The largest man-made satellite currently in orbit around the Earth is the International Space Station. Some satellites, called microsats, nanosats, or picosats, can be as small as 10 cm (3.937 inches) in diameter and 0.1 kg (0.22 pounds) in mass.

Satellites have an operating lifespan between five and 20 years. As of 2008, the former Soviet Union and Russia had nearly 1,400 satellites in orbit, the USA about 1,000, Japan more than 100, China about 80, France over 40, India more than 30, Germany almost 30, the UK and Canada 25, and at least ten each from Italy, Australia, Indonesia, Brazil, Sweden, Argentina, Saudi Arabia, and South Korea. The company Sea Launch — a consortium of four companies from the United States, Russia, Ukraine and Norway — has launched a few satellites into orbit from international waters every year, although the company filed for bankruptcy in 2009.

As space technology matured, satellites were launched for military and commercial purposes. The price of satellite launches has dropped to as low as a few million dollars for light satellites, and a few tens of millions for heavy satellites. This put satellite technology within the reach of many nations and international companies.

The SSN was founded in the wake of the launch of Sputnik, the first artificial satellite , by the Soviet Union in October 1957. Orbiting the planet at 20,000 mph (32,186.88 kph) while emitting a constant radio signal, Sputnik was a red flag that told America not to take its technological dominance for granted. In the following decade, the Space Race between the USSR and USA occurred, ending with Apollo landing in July 1969.

Satellites are tracked by United States Space Surveillance Network ( SSN ), which has been tracking every object in orbit over 10 cm (3.937 inches) in diameter since it was founded in 1957. There are approximately 3,000 satellites operating in Earth orbit, according to the US National Aeronautics and Space Administration ( NASA ), out of roughly 8,000 man-made objects in total. In its entire history, the SSN has tracked more than 24,500 space objects orbiting Earth. The majority of these have fallen into unstable orbits and incinerated during reentry. The SSN also keeps track which piece of space junk belongs to which country.

Michael is a longtime wiseGEEK contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

Discussion Comments

anon939383 March 13, 2014 @anon350190 (Post 64): Wrong. GPS uses satellites.

anon352897 October 26, 2013 It's amazing that with all the tech we have floating in space, that the world is limited to what the governments can see. Google shows us some things but the government sees everything in real time and I want to see the earth in real time. I want to zoom down on the ocean and see some whales moving, I want to see live Tokyo at night and look at the glaciers in the North Pole regions. I want to see the real movement of the waves on the beaches in Australia. These things can be done and the ones who paid for them to be made are not allowed to enjoy what they offer.

anon350190 October 2, 2013 Go and see if you can find any believable pictures of earth from space. I can't find any, therefore I suspect we may have no satellites up there. Why have stealth planes or submarines when satellites would see them? The television uses a system called skywave and is not receiving anything from space. GPS uses Lowran, which was developed during World War II, not satellites.

anon339326 June 22, 2013 Even if satellites don't deplete ozone when they're placed into orbit, is it possible that they deplete ozone by being in orbit? (e.g. maybe they reflect and concentrate sunlight on certain parts of the atmosphere, like a lens placed in the sun concentrates sunlight enough to burn a whole through things). Clearly every satellite in orbit also sends electromagnetic (microwave?) signals back to earth, do we know that these don't derange the ozone layer?

anon298426 October 20, 2012 @anon38591: Any hole in the ozone layer quickly patches up at a speed faster than any vehicle/craft travels, known to the public. Therefore, any temporary break of the ozone via any object is very insignificant. It's like taking a dud rocket and crashing it into the sea to make a hole in the water. However, the water quickly closes in behind the rocket when it falls in. Therefore, you need not worry. The only way our ozone could be completely destroyed is if something massive tears the ozone off, in which case that massive object would cause more problems than just our ozone. And we will have seen it coming way before it happens.

anon298424 October 20, 2012 @anon44975: Satellites run by solar energy, which is why they last as long as they do. In terms of how much solar energy it absorbs and uses an order to function optimally, that is a question I unfortunately cannot answer.

anon249887 February 23, 2012 Question 1: What is currently the total mass of artificial satellites in space, including all contents such as people, air and supplies? In other words, how much of Earth's mass has been sent into orbit? Question 2: What is the maximum amount of mass we can put into space before Earth's gravity changes from 9.801?

anon190931 June 27, 2011 could these satellites be causing cancer? What about space junk?

anon162692 March 24, 2011 How many navigation satellites orbit the earth?

anon150215 February 7, 2011 FYI only -- In your answer to question "how many satellites are orbiting earth" reference is made to "U.S. Space Surveillance Network (SSN). However, when I clicked on "SSN" for its link, it took me to WiseGEEKs description Of "Social Security Number". Have a nice day.

anon148613 February 2, 2011 is extreme weather caused by interaction between earth's gravity and artificial satellites which are chaotic? (cannot be numerically integrated)

anon124576 November 6, 2010 @anon83432: If you read it again, it clearly states the largest man-made satellite.

anon120753 October 21, 2010 OK what people don't tell you is the ozone layer can be destroyed with water but it fixes itself over time.

anon106416 August 25, 2010 about the legality of "spying": Orbit (and outer space) do not pertain to laws of the country over which they would be hovering, or passing. I'm sure that some ownership edicts have been put forth. I'm not familiar with the subject. Maybe someone can enlighten us.

anon83519 May 11, 2010 it's legal to spy on us because we allowed the passing of things like the patriot act, homeland security act, etc. As long as we catch those terrorists. I'm going to research yearly income statements from these launch companies. I bet that's a pretty good business to be in.

anon83479 May 11, 2010 what new companies have launched satellites this year 2010? Let me know, people!

anon83447 May 11, 2010 The business of retrieving lost and non functional satellites. will it be a money spinner? Let's think.

anon83432 May 11, 2010 Actually, the largest satellite in earth's orbit is the moon, not the international space station.

anon83429 May 11, 2010 Are there any natural satellites other than the moon that orbits the earth? Like space rocks?

anon77718 April 15, 2010 Maybe all these satellites are causing global warming.

anon73191 March 26, 2010 how is one orbit actually formed around a planet?

anon70230 March 12, 2010 What happens to the satellites that are terminated?

anon59854 January 10, 2010 How many companies are this moment that are working on satellite industry (and also that one connected to government program) in the world? Thank you very much in advance.

anon57755 December 27, 2009 Actually only USA has about 560 satellites in orbit But the truth is that right now there are 2,271 satellites in orbit around the Earth. Russia has the most satellites in orbit (1,324 satellites), followed by the USA with 658 satellites.

anon55581 December 8, 2009 Satellite launch does not cause ozone depletion, as the vast majority of rocket bodies use O2, H2, and H2O2 and other non fossil fuels for the launch propellant. The by-products of these are water and air only. This leads to no holes in the ozone layer. In addition, satellites simply by their location cannot cause a hole in the ozone layer, anymore than you swimming in a lake would cause a hole in the water. When you move, the space you just were occupying is now filled with water. Hope this helps clear the ozone hole confusion.

anon54169 November 27, 2009 For those asking if satellites causes spread in the hole in the ozone. Not really. The rockets might cause some problems, but most satellites are above the atmosphere, just in location for the orbital pull from the earth. Most are powered by solar panels and orbit is provided by the earth's gravity. There are a few satellites that have boosters to control movements, but those are usually owned by governments since they might need to change its location suddenly. Many satellites can perform their jobs by just the use of earth's orbital pull since they usually have sister satellites that communicates and provide assistance on their tasks.

anon48454 October 12, 2009 The definition of satellite here is anything larger than 10cm in diameter. So for any experiment that has a bunch of small satellites that can be released from the shuttle or an automated rocket -- every single one of those counts. So there could be a hundred satellites (albeit small ones) released from a single rocket/shuttle mission. Don't forget, all space junk is also dubbed a satellite (again, as long as its over 10 cm) so that could up the number as well. -Timmy

anon47559 October 5, 2009 why is it legal for the government to spy on us?

anon44975 September 12, 2009 I am an electronic student. I was working on my thesis. Please send to me a list of information about satellites still in orbit, with important parameters. These include :( weight of satellite; mission of satellite; orbit name of satellite) with the quantity of used electric power (in watts) in this satellite. For example: quantity of used electric power [w]; orbit name of satellite; mission of satellite; weight of sat; name of sat; 1700 GEO? dispatching; 2200KG; TDRS.

anon43055 August 25, 2009 There's 560 satellites that function as desired in orbit, hence 560 man-made satellites with the desired use, as for 1000 satellites a year. Most launches fail to achieve the desired orbit and/or are hit by an object orbiting the earth (rocks or other satellites). Three a day is approximately correct since commercial satellites are launched to replace older models and most fail to achieve the desired orbit so a re-launch will occur. Also three a day is correct as it's not just one satellite launched by the same station and not all satellites are for orbiting the earth. Although the life-span of a satellite is between 5 to 20 years, technology evolves at a faster rate and old satellites are usually terminated.

anon38591 July 27, 2009 how much of a hole in the ozone does a satilite make?

anon32461 May 21, 2009 how can a country launch 1000 satellites a year? that's like launching around 3 satellites a day!

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