The United States Space Surveillance Network (SSN) detects, tracks, catalogs and identifies artificial objects orbiting Earth, e.g. active/inactive satellites, spent rocket bodies, or fragmentation debris. The system is the responsibility of United States Space Command and operated by the United States Space Force and its functions are:Predict when and where a decaying space object will re-enter the Earth's atmosphere; Prevent a returning space object, which to radar looks like a missile, from triggering a false alarm in missile-attack warning sensors of the U.S. and other countries; Chart the present position of space objects and plot their anticipated orbital paths; Detect new artificial objects in space; Correctly map objects traveling in Earth orbit; Produce a running catalog of artificial space objects; Determine ownership of a re-entering space object;

Operation Moonwatch was an amateur science program formally initiated by the Smithsonian Astrophysical Observatory (SAO) in 1956. The SAO organized Moonwatch as part of the International Geophysical Year (IGY) which was probably the largest single scientific undertaking in history. Its initial goal was to enlist the aid of amateur astronomers and other citizens who would help professional scientists spot the first artificial satellites. Until professionally staffed optical tracking stations came on-line in 1958, this network of amateur scientists and other interested citizens played a critical role in providing crucial information regarding the world's first satellites.