The satellite was only 2 percent the mass of Sputnik 2, however, at 30 pounds 13 kg. The Sputniks and Explorer 1 became the opening shots in a space race between the United States and the Soviet Union that lasted until at least the late s.
The focus on satellites as political tools began to give way to people as both countries sent humans into space in 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. Satellites, of course! Satellites are any objects that revolve around orbit another object in space. Some satellites are natural , while others are artificial man-made. The moon is an example of a natural satellite that orbits the Earth. We're going to focus , though, on the man-made satellites.
Artificial satellites are machines that humans launch into orbit , usually around the Earth. Artificial satellites can be sent to orbit other planets, too. For example, there are currently satellites orbiting the Moon , the Sun, and several other planets, including Mercury, Venus, Mars, and Saturn.
The Soviet Union launched the first artificial satellite — Sputnik 1 — on October 4, The United States launched its first artificial satellite — Explorer 1 — about four months later. Since that time, over 2, satellites have been launched into space. Would you have ever guessed there are that many satellites up there in the sky , traveling around the Earth over and over again? What in the world do they do up there? Why do we need so many of them? Artificial satellites are used for all sorts of purposes.
Satellites like the Hubble Space Telescope, the International Space Station, and the Russian Mir space station help scientists explore space in new and exciting ways. Communications satellites help us communicate with people all over the world. Weather satellites help us observe the Earth from space to help predict weather patterns. Radio and television satellites beam our favorite songs, movies, and television shows to Earth for us to enjoy.
Without these satellites, we couldn't use GPS devices to find our way while traveling. If you're wondering how that many satellites stay in orbit without bumping into each other, just remember that space is very…well… spacious!
Compared to our measurements on Earth, the size of space seems infinite. Even though there's a lot of room in space, satellites are launched into orbits at different distances from Earth. Some may be as close as miles above Earth, while others may be as far away as 20, miles or more.
Most artificial satellites orbit within miles of Earth or what scientists call low-Earth orbit. These satellites have to travel very fast — about 17, miles per hour — to avoid being sucked back into Earth's atmosphere. Sooner or later, though, the force of gravity will pull all objects, including artificial satellites, back to Earth. Although at least one piece of space junk returns to Earth every day, it's rare that anyone ever notices.
So no need to worry that the sky is falling! Aren't satellites out of this world? Be sure to explore the following activities with a friend or family member:. We're glad you're enjoying learning about space, Hope! Check them out! GREAT question! Typically they send information via radio signals back to earth, which are received by antennas. Fun topic to wonder about, huh Jacob?
Thank you so much for bringing this to our attention, Jordy! We have corrected the text. If you like Xbox, be sure to check out these Wonders about video games! We're glad you learned something new, Wonder Friend!
We encourage you to keep researching about this Wonder at your library and online! Thanks for the suggestion, Lochsloy! We always appreciate hearing from our readers and take their suggestions into consideration! Awesome, George! We bet you can learn a lot from her. Wonder Is the Sky Falling? Hi Wonder Friend! We're so glad that we could help you with your project, JollyJohn! We want to make sure you're writing down ideas and thoughts of your own, too!
Thanks for sharing your comment and making us smile! We're so glad you think so, Eli! That's OK, Clayton! A rocket can go 25, miles per hour!
Once the rocket reaches the right location above Earth, it lets go of the satellite. The satellite uses the energy it picked up from the rocket to stay in motion. That motion is called momentum. It moves fastest when it's closest to the planet -- a point known as perigee -- and slowest when it's farthest from the planet -- a point known as apogee. Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar.
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