3: communication satalites are geostationary bu there very nature
Not necessarily. Some Russian comm sats use highly elliptical orbits which spent most of their time over Russia and then quickly pass over the other side of Earth (their perigee is over the Antarctic, and apogee of orbit is over Russia). A common such orbit is called Molniya and has a period of 12 hours at high inclinations (often 63.4 degrees) with respect to the equator. These are good because there is better visibility of the satellite at high lattitudes.
Any directional antenna (i.e. a "dish") can transmit and receive. You need a licence to transmit at a given wavelength range. Therefore in order to have an uplink you will need licence from FCC, unless rules are changed or you use a public wavelength. Also, it will not be that easy to listen to uplink info since your direcitonal antenna would have strong signal only in a narrow beam pointed at the satellite.
In my uni they just hire a bunch of upper level undergrads to grade the assignments for intro CS classes (the ones with lots of people). They pay them like $7/hour and free pizza during all-night grading sessions. Sometimes you just demo your program to the consultant, in the computer lab assigned for the class. Such a demo is good because then you have no excuse for it not working. FYI for the intro CS class they use CodeWarrior here too, but for other CS classes it's either Visual Studio or gcc/g++ and I've has classes where YOU PICK YOUR LANGUAGE OF CHOICE! How cool is that.
They will not always burn fully so it must be ensured that what is left falls somewhere into a safe zone, like the ocean for example. Deorbiting something with a target drop zone in mind is not exactly trivial.
How about Bell Atlantic becoming Verizon? I keep trying to imagine a VERtical horIZON, even though this is probably not what it stands for. To think that someone got paid millions to come up with that name. Probably the same lame company that came up with Agilent.
I was talking about the default constructor for Hashtable in JDK1.3 : A call to new Hashtable() will just call new Hashtable(11, 0.75) IIRC.
Also, you got me wrong about the growing of size. I said it grows *BY* (size+1). This means that if the old size was sz, the new one will be sz+(sz+1)==2*sz+1.
So we both meant the same thing.
Default size for Java Hashtable is 11 and grows by (size+1) every time it needs resizing. Surely you can afford to allocate 11 pointers == 44 bytes when only your virtual machine takes ~20 megs.
No. You would need an oxidizer (like, erm, oxygen) so that there will be some sort of chemical reaction going on. Like ethanol + oxygen makes water and carbon dioxide, i.e. good for propulsion, since they produce large amounts of hot gas.
If chemical rockets were hard to come by, but there were still a big market for getting stuff up into space, wouldn't it just accelerate the development of more efficient launch systems? This will only provide less of an incentive to improve.
There is a certain amount of energy required to get something into orbit. Chemical rockets may not have the best of efficiencies -- ~90% of their mass is fuel which you must accelerate as well, but the other alternatives are currently not that viable. Nuclear rockets are a possibility, but people don't like the sound of the word "nuclear". These are estimated to have a specific impulse of at least 850, compared to 420 for H2-O2. (Specific impulse is impulse per unit mass of fuel). The thing is that there are people ready to pay the price for chemical rockets to send stuff to sapce right now and there is currently no better way to do it.
Actually hydrazine is usually not used as launch fuel, but as fuel for change of orbits and in general as attitude control fuel. For launches kerosene-oxygen is common (apart from hydrigen-oxygen) which produces carbon dioxide and water. Solid fuel boosters are the dirty ones, but for LEO satellites they are usually not necessary.
Low earth orbit is about 5000 mph. Also, most pieces travel along the same direction - west to east orbit. So the relative velocities of objects are not even that much.
I think by vectors they mean long arrays of power-time and power-frequency data on which they apply Fourier and other transforms. This is not exactly the same as graphics where you need to apply a perspective xform to many 3d vectors and then rasterize a bunch of polygons.
(4) Rockets aren't exactly green machines either. Pump our oceans full of chemicals? I don't think so.
Big rockets are usually powered by liquid hydrogen and oxygen. The end result is water. Smaller ones may use RP1 (kerosene) and liquid oxyden but the end result of this is still water, plus carbon dioxide. None of these are toxic. Solid fuel boosters usually use some sort of nitrogen compound and the end result is some sort of nitogen oxide, which is also non-toxic (mostly that is, some particular compounds of N and O are called laughing gas IIRC and they make you errr, happy when you inhale). In general most chemical rocket boosters are quite environmentally friendly.
Privacy is not a "right"; it is an encumberment to freedom.
You mean I am free to watch you doing it with your girlfriend and you preventing me from looking is an encumberment to MY freedom? Give me a break. Privacy is a right (defined by law in some countries by the way).
Plutonium is a good to use for a power source. It is not used in a nuclear reaction, but its temperature is used to generate electricity by making a thermocouple between the plutonium and the space around. It's good because it's halflife (81 years IIRC) is suitable for medium term missions outside the orbit of Mars. It is dangerous (deadly actually) if you inhale plutonium dust, but when it is in solid pelletized form it can't cause much damage, if you don't get too close. The Russians have crashed plutonium power generators a bunch of times and have recovered the power package mostly intact and posing no danger.
And, the smart software to control space probes and spot signs of life! That's rich. While we're at it lets write some software to create world peace and feed the masses!
Actually autonomous navigation software is pretty advanced and getting better all the time. All NASA spacecraft have by spec a certain period of time that they have to be able to survive unattended, because communication is usually not maintained all the time. Deep Space I, which is a current mission testing new technologies has very advanced autonomous navigation software and in fact its star sensor (the main navigation tool) failed but it is still operational because they were able to completely reprogram the craft to use its multipurpose science camera for navigation. It's cool stuff. I know you are a troll but whatever.
is that the article says that only the vital signs monitoring communications were overloaded. I'm assuming when those are received, they are forwarded over the network to the NASA medical teams and that's where the cracker came into play, by consuming a lot of bandwidth. Other communications including telemetry are probably not sent over the same communication channels, so there was no danger of the cracker taking control of the shuttle like many people above speculate.
a) It does not have enough fuel to slow down enough. It's orbital velocity is now very fast.
b)It has thrusters, but it does not have enough fuel for the thrusters. You cannot stop something dead in space. Do you know how much fuel would be needed to stop its orbiting the center of the galaxy?
This thing has become so radioactive that here on earth nobody would even want to get close to it. Are you saying that you want to bring 10 tons of highly radioactive stuff to crashland on Earth?
Besides Galileo does not have enough fuel to get back here.
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3: communication satalites are geostationary bu there very nature
Not necessarily. Some Russian comm sats use highly elliptical orbits which spent most of their time over Russia and then quickly pass over the other side of Earth (their perigee is over the Antarctic, and apogee of orbit is over Russia). A common such orbit is called Molniya and has a period of 12 hours at high inclinations (often 63.4 degrees) with respect to the equator. These are good because there is better visibility of the satellite at high lattitudes.
Any directional antenna (i.e. a "dish") can transmit and receive. You need a licence to transmit at a given wavelength range. Therefore in order to have an uplink you will need licence from FCC, unless rules are changed or you use a public wavelength. Also, it will not be that easy to listen to uplink info since your direcitonal antenna would have strong signal only in a narrow beam pointed at the satellite.
In my uni they just hire a bunch of upper level undergrads to grade the assignments for intro CS classes (the ones with lots of people). They pay them like $7/hour and free pizza during all-night grading sessions. Sometimes you just demo your program to the consultant, in the computer lab assigned for the class. Such a demo is good because then you have no excuse for it not working.
FYI for the intro CS class they use CodeWarrior here too, but for other CS classes it's either Visual Studio or gcc/g++ and I've has classes where YOU PICK YOUR LANGUAGE OF CHOICE! How cool is that.
the largest non-steerable radio telescope remains Arecibo at 1000 feet diameter.
They had initially planned to launch 77 (hence the name Iridiuam, chemical element 77) but they launched 66, the remaining 11 left as spares.
They will not always burn fully so it must be ensured that what is left falls somewhere into a safe zone, like the ocean for example. Deorbiting something with a target drop zone in mind is not exactly trivial.
How about Bell Atlantic becoming Verizon? I keep trying to imagine a VERtical horIZON, even though this is probably not what it stands for. To think that someone got paid millions to come up with that name. Probably the same lame company that came up with Agilent.
It's boron nitride (BN), not nitrate.
I was talking about the default constructor for Hashtable in JDK1.3 : A call to new Hashtable() will just call new Hashtable(11, 0.75) IIRC. Also, you got me wrong about the growing of size. I said it grows *BY* (size+1). This means that if the old size was sz, the new one will be sz+(sz+1)==2*sz+1.
So we both meant the same thing.
Default size for Java Hashtable is 11 and grows by (size+1) every time it needs resizing. Surely you can afford to allocate 11 pointers == 44 bytes when only your virtual machine takes ~20 megs.
No. You would need an oxidizer (like, erm, oxygen) so that there will be some sort of chemical reaction going on. Like ethanol + oxygen makes water and carbon dioxide, i.e. good for propulsion, since they produce large amounts of hot gas.
You are right. I did my caluclation in miles per second.
If chemical rockets were hard to come by, but there were still a big market for getting stuff up into space, wouldn't it just accelerate the development of more efficient launch systems? This will only provide less of an incentive to improve.
There is a certain amount of energy required to get something into orbit. Chemical rockets may not have the best of efficiencies -- ~90% of their mass is fuel which you must accelerate as well, but the other alternatives are currently not that viable. Nuclear rockets are a possibility, but people don't like the sound of the word "nuclear". These are estimated to have a specific impulse of at least 850, compared to 420 for H2-O2. (Specific impulse is impulse per unit mass of fuel). The thing is that there are people ready to pay the price for chemical rockets to send stuff to sapce right now and there is currently no better way to do it.
Actually hydrazine is usually not used as launch fuel, but as fuel for change of orbits and in general as attitude control fuel. For launches kerosene-oxygen is common (apart from hydrigen-oxygen) which produces carbon dioxide and water. Solid fuel boosters are the dirty ones, but for LEO satellites they are usually not necessary.
Low earth orbit is about 5000 mph. Also, most pieces travel along the same direction - west to east orbit. So the relative velocities of objects are not even that much.
I think by vectors they mean long arrays of power-time and power-frequency data on which they apply Fourier and other transforms. This is not exactly the same as graphics where you need to apply a perspective xform to many 3d vectors and then rasterize a bunch of polygons.
(4) Rockets aren't exactly green machines either. Pump our oceans full of chemicals? I don't think so.
Big rockets are usually powered by liquid hydrogen and oxygen. The end result is water. Smaller ones may use RP1 (kerosene) and liquid oxyden but the end result of this is still water, plus carbon dioxide. None of these are toxic. Solid fuel boosters usually use some sort of nitrogen compound and the end result is some sort of nitogen oxide, which is also non-toxic (mostly that is, some particular compounds of N and O are called laughing gas IIRC and they make you errr, happy when you inhale).
In general most chemical rocket boosters are quite environmentally friendly.
Privacy is not a "right"; it is an encumberment to freedom.
You mean I am free to watch you doing it with your girlfriend and you preventing me from looking is an encumberment to MY freedom? Give me a break. Privacy is a right (defined by law in some countries by the way).
Plutonium is a good to use for a power source. It is not used in a nuclear reaction, but its temperature is used to generate electricity by making a thermocouple between the plutonium and the space around. It's good because it's halflife (81 years IIRC) is suitable for medium term missions outside the orbit of Mars. It is dangerous (deadly actually) if you inhale plutonium dust, but when it is in solid pelletized form it can't cause much damage, if you don't get too close. The Russians have crashed plutonium power generators a bunch of times and have recovered the power package mostly intact and posing no danger.
And, the smart software to control space probes and spot signs of life! That's rich. While we're at it lets write some software to create world peace and feed the masses!
Actually autonomous navigation software is pretty advanced and getting better all the time. All NASA spacecraft have by spec a certain period of time that they have to be able to survive unattended, because communication is usually not maintained all the time. Deep Space I, which is a current mission testing new technologies has very advanced autonomous navigation software and in fact its star sensor (the main navigation tool) failed but it is still operational because they were able to completely reprogram the craft to use its multipurpose science camera for navigation. It's cool stuff. I know you are a troll but whatever.
It would be too long to wait for a proper betting pool, but any guesses as to how long it will be before they try this in space?
I've heard that the Russians tried it in the 50s, but back then there weren't materials that are light enough, so it didn't work as well.
I guess they are like NaN in Java -- no two NaN's are the same (i.e. == will never return true and you have to use equals() to compare them).
is that the article says that only the vital signs monitoring communications were overloaded. I'm assuming when those are received, they are forwarded over the network to the NASA medical teams and that's where the cracker came into play, by consuming a lot of bandwidth. Other communications including telemetry are probably not sent over the same communication channels, so there was no danger of the cracker taking control of the shuttle like many people above speculate.
a) It does not have enough fuel to slow down enough. It's orbital velocity is now very fast.
b)It has thrusters, but it does not have enough fuel for the thrusters. You cannot stop something dead in space. Do you know how much fuel would be needed to stop its orbiting the center of the galaxy?
This thing has become so radioactive that here on earth nobody would even want to get close to it. Are you saying that you want to bring 10 tons of highly radioactive stuff to crashland on Earth?
Besides Galileo does not have enough fuel to get back here.