A number of in-development constellations of satellite telecommunications from low and medium Earth orbit (LEO and MEO) are set to pass milestones in 2018. Launches of clusters of production satellites and prototypes are planned, as is one entry into service. The space industry is eager to see if the promise of dramatic improvement in broadband performance and cost can crystallize into a
successful business model.
Credit: Thales Alenia Space

Iridium Next
Goal: Enhanced Iridium global mobile communications on land, at sea and in the skies
Number of satellites: 66 (plus 9 spares)
Satellite manufacturer: Thales Alenia Space, in partnership with Orbital ATK
Satellite weight: 860 kg (1,900 lb.)
Year announced: 2009
Planned service-entry year: 2018
Orbit altitude: 780 km (485 mi.) 
Description: Iridium Next is betting on established reputation for truly global communications and is increasing bandwidth—up to 1.4 Mbps. The company is thus targeting safety services for the cockpit but not passenger-cabin Wi-Fi. The interconnected satellites will operate in L band and Ka band. Each is carrying a secondary payload that provides satellite-based tracking of aircraft (under the Aireon brand) and ships. As of mid-November, 30 Iridium Next satellites were in orbit.
Goal: Enhanced availability of broadband access in the U.S. and globally
Number of satellites: 2,956
Satellite manufacturer: Boeing
Satellite weight: N/A
Year announced: 2016
Planned service-entry year: Within six years after license is granted
Orbit altitude: 1,200 km (745 mi.)
Description: Boeing plans to deploy the first part of the system—1,396 satellites operating at an altitude of 1,200 km—within six years once the license is granted, and it aims to subsequently increase the constellation to a total of 2,956. It will use the V band, for which it promises efficient reuse, for fixed satellite service. The application was filed in June 2016.
Credit: LEOSAT

LeoSat
Goal: Global, enterprise-grade, high-speed and secure data network
Number of satellites: 78 to 108
Satellite manufacturer: Thales Alenia Space
Satellite weight: 1,250 kg (2,755 lb.)
Year announced: 2015
Planned service-entry year: 2022
Orbit altitude: 1,400 km (895 imi.)
Description: LeoSat aims to orbit a constellation of small, high-throughput Ka-band spacecraft to deliver internet services globally. It plans to have all of its satellites interconnected through laser links, creating “an optical backbone in space about 1.5 times faster than terrestrial fiber backbones” and without the need for any terrestrial touchpoint. The constellation will thus provide “instant infrastructure from anywhere to everywhere,” it says. The first launch is scheduled for 2019.
Credit: ONEWeb

OneWeb
Goal: Internet service for all, to bridge the digital divide by 2027
Number of satellites: 900 (including 648 operational)
Satellite manufacturer: OneWeb Satellites, a joint venture with Airbus
Satellite weight: 150 kg (330 lb.)
Year announced: 2015
Planned service-entry year: 2019
Orbit altitude: 1,200 km (745 mi.)
Description: OneWeb hopes to use the low cost of its mass-produced satellites to offer internet links totaling 10 terabits per second to mobile operators and internet service providers. Ground terminals with embedded LTE, 3G, 2G and Wi-Fi will include simple rooftop terminals that can be installed on schools and other public buildings in the developing world. OneWeb plans to use both Ka and Ku bands.
SpaceX Starlink
Goal: Wide range of broadband and communications services for residential, commercial, institutional and governmental users worldwide
Number of satellites: 4,425 (plus in-orbit spares)
Satellite manufacturer: SpaceX
Satellite weight: N/A
Year announced: 2015
Planned service-entry year: 2024
Orbit altitude: 1,110-1,325 km (685-823 mi.)
Description: SpaceX intends to use Ku and Ka bands and an optical intersatellite link. As of May, SpaceX planned to launch a prototype by the end of 2017 and another early in 2018. An operational launch campaign to start the 4,425-satellite constellation would follow in 2019. SpaceX is pressing Congress for policies that would allow for spectrum sharing and incentives for companies that use “spectrally efficient” technologies.
Samsung
Goal: Monthly 200-GB capacity for 5 billion users worldwide
Number of satellites: 4,600
Satellite manufacturer: N/A
Satellite weight: N/A
Year announced: 2015
Planned service-entry year: 2028
Orbit altitude: 1,500 km (930 mi.)
Description: In a paper released in 2015, Farooq Khan, then president of Samsung Research America, outlined a vision “to make affordable internet services available to everyone in the world via low-cost micro-satellites.” Those satellites would be interconnected and operate in the V band.
Credit: Thales Alenia Space

SES O3B
Goal: Fiber-optic-cable-like internet service
Number of satellites: 27
Satellite manufacturer: Thales Alenia Space (O3b), Boeing (O3b mPower)
Satellite weight: 700 kg (1,543 lb.) (O3b), N/A (O3b mPower)
Year announced: 2008 (O3b) and 2017 (O3b mPower)
Planned service-entry year: 2021 (O3b mPower); O3b has been in service since 2014
Orbit altitude: 8,000 km (4,970 mi.)
Description: Founded to bridge the digital divide globally, O3b has evolved to a more business-to-business approach. A large cruise ship can now be followed and provided with 1 Gbps connectivity in Ka band. SES took over 100% of the company in 2016 and is now planning on synergies between its geosynchronous-Earth-oribit and MEO satellites, meaning the latter may partly replace the former. The constellation will have 20 current-standard satellites, after the launches scheduled for 2018-19. In addition, seven next-generation O3b mPower satellites will each feature 4,000 steerable beams for much greater capability at lower cost. Covered area spans 45 deg. S. Lat. and 45 deg. N. Lat.
Credit: Telesat LEO

Telesat LEO
Goal: Universal and cost-effective fiber-optic-cable-like connectivity for business, government and individual users
Number of satellites: At least 117
Satellite manufacturer: Airbus’ SSTL and Space Systems Loral (first two prototypes)
Satellite weight: N/A
Year announced: 2016
Planned service-entry year: 2021
Orbit altitude: 1,000 km (620 mi.) (polar orbits) and 1,248 km (inclined orbits)
Description: Telesat’s LEO satellites will operate in Ka band and use optical intersatellite links. Targeted are “busy airports; military operations on land, sea and air; major shipping ports; large, remote communities; and other areas of concentrated demand,” according to the company. Telesat says it will offer a cost per megabit per second equal to or lower than the lowest on the market or being developed. Two prototype satellites are scheduled for launch in 2018.