For the simple stuff, there are wind tunnels. For everything else, there's computers.
Wrong. For simple stuff there are computers, for everything else there's wind tunnels. Just because a computer can model something, does not mean we know how to model it.
Exactly true. These behemoths are low speed. Great for testing large (and full-scale models), but poor for testing at the speeds that the private and military sectors want to see.
"Surely it doesn't cost that much to run". It incurs a cost to run, and yes it would be nice for science to keep open, but if it's running in negative dollars maybe it needs to go.
As a wide-eyed recent Aerospace Engineering graduate, I rest assure that this is NOT being closed because of numerical methods. As for many other engineering fields, numerical methods help a lot, but one simply cannot replace real-life testing. Simulation, while helpful, simply is nowhere CLOSE to replacing wind tunnels. Numerical methods won't replace us, they will help us.
I think that there are some misconceptions about nuclear power for space propulsion. It seems that people are imagining nuclear warheads or nuclear reactors. Nuclear space propulsion ideas typically rely on power harnessed from the natural decay of radioactive isotopes. It's still very much of a conceptual technology, however.
Features don't sell software for me. Getting from point A to point B as easiest as possible is what sells to me. That's why I choose Windows over Linux. Innovation, bells and whistles, "well our open source software isn't sold by the super evil MS" don't sell to me. Make it easy, and I would use Linux because it is free (and marginally more secure).
Lift and drag are proportional to 1/2*density of fluid*surface area*Velocity squared. (L, D ~ 1/2*rho*S*V^2).
A lifting surface generates no lift in a vacuum, thus the need for reaction mass in space. As air thickens, a lifting surface generates more lift, so much so that my plane flies noticably better in the winter than the summer, simply because colder air is generally more dense than warmer air at the same barametric pressure and altitude.
The effect is much more pronounced in water because of density, not viscosity.
No very ridiculous. Drag force is typically proportional to the square of the velocity. This thing apparently moves at 1 knot. Reductions in speed save you quite a bit of energy, actually. Viscosity becomes a player at higher speeds.
The "slingshot effect" is only useful for trajectory changes. It allows one to save fuel when changing directions. Due to conservation of energy, when you approach a planet and slingshot away from it, you end up with the same velocity on the way out as the way in. You will accelerate as you approach a planet, but you will decelerate the same amount on the way out.
It's extremely hard to test at supersonic speeds because supersonic wind tunnels are designed for a specific mach number. The geometry of the wind tunnel must be changed if a new supersonic mach speed is desired. Most supersonic wind tunnels have multiple test sections, each designed for a specific speed. Because of the nature of supersonic flow, the wind tunnel geometry must be "right" at each supersonic speed in order to ensure wave-free, "clean flow". Otherwise, any data collected is useless. As for testing at a sonic speed (mach = 1), that is extremely hard. The *only* place in a wind tunnel where the mach number can be one is at the throat (in a converging/diverging nozzle). Note that adding heat will always drive flow towards mach 1 (regardless of supersonic or subsonic flow). The only way to accelerate flow once it has reached mach one in a wind tunnel is a cross secional area increase. Wind tunnels are not developed so that one could place a test piece at the throat of the tunnel (I've never heard of one that is.)
sonic booms- concorde at Mach 2 gives big bangs for tens of miles; Mach 27+ sonic booms are going to reach hundreds or thousands of miles
Sonic booms occur at mach 1.
Orbital mechanics issues: to a reasonable approximation anything fired from the earth,
still intersects the earths orbit twice per year, and takes a year to complete 1 orbit. You have to fire it quite fast to avoid this issue. It takes a LOT of speed to fire something from the earth and get it to impact the Sun; off-hand you'd need maybe Mach 32 or so
If you change the eccentricity and inclination of the orbit a little, it most likely won't intersect earth orbit. It's not necessarily the speed that you need to get it to impact into the sun, it's the delta V. Once you escaped earth, one would have to slow the craft considerably from earth's orbit speed to make the orbit intersect the sun.
There's always a lot of talk of shooting nuclear waste into the sun and/or into space as an alternative to underground storage. Over the past 30 years, 77,000,000 lbs (35,000,000 kg) of nuclear waste (from reactors) has been created. Rockets commonly used today for space launches (Atlas, Delta, Titan, etc) can put about 4,000 - 5000 lbs into an earth escape trajectory.
Give these numbers, that would require about 15,400 launches to get the nuclear waste off the earth and out of earth orbit. The rockets that we would most likely use for this have a failure rate of about %5. This would make about 800 failures. 800 failures in which 5000 lbs of nuclear waste could potentially be spread into the atmosphere and the air.
I know these numbers are just numbers, and statistics are just statistics, but I think it shows that the risks for launching nuclear waste into space are unacceptable.
Since there's no resistivity, that means that calculations will be almost instantaneous, right? And it will have very low power consumption, no waste heat, and be incredibly small?
So this sort of thing could easily mean that we could have tiny computers that run for a long time on a single battery and are ninety billion times better than anything we currently have, right?
Sounds like magic to me. If it's too good to be true, it probably is.
It seems a lot of open source programs do in fact have little error handling. Most open source programs seem to focus on functionality, rather than usability. It gets you from point A to point B, and doesn't give you much help in between. If the user is not a master programmer, any errors usually end up being cryptic and nonsensical. It seems that a lot of commercial software has decent error recovery, and prevents user error effectively. Now I know there are many exceptions, but I think it simply has to do with the fact that commercial programmers get paid to do their work, and competition forces companies to put out products that are competitively usable.
Are you people never satisfied? You complain about how narrow minded people are, and when they change thier stance so that it aligns with yours, you complain that they change their stance. I can understand the distrust. However, blasting people that join your side doesn't do much to help your cause.
You've *had* to play through some stinkers now and then? Yes, it is indeed awful when a bad game comes out. Ignoring and and not caring about it is very hard.
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For the simple stuff, there are wind tunnels. For everything else, there's computers.
Wrong. For simple stuff there are computers, for everything else there's wind tunnels. Just because a computer can model something, does not mean we know how to model it.
Exactly true. These behemoths are low speed. Great for testing large (and full-scale models), but poor for testing at the speeds that the private and military sectors want to see.
"Surely it doesn't cost that much to run". It incurs a cost to run, and yes it would be nice for science to keep open, but if it's running in negative dollars maybe it needs to go.
As a wide-eyed recent Aerospace Engineering graduate, I rest assure that this is NOT being closed because of numerical methods. As for many other engineering fields, numerical methods help a lot, but one simply cannot replace real-life testing. Simulation, while helpful, simply is nowhere CLOSE to replacing wind tunnels. Numerical methods won't replace us, they will help us.
Why do people feel the need to romanticize hacking? Do people need to validate the fact that they are programmers?
Some people love to do what they do and may have a skilled hand at it, but that does not make it like painting.
It's interesting how the knee-jerk reaction to the letters "DRM" completely disappears with the input of Linus.
Normally I wouldn't mind, but once you've studied latin it's hard to avoid the urge to call it 'virii'.
If you had actually studied Latin, you'd know that the latin plural of "virus" is not "virii".
Come on, if it's an honest mistake and you are an honest person, why would you insist on robbing them?
The U.S. is planning to sit around and watch.
Are we supposed to go do it again? Considering we did this four decades ago?
I think that there are some misconceptions about nuclear power for space propulsion. It seems that people are imagining nuclear warheads or nuclear reactors. Nuclear space propulsion ideas typically rely on power harnessed from the natural decay of radioactive isotopes. It's still very much of a conceptual technology, however.
Features don't sell software for me. Getting from point A to point B as easiest as possible is what sells to me. That's why I choose Windows over Linux. Innovation, bells and whistles, "well our open source software isn't sold by the super evil MS" don't sell to me. Make it easy, and I would use Linux because it is free (and marginally more secure).
How could it possibly be theft if I don't click on ads, ever?
Some artillery shells have attitude control systems.
Umm... anyone know how that is supposed to happen?
Magic.
Lift and drag are proportional to 1/2*density of fluid*surface area*Velocity squared. (L, D ~ 1/2*rho*S*V^2).
A lifting surface generates no lift in a vacuum, thus the need for reaction mass in space. As air thickens, a lifting surface generates more lift, so much so that my plane flies noticably better in the winter than the summer, simply because colder air is generally more dense than warmer air at the same barametric pressure and altitude.
The effect is much more pronounced in water because of density, not viscosity.
No very ridiculous. Drag force is typically proportional to the square of the velocity. This thing apparently moves at 1 knot. Reductions in speed save you quite a bit of energy, actually. Viscosity becomes a player at higher speeds.
The "slingshot effect" is only useful for trajectory changes. It allows one to save fuel when changing directions. Due to conservation of energy, when you approach a planet and slingshot away from it, you end up with the same velocity on the way out as the way in. You will accelerate as you approach a planet, but you will decelerate the same amount on the way out.
It's extremely hard to test at supersonic speeds because supersonic wind tunnels are designed for a specific mach number. The geometry of the wind tunnel must be changed if a new supersonic mach speed is desired. Most supersonic wind tunnels have multiple test sections, each designed for a specific speed. Because of the nature of supersonic flow, the wind tunnel geometry must be "right" at each supersonic speed in order to ensure wave-free, "clean flow". Otherwise, any data collected is useless. As for testing at a sonic speed (mach = 1), that is extremely hard. The *only* place in a wind tunnel where the mach number can be one is at the throat (in a converging/diverging nozzle). Note that adding heat will always drive flow towards mach 1 (regardless of supersonic or subsonic flow). The only way to accelerate flow once it has reached mach one in a wind tunnel is a cross secional area increase. Wind tunnels are not developed so that one could place a test piece at the throat of the tunnel (I've never heard of one that is.)
Yes, heaven forbid something produced by Microsoft actually be useful and/or well written.
None of the satellites currently in orbit achieved escape velocity (about 15 miles per second).
sonic booms- concorde at Mach 2 gives big bangs for tens of miles; Mach 27+ sonic booms are going to reach hundreds or thousands of miles
Sonic booms occur at mach 1.
Orbital mechanics issues: to a reasonable approximation anything fired from the earth, still intersects the earths orbit twice per year, and takes a year to complete 1 orbit. You have to fire it quite fast to avoid this issue. It takes a LOT of speed to fire something from the earth and get it to impact the Sun; off-hand you'd need maybe Mach 32 or so
If you change the eccentricity and inclination of the orbit a little, it most likely won't intersect earth orbit. It's not necessarily the speed that you need to get it to impact into the sun, it's the delta V. Once you escaped earth, one would have to slow the craft considerably from earth's orbit speed to make the orbit intersect the sun.
There's always a lot of talk of shooting nuclear waste into the sun and/or into space as an alternative to underground storage. Over the past 30 years, 77,000,000 lbs (35,000,000 kg) of nuclear waste (from reactors) has been created. Rockets commonly used today for space launches (Atlas, Delta, Titan, etc) can put about 4,000 - 5000 lbs into an earth escape trajectory.
Give these numbers, that would require about 15,400 launches to get the nuclear waste off the earth and out of earth orbit. The rockets that we would most likely use for this have a failure rate of about %5. This would make about 800 failures. 800 failures in which 5000 lbs of nuclear waste could potentially be spread into the atmosphere and the air.
I know these numbers are just numbers, and statistics are just statistics, but I think it shows that the risks for launching nuclear waste into space are unacceptable.
250,000 is a quarter million I believe. I guess quality and functionality are a function the amount of code, eh?
Since there's no resistivity, that means that calculations will be almost instantaneous, right? And it will have very low power consumption, no waste heat, and be incredibly small?
So this sort of thing could easily mean that we could have tiny computers that run for a long time on a single battery and are ninety billion times better than anything we currently have, right?
Sounds like magic to me. If it's too good to be true, it probably is.
It seems a lot of open source programs do in fact have little error handling. Most open source programs seem to focus on functionality, rather than usability. It gets you from point A to point B, and doesn't give you much help in between. If the user is not a master programmer, any errors usually end up being cryptic and nonsensical. It seems that a lot of commercial software has decent error recovery, and prevents user error effectively. Now I know there are many exceptions, but I think it simply has to do with the fact that commercial programmers get paid to do their work, and competition forces companies to put out products that are competitively usable.
Are you people never satisfied? You complain about how narrow minded people are, and when they change thier stance so that it aligns with yours, you complain that they change their stance. I can understand the distrust. However, blasting people that join your side doesn't do much to help your cause.
You've *had* to play through some stinkers now and then? Yes, it is indeed awful when a bad game comes out. Ignoring and and not caring about it is very hard.