Space probes/satellites also are sensitive enough to rely on leap-seconds. If you dilute these by breaking them up throughout the day, figuring out ephemerides would be complicated.
Sure, if it's fast enough. Solar powered aircraft tend to be driven by large, slow-turning propellers. Even commercial jet aircraft typically can't beat the Sun from the eastern US to the west, so I doubt we'll be seeing such a solar powered aircraft anytime soon.
The ISS is inclined at 51.6 degrees relative to the equator (this was the lowest inclinations the Russians can get to from Balkanor without a costly plane-change maneuver)
For us, going to ISS is somewhat less efficient because we have to launch on a northerly azimuth out of the Cape instead of due east, which would maximize the 'boost' from the earth's rotation.
In short, the ISS is a research lab, not really a truck stop. Going there wastes propellant.
And while the CM and lander might be able to be designed to fit in the shuttle bay, the earth departure stage to push them to the moon is very large. Getting to lunar orbit in 9 hours is impressive for such a small vehicle, but it didn't have to enter lunar orbit, it just flew by. Slowing down to enter orbit takes a lot of propellant if you want to get there fast (have a high relative velocity)
Aren't pretty much all low-speed aerodynamics based on this? Isn't this pretty similar to the Kutta Condition? (Air tends to leave a sharp edge parallel to that edge).
If air didn't stick to smooth leading edges, aircraft could never get enough L/D to fly subsonic.
I find Fortran90/95 pretty nice to program in. It's still lacking in string manipulation (Fortran was never really designed for that and can't compete with Perl or Python) and exception handling would be nice.
Of course, its probably largely the lack of such features that contributes to the execution speed of Fortran.
Well bias your altitude reading. Essentially raise the altitude of what the aircraft understands to be ground level. That way, if you come in at 400 ft +/-300 ft, you should be OK.
Here are the issues I can see with these replacing satellites:
1. What about night? These things are going to be unable to see the sun for several hours every day, instead of two days a year. You need to size the batteries to be capable of handling that period. That much weight on a solar aircraft would be difficult.
2. Wear and tear. High altitude aircraft will have to deal with high altitude winds, and have motors running constantly. You can bring them down to service them, but what if they crash. How often will that happen? Geosats are built to last for 10 years on average.
3. Maintainence. What are the operations costs of a fleet of these vehicles vs. a fleet of satellites.
I would expect high altitude blimps to be a more cost effective replacement for satellites, although I dont think the satellite industry has anything to worry about for another few decades.
When I bought my HDTV, I considered all technologies available for under $3500 or so. The diversity in techologies here is a good thing, because it gives the consumer more choice.
Plasma: Wall-mountable, visible pixel grid, burn-in, more expensive for a given size
DLP: Not wall mountable, typically no visible pixel grid, no burn in, requires periodic bulb replacement, rainbows for some people.
LCD RP: Not wall mountable, visible pixel grid, no burn in, requires periodic bulb replacement, issues with dead pixels
That was pretty much led me to choose DLP. The pixel grid issues are getting better, and I've never seen rainbowing on my DLP, but I gather thats an issue with the viewer as much as it is with the television.
In short, I don't want a technology to 'win' because then it hampers my choice and I may be stuck with issues I'd rather avoid.
VBA was a nice basic language for doing simple calculations. The fact that it was inside Excel meant we had access to quick 2D visualization, pretty good organization via a spreadsheet, and some of Excel's better tools like Solver.
We can do everything outside of Excel, but you lose the quick user interface unless you go to something more expensive like MATLAB.
Doesn't matter how many you fire. Theres no guarantee the next one will work.
I saw a graphic of launch insurance costs for commercial satellites a few months ago, the costs are really spiralling out of control. But until we have a space elevator or anti-gravity, riding an explosion of chemicals to orbit is the best system we got.
I'm sure you've probably already read it, but Dive Into Python (http://diveintopython.org) Is a great starting point, in conjunction with the references at python.org.
As far as humor in learning sources, I enjoy the subtle humor in many Oreilly books. But this is over-the-top, not funny, and worst of all, not informative.
I'm not arguing they may be more suseptable, but I hope your "fall from the sky" quote is figurative.
GPS satellites are in 12 hour orbits, high enough that they probably wont EVER fall from the sky, save a conservative guess of a few millenia.
Dead satellites keep orbiting. Every geostationary bird is still up there. The one caveat is there are a few "graveyards" where the gravitational field of the earth makes them less suseptable to longitudinal drift. Most of these birds are moved to the 'graveyards' when theyre almost out of propellant, to keep them from interfering with new birds and to keep the geostationary slots relatively clear.
I'm not aware of any plans to keep Medium-Earth-Orbit (MEO) satellites like the GPS birds in disposal orbits after their useful lifespans.
There are many tools that NASA has developed that fall under International Trafficing-in-Arms (ITAR) restrictions, which essentially means theyre restricted to being deployed to US nationals only. Generally, software that is useful for putting spacecraft on target can also be useful for putting missiles on target.
Theres also the issue of civil service vs. contractor development, as was already mentioned. JPL has developed a lot of fine software, but since they are a semi-private organization that needs profits to operate, they charge (sometimes a great deal) for their software to prevent competing entities (such as APL) from grabbing their work for free.
And patent squatting, or whatever you care to call it when a company sits on a patent without utilizing it, simply to stifle competition, should be illegal.
Its great that most macros work independent of operating system. But the debugging environment is far superior on Office for Windows (variable watches, etc). Also, there are some odd differences in a few places (FileFind vs. FileSearch, for instance) that can be accounted for but don't seem necessary on the surface.
Slashdot Mirror
Space probes/satellites also are sensitive enough to rely on leap-seconds. If you dilute these by breaking them up throughout the day, figuring out ephemerides would be complicated.
Can anyone code up a knife that allows me to cut a portal in space-time between two worlds?
Sure, if it's fast enough. Solar powered aircraft tend to be driven by large, slow-turning propellers. Even commercial jet aircraft typically can't beat the Sun from the eastern US to the west, so I doubt we'll be seeing such a solar powered aircraft anytime soon.
The ISS is inclined at 51.6 degrees relative to the equator (this was the lowest inclinations the Russians can get to from Balkanor without a costly plane-change maneuver)
For us, going to ISS is somewhat less efficient because we have to launch on a northerly azimuth out of the Cape instead of due east, which would maximize the 'boost' from the earth's rotation.
In short, the ISS is a research lab, not really a truck stop. Going there wastes propellant.
And while the CM and lander might be able to be designed to fit in the shuttle bay, the earth departure stage to push them to the moon is very large. Getting to lunar orbit in 9 hours is impressive for such a small vehicle, but it didn't have to enter lunar orbit, it just flew by. Slowing down to enter orbit takes a lot of propellant if you want to get there fast (have a high relative velocity)
Nothing except an MBA in physics
Aren't pretty much all low-speed aerodynamics based on this? Isn't this pretty similar to the Kutta Condition? (Air tends to leave a sharp edge parallel to that edge).
If air didn't stick to smooth leading edges, aircraft could never get enough L/D to fly subsonic.
Flying Cars + GPS + central redundant navigation systems
We'll have flying cars. People just wont be allowed to control them themselves, except for maybe an emergency landing mode.
As a bonus, we could call the central control system 'Skynet'
I find Fortran90/95 pretty nice to program in. It's still lacking in string manipulation (Fortran was never really designed for that and can't compete with Perl or Python) and exception handling would be nice.
Of course, its probably largely the lack of such features that contributes to the execution speed of Fortran.
Well bias your altitude reading. Essentially raise the altitude of what the aircraft understands to be ground level. That way, if you come in at 400 ft +/-300 ft, you should be OK.
Just have a servo deploy a parachute when youre above your landing site. Then you can forgive a few hundred feet of accuracy in altitude.
Here are the issues I can see with these replacing satellites:
1. What about night? These things are going to be unable to see the sun for several hours every day, instead of two days a year. You need to size the batteries to be capable of handling that period. That much weight on a solar aircraft would be difficult.
2. Wear and tear. High altitude aircraft will have to deal with high altitude winds, and have motors running constantly. You can bring them down to service them, but what if they crash. How often will that happen? Geosats are built to last for 10 years on average.
3. Maintainence. What are the operations costs of a fleet of these vehicles vs. a fleet of satellites.
I would expect high altitude blimps to be a more cost effective replacement for satellites, although I dont think the satellite industry has anything to worry about for another few decades.
Why not formulate some voting/moderation system to keep malicious content at bay?
Anyone is allowed to add anything. If the section they add is modded down enough, they wont be able to mod as much for the next month.
Changing/removing existing sections should be more difficult. The more modded-up a section, the harder it is to change.
When I bought my HDTV, I considered all technologies available for under $3500 or so. The diversity in techologies here is a good thing, because it gives the consumer more choice.
Plasma: Wall-mountable, visible pixel grid, burn-in, more expensive for a given size
DLP: Not wall mountable, typically no visible pixel grid, no burn in, requires periodic bulb replacement, rainbows for some people.
LCD RP: Not wall mountable, visible pixel grid, no burn in, requires periodic bulb replacement, issues with dead pixels
That was pretty much led me to choose DLP. The pixel grid issues are getting better, and I've never seen rainbowing on my DLP, but I gather thats an issue with the viewer as much as it is with the television.
In short, I don't want a technology to 'win' because then it hampers my choice and I may be stuck with issues I'd rather avoid.
VBA was a nice basic language for doing simple calculations. The fact that it was inside Excel meant we had access to quick 2D visualization, pretty good organization via a spreadsheet, and some of Excel's better tools like Solver.
We can do everything outside of Excel, but you lose the quick user interface unless you go to something more expensive like MATLAB.
Doesn't matter how many you fire. Theres no guarantee the next one will work.
I saw a graphic of launch insurance costs for commercial satellites a few months ago, the costs are really spiralling out of control. But until we have a space elevator or anti-gravity, riding an explosion of chemicals to orbit is the best system we got.
Theyre already getting paid! Companies that use more bandwidth have to pay more. Its already like that.
As as the previous commenteur said, any charge from verizon comes back to you. You wouldn't seriously expect the provider to just eat it would you?
They've exceeded their lifetime many times over! Its absolutely astounding that you'd call it a hitch that they have an expected end-of-life.
Are you still driving a 1984 Pinto in mint condition or something?
Can't. I work for NASA. Can't vote for a party that thinks the government has no role in research.
I'm sure you've probably already read it, but Dive Into Python (http://diveintopython.org) Is a great starting point, in conjunction with the references at python.org.
As far as humor in learning sources, I enjoy the subtle humor in many Oreilly books. But this is over-the-top, not funny, and worst of all, not informative.
I'm not arguing they may be more suseptable, but I hope your "fall from the sky" quote is figurative.
GPS satellites are in 12 hour orbits, high enough that they probably wont EVER fall from the sky, save a conservative guess of a few millenia.
Dead satellites keep orbiting. Every geostationary bird is still up there. The one caveat is there are a few "graveyards" where the gravitational field of the earth makes them less suseptable to longitudinal drift. Most of these birds are moved to the 'graveyards' when theyre almost out of propellant, to keep them from interfering with new birds and to keep the geostationary slots relatively clear.
I'm not aware of any plans to keep Medium-Earth-Orbit (MEO) satellites like the GPS birds in disposal orbits after their useful lifespans.
I'd love to have the sensation of pulling G's while flying a flight simulator.
There are many tools that NASA has developed that fall under International Trafficing-in-Arms (ITAR) restrictions, which essentially means theyre restricted to being deployed to US nationals only. Generally, software that is useful for putting spacecraft on target can also be useful for putting missiles on target.
Theres also the issue of civil service vs. contractor development, as was already mentioned. JPL has developed a lot of fine software, but since they are a semi-private organization that needs profits to operate, they charge (sometimes a great deal) for their software to prevent competing entities (such as APL) from grabbing their work for free.
Its not uncommon in the commercial launch business. Launches are so expensive that full-up testing is usually infeasible without a paying customer.
And patent squatting, or whatever you care to call it when a company sits on a patent without utilizing it, simply to stifle competition, should be illegal.
Its great that most macros work independent of operating system. But the debugging environment is far superior on Office for Windows (variable watches, etc). Also, there are some odd differences in a few places (FileFind vs. FileSearch, for instance) that can be accounted for but don't seem necessary on the surface.