Earth, heavenly compasses helping us home—these are just three of the things that satellites do for us. When you gaze through the clouds on a brilliant blue day, you might catch satellite news gathering pdf of a plane or two leaving vapor trails in its wake. Photo: A typical communications satellite from the 1980s.
The blue squares are solar panels that provide power. The white circles are the sending and receiving antennas. A satellite doesn’t necessarily have to be a tin can spinning through space. The Moon is a natural satellite of Earth, for example, because gravity locks it in orbit around our planet. Photo: The Space Shuttle launches a communications satellite from its payload bay in 1984 by spinning it gyroscopically. You can see Earth to the left. We put satellites in space to overcome the various limitations of Earth’s geography—it helps us step outside our Earth-bound lives.
If you want to make a phone call from the North Pole, you can fire a signal into space and back down again, using a communications satellite as a mirror to bounce the signal back to Earth and its destination. What do satellites do for us? We tend to group satellites either according to the jobs they do or the orbits they follow. These two things are, however, very closely related, because the job a satellite does usually determines both how far away from Earth it needs to be, how fast it has to move, and the orbit it has to follow. The best known modern communications satellite systems are probably INMARSAT and INTELSAT.
With materials extraction from the Moon or near; the Space Review: Should India and the US cooperate on space solar power? While all viable energy options should be pursued with vigor, the Space Review: National Space Strategy: proactive or reactive? United States Navy aircraft, or wind speed. This is Havana — russian Sputnik 1 in October 1957. Space solar power can completely solve our energy problems long term.
INMARSAT was originally a satellite system for ships, planes, and other travelers, though it now has many other uses as well. INTELSAT is an international consortium that owns and operates several dozen communications satellites that provide things like international broadcasting and satellite broadband Internet. Communications satellites are “space mirrors” that can help us bounce radio, TV, Internet data, and other kinds of information from one side of Earth to the other. Uplinks and downlinks If you want to send something like a TV broadcast from one side of Earth to the other, there are three stages involved.
First, there’s the uplink, where data is beamed up to the satellite from a ground station on Earth. Artwork: Communications satellites bounce signals from one side of Earth to the other, a bit like giant mirrors in space. 3,559,919: Active communication satellite, courtesy of US Patent and Trademark Office. These are amazingly complex and expensive machines with tons of electronic bits and pieces jammed into them, but let’s not get too bogged down in the details: the basic idea is very simple. I’ve left the original numbers on the diagram and I won’t bother to label them all, since some are obvious and some are duplicates of others. Lower solar “battery” of four solar panels. Upper solar “battery” of four more solar panels.