I am curious with the mechanism, how space shuttle can fly to the moon, does it fly following the track which is calculated first (like auto pilot or something) or the gravity itself which give the path to the space shuttle\n\nthx
207948
The Space Shuttle can’t fly to the Moon—it only makes it about one five-hundredth of the way there, to low Earth orbit—because it doesn’t have the sheer thruster-power required to do so.\n\nIf you were to design a mission to the Moon, though, you’d need to use a carefully-calculated trajectory that takes into account the gravitational effects (and the mutual motions) of both Earth and the Moon.  The first step is to escape Earth’s gravity enough to head toward the Moon (and not just into a different orbit around Earth), so you fire your thrusters to change your velocity.  Then you need to aim for where the Moon will be (’cuz it’s constantly in motion around Earth, remember).  And then you have to enter orbit around the Moon, firing your thrusters again to position yourself properly in orbit.\n\nThat’s one way.\n\nESA’s SMART-1 spacecraft took a somewhat different approach.  It’s a lightweight ship that was launched with several other satellites into a geostationary orbit—about 50 times higher than the Shuttle flies.  Except that SMART-1 didn’t “circularize” its orbit like the other satellites; instead, it pushed itself into an orbit that took it very close to Earth then very far away.  Engineers timed the spacecraft’s most distant passes to take advantage of the Moon’s gravitational attraction, and eventually, SMART-1 nudged itself into orbit around the Moon.  In this case, very little thrust was used on the part of the spacecraft, so it could allow gravity to do most of the work.\n\nIn short, engineers tend to plan spacecraft trajectories very carefully, using a combination of thrust and gravity to get a ship exactly where they want it.\n\n\nRyan Wyatt\nRose Center for Earth & Space\nNew York, New York
331689
The Shuttle was only ever meant to be used to go into orbit.  The grand idea behind the shuttle program was to use it as a taxi/moving van to get people and cargo into orbit.  Once there, spacecraft to go to the moon and other planets would be assembled from parts brought by the Shuttle, much as is being done with the International Space Station.\n\nThe references to the Shuttle taking astronauts to other planets and beyond was in reference to the Shuttle's being a stepping stone and advancement as a reusable transportation system.
348449
A camera was mounted on the leg of the lander.  It was activated upon landing.\n\n1) Twelve 12 American astronauts have walked on the moon.\n\nApollo 11: Neil Armstrong & Buzz Aldrin\nApollo 12: Pete Conrad & Alan Bean\nApollo 13: << failed to land on the moon >>\nApollo 14: Alan Shepard & Edgar (Ed) Mitchell\nApollo 15: David Scott & James Irwin\nApollo 16: John Young & Charles Duke\nApollo 17: Eugene (Gene) Cernan & Harrison Schmidt\n\n\n2) Why haven't we been back?  \n\na) American astronauts visited the moon on six occasions.\n\nb) The "moon race" was an extension of the cold war. It was mostly about national prestige. We got there first and achieved our primary objective. There was some good science: surveys, measurements, sample collection. But it was mostly about being there first. Once we achieved our primary objective, there was no political will to go back. There still isn't.  Perhaps, if we discover He3 or something else valuable, there will be.\n\nc) I used to travel to Crested Butte, Colorado every year to ski. Because I don't go anymore, does it mean that I never went?\n\n\n3) What about the Van Allen radiation belts?  Wouldn't it have killed the astronauts?\n\nThe existence of the Van Allen radiation belts postulated in the 1940s by Nicholas Christofilos.  Their existence was confirmed in *1958* by the Explorer I satellite launched by the USA. \n\nThe radiation in the Van Allen radiation belts is not particularly strong.  You would have to hang out there for a week or so in order to get radiation sickness.  And, because the radiation is not particularly strong, a few millimeters of metal is all that is required for protection.  "An object satellite shielded by 3 mm of aluminum will receive about 2500 rem (25 Sv) per *year*."\n\n"In practice, Apollo astronauts who travelled to the moon spent very little time in the belts and received a harmless dose. [6]. Nevertheless NASA deliberately timed Apollo launches, and used lunar transfer orbits that only skirted the edge of the belt over the equator to minimise the radiation."  When the astronauts returned to Earth, their dosimeters showed that they had received about as much radiation as a couple of medical X-rays.\n\n\n4) The U.S. government scammed everyone?  \n\nIn 1972, there was a politically motivated burglary of a hotel room in the Watergate Hotel in Washington, D.C. There were only about six or eight people who knew about it. However, those people, including Richard M. Nixon, the President of the United States, failed to keep that burglary a secret. It exploded into a scandal that drove the President and a number of others from office.\n\nIf six or eight people couldn't keep a hotel room burglary a secret, then how could literally thousands of people could have kept their mouths shut about six faked moon landings? Not just one moon landing, but six of them!\n\n\n5) What about the USSR?  \n\nEven if NASA and other government agencies could have faked the six moon landings well enough to fool the general public, they could NOT have fooled the space agency or military intelligence types in the USSR. The Soviets were just dying to beat us. If the landings were faked, the Soviets would have re-engineered their N-1 booster and landed on the moon just to prove what liars Americans are. Why didn't they? Because the landings were real and the Soviets knew it.\n\n\n6) Why does the flag shake?  Where are the stars?\n\nTake a look at the first two websites listed below.  They deal well with all of the technical questions.\n\n\n7) Finally, please tell us what you would accept as definitive evidence that the six moon landings were real. Is there anything?
60014
To use the gravitational sling, all that NASA is doing is using the well known principles of celestial mechanics and orbits. Both the parabolic and hyperbolic orbits will enable a space vehicle to pass by gravitational body and escape. This requires some computing of course, but it is not that hard to do. One just needs to aim the craft in the right direction at the right speed. \n\nEven more interesting is the use of the chaos method. One can save energy by using chaos theory to send vehicles to distant objects. This is a bit less obvious than the "slingshot" or gravity assist, and is described in the first reference (I met and listened to some lectures by the chaos method's inventor; very interesting). NASA might be starting to use this method now that it has been proven by the Japanese and Europeans. NASA's JPL really hated the method when it first came out and fired the guy who invented it. He now is a tenured professor at Princeton. \n\n2. There are lots of power sources for space vehicles. Some are used currently and some are in the planning stages. Solid and liquid chemical rockets were very common and nuclear power as well. Solar sails and ion propulsion are going to be more prominent in the future, probably. \n\n3. Steering is done just as you would expect; Newton's third law, coupled with mechanism to control the direction of the ejecta. For tracking and control, the spacecraft send signals back and forth to us on earth using very sophisticated error correcting codes that use some very interesting mathematics. \n\n\n4. Well there are incidents where space craft are hit by debris, but obviously it does not happen very frequently or else it would be more of a problem, and accomodations for this would have to be made. Most of the failures of spacecraft are due to something else, I believe.
130577
The most famous "fact" is the footage of the flag fluttering while its being placed on the moon surface. Since there is no air on the moon, there can't be any wind, so how did the flag flutter? Another one is that there is some sort of radiation belt between the Earth and the moon, and humans would not be able to pass through this belt without suffering serious damage. Besides, NASA had a LOT of money in the Apollo project. If it was faked, it was the greatest special effects ever created.
50072
Space craft [usually] rely on rockets in space.  Rockets burn some fuel with some Oxidizer to produce lots of hot expanding gasses which are pushed out of the nozzle of the rocket.  When these gasses are pushed out the back of the rocket, they cause a change in momentum which accelerates the rocket forward.\n\nNewton’s 3rd law states, for every action, there is an equal and opposite reaction.\nSo if the action is that the rocket exhaust is pushed out the back of the space craft, then the equal and opposite reaction would be for the space craft to be pushed forward.\n\nThe law of conservation of momentum tells us that momentum is always conserved.  If a spacecraft is moving with some initial velocity (could be zero) that space craft has some momentum associated with it.  At any point in time later on, the momentum of all the parts to that space craft needs to equal up to that original value.  So if part of the craft (the burning fuel) is pushed out one direction, in order to conserve momentum, the other part of the craft needs to be pushed the other direction [otherwise it is breaking the law].\n\nIt is somewhat of a difficult concept to understand, I hoped I explained it well.\n\nRockets do not just work in space.  Obviously you can still use a rocket down here on Earth and it works for the same reasons it work in space.  The principle of how the rocket works is not just exclusive to rockets.  For example, if you sat on one of those chairs with wheels holding a heavy bag of sand, then you pushed/threw the bag away from you, you and the chair would start to move in the other direction.
255723
Good grief -- I've only been visiting this site for a month, and this is about the fifteenth time someone has asked this same ludicrous question.\n\nYes, we landed on the moon. \nYes, we went back several times. \nYes, we left things on the moon that can still be seen today. \nYes, we left a flag on the moon -- but it wasn't flapping in the breeze in the famous photo: its momentum after being unfurled has kept it moving in the absence of anything to slow it down.\n\nYes, we brought back samples of dust and rocks that have been studied for nearly 40 years. And there's nothing like them anywhere on Earth.\n\nNo, we haven't gone back since the landings because there are no economically viable reasons to do so in this modern era of cost-effectiveness and the bottom line driving science. But just because we haven't been back doesn't mean we were never there in the first place.\n\nThe U.S. was in a major competition with the Soviets to prove our scientific superiority. If we'd never landed on the moon, and it was all a sham, do you think the thousands of NASA employees would be able to keep the secret? Do you think every other nation in the world would remain complicit in the "greatest hoax ever perpetrated"?\n\nIsn't there a FAQ on Yahoo Answers that could put this baby to rest??  I can't believe that people still think this was some kind of hoax!
345562
This is a very basic question and you need to get extra help if you are having trouble solving this in your physics class.\n\nAcceleration is force / mass.  (from F = ma).\n\nThus, for the astronaut\n\n120 = 79(a)\na = ~1.52m^2/s\n\nAnd the satellite\n\na = 0.182\n\nNow they travel in opposite directions (BOTH of them move). So calculate how far the astronaut travels, how far the satellite travels, and add them. Simple kinematics:\n\np = 2a(t^2) + v(t)
544476
Well, the rocks don't float away because even though they may float very high, they still come back down, they usually don't have enough velocity to break the gravitational pull of the moon, even the shuttles are effected by gravity, but it SEEMS weightless because they're in a state of constant freefall while maintaining a certain horizontal velocity so they orbit the earth, in simpler terms, they're falling over the side of the world all the time.  Anyway, those rocks that may fly up, come back down, and they bounce, however they don't bounce as high, and eventually come to a rest, and as for anything that's not bolted down floating away, that's just stupid, because the moon has gravity, it's only 1/6th of Earth's gravity, but it's still there. (By the way, the level of stupidity in your question is aggravating me.)  The moon suits had to be weighted so when the astronaughts pushed on the ground with their feet, they didn't just blast off about a hundred meters into the sky.\n\nPS.  ANYONE who asks that sort of question sounds like an uneducated mendicant.\n\nPPS. If yer curious about my age, I'm 17
525298
the moon does have gravity, and the flag was not waving it was shaking when they put it in the ground, \n\ncheck this out this video\n\nhttp://www.youtube.com/watch?v=qMrUpCjVHIk
23329
because we have the technology to do it, so why wouldnt't we do it? i am myself a physics major and i know for a fact that it is possible. it is not really as hard as you think. you just design a rocket(which isnt much harder than designing a plane) and it just needs a lot of fuel and energy to surpass the escape velocity put forth by the earth's gravitational field, and it just has to be made of a sturdy material with a high melting point so it doesn't melt. once you're in outer space, it does not require much fuel to navigate, and all you have to do is get it to the moon and land... and as far as people being inside, yeah, just add oxygen and reserves of compressed oxygen to make those levels stable(just like they do in airplanes).\n\nalso, i know plenty of engineering majors. NASA offers internships, NASA recruits a hell of a lot of engineers and rocket designers and has way too many rocket designs for none of them to work... also, you can go to a rocket launching and see any of the rockets take off...\n\nbesides from being a physics major and thus knowing that we are actually capable of the technology- also, what reason would they have for making it up? there is really no benefit to it.. just to say "haha, look, we did it"... obviously we are using too many billions of dollars and such on space equipment and programs and rockets(which anyone can go see on tours at NASA). we wouldnt spend that much money on what? to have a nice big laugh at NASA? "haha, we fooled everyone!" come on now...
544607
I watched a very interesting show that proposed a theory about ships vanishing.  He also gave a very convincing demonstration.  He believes a ship can be sunk immediately if the earth beneath the water was to "Burp" huge amounts of Methane.  This occurrence has happened in a lake in Africa which killed off an entire village.   \n\nHe demonstrated how this would work (in a lab).   He had a huge tank filled with water, that enabled him to have tiny bubbles be emitted from the bottom, with a model ship floating above.  As soon as the tiny bubbles reached the ship, it sank immediately to the bottom.  It showed that the people on board would not have time to call for help.   Air (or Methane gas) will reduce the buoyancy of the ship and sink it.   \n\nSo, this could explain how a ship could vanish without a trace or getting an SOS before it sank.   As for the planes, well, they do fall from the sky for many reasons, and the Ocean (even just the Bermuda Triangle) is a pretty big area.\n\nI was Aircrew in the Navy, and had been on Search and Rescue missions in that area. . .I have to tell you, when we were searching, we never found anyone. . .it was very difficult to see anything.\n\nPlease. . . Vote. . .
301055
There's some confusion here, and some odd reality as well, which might be part of the source of the confusion. Our 'natural' impression of what's going on in many cases doesn't quite fit what's really going on in detail.\n\n1) Gravitational force doesn't exist 'on Earth'. You are aware of it, when you stand on something, only becuase you're standing on something, which is probably why the phrase 'on Earth' is used. The something is pushing back with a force equal to the force of attraction between you and the Earth. If you were to be falling free (as in skydiving, leaving aside air resistance, or in orbit on the Space Station), you would still be acted upon by the gravitational attractive force between you and the Earth, but you'd feel no such force. It's true the force diminishes (as the square of the distance between the bodies involved), but it still exists. And any body with the mass and size of the Earth will have the same gravitational attraction to you if you were near it (or on it) as the Earth.\n\n2) We can see such a force. Assorted satellites have orbited the Moon. Several folks have walked on the Moon (even hit a golf ball on the Moon) and, except that it's a smaller force (with the changes one would predict, including distance off the tee), the gravtational force of the Moon behaved just exactly as expected. The gravitational attraction of the Moon on you at the surface of the Earth is quite small (and easy to calculate) in comparison to that of the Earth. But in principle you are correct about its changing value. As you sit in your backyard (for 24 hours), and as the Moon orbits the Earth, you will indeed experience (but not really be aware of) the varying force between you and the Moon as it moves (and as the Earth rotates under it). Just as the Earth experiences changes in the direction of the gravitational attraction between itself and the Moon; but you are not so sloshy as sea water and so you don't actually feel (or diaplay) any tidal effects. And neither does the sea either feel its tides, I suppose. If you were quite close to a black hole, your height (and indeed your thickness) would be enough to experience very extreme tidal effects in a gravitational field of that intensity. Far worse than the high and fast tides in the Bay of Fundy in SE Canada, dramatic though they be. \n\n3) As long as the masses of the Earth and Moon remain the same, the gravitational force between them will be constant. The complication introduced by their motions about the common center of gravity in the two body system are mere complications. Hard to deal with mathematically, but mere complications none the less. \n\n4) There are thousands of planets in the Solar System, if your definition of planet is an independently orbiting chunk of stuff. On the other hand, there are only three planets (Jupiter, Saturn, Uranus) if you consider all the rest of those chunks (including the Earth) as merely trivial debris. Or some intermediate value if the orbit has to be primarily about the Sun, not another body. The Earth has one moon, Jupiter has lots (some largish), Mars has two (both smallish), ... Recently, the Hayden Planitarium in NYC revised an exhibit on the Solar System and demoted Pluto from planethood. With the expected storm of objection and discussion. And there have been found of late a couple of large, very distant, and very cold chunks rather farther out than Pluto. Are they planets? Or not? Jump in and join the arguement, it's pretty lively.\n\nAs for the claim that some 10th planet is really really magnetic and causing weather problems here... Magnets are rather hard to arrange in bulk form which is why so few materials have bulk magnetic properties; it requires alignment of the electrons at the atomic level across trillions of atoms, which is usually pretty haphazard and self cancelling. But even if a mountain could be made entirely magnetic (ie, no cancella
286241
As I have told every one else who asks this, yes, it is scientifically plausible, but whether we would be able to successfully use this technology is indeed questionable. As we have seen on the show, all of the technology is so far beyond our level of comprehension and understanding, as Jacob/Selmak was trying to explain to Jack in Exodus, when he wanted him to leave the Mothership with the Tok'ra, and he was right about how far beyond us the technology is. For example, in Tangent when they attempted to modify a death glider, even Carter admitted that they didn't completely understand the physics of the ship, and as Jacob Selmak stated:\n"And, what were you thinking, anyway? Retrofitting a death glider? You should have known better. The technology you're screwing around with is way over your head!......you've got to learn to take small steps. You can't just slap a US Air Force sticker on the side of a death glider and call it yours. Advancement like that has to be earned."\n\nAnyway back to your original question, as I said earlier, it's really only a matter of science; take for example the Asgard beaming technology and the Goa'uld transport rings. Transport rings, when in position, transmit all matter within their circular formation to another pair of rings at a different location, utilizing a conduit of bright energy. If there is a person or object on the receiving end, the rings can exchange the two simultaneously. Asgard transporters on the other hand, use energy beams to dematerialize their subjects and send their energy forms away at near-light speeds to the designated coordinates.
459758
well for a candle to burn and have a visible flame we need 2 things convection currents and gravity to support those convection currents. both missing in the space shuttle :))
31389
engines for space craft don't need to constantly exert forward thrust to keep going, like airplanes. They need to to escape the earth's gravity, but once cleared, they can keep going on forward momentum, using brief propulsion to correct the course of the space craft. \n\nMars and the moon cannot use gasoline based craft, there's no oxygen to burn, so they likely need electric motors, maybe solar powered. Not exactly sure on this but I would say an electric motor of sorts.
476385
Think of a spacecraft flying in orbit like a swinging pendulum.  You need energy to get it started, but once it is oscillating, it will stay in that state for a long time.  If you wanted to increase or decrease the pendulum oscillation that would require energy too.  But once it is in a new oscillation cycle, it will tend to stay there.\n\nSimilarly, a spacecraft needs to burn a lot of fuel to get *into* or *out of* an orbit.  Staying in a particular orbit requires very Little energy.  If there were no momentum losses, then staying in orbit would require no energy.\n\nAn orbit is an ellipse with a massive body (like the Earth) at one focus.  Ellipses are like flattened circles.  The higher the eccentricity of the ellipse, the flatter it is.  The Earth's orbit around the Sun has a very low eccentricity and is therefore quite circular. \n\nSo long as a spacecraft is flying in an ellipse  shaped orbit then it needs almost no energy to stay there.  If it needs to maneuver (like the shuttle docking with the ISS) then it needs to fire its thrusters to slowly change its orbit to match the object it is trying to rendezvous with.\n\nSuppose you wanted to escape Earth's gravity.  You fire thrusters for 10 seconds.  Now your orbit is a flatter ellipse; your eccentricity just increased.  However, you are still in orbit around the Earth.  Part of your orbit may be far away from the Earth, but you are still under influence of Earth's gravity.  You will realize that there is a critical speed -- called the escape velocity -- which will allow you to go so fast that the Earth cannot pull you back.  This is like swinging a pendulum so fast that instead of rocking back and forth about a point, it just spins in circles.\n\nThe important concept here is that gravity does not stop pulling on you when you leave Earth's atmosphere.  All spacecraft in Earth orbit are feeling its gravitational pull.  However, they are all in a state of perpetual free fall.  They are falling towards the Earth, but at the same time they are moving around it fast enough that they keep 'missing'.  This is the same as if you took a ball on a string and spun it around in a circle.  The string has tension; the ball is accelerating toward you.  But its velocity is in the direction of travel (along the circumference) so it stays in a circular path.