PARIS — Startup satellite broadband provider O3b Networks will deliver 500 megabits per second of Ka-band broadband connectivity to the world’s largest cruise ship under a contract expected to be announced June 23.

In the latest demonstration of the growing appeal of the maritime sector for satellite fleet operators whose core business is elsewhere, O3b is signing a five-year contract with Royal Caribbean Cruises Ltd. to provide bandwidth to the Oasis of the Seas starting in mid-2013. The ship, whose itinerary is limited to the Caribbean, has capacity for 8,000 crew and passengers.

O3b, based in Britain’s Channel Islands, is building a unique satellite infrastructure that features satellites in 8,100-kilometer equatorial orbits that provide Ka-band bandwidth to telecommunications operators and other corporate customers located between 45 degrees north and 45 degrees south of the equator.

Backed by SES of Luxembourg, a major fixed satellite services fleet operator, O3b has 12 satellites under construction by Thales Alenia Space of Cannes, France.

The satellites are scheduled for launch starting in early 2013, when four spacecraft are set to be orbited by a Europeanized version of Russia’s Soyuz rocket operated from Europe’s Guiana Space Center on South America’s northeast coast. A second group of four satellites is set for launch on a Soyuz between April and June of next year, forming the core network of eight spacecraft. With these eight satellites, O3b expects to start commercial service by September. A third group of four satellites is scheduled for launch in 2014.

Operating in low Earth orbit, O3b’s satellites drift over their 600-kilometer-diameter coverage areas, requiring tracking antennas to switch to each succeeding satellite as it passes overhead.

Given this network architecture, O3b’s capacity over the oceans in its coverage area would be fully available for maritime users. The alternative is that they fly empty for the part of their orbit.

Each satellite has 10 beams, each capable of handling 600 megabits per second of bandwidth downlink and 600 megabits per second uplink.

O3b Chief Executive Steve Collar, in an interview, said the O3b satellites can offer maritime customers a multiple of the bandwidth they could get from competing satellite systems in Ka- or Ku-band.

Collar said his company is positioning itself as an alternative for that portion of the maritime market that needs real broadband. For the moment, he said, O3b is focusing on cruise ships and mega-yachts.

“The cruise ship industry today is lacking in broadband,” Collar said. “We can offer the part of the market seeking high-end connections. We are thinking of a market that is between 30 and 40 vessels in this class. We are also targeting the oil and gas sector. Today there is no good existing solution for seismic operations and we can address that market. The same is true for [maritime] government applications, which have a similar demand for broadband.”

Hardly a week has passed in recent months without a satellite industry consultancy, a satellite fleet operator or a manufacturer of satellite ground gear pointing to growing demand for broadband among maritime customers.

Those already in the maritime market, such as mobile services operator Inmarsat of London and Telenor of Norway, are adding Ka-band capacity to their fleets to provide increased bandwidth.

Those historically out of the maritime market, such as fleet operators SES, Intelsat of Luxembourg and Washington, Eutelsat of Paris and Telesat of Canada, are tinkering with their fleets to capture maritime customers.

Collar said none of them can offer the throughput of O3b with the low latency — the speed of the signal’s round trip between the satellite and the user — that O3b’s low-orbiting satellites can provide. The relative merits of low orbit versus geostationary orbit 36,000 kilometers over the equator for voice transmissions and certain Internet applications are regularly debated in the satellite telecommunications industry.

Once its O3b service begins, Royal Caribbean will be able to conduct a side-by-side comparison of O3b’s Ka-band offer with a competing Ku-band service the cruise company has installed on other vessels. The Oasis of the Seas will be outfitted with three 2.2-meter tracking antennas to communicate with the O3b satellites.

Peter B. de Selding was the Paris bureau chief for SpaceNews.