| Ask the above title question of anyone in this, our | | | | outer space - thus, there is no "drag" force - once |
| Age of Information, and listen to the answers. | | | | the horizontal speed and altitude are in "sync". |
| Everyone living today has been aware of space | | | | Therefore, the orbiting vehicle (Mercury, Apollo, |
| adventurism: the first flights, then orbits by Russia | | | | Shuttle or moon) will continue to coast along in their |
| and the U.S.; then onward to the moon (the | | | | orbiting journeys about Earth. |
| heart-gripping uncertainly of survival of astronauts on | | | | A critical next question: once achieving such high |
| Apollo 13); the first steps of a human on the moon | | | | velocity and orbit, how did these vehicles make it |
| ("A giant leap for mankind"); the Space Shuttle | | | | back to Earth safely - considering the fiery paths of |
| exploits (and fiery disastrous explosions); the | | | | meteorites plowing through Earth's atmosphere from |
| astonishing assembly of the complex and gigantic | | | | outer space? How did the space scientists (NASA et |
| Space Station (cooperation between the U.S. and | | | | al) achieve safe reentry for Astronauts on Mercury, |
| Russia)! Space achievements in the past half-century | | | | Apollo and the Space Shuttle? |
| rank with the history-book adventures of Magellan | | | | ______________ |
| and Columbus in probing the unknown. | | | | It is April 12, 1981, the Space Shuttle is on the |
| Most everyone knows what gravity is, they have | | | | launching pad at Cape Kennedy after nine years and |
| heard the story of Sir Isaac Newton (an apple falling | | | | billions of dollars spent in innovative technologies. A |
| from a tree), his Laws of Motion ("A body at rest will | | | | top technical management team of cognizant |
| remain at rest; a body in motion will remain in motion, | | | | Engineering managers of all major systems and |
| traveling in the same direction - in both cases, until an | | | | subsystems - from both NASA and major |
| external force acts upon that body."). Thus, what is it | | | | subcontractors - has been designated and assembled |
| that keeps such vehicles up in the sky: the orbiting | | | | to witness the launch, purpose: so that immediate |
| Mercury and Apollo vehicles of the past, the Space | | | | technical decisions can be made, should any |
| Shuttle and Space Station of today? Most everyone | | | | emergency arise. We have been placed as close to |
| will tentatively mumble "gravity" (perhaps hopefully - | | | | the launch site as is considered safe - if an explosion |
| knowing that gravity is somehow involved, but | | | | occurs during launch or early lift-off (about three |
| uncertain as to how). | | | | miles) - to visually witness the first moments. We are |
| Therefore, the answer to this question: "gravity" is | | | | seated on a rising array of wooden benches as if at |
| certainly involved (Newton and his apple) - but | | | | a high school athletic field. |
| gravity should actually force all this orbiting hardware | | | | Everyone is quiet, apprehensive, each aware of what |
| (also the moon) to fall to Earth! Why don't they? (If | | | | could go wrong in his (or her) technical area; greeting |
| the questioner holds back any further comment until | | | | each other with solemn nods. Only recently, many |
| the questionees respond further; probably half will | | | | had participated in an exhaustive briefing to top |
| venture uncertainly, "Maybe there is no gravity in | | | | NASA officials at the final Flight Readiness Review |
| space".) | | | | conference - as to the possibilities, probabilities and |
| Then you say (not laughing, as the objective is to | | | | consequences of failure in any area. Everyone speaks |
| teach, not disparage), "You're correct in saying | | | | in hushed tones. Three miles away, powerful |
| gravity is involved, however, gravity force is always | | | | flood-lights show the Shuttle assembly standing |
| active, no matter how far away from our Earth. | | | | vertically on the launch pad, the Orbiter |
| Gravity is always pulling everything toward Earth's | | | | (astronaut-carrying vehicle), the large center fuel tank |
| center, (including humans - measured by our weight | | | | and the two solid boosters - all a brilliant white under |
| on a scale). The force of gravity is an attraction | | | | the concentration of flood-lights, limned against the |
| between two masses - in orbiting vehicles, it is equal | | | | dark, morning sky. |
| to the product of the masses of Earth and the | | | | There is a hush, then the calm, emotionless voice of |
| object (humans, Shuttle, Space Station or moon), | | | | the NASA announcer counts down the seconds, |
| divided by the square of the distance between the | | | | then, "Lift-off, we have a lift-off!" A thrill of |
| mass centers). The key question is why these items | | | | excitement ripples through the crowd. Slowly, the |
| remain in orbit about Earth; why don't they fall onto | | | | Shuttle assembly rises; all hold their breaths as fingers |
| Earth? The answer is that they do - they are | | | | of fire emanate from the three powerful engines and |
| constantly falling to Earth - they are constantly falling | | | | the solid rocket boosters. The brilliant exhausts |
| to Earth, but are also traveling so fast around Earth, | | | | gradually lengthen as the Shuttle slowly rises - then |
| that gravity is pulling them into an orbit about Earth. | | | | the flames lift clear of the launch pad - then the |
| In actual fact, space vehicles in orbit (and the moon) | | | | vehicle climbs, gradually increasing speed and |
| are attempting to travel in a straight line, however | | | | diminishing in size - until it is tiny, high in the sky and |
| Earth's gravity pulls them into a circular (or elliptical) | | | | leveling off. It then rapidly accelerates, growing |
| orbital path. | | | | smaller and smaller until it is out of sight. A cheer |
| To be precise, to put the Space Shuttle or any | | | | resounds, as everyone rises and yells, excitedly |
| vehicle into orbit, it must be rocketed with such | | | | pounding each other's back, on everyone's face, a |
| horizontal speed that the constant pull of gravity | | | | broad smile. Gradually many sit down again, breathing |
| forces it into an Earth orbit. Thus, to achieve orbit, | | | | deep breaths. |
| the Space Shuttle has to be accelerated and | | | | NASA personnel begin shepherding everyone into the |
| propelled to a horizontal speed of about 18,000 miles | | | | buses, to be taken to Control Center for more |
| per hour - to reach the required velocity for a | | | | congratulations; to watch for awhile on the computer |
| near-Earth orbit at somewhere over a hundred miles | | | | screens; to relax with coffee and sweet-rolls; then to |
| altitude. The faster the speed, the higher the orbit. | | | | be briefed by NASA regarding the flight to California |
| Since the orbit altitude is much higher than the Earth's | | | | and Edwards Air Force Base - for the next challenge |
| atmosphere (air molecules are also affected by | | | | and uncertainty, a safe re-entry and landing. |
| gravity), the orbiting vehicles travel in the vacuum of | | | | |