why don't space craft burn leaving earth??
817981
As others have said, it's all about speed. \n\nIt's a minor point really, but it's a common misconception that it is the friction with the air that causes objects hitting the Earth's atmosphere at high speed to heat up. Actually it's not friction. The heating up is caused by the fact that the air in front of the object cannot get out of the way fast enough, so it's gets compressed in front of the object. As the air gets compressed the pressure rises and as the pressure rises so does the temperature. This is what causes the burning up effect.\n\nWhen a space craft is blasting off into orbit, as its speed rises it's also gaining altitude. At higher altitudes the atmosphere is less dense, so this compression of the air in front of the space craft never becomes a problem.\n\nIf a space craft used its rockets to slow its decent back to Earth then it wouldn't have any problems with burning up on re-entry. The reason they don't do this is because of the weight of the fuel that would be needed to do it. With current technology, no spacecraft could carry that amount of fuel and still be able to get into orbit.
145934
You need to go from 0 to 11.2 km/s (earths escape velocity) and you need to overcome earths gravitational pull, which is 9.82 N/KG, in order to do so. You are constantly being accelerated downward with one G (9.92 m/s^2). If you would create a force upwards of one G you would hover (0 G). Let´s say you had a rocket engine that could thrust your spaceship upwards with 2 Gs. How long would it take to reach escape velocity? You use the equation t=v/a where v is 11200m/s and a is 9.81m/s^2 and get 1141.7s. You need to accelerate for 19 minutes to reach escape velocity. Would be sweet if you could do that but it is a long time to keep an engine running. Let´s accelerate twice as fast. Put a as 20m/s^2 and you´ll get 560 seconds or 3.3 minutes. \nOK. So now we´re cooking. How much thrust do you need to get this kind of acceleration? It´s another simple equation: F=ma. We have a (20m/s^2). But you also need m that is the mass of the spacecraft. This we can only guess but lets say a tonne (1000 kg). Then it is pushing downwards onto the launch pad with the force of 1 G wich is 9810 N (9.81x1000). We need to overcome this by adding another G to our thrust so a is 3Gs or 29.81m/s^2 (20 + 9.81). Thus we get 29810 N of thrust for 560 seconds to kick that 1 tonne payload into outer space. That´s 40.5 horsepowers to you non-metric folks (go metric already. A pound isn´t alwasy a pound is it? So measuring thrust in pounds isn´t valid). "But wait. Doesn´t that sound a little too sweet? 40.5 hps? My old Dodge can do better than that". That is correct. You also need fuel to make thrust. The fuel adds weight to the spacecraft which means we need more thrust. Whch means the need for more fuel. Also the craft is exposed to alot of drag from the air. More fuel. More weight. The farther you get from earth the less the value of a G gets but the spacecraft uses up fuel which makes up for the amount of force needed for acceleration. And so on. So this little thought experiment can only take us so far but I´ll stop here anyway. Now you got an idea atleast.
469016
Great question.\n\nThe reason that they don't collide is that the moon is moving to fast.\n\nCheck this out- when the space shuttle is up in space it is only about a 100-150 miles up there. Why doesn't it just fall out of the sky and crash into the planet? \n\nWell the answer to why things don't fall out the sky is because they are in orbit- duh-. The space shuttle is not only up in space it is also moving sideways at a tremedous speed. The shuttle IS falling out of the sky, but the reason it doesn't ever hit the ground is all that sideways motion. Everytime it starts falling, the earth has moved out of the way ( sideways- remember) so it changes direction and starts to fall again, well guess what the earth has moved out of the way again. This keeps repeating and repeating. in essence anything in orbit- satelites, moons, and space shuttles are always falling but they never seem to get there. That is why the moon never hits the earth. It's important to remember that just because you are in space does not mean gravity is not pullin you down. I assure you if the shuttle was somehow able to suddenly stop it would fall out the sky like a rock. The reason the people in the space shuttle are floating is because they are falling and not because they are in space.\n\nI just have to add a little more to this statement- You know that in freefall ( you jumped out of a airplane ) you can't feel gravity and there is no up or down or sideways. The same thing with being in orbit since you are always falling you can't feel gravity either. One other thing the people that wrote first on this question really need to double check their facts. The Perfect distance and gravity cancelling out stuff is wrong. The moon could and used to be much closer to earth. It also went around earth much faster, but because of tidal action the moon has slowed down and gone into a farther out orbit. The moon even today is leaving the earth at about three inches a year. It is slowing down and so is our day- our day is getting longer because of the moon
539111
There is a problem with the previous answer... the earth's escape velocity is around 25,000MPH... that number is based on an object without any propulsion, mankind has yet to develop a rocket or other propulsion system that can reach that speed... just wanted to clarify that ;)  we can't hit mach 30 (mach I is 720mph, 22,500mph is about mach 30) yet, but we can leave the earth's gravity field because of continuous propulsion (lots of rocket fuel)
957293
Rockets go at many different speeds depending on the application. A good example is the speed a rocket needs to go when leaving the earth and going into earth orbit. This is called "escape velocity". For rockets leaving the north pole where the spin of the earth is not a factor, the escape velocity is 11.2 km/sec (approx. 25,000 miles per hour).\n\nOnce out of earth orbit, rockets attached to spacecraft may increase speed to reach distant planets. Speed will stay the same until the rocket is ignited. Once the rocket is burning, the speed will continue to increase. Small rocket engines, like "ion engines", with very low but continuous thrust will keep the rocket accelerating for a very long time.
174378
It does, and at the same time, it doesnt, it depends on the situation.\n\nIf you were to take a rocket out so far away from any gravitaitonal fields that they were insignificant and remove any of type of friction/forces acting on the space craft, then it wouldnt need a rocket to continue moving due to Newtons 1st law of motion (inertia).\n\nHowever, in any real, practical, situation, a space craft does need a rocket to keep moving, eventually.\nTake this example.  If you had a space craft in space at the edge of the Earth's atmosphere so that air resistance was negliglible and fire the rockets off initially to start moving but then shut them down.....eventually, then rocket would come to a stop.  This would happen because of Earth's gravitational pull on the rocket, just because something is in space doesnt mean there is no gravity. Gravity acts as the unbalanced force to slow/stop/reverse the space craft, if the rockets arent fired to counter act this, the craft will eventually fall back to Earth.\nThere is a special case to this example, however.  If the space craft were to originally lauch at the escape velocity for Earth, it would never fall back down as that is defined as the minimum velocity needed to escape the Earth's gravitaitonal pull forever, bu this still isnt to say that the craft wont slow down as Earth continues to exert a force on it.\n\nIn space, as with everywhere else in the universe, an object will only maintain a constant velocity if the net force acting on the object is zero.  If there is any force acting on the object (be it due to gravity, friction, whatever), there will be some acceleration which will cause a change in velocity with respect to time.
351366
The earth is continuously bombarded by small cosmic dust particles, ranging in sizes. The bigger onces millimeter size and bigger burn up in the atmosphere of the earth leaving visible traces that may last seconds or longer.
1035230
First of all, it depends on what you need the thruster for. Chemical rockets (solid, liquid, and hybrid) are the only ones with strong enough thrust to get off the Earth, but once you're in orbit even a low continuous thrust will get you where you want to go, if you have the time.\n\nChemical rockets combine fuel and oxidizer to create thrust. Liquid and solid fueled rockets are just what they sound like; hybrids use a solid fuel but a liquid oxidizer to to start and stop the burn. This helps to deal with one of the biggest problems with solid fuel rockets - once they're lit, they can't be shut off. A hybrid can be throttled off just by stopping the flow of oxidizer.\n\nHall effect and ion thrusters are a bit different. They use a fuel (typically a light gas, but there's a particular type that uses solid Teflon) that is ionized and then passed through a magnetic field to accelerate it to very high speeds. The drawback is that the acceleration is very low, so it can't be used to launch off the Earth. The plus is that you don't really need the high thrust of a chemical rocket in space - it just takes you longer to get anywhere. There was a British spacecraft that went from Earth orbit to the Moon using only ion thrusters; it took eighteen months!
628520
Look at how many sattelites we put up... there is something wrong with your reasoning, you're ignoring a lot of the facts.  How is it more difficult now?  A civilian recently built and flew his own spacecraft into space 3 times successfully.  Hundreds of satellites are orbiting the earth as we speak.  How does it seem space travel is more difficult?  We have several astronauts in a spacestation right now... Civilians have purchased tickets into space, the people on the space station have been relieve, replaced, etc multiple times... As far as the moon goes, there really isn't/wasn't any reason to go back, not a whole lot there if ya know what I mean ;)  They're working on mars projects continuously... just because a few landers and orbiters crash doesn't mean things are more difficult.  If you do some research you will find literally hundreds of crashes, mislaunches, explosions, and other quality errors; the old times make the number and degree of current mistakes seem almost trivial.  Science and technology have proven themselves time and time again when it comes to space, and it keeps getting better.
976856
One applied retro answer is that orbittall materials are non\n   solid at present because the burn stage is under study.  The\n   report you need is that solid fuel is the larger producer in space.\n   Solid fuel is theoretically stored in orbit itself.  The great weight\n   study shows that hi weight materials need be atomically \n   numbered to hold reactives at minimum meaning nuclears\n   are not released into exposure to inhabitants.  Fuel gives some\n   spoiled carbons, and activated pollutants and the luck  of\n   recent atomic science has eliminated this weight and blows\n   smoke out the exhaust.  With burn, clean burn, hot burn \n    issues many engines, furnaces, can be compared in package.
1061904
You have confused.space air will not touch the earth.
1082872
The sky's the limit!  Sorry, couldn't resist.\n\nIt really depends on what advances are made in physics and technology.  Right now it looks like it would be very unlikely that man will ever leave the solar system.  The reason for that is because it takes so much energy to push a craft at the speeds necessary to get anywhere in a decent amount of time.  NASA recently launched a tiny, little probe to Pluto, which will take 10 years to arrive.  To send a crew of people that far, a much larger craft would be needed to support the life systems, which means far more energy would be required to push it.  The energy source would further increase the mass of the craft and increase the energy requirements, etc.\n\nI think our best bet with "conventional" technology would be to send a suicide mission to Alpha Centauri (the next-nearest star).  I don't know what the point would be of sending humans there, but it could be done over a period of maybe 100 years.  The original astronauts might not make it, but they could have children or grandchildren during the voyage who could reach the star.\n\nIf scientists ever figure out how to create and travel through wormholes or other theoretical means, then there's really no limit to how far we can go.
709262
Don't forget that large bodies like the earth itself, and the sun, are themselves held together with gravity.\n\nProbably the first thing that we would notice is that the earth would immediately lose its atmosphere as it went flying off the planet into space, as would the oceans.  Everything on the surface of the planet would go flying off due to the centrifugal force of its spinning ... buildings would just rip off their foundations like cheese shaking off a cheese-puff.  Without an atmosphere, it's doubtful you and I would live more than 15 or 30 seconds.\n\nThe earth  would immediately break apart in a big cloud of hot liquid iron (the core of the earth) and all the stuff on the surface.\n\nThe moon would also disolve into a huge cloud of hot rocks and sand.\n\nThe sun would explode rather violently, as the pressure from the burning of the inner core would suddenly have no force counteracting it.  The same would be happening to every star and planet in the universe.  And galaxies themselves would fly apart (as they too are held together with gravity).\n\nAnd yes, what is left of the earth would fly away from what is left of the sun ... although it would be quickly overtaken by the exploding sun.\n\nBut, of course, it ain't gonna happen.  I'll bet everything I own on it.  :-)  \n\nThink of this as a great way to get back in with your girlfriend ... "Hey baby, if gravity were suddenly to disappear, we need to be holdin' each other really tight!"  (You take it from there).
322590
You do not possibly have enough information to answer this question properly, you need to know, where it is at, how far from the sun, like the others said, is there a planet or any obstacle between it and the sun, what is it's current temp, so on and so on....here is something about tempature in space though\n\nEmpty space itself cannot have a temperature, unless you mean some abstruse question about quantum vacuums.\n\nHowever, if you put a physical object into space, it will reach a temperature that depends on how efficiently it absorbs and emits radiation and on what heating sources are nearby.  For example, an object that both absorbs and emits perfectly, put at the Earth's distance from the Sun, will reach a temperature of about 280 K or 7 C. If it is shielded from the Sun but exposed to interplanetary and interstellar radiation, it reaches about 5 K.  If it were far from all stars and galaxies, it would come into librium with the microwave background at about 2.7 K. Spacecraft (and spacewalking astronauts) often run a bit hotter than 280 K because they generate internal energy.
661933
The thrust of rocket engines are how ships are controlled in space.  Many of the forces that affect air ships (drag, lift, gravity) do not apply since you specified no air or gravity.\n\nTechnically, air ships don't go to space, so there's no real answer to this question.  Richard Branson's Space Ship One recently flew to the edge of space and then landed like a plane, but (as the name indicates) it was a space ship, not an air ship.\n\nAnd there are air and gravity in space.  Gravity holds galaxies, separated by millions of light years, together, so gravity will definitely act on space ships only 100 or 200 miles above the earth.  What causes weightlessness in orbit is not a lack of gravity, but free fall.  The atmoshere is very, very thin at the altitudes where satellites and the shuttle fly, but it is that thin air, causing frictional drag on satellites and the space station, that require constant reboosting to keep them in orbit.\n\nKey to effective flight and control is stabilization, so in addition to moving and turning a ship in space, thrusters also are used to keep it from spinning (reaction wheels also are used for this function).
647242
A rocket doesn't have to fly a certain speed to leave the earth.  A rocket has an engine which means that it needs no minimum speed to get out of the earth's gravitational field.  Escape velocity is based on an object which will not be experiencing powered flight.  A rock thrown upward from the ground will need an initial velocity of 11.2km/s upwards to leave the gravitational field of earth.  A rocket needs to go just fast enough to continue moving (assuming a VERY large amount of fuel to continue engine burn for this duration).
835630
There are no real inertial speeds in space like there are on earth! Humans can travel at any speed relative to the solar systems planets! Whether you are travelling at 500kph or 500.000kph! you would not notice the difference in space! But you would on the earth! So deep space travel is possible, for humans, but to sustain them with food and water! is another thing! A power source! is another problem, Plus! They have to stop when they get to where they are going. So the energy they have built up in speed has to be 'Bled off' as they approach their target! Another problem man has not yet worked out, is space debris! you hit something at 500.000kph! even the size of a marble! and it will go straight through you! the spacecraft! and anyone standing behind you when it hits!!! And that is assuming that the marble is just hanging in space! It could be doing a couple of million kph, it's self!!!! So space is much more formidable than you think!