Artificial Satellites

If you taking care of the GPS, It will last about 5 years

millions, if you count natural satellites.

sir frances laponial discovered satellite RNAS

A satellite that's designed to be used for communications carries a radio repeater ... a radio receiver, plus a transmitter that re-transmits everything the receiver hears. Two places on earth that can't communicate by radio because there's too much stuff between them ... like trees, buildings, mountains, or the spherical bulge of the earth ... may still be able to hook up if they can both see the satellite. Both of them can point their antennas at the satellite, transmit toward it, and let it "repeat" their transmissions back to earth. Then they can talk to each other. Of course, the satellite is so far away that it takes noticeable time for the signals to follow this route ... it's a little more than 1/4 second just for the radio waves to travel end-to-end, each way through a geostationary satellite. That's the reason that conversation is often so difficult on an international or even a domestic satellite telephone circuit.

Radar satellites locate clouds and measure heights while orbiting earth above the atmosphere, and ground stations hold instruments that measure air pressure, temperature, dew point, etc.

There are many.

I like men :)

Because its wings are tired. But seriously; Keep reading you will get the laymans answer as well. The following answer and translation are provided by Ken Jenks

(kjenks@gothamcity.jsc.nasa.gov).

The "Ascent Guidance and Flight Control Training Manual," ASC G&C 2102,

says:

"During the vertical rise phase, the launch pad attitude is

commanded until an I-loaded V(rel) sufficient to assure launch tower

clearance is achieved. Then, the tilt maneuver (roll program)

orients the vehicle to a heads down attitude required to generate a

negative q-alpha, which in turn alleviates structural loading. Other

advantages with this attitude are performance gain, decreased abort

maneuver complexity, improved S-band look angles, and crew view of

the horizon. The tilt maneuver is also required to start gaining

downrange velocity to achieve the main engine cutoff (MECO) target

in second stage."

This really is a good answer, but it's couched in NASA jargon. I'll try

to interpret.

1) We wait until the Shuttle clears the tower before rolling.

2) Then, we roll the Shuttle around so that the angle of attack

between the wind caused by passage through the atmosphere (the

"relative wind") and the chord of the wings (the imaginary line

between the leading edge and the trailing edge) is a slightly

negative angle ("a negative q-alpha"). This causes a little bit of

"downward" force (toward the belly of the Orbiter, or the +Z

direction) and this force "alleviates structural loading."

We have to be careful about those wings -- they're about the

most "delicate" part of the vehicle.

3) The new attitude (after the roll) also allows us to carry more

mass to orbit, or to achieve a higher orbit with the same mass, or

to change the orbit to a higher or lower inclination than would be

the case if we didn't roll ("performance gain").

4) The new attitude allows the crew to fly a less complicated

flight path if they had to execute one of the more dangerous abort

maneuvers, the Return To Launch Site ("decreased abort maneuver

complexity").

5) The new attitude improves the ability for ground-based radio

antennae to have a good line-of-sight signal with the S-band radio

antennae on the Orbiter ("improved S-band look angles").

6) The new attitude allows the crew to see the horizon, which is a

helpful (but not mandatory) part of piloting any flying machine.

7) The new attitude orients the Shuttle so that the body is

more nearly parallel with the ground, and the nose to the east

(usually). This allows the thrust from the engines to add velocity

in the correct direction to eventually achieve orbit. Remember:

velocity is a vector quantity made of both speed and direction.

The Shuttle has to have a large horizontal component to its

velocity and a very small vertical component to attain orbit.

This all begs the question, "Why isn't the launch pad oriented to give

this nice attitude to begin with? Why does the Shuttle need to roll to

achieve that attitude?" The answer is that the pads were leftovers

from the Apollo days. The Shuttle straddles two flame trenches -- one

for the Solid Rocket Motor exhaust, one for the Space Shuttle Main

Engine exhaust. (You can see the effects of this on any daytime

launch. The SRM exhaust is dirty gray garbage, and the SSME exhaust is

fluffy white steam. Watch for the difference between the "top"

[Orbiter side] and the "bottom" [External Tank side] of the stack.) The

access tower and other support and service structure are all oriented

basically the same way they were for the Saturn V's. (A side note: the

Saturn V's also had a roll program. Don't ask me why -- I'm a Shuttle

guy.)

Satellites positioned over a specific point are not 'hovering motionless'.

The smaller an orbit is, the shorter its period of revolution, and the larger an orbit is,

the longer its period of revolution. Communications satellites are carefully placed in

an orbit that's just exactly the correct size so that its period is 24 hours. That way,

the satellite appears motionless in the sky, and you don't need a tracking antenna

to follow it. That unique distance happens to be 26,199 miles from the center of the

Earth. In order to revolve completely around a circle that size every 24 hours, the

satellite is moving at roughly 6,860 miles per hour.

Even if the satellite did stop dead in its tracks, it would be in space and take

some time to be attracted towards earth. Once it gained speed (attracted by

the Earth's gravity) and fell into the atmosphere, it would likely burn up, as the

air friction heated it. Heavy metallic fragments might reach the ground.

Do you have a digital camera ? The digital camera takes a picture when you push the button, then translates a description of the image into a load of digital data, which is stored in the camera until you decide to move it somewhere. Then you can dump the data to a laptop, put it on a CD or DVD, e-mail it to your mother, or send it through a data-cable to a printer. The satellite simply has a digital camera on board. It takes a picture whenever ground controllers tell it to, or when its on-board computer decides it's time for a snap. The digital camera translates a description of the image into a load of digital data, which is stored in the satellite until the ground controllers decide to move it somewhere. Then the data is radio-transmitted to earth, where the controllers can store it in a laptop, put it on a CD or DVD, e-mail it to their mother, send it through a data-cable to a printer, or send it via the web to the local TV station for the 11:00 news.

Vanguard1

It is a geostationary operational environmental satellite, though I'm not sure what is does.

Low Earth Orbit

At present there are around 24-32 satellites orbiting in medium earth orbit(11,000 miles)
more the satellites more accurate navigation is produced.

For any body in a closed orbit around another body, the farther apart the two bodies are, the slower the satellite moves in its orbit.. When the Space Shuttle is in "low earth orbit", it moves faster than the Moon is moving in its orbit. A satellite in an elongated orbit, that spends some of the time close to the earth and some of the time farther away, moves fastest at its lowest altitude, and slowest when it is furthest away.

A sun-synchronous orbit is one that places a satellite over a given location at the same mean solar time on successive orbits. This is accomplished by tuning the orbital altitude and inclination.

The object is to have the same solar illumination angle at each approach, with the same orbital motion (ascending, descending). This is useful for surface observations, as with weather or spy satellites.

A Satellite SID will be your Serial Identification Number. Its much like an IP address that designates your modem. This is used so that your Satellite provider can keep track of who is requesting service from them. Your Modem will send the SID to the satellite which will then verify that modem should have service. If you cancel your payments they will block that SID which is tied to your Name and Account.

AORW = Atlantic Oceanic Region West

AORE = Atlantic Oceanic Region East

POR = Pacific Oceanic Region

IOR = Indian Oceanic Region

These abbreviations refer to Inmarsat communication satellites (low orbit) that cover these regions, for maritime and aviation use.

the beginning of the space race

Often the very same way you would use electricity.

The problem with Hubble Space Telescope (the HST, or just the "Hubble") was that the primary reflector, that is, the mirror which redirects the incoming light to focus it, was ground using an incorrectly calibrated reference as a guide. This left it "out of focus" in areas farther from the center. There were a couple of checks for accuracy made with secondary references, and they were off, but the "warning" was ignored and the opinion was offered that the two secondary references were not as accurate as the primary reference was. More information can be had by reading the Wikipedia post on the Hubble. A link to that post can be found below.