Artificial Satellites

A satellite in Geosychronous Earth Orbit (GEO) orbits the Earth in the same time period that the Earth spins, so the satellite appears to be stationary over one spot above the Earth's equator. It's always looking down at the same area of the Earth.

A satellite in a polar orbit will pass quickly over any one spot on Earth and keep going. It can't watch the same area for a long period. Depending on the altitude of the orbit, it may take days or weeks to pass over the same area again. However, polar orbits are typically much lower, permitting a much higher resolution image. This is very important for photo imagery, but not so much for weather.

satellite =)

polar satallite

The history of sputnik dates back to December 1954. It was developed as part of a larger picture for rocket technology. It was also put into development as the rest of the countries were also working on similar projects.

Do you mean the Chandra X-ray observatory? Chandra does not operate in the gamma ray wavelengths, it typically can observe light in the "soft" X-ray wavelengths (from about 10 to .10 nm). Gamma rays generally have wavelengths of .001 nm or smaller.

Earth's atmosphere actually absorbs most X-rays, so in order to see at that wavelength, a space telescope was needed. Also, X-rays and gamma rays are so energetic that they cannot be gathered by normal means such as a curved optical mirror used in most "optical" telescopes (for visible wavelengths and even some infrared/ultraviolet imaging). X-ray light will pass right through these kinds of mirrors. Chandra uses a series of concentric parabolic mirrors that slightly deflect the paths of x-ray photons towards a detector.

Here are some images to compare optical mirrors to Chandra's mirrors.

wisconsinastronomy.org/images/scopes/NewtCut_m.jpg

spie.org/Images/Graphics/Newsroom/Imported/11_243_0_2006-01-17/11_fig2.jpg

Hope this helps.

Nasa lunched

Expedition 21 Soyuz Launch to International Space Station September 30

From the question, I'm guessing that when the questioner reads the term "polar orbit", he's picturing the satellite doing a little tiny circle in the sky over the North Pole. This is not an accurate understanding of the term. Remember that the center of the orbit of an artificial satellite has to be at the center of the earth. A 'polar orbit' is an orbit that covers both poles. If you picture the globe of the earth, the satellite's orbit is a circle standing up, with the satellite traveling up and down, passing over both poles in each complete revolution of the earth. As the earth rotates, every point on earth passes under the orbit, and sooner or later, every point on earth will be visible from the satellite.

Communications satellites, launched in the 1960's. There were 2 Echo satellites, which were passive (the signal would bounce back to earth like a mirror). The Telstar satellites were active, meaning that the signal was retransmitted back to earth.

The "Satellite" name is simply a model brand name and therefore the laptops bear ... Some Satellites also lacked an internal floppy disk drive, but a port on that.

With large number of low-earth-orbit satellites and the geo-synchronous orbit stuffed full of communications satellites, there aren't all THAT many "medium" altitude satellites. But there are some.

The GPS navigation satellites, for example, are in highly inclined 12-hour orbits, and an unknown number of military "spy" satellites are in that middle range.

I'm assuming you are talking about GPS when you say "satellite." RF tracking can be directional. It takes three RF receiver stations to triangulate the position of an RF transmitter and is usually less accurate than GPS. RF is also more limited by range, so the RF tracking stations are usually required to be mobile depending on the strength of the transmission signal.

A polar orbit (as opposed to an equatorial orbit) passes over the poles, north and south. A low orbit is relatively close to the Earth (or other object being orbited), it might be a few hundred miles up.

I believe that NASA not only sends the satellites up they also monitor them on a daily basis.

They are called maps

The satellites of Uranus revolve around the planet in planes almost perpendicular to its orbit.

250 msec

Galileo

Orbits within the atmosphere are not stable due to atmospheric friction. Friction slows (and heats) the satellite, dropping its orbit still lower (where there's more friction, therefore more slowing and heating). Eventually the satellite burns up. This is essentially what happened to Skylab and more recently to Mir.

Large rockets, computer control, compact fuel.

They usually get their energy from the Sun, but they may also have a nuclear reactor. That's how they get their energy; how they work in detail would depend on what they are supposed to do. There are satellites for many different purposes.

Most moons orbiting the various planets of our solar system are considered "satellites" - more specifically, "natural satellites".

In addition, the more general use applies to the various space modules, etc., orbiting around the earth or around other planets of the solar system. As they are the result of human device, they are considered, "artificial Satellites". Sputnik 1, as the very first of these, acts as prime example.

agila 11

A propagation delay is the amount of time it takes radio waves to travel from the surface of the Earth to the satellite and then back down to the Earth. The calculation of the delay is based upon the altitude and position of the satellite systems.