Growth in high-throughput communications satellite capacity continues with the Dec. 9 launch of the first of Inmarsat's four Global Xpress Ka-band spacecraft. By the end of 2014, when three of the new Inmarsat-5s are planned to be in orbit, Inmarsat will be the first operator to provide global Ka-band services to fixed and mobile terminals with speeds up to 50 Mbps.

The Global Xpress constellation of Boeing 702HP satellites, which includes a fourth spacecraft on order to provide redundancy and additional capacity, represents a $1.6 billion investment by Inmarsat in the mobile broadband market. Satellites are a popular solution for mobile communications, such as to aircraft in flight and ships at sea. Carriers such as United Airlines, Southwest Airlines and JetBlue plan to add Wi-Fi across their entire fleets of aircraft.

High-throughput satellites are a significant development in the industry. They can handle much larger amounts of data, at higher speeds, than traditional satellites through frequency reuse and spot beams. Satellites can aim beams at specific locations, allowing them to use the same frequency for multiple customers and increasing the bandwidth a satellite can handle.

The Ka-band portion of the electromagnetic spectrum is popular for high-throughput satellites. This is partly because it lends itself to spot beams, as it is narrower than bands such as Ku. Ka-band is also readily available, as it is not used for other applications. Ku-band, for example, is used for direct-to-home television broadcasting. Satellites such as EchoStar XVII and ViaSat-1 have popularized the use of Ka-band for satellite broadband Internet. But the high-throughput technology can be used on satellites that operate at any frequency.

Ka-band satellites will be a primary supplier of the bandwidth needed to provide in-air broadband Internet connections, especially on oceanic routes, where terrestrial transmitters are not available. Beginning in 2015, Gogo in the U.S. and OnAir in Europe will provide Global Xpress services to airlines. Honeywell will produce the avionics and service the business aviation market. Boeing will sell civil and military Ka-band capacity to the U.S. government.

Intelsat also is eyeing the aviation market for its planned fleet of EpicNG high-throughput satellites, the first two of which—Intelsat 29e to be launched in 2015 and 33e to follow in 2016—will provide broadband services using Ku-band frequencies, which it argues can penetrate weather better than Ka-band. Panasonic Avionics has selected the 29e and 33e satellites for its global in-flight communications services, which include Wi-Fi, mobile phone and live television. Boeing is under contract to build five 702MP medium-power satellites for Intelsat.

The growth of high-throughput communications for mobile computing has blurred the divide between fixed satellite service providers such as Intelsat and mobile satellite service (MSS) providers like Inmarsat. In an attempt to capture the market for mobile data, many traditionally fixed satellite service providers have tapped the MSS market. For example, satellite companies such as SES in Europe and Telesat in North America now sell capacity to the airline in-flight broadband and shipping markets.

Although Inmarsat's Global Xpress will provide the first global Ka-frequency broadband services from a single operator, there are several regional high-throughput satellites already in service and more are planned. Launched in 2012, ViaSat-1 provides Ka-band coverage of North America and Hawaii. JetBlue and another major U.S. airline were expected to begin using ViaSat for in-flight internet and television services by the end of 2013.

At the time, the Space Systems/Loral-built ViaSat-1 was the highest-capacity communication satellite to be launched: That crown is set to be taken by ViaSat-2 when it is orbited in mid-2016. A Boeing 702HP satellite, ViaSat-2 will increase Ka-band capacity over North America and extend coverage over Central America, the Caribbean, the northern edge of South America and on to the primary aeronautical and maritime routes across the Atlantic.

Other regional Ka-band service providers include Abu Dhabi's Al Yahsat, which operates two EADS Astrium/Thales Alenia Space satellites covering the Middle East, Africa, Europe and South-West Asia. Eutelsat covers Europe with the Astrium-built KA-Sat. Australia's NewSat plans to serve the Middle East, East Africa and South West Asia beginning in 2015, with the launch of the Lockheed Martin-built Jabiru-1. Before then, NewSat's Jabiru-2 payload is expected to be launched in 2014 onboard Malaysia's Measat 3b geostationary satellite. Jabiru-2 will cover Australia, Papua New Guinea, Timor Leste and the Solomon Islands.

O3b Networks, which is building a medium-Earth-orbit Ka-band constellation designed to bring broadband connectivity to the “other 3 billion” customers in the developing world, launched the first four of 12 Thales Alenia-built satellites in June 2013. The delayed launch of the second four is set for the first quarter of 2014. O3b's investors include SES and Google.

While O3b's satellites each weigh just 700 kg (1,543 lb.), the trend has been toward larger, increasingly powerful spacecraft better able to support smaller ground equipment. These satellites can handle the large number of high-power transponders needed to transmit high-definition video, broadband Internet and other data services that are in demand. Lithium-ion batteries and gallium-arsenide solar cells are being used to increase satellite power output.

Boeing, Lockheed Martin and Space Systems/Loral (now owned by Canada's MacDonald, Dettwiler & Associates) have seen success by focusing on large satellites. In July 2013, the European Space Agency launched the Astrium-developed Alphasat, Europe's largest-ever communications satellite. Exceeding 6,600 kg on launch, Alphasat has joined Inmarsat's L-band mobile-communications fleet. For future missions, the new Alphabus design will be able to provide up to 22 kW. of power to advanced payloads weighing up to 2,000 kg.

But the market for smaller satellites is also opening up. Asia Broadcast Satellite and Mexico's Satmex are jointly procuring four satellites based on Boeing's new 702SP bus, a lightweight platform that uses all-electric propulsion to reduce launch mass and cost. Xenon-ion propulsion has been used in the past to keep satellites in their intended orbits, but not to put them into orbit after launch. This is because electric propulsion is slower than chemical thrusters, and it can take up to six months to reach orbit. The advantage is that ion propulsion does not require the large amounts of oxygen and hydrogen that are used as propellant. This can save substantial weight, reducing launch costs and increasing the number of transponders a satellite can carry. Boeing, meanwhile, has launched its Phantom Phoenix line of small satellite prototypes, available in three configurations: 500-1,000 kg, 180 kg and 4-5 kg.

Operational constellations of smaller, lower-orbiting satellites are being renewed and extended. Iridium Communications plans to begin launching its 66-satellite Iridium Next constellation in 2015. Hosted-payload space on the 800-kg Thales Alenia-built spacecraft has been fully sold, so the operator is offering to launch third-party payloads on stand-alone satellites under the name Iridium Prime. This will take advantage of the existing satellite production line and operating infrastructure. The major hosted-payload customer for Iridium Next is Aireon, a joint venture between Iridium and Nav Canada to provide space-based tracking of aircraft in remote and oceanic airspace using automatic dependent surveillance-broadcast.

Orbcomm plans to launch 18 second-generation OG2 satellites, focused on the machine-to-machine communications for asset management. The delayed launches are planned for 2014 and manufacturer Sierra Nevada Corp. has options to build another 30 of the 142-kg satellites. All the OG2s will incorporate automatic identification system (AIS) payloads to track ships globally. ExactEarth, meanwhile, launched a fifth AIS satellite for its global vessel monitoring service in November.

The top commercial communications satellite manufacturers include Boeing, EADS Astrium, Lockheed Martin, Orbital Sciences Corp., Space Systems/Loral and Thales Alenia Space. In the past, Boeing and Lockheed Martin have focused on government programs, but as these wind down, the satellite giants are reentering the commercial marketplace.

Meanwhile, to cut costs, militaries have come to rely upon the commercial sector. The U.S. Navy is supplementing UHF capacity on its UFO and MUOS constellations with capacity provided by Intelsat General, the U.K.'s Skynet service, and Italy's Sicral. The UHF capacity crunch is caused partly by delays to the Lockheed Martin-led MUOS program, which is replacing the UFO fleet, and because of increased demand for bandwidth from warfighters.

Hosted-payload schemes, under which a government pays an operator to install a government-developed payload on board a commercially operated satellite, are another concept the military hopes will increase capabilities and reduce costs. Developing a hosted payload for a commercial satellite is much cheaper than designing, building, launching and maintaining a satellite or constellation. It gives the government the flexibility to deploy a single payload where it is most needed onboard a satellite already scheduled for launch. In turn, payment for hosting payloads helps commercial operators fund new satellite purchases.

But there are hurdles in the way of hosted payloads, including a lack of dedicated funding lines, a lack of standardized business or pricing models on which to base contracts, and a development process that does not coincide with a commercial development cycle. Hoping to resolve this, the Pentagon in August released a solicitation for an “indefinite delivery/indefinite quantity” contracting vehicle that will pre-qualify bidders and enable the U.S. Air Force to regularly use space on commercial satellites to host payloads.

Some U.S. military planners are pushing for smaller, less expensive satellites as alternatives to the current crop of large, complex and costly platforms. Known as disaggregation, the concept would consist of purchasing larger numbers of smaller, relatively less sophisticated satellites than the current fleets of AEHF, MUOS and others. Networks of smaller satellites would be more resilient to attacks, and disaggregation could reduce costs and development times, but it requires a change in the Pentagon's mindset.

European nations, with considerably smaller financial resources, use data-sharing agreements to maximize their space capabilities. The U.K., France and Italy are separately developing their respective Skynet 5, Syracuse III and Sicral military communications satellites, but have agreed to bundle their services to provide NATO with UHF and SHF communications capacity.

This approach is especially useful within the reconnaissance sector, where having more satellites translates into greater coverage and increased refresh rates. Italy, France, and Germany have established a multilateral agreement by which they will exchange set periods of satellite tasking on each other's reconnaissance satellites: France's Helios 2 and Pleiades, Italy's Cosmo-SkyMed and Germany's SAR Lupe.

While some planners have discussed creating a single pan-European satellite architecture, several hurdles need to be overcome. European nations would need to purchase ground equipment that would be compatible with a new system. Governments continue to argue over the makeup and capabilities of such a system, and the most likely course will be for European countries to continue the current arrangement in which each builds smaller networks and shares capabilities.

In terms of value, the U.S. accounts for more than two-thirds of military satellite production, forecast to be worth more than $22 billion over the next decade. Over the same period, Japan will account for 7.8% of satellite purchases by value, Russia 5.7%, France 4.2% and China 4.2%. Boeing and Lockheed Martin will continue to dominate the military satellite market. Other major players include Mitsubishi, Astrium and Russia's ISS Reshetnev.

—With Amy Svitak in Paris