On that count, NASA succeeded. Explorer 1 sent data back to Earth for four months, ceasing communications on May 23, The satellite remained aloft for more than a decade before re-entering Earth's atmosphere on March 31, Explorer 1 spawned a series of other satellites.
While Explorers 2 and 5 failed due to rocket stage problems, Explorers 3 and 4 both launched successfully in and transmitted science from orbit.
Even though the satellites are no longer working, their legacy remains. They launched the United States into space and showed that it was possible to do science from orbit. Explorer 1 discovered the Van Allen belts , and subsequent missions in the Explorer series uncovered more details about their nature. Today, the belts are being probed in more detail by the Van Allen probes, which launched in This is the first time that two spacecraft simultaneously studied the belts.
It is not typical for a mission to start science observations right away as the instruments are still being configured. A fortuitously timed solar storm led to an immediate finding: the Van Allen probes uncovered evidence of a third belt affected by the storm, as well as the two belts that were already known.
Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community space. Elizabeth Howell is a contributing writer for Space. She is the author or co-author of several books on space exploration.
Elizabeth holds a Ph. She also holds a bachelor of journalism degree from Carleton University in Canada, where she began her space-writing career in Besides writing, Elizabeth teaches communications at the university and community college level, and for government training schools. To see her latest projects, follow Elizabeth on Twitter at howellspace. Elizabeth Howell. Later in the decade, however, the aims of both countries began to split. While the United States went on to land people on the moon and create the space shuttle, the Soviet Union constructed the world's first space station, Salyut 1 , which launched in Other countries began to send their own satellites into space as the benefits rippled through society.
Weather satellites improved forecasts, even for remote areas. Land-watching satellites such as the Landsat series tracked changes in forests, water and other parts of Earth's surface over time. Telecommunications satellites made long-distance telephone calls and eventually, live television broadcasts from across the world a normal part of life. Later generations helped with Internet connections.
With the miniaturization of computers and other hardware, it's now possible to send up much smaller satellites that can do science, telecommunications or other functions in orbit. It's common now for companies and universities to create "CubeSats", or cube-shaped satellites that frequently populate low-Earth orbit.
These can be lofted on a rocket along with a bigger payload, or sent from a mobile launcher on the International Space Station ISS. The ISS is the biggest satellite in orbit, and took over a decade to construct.
Piece by piece, 15 nations contributed financial and physical infrastructure to the orbiting complex, which was put together between and Program officials expect the ISS to keep running until at least Every usable artificial satellite — whether it's a human or robotic one — has four main parts to it : a power system which could be solar or nuclear, for example , a way to control its attitude, an antenna to transmit and receive information, and a payload to collect information such as a camera or particle detector.
As will be seen below, however, not all artificial satellites are necessarily workable ones. Even a screw or a bit of paint is considered an "artificial" satellite, even though these are missing these parts. A satellite is best understood as a projectile, or an object that has only one force acting on it — gravity. Technically speaking, anything that crosses the Karman Line at an altitude of kilometers 62 miles is considered in space. However, a satellite needs to be going fast — at least 8 km 5 miles a second — to stop from falling back down to Earth immediately.
If a satellite is traveling fast enough, it will perpetually "fall" toward Earth, but the Earth's curvature means that the satellite will fall around our planet instead of crashing back on the surface. Satellites that travel closer to Earth are at risk of falling because the drag of atmospheric molecules will slow the satellites down.
Those that orbit farther away from Earth have fewer molecules to contend with. There are several accepted "zones" of orbits around the Earth. One is called low-Earth-orbit , which extends from about to 2, km about to 1, miles. This is the zone where the ISS orbits and where the space shuttle used to do its work. In fact, all human missions except for the Apollo flights to the moon took place in this zone. Most satellites also work in this zone.
Geostationary or geosynchronous orbit is the best spot for communications satellites to use, however. This is a zone above Earth's equator at an altitude of 35, km 22, mi.
At this altitude, the rate of "fall" around the Earth is about the same as Earth's rotation, which allows the satellite to stay above the same spot on Earth almost constantly. The satellite thus keeps a perpetual connection with a fixed antenna on the ground, allowing for reliable communications. When geostationary satellites reach the end of their life, protocol dictates they're moved out of the way for a new satellite to take their place. In December, America attempted to launch a satellite of its own, called Vanguard , but it exploded shortly after takeoff.
On January 31, , things went better with Explorer I , the first U. In May , President John F. Kennedy declared that America should put a man on the moon by the end of the decade.
NASA has continued to make great advances in space exploration since the first moonwalk, including playing a major part in the construction of the International Space Station. The agency has also suffered tragic setbacks, however, such as the disasters that killed the crews of the Challenger space shuttle in and the Columbia space shuttle in But if you see something that doesn't look right, click here to contact us!
Under Hitler, the Nazi Party grew into a mass movement and ruled Germany as a totalitarian state from to By the beginning of , The Doors were well-established members of the Los Angeles music scene. As the house band at the Whiskey a Go Go on the Sunset Strip, they had built a large local following and strong industry buzz, and out on the road, they were fast becoming known as a After eight hours of furious fighting, a change in wind direction prompted the Spanish to break off Nearly one billion television viewers in 74 countries tune in to witness the marriage of Prince Charles, heir to the British throne, to Lady Diana Spencer, a young English schoolteacher.
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