The orbital periods of MEO satellites range from about 2 to nearly 24 hours.Telstar 1, an experimental communications satellite launched in 1962, orbited in MEO.
Satellites in MEO orbits are perturbed by solar radiation pressure which is the dominating non-gravitational perturbing force. Other perturbing forces include: Earth's albedo, navigation antenna thrust, and thermal effects related to heat re-radiation.
^Orbital periods and speeds are calculated using the relations 4π2R3 = T2GM and V2R = GM, where R, radius of orbit in metres; T, orbital period in seconds; V, orbital speed in m/s; G, gravitational constant, approximately 6.673×10−11 Nm2/kg2; M, mass of Earth, approximately 5.98×1024 kg.
^Approximately 8.6 times (in radius and length) when the moon is nearest (363104 km ÷ 42164 km) to 9.6 times when the moon is farthest (405696 km ÷ 42164 km).
"Definitions of geocentric orbits from the Goddard Space Flight Center". User support guide: platforms. NASA Goddard Space Flight Center. Archived from the original on May 27, 2010. Retrieved 2012-07-08.
^"The Global Navigation System GLONASS: Development and Usage in the 21st Century". 34th Annual Precise Time and Time Interval (PTTI) Meeting. 2002. Retrieved 28 February 2019.