• Low Earth Orbit Satellites
• Medium Earth Orbit
• Medium Earth Orbit Definition
• Medium Earth Orbiting Satellites
• Medium Earth Orbits Are Used Primarily For Satellites

Medium Earth orbit (MEO), sometimes called intermediate circular orbit (ICO), is the region of space around Earth above low Earth orbit (altitude of 2,000 km (1,243 mi) above sea level) and below geosynchronous orbit (altitude of 35,786 km (22,236 mi) above sea level).^[1]

The orbit is home to a number of artificial satellites – the most common uses include navigation, communication, and geodetic/space environment science.^[1] The most common altitude is approximately 20,200 kilometres (12,552 mi), which yields an orbital period of 12 hours, as used, for example, by the Global Positioning System (GPS).^[1] Other satellites in medium Earth orbit include Glonass (with an altitude of 19,100 kilometres (11,900 mi)^[2]) and Galileo (with an altitude of 23,222 kilometres (14,429 mi))^[3] constellations.Communications satellites in MEO include the O3b and forthcoming O3b mPOWER constellations for telecommunications and data backhaul to maritime, aero and remote locations (with an altitude of 8,063 kilometres (5,010 mi)).^[4] Communications satellites that cover the North and South Pole are also put in MEO.^[5]

Typically the orbit of a medium earth orbit satellite is about 10,000 miles (16,093.44 km) above earth. In various patterns, these satellites make the trip around earth in anywhere from 2-12 hours, which provides better coverage to wider areas than that provided by LEOs. In 1962, the first communications satellite, Telstar, was launched. Low Earth Orbit (LEO) is a popular place. It is where the majority of space missions are sent, where all of our satellites reside, and where the ISS orbits the planet. (Medium Earth Orbit.

Low Earth Orbit Satellites

The orbital periods of MEO satellites range from about 2 to nearly 24 hours.^[1]Telstar 1, an experimental communications satellite launched in 1962, orbited in MEO.^[6]

Satellites in MEO orbits are perturbed by solar radiation pressure which is the dominating non-gravitational perturbing force.^[7] Other perturbing forces include: Earth's albedo, navigation antenna thrust, and thermal effects related to heat re-radiation.

See also[edit]

• Geostationary Earth orbit (GEO)
• High Earth orbit (HEO)
• Highly elliptical orbit (HEO)
• Low Earth orbit (LEO)

Notes[edit]

1. ^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.
2. ^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).

References[edit]

1. ^ ^abcd'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.
2. ^'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.
3. ^Galileo Satellites
4. ^O3b satellites
5. ^Satellite Basics: Solution BenefitsArchived 2013-11-19 at Archive.today
6. ^'Medium Earth Orbit'. Archived from the original on 2017-06-09. Retrieved 2007-01-04.
7. ^Bury, Grzegorz; Sośnica, Krzysztof; Zajdel, Radosław; Strugarek, Dariusz (February 2020). 'Toward the 1-cm Galileo orbits: challenges in modeling of perturbing forces'. Journal of Geodesy. 94 (2): 16. doi:10.1007/s00190-020-01342-2.

WASHINGTON — SES says its constellation of medium Earth orbit O3b satellites now has the ability to expand from an equatorial system to a global system thanks to new approvals from U.S. telecom regulators.

Medium Earth Orbit

On June 8, SES said the U.S. Federal Communications Commission approved the Luxembourg company’s request to sell satellite connectivity services in the U.S. with 26 additional O3b satellites. Those satellites would operate in both inclined and equatorial orbits, expanding O3b’s coverage from its present 50 degrees out from the equator all the way to the poles.

Medium Earth Orbit Definition

With 16 satellites already in space, SES’s new authorization will permit it to operate a total of 42 satellites in medium Earth orbit. The new satellites will include four more first-generation satellites built by Thales Alenia Space for launch next year on an Arianespace Soyuz, 10 satellites in inclined orbits, and 12 satellites in equatorial orbits.

SES said the FCC approval enables the company to “triple its next-generation O3b mPOWER fleet” for which Boeing is building the first seven satellites in anticipation of a 2021 launch. Each O3b mPower satellite has more than 10 times the capacity of the first-generation satellites, according to SES. The first seven are estimated to provide some 10 terabits of total throughput.

SES, when announcing O3b mPower last September, said the first seven satellites would cover 80 percent of the Earth’s surface, but would not be limited to that coverage footprint.

“We designed O3b mPower as a system, not as a bunch of satellites, and not as limited to the first seven satellites that we launch,” Steve Collar, then CEO of SES Networks and now CEO of all of SES, said at a press conference. “O3b mPower will be and is conceived as being a fully global system.”

SES operates the O3b satellites in 8,000-kilometer orbits, roughly a fourth of the distance to Earth compared to geostationary satellites, enabling significantly lower signal lag.

To date all of SES’s O3b satellites operate in Ka-band, using high-throughput spot beams for broadband connectivity and network services. The FCC’s approval included rights to six satellites with higher frequency V-band — a region of spectrum satellite operators have been testing for commercial use. SES is the second company to obtain FCC approval for V-band satellite communications following Hughes Network Systems in March. Other companies including Boeing, Viasat, SpaceX, OneWeb, Theia Holdings and Telesat have also requested authorization for V-band satellite systems.

Industry reservations

Medium Earth Orbiting Satellites

SES’s application for new O3b satellites faced opposition from Iridium, Telesat and Viasat.

Iridium petitioned the FCC to deny SES’s application because it included access to some frequencies designated for mobile satellite services operators like Iridium.

Mobile satellite services operators and fixed satellite services operators are losing their distinction as operators of both kinds seek to provide data services to the same platforms such as aircraft, cruise ships and oil rigs.

The FCC sided with SES’s view that O3b’s mobile satellite services operations “have the same characteristics as its [fixed satellite services] operations.”

Canada-based Telesat asked the FCC to give priority to operators who have earlier spectrum filings with the International Telecommunication Union. Such prioritization would give Telesat, which is planning a low Earth orbit constellation of 117 satellites, first rights to certain Ka-band frequencies over SES. The FCC rejected Telesat’s proposal, but stipulated that SES comply with the commission’s spectrum-sharing rules.

Medium Earth Orbits Are Used Primarily For Satellites

Viasat voiced concern about O3b signal power levels and the risk they could interfere with geosynchronous satellites. The FCC said a newly adopted rule requires satellites outside of the geostationary arc not cause unacceptable interference to geostationary satellites providing fixed data or broadcast television services, and conditioned SES’s authorization on obeying this rule. SES’s O3b satellites must also adhere to any future power limitations the FCC — and to an unspecified extent, the ITU — sets on V-band, the agency said.