Science-can you explain to your children what keeps them up in the space station or the Moon?

The question of title over anyone in this, our information age and listen to the answers. Everyone living today have been aware of adventurism: the first space flights, then orbits from Russia and United States; then continue on the Moon (the heart-gripping uncertain of survival of the Apollo 13 astronauts); the first steps of a human on the Moon ("a giant step for mankind"); the exploit of the Space Shuttle (and fiery explosions disastrous); the amazing Assembly of space station complex and gigantic (cooperation between the United States and Russia)! Space results in the past half-century achievements rank with the adventures of story-book of Magellan and Columbus in probing the unknown.

Most everyone knows what gravity is, they have heard the story of Sir Isaac Newton (an Apple fall from a tree), his laws of motion ("a body at rest will remain at rest; a body in motion will stay in motion, traveling in the same direction-in both cases, until an outside force acting on the body. "). So, what is keeping these vehicles in heaven: orbiting mercury and Apollo vehicles of the past, the Space Shuttle and space station today? All will be provisionally mumble "gravity" (maybe there is hope-knowing that gravity is somehow involved, but uncertain about how).

Therefore, the answer to this question: "gravity" is certainly involved (Newton and his apple)-but the severity should impose actually all this hardware orbito (the Moon) to fall to the ground! Why don't they? (If the interrogator takes back any further comment until the questionees answer further; probably half will be venturing so uncertain, "Perhaps there is no gravity in space".)

Then she says (don't laugh, as the goal is to teach, not discredit), "you are quite correct in saying the gravity is involved, however, the force of gravity is always active, no matter how far away from our land. Gravity is always pull toward the center of the Earth, (including humans-measured by our weight on a scale). The force of gravity is an attraction between two masses-in vehicles in orbit, is equal to the product of the masses of the Earth and the object (humans, Shuttle, space station or the Moon), divided by the square of the distance between the centers of mass). The key question is why these items should remain in orbit on Earth; Why not fall upon the Earth? The answer is that they do-they are constantly falling to the ground-they are constantly falling to Earth, but are also travelling so fast around the Earth, gravity is pulling in an orbit on the Earth. In reality, space vehicles in orbit (and moon) are trying to travel in a straight line, however, Earth's gravity pulls them in a circular path orbito (or elliptical).

To be precise, to put the Space Shuttle or any vehicle in orbit, it has rocketed with such speed that the gravitational constant pull strength in an orbit. So, to reach the orbit, the Space Shuttle has to be accelerated and pushed to a horizontal line of approx 18,000 miles per hour-to reach the speed necessary for near-Earth orbit somewhere over a hundred miles altitude. Faster speeds, higher orbit. Since the altitude of the orbit is much higher than the Earth's atmosphere (air molecules are influenced by gravity), orbiting vehicles travel in the vacuum of outer space-so, there is no "drag"-once the horizontal speed and altitude are "synchronized". Therefore, the vehicle orbito (mercury, Apollo, shuttle or moon) will continue to costa in their journeyings orbiting the Earth.

A critique of the next question: once I attain such high velocity and orbit, how did these vehicles make it back to Earth safely-considering the Fiery Meteor trails ploughing through the atmosphere of the Earth from space? How did scientists from space (NASA et al) reach safe return for astronauts on Mercury, Apollo and the Space Shuttle?
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12 April 1981, the Space Shuttle is on the launch pad at Cape Kennedy after nine years and billions of dollars spent in innovative technologies. A team of top technical management of engineering managers aware of all the major systems and sub-systems-by NASA and subcontractors important-has been designated and assembled to witness the launch, purpose: for immediate decisions can be made, techniques should any emergency arise. We have been placed closer to the launch site as it is considered safe-if an explosion occurs during launch or first lift-off (about three miles)-a witness visually first moments. We are sitting on a growing range of wooden benches as if to a high school athletic field.

Everyone is quiet, apprehensive, all knowledge of what could go wrong at technical area (or her); greeting each other with solemn nods. Just recently, many had participated in a thorough briefing of senior NASA officials to the Conference final Flight Readiness Review-as for the possibility, probability and consequences of failure in any area. Everyone speaks in hushed tones. Three kilometres away, flood-powerful lights show the Shuttle standing vertically on the launch pad, the Orbiter (handicapped astronaut vehicle), the Center fuel tank and the two solid Boosters-all a brilliant white beneath the concentration of flood-lights, limned against the dark sky, in the morning.

There is a silence, then the calm, emotionless voice of announcer NASA countdown of seconds, then "lift-off, we have a take-off!" A shiver of excitement ripples through the crowd. Slowly, rises the shuttle assembly; all hold their breaths as fingers fire emanate from three powerful engines and solid rocket boosters. The brilliant discharges stretch gradually as the Shuttle increases slowly-then the elevator clear flames Launchpad-then the vehicle climbs gradually increasing speed and decreasing in size until it is very small, high in the sky and leveling. Then accelerates rapidly, growing smaller and smaller until it's out of sight. Echoing a cheer, as everyone stands up and shouts excitedly, pounding each other's back, on the face of all, a broad smile. Gradually many sit back, breathe deep breaths.

NASA personnel begin all pastoralism in buses, to be taken to the control center for more compliments; looking for a little computer screens; to relax with a coffee and sweet-rolls; Therefore, to be informed by NASA for flight in California Edwards Air Force Base-for the next challenge and uncertainty, a safe reentry and landing.