Space flight started as a purely governmental effort in the 1950s, mainly politically motivated by the Cold War. However, in the past few decades, potential economic benefits have encouraged numerous industries to establish themselves in space. Commercial space transportation has grown into a huge business, with global revenues of hundreds of billions of dollars.
After the Challenger disaster in 1986, NASA's Space Shuttle was banned from carrying commercial payloads. As a result, private companies started to build and operate their own launch vehicles — rockets that launch satellites into orbit. There are now several private or state-owned commercial “spaceports” in the U.S. that companies can use, in addition to federal government-owned launch sites. Now, more than 25% of all launches conducted worldwide are commercial in nature. The role of these commercial space companies is only going to grow with the 2011 retirement of the Space Shuttle from service. People have known it was possible to bounce signals off an object in orbit since the 1950s, when the U.S. used the Moon to reflect radar signals. In 1958, the U.S. launched the first communications satellite. It broadcast a Christmas message from President Eisenhower for twelve days before the batteries failed. In the 1960s, private companies started building their own satellites. They were launched using converted intercontinental ballistic missiles. AT&T was the first to approach the government with this idea, and their satellite, called, TelStar 1, was the first to transmit phone calls and television signals between Europe and North America.
Communications satellites relay information from one point on the Earth to another. A satellite receives information from a transmitter on the Earth, amplifies the signal, and sends it back down to a receiver at another location on the surface. Most satellites use solar panels for a power source, combined with batteries to store the Sun’s energy while passing through the Earth’s shadow. Most satellites are in geosynchronous orbits; they orbit the Earth at the distance where their orbital period is the same as the rotation period of the Earth, or about 24 hours. This occurs at a height of about 36,000 km above the Earth’s surface. A satellite orbiting at this height will remain stationary with respect to the surface. This is perfect for communications satellites, because they will always be in sight of the same receiving and transmitting stations on Earth.
Satellites were first used mainly for telephone communications. Television usage grew to dominate the market in the 1970s. However, now that internet use is expanding exponentially, data traffic is increasingly more important. Today, the entire world’s communication systems are dependent on artificial satellites. Phones, radio, and television all use satellites in orbit around the Earth. Even an activity as essential as paying with a credit card would be impossible without satellites to relay that information over long distances. There are now about 5,000 man-made satellites in orbit around the Earth, although probably less than a thousand of those are still in use. These have been launched by many different countries, including the U.S., Russia, Japan, China, France, India, Israel, Australia, UK, and the European Space Agency. There are many more commercial satellites than those owned by military or civil governments. Among satellites in geosynchronous orbits, almost 80% are commercial in nature.
On July 10, 1962, Telstar, first telecommunications satellite, is put into orbit. Click here for original source URL.
Satellite launching is a big business. More satellites are launched each year to enable global telecommunications. While alternatives to rockets have been sought, including space cannons and space elevators, the technology has not yet been demonstrated to work. Instead, companies like Space X and Orbital Sciences Corp. continue to develop rockets. Space X in particular is working with NASA to develop new vehicles to carry supplies to and from the International Space Station.
Human space flight, like air flight, started as a government endeavor, but that may not be the case in the future. Privately owned companies are starting to explore the possibility of putting people into space. In 1996, the “Ansari X Prize” was offered to encourage the development of human space flight for tourism purposes. It was modeled after the prizes that spurred the development of civil aviation in the 1920s. A $10 million prize, funded by private individual and corporate donations, would be given to the first team to build and launch a spaceship able to carry three people to 100 kilometers above the Earth, return safely, and repeat the trip within two weeks. Twenty-seven thousand people showed up for the first launch of one of the competitors, SpaceShipOne, indicating the widespread public enthusiasm for this next step in space travel. With successful completion of both launches on October 4, 2004, Scaled Composites succeeded in winning the Ansari X Prize. Scaled Composites has now partnered with Virgin Galactic to develop a commercial spacecraft, SpaceShipTwo. A factory to build these craft is built in the Mohave desert and investors ranging from actors to athletes, and including Steven Hawking, have prepaid for flights on this futuristic craft.
The idea of “space tourism” sounds fanciful, until you recall that many space probes cost less than an expensive Hollywood movie. With a cost of around $10,000 per kilogram to launch into orbit, a joyride in space becomes affordable for the richest few percent of the Earth’s population. Space tourism proved to be more than just a dream in 2001 when millionaire Dennis Tito paid the Russian Government for a trip to the International Space Station. The cost: $20 million for a round-trip flight and two week’s stay on the space station (plus six months of intensive training, and the need to learn Russian!). There have been seven space tourists who have been in Earth orbit using Russian launch vehicles. By 2030, it is feasible to think that space tourism will take off and thousands of people will have paid their way into suborbit.