What Is The Oldest Manmade Object In Earth Orbit?
Answer: Vanguard 1
Vanguard 1 can’t claim to be the first artificial satellite in Earth orbit–that distinction belongs to Soviet launched Sputnik 1. Vanguard 1 is actually the fourth artificial satellite–after Sputnik 1 (USSR), Sputnik 2 (USSR), and Explorer 1 (USA). Despite being the fourth artificial satellite launched into space, Vanguard can lay claim to several titles.
The most notable of the titles it can claim is: longest artificial satellite in Earth orbit. Launched on March 17, 1958, Vanguard 1 has been in orbit for over 50 years and has orbited the Earth over 200,000 times (it completes a full orbit every 134.2 minutes). Unlike the three satellites launched prior to it, Vanguard 1 has not succumbed to orbital decay and burned up in the atmosphere.
Vanguard 1 was originally launched as part of a two-part program. The primary function of Vanguard 1 was to serve as a test platform for the 3-stage satellite launch rockets used for Project Vanguard. Since getting something into Earth orbit is neither a small nor inexpensive task, the satellite was configured to perform tests and observations once it was in orbit. Among the various tests undertaken by Vanguard 1 were temperature testing as well as studies on atmospheric density and satellite drag.
The effect of atmospheric drag and rate of orbital decay at high altitudes were two of the more useful contributions made by Vanguard 1. Although it was only operational until May of 1964, the data transmitted was invaluable for future satellite launches. Scientists had predicted, for example, that Vanguard 1 would have an orbital decay of 2,000 years. It turns out that, due to various variables and effects that had been excluded from their calculations, the orbital decay of Vanguard 1 is more like 240 years–Earth’s longest lived artificial satellite will burn up in the atmosphere around 2198, not 3958.
In addition to being the longest lived artificial satellite, Vanguard 1 also has the distinction of being the first satellite with solar panels.