storable fuels provide a valuable buffer against supply and transport disruptions, and any nation which ignores this in a push to go "green" is risking trouble on a scale which would make California's blackouts look trivial.
(Yeah, I'm back. Maybe.)
I'd also like you to say what the incentive would be to make new inventions, when one could live off the old ones in perpetuity. Whither progress?
At what point, if ever, does society have a right to say that the author/inventor has received enough and no longer has the right to use the police and courts to extract monopoly rents from the rest of society?
This is one of the better posts on the issue thus far, and rates an "Insightful".
I hate to make "me too" posts, but that was very much worth reading and I'd like to thank Zeio for the effort. (This is posted without a +1 bonus to keep it under the radar of people reading at +2, and anyone reading at +1 probably doesn't mind a little fluff.)
Then the cheaply-made cutting board breaks. Or you move. Suddenly your knife doesn't work, and you have to buy all-new cutlery so you can do your basic cooking tasks. Not so good any more, is it? Thing is, if you had $200 invested in a good set of knives, wouldn't it be worth $99 to get a gadget that would let you use the knives as you want to? Aren't the people really bent on mayhem (or theft) going to find a way to do their dirty work no matter how many silly legal obstacles you put in their way?
I know you're playing Devil's Advocate, but I'd take issue with this. I subscribe to Sturgeon's Law, with Spamalamadingdong's corollary: Sturgeon was an optimist (an hour listening to Top 40 radio will confirm this to any open-minded person). I don't see that the work of Mozart, or Beethoven, or Debussie, or Ellington was impaired in the slightest by the lack of the DMCA, and I don't think we need such absurd hoarding of authority by publishers today any more than we did then.--
This Pluto mission is beginning to look a lot like our Halley mission: underfunded, behind the schedule set by Nature, and fated to be cancelled instead of launched. At that, the poster has a decent argument: research dollars are scarce enough that we should spend them on missions which will actually fly.
Not that I agree that this means we should bypass Pluto. On the contrary, I think we should gear up to go ASAP. Something like the DS-1 propulsion system, perhaps with improved concentrators, might do the trick; while nuclear is the natural choice for anything going that far from old Sol, I don't think we're going to see it. Heck, if these things can be done cheap enough we should launch two, or even three; redundancy never hurt anyone's chances.
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The Long-EZ has a Vne (never-exceed speed) far below Mach 1, and no thermal protection system. Even if you can keep the speed down on the way up through the atmosphere (losing velocity to gravity every second), once you have boosted to space you are coming down again on a ballistic trajectory until there's enough air to make your aerodynamic devices effective again. It only takes a drop of about 3 miles to break Mach 1; the edge of space is considered to be at 50 miles. The Long-EZ airframe isn't going to cut it for that trip.
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You can't use HTML tags in Slashdot subject lines. I assume this means you can't use the < and > characters, either. If you want to use either character, you have to write it as < or >.
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People prefer private automobiles for a reason. Unless the mass transit offers a large advantage (or loses some of its disadvantages), people will still prefer to use private automobiles. Given that preference, changing the automobile will probably do more to eliminate greenhouse emissions than changing the subsidies for buses and trains (except at the very bottom end of the economic spectrum, where people can't afford a great deal of anything). At the very least you won't be trying to fight people's desire for independence and a personal "cocoon" against unpleasant or even hostile elements and/or people.
(This is one of my complaints about the "watermelons", who are green on the outside and red on the inside. They claim to be concerned about the environment, but their proposals for addressing environmental issues all involve re-shaping society in their preferred image - and that in turn causes the environmental message to be resisted, even rejected outright.)
Consider the population density and pedestrian-unfriendliness of most suburbs, plus the increasing change of commuting patterns from suburb-downtown to suburb-suburb. Now ask yourself if people will need to use their cars anyway, and once in them if they will get out of them before they've arrived where they want to go.--
American society (especially the so-called Christians who haven't figured out that the gospels are about love and tolerance) needs to figure out that if we were meant to run around naked we would have been born that way. On the other hand, I haven't seen any society which has been improved by the elevation of casual violence to a public spectacle, and the desensitization to death by showing people tens of thousands of simulated killings before the age of 18. If you asked me if Big Brother or a standard fsck-and-suck porn flick were more likely to mess up a kid, I'd have to review them both but I bet I'd vote for Big Brother... and I'll bet a majority of psych professionals would agree with my appraisal.
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