PARIS — Mobile satellite services operator Inmarsat on March 6 told investors to expect almost no growth in its core business in the next two years as its subscriber base transitions to new-generation services and troop withdrawals from Iraq and Afghanistan reduce military use.

But starting in 2014 with the entry into service of Inmarsat’s $1.2 billion Global Xpress Ka-band broadband satellite service, the company expects its revenue to grow by between 8 and 12 percent a year for at least three years.

In conference calls, Inmarsat officials readily conceded that the company’s 20 percent revenue growth in 2011, to $1.4 billion, was almost entirely due to payments from LightSquared of Reston, Va., a company that had been paying to use Inmarsat spectrum in North America to develop its own hybrid satellite-terrestrial broadband wireless network.

Following extensive testing that showed LightSquared’s planned service would interfere with commercial and government use of the GPS positioning, navigation and timing satellite constellation, U.S. regulators have declined to give the company an operating license. LightSquared’s survival is now in question.

Inmarsat has received $490 million from LightSquared so far, including $204 million in 2011. LightSquared missed a $56 million payment due in February. A $30 million payment is due March 31.

“There is now significant uncertainty regarding the future of LightSquared,” Inmarsat Executive Chairman Andrew Sukawaty said. “We knew it was high risk, and we structured [our LightSquared agreement] accordingly. We had to be sure our business was protected, and we believe it is.”

Without saying so directly, Sukawaty made clear that prudent investors should assume that Inmarsat will receive no more cash from LightSquared.

Inmarsat Chief Financial Officer Rick Medlock said some $239 million in LightSquared payments have yet to be booked by Inmarsat and is viewed as deferred revenue pending Inmarsat’s expenses to clear its use of L-band spectrum in North America to accommodate LightSquared. Medlock said it remained uncertain when Inmarsat would be able to book this revenue.

An Inmarsat spokesman said after the calls that none of the revenue received from LightSquared is at risk of being returned. The only question is when it will be booked, the spokesman said.

Inmarsat’s business selling mobile satellite communications services to the U.S. and allied militaries in Iraq and Afghanistan totaled some $40 million in 2010 and dropped to around $20 million in 2011, Medlock said. The figure likely will continue to decrease in 2012, he said.

In addition to the effect of the troop withdrawal, Inmarsat in 2011 suffered from what company officials say are the temporary effects of migrating maritime customers to Inmarsat’s latest Fleet Broadband higher-speed service. Commercial fleets do not change out equipment overnight, and Inmarsat has said those that do upgrade to the new equipment naturally spend less because, on a per megabyte basis, the new service is much less expensive.

As they adapt to the new gear, customers will increase their monthly spending, a phenomenon that Inmarsat’s new chief executive, Rupert Pearce, said started to become visible in late 2011. Inmarsat is also adding a low-end Fleet Broadband 150 product to extend the product into smaller ships, including coastal fishing vessels and cruise ships.

Pearce said 25 percent of recent Fleet Broadband installations have been of the 150 model.

How much of a threat to Inmarsat’s maritime business is posed by traditional satellite operators whose Ku-band satellites include offshore coverage is a matter of debate in the industry. Inmarsat has lost a couple of recent competitions for new installations on commercial fleets but insists that the publicity surrounding the entry of VSATs, or very small aperture terminals, into the maritime market has exaggerated the picture.

Notwithstanding that assessment, Inmarsat has decided to try to make life more difficult for VSAT network operators. For midsize ships, Inmarsat is raising its user charges to encourage subscribers to migrate to the new-generation Fleet Broadband service.

For larger ships, Inmarsat will begin slapping a monthly charge on ships that have Inmarsat hardware, regardless of whether they use the service.

Pearce said the price rise will not affect vessels that actually use the Inmarsat service. But it will end what he called the “free-riding” that occurs when ships keep the Inmarsat equipment for when they are beyond VSAT coverage or in weather too rough for VSAT links, but otherwise use only VSAT gear.

“The legitimacy that we have given them has come to an end,” Pearce said, adding: “I don’t think we have been hearing squeals” in protest of the price increase among customers, only among VSAT network operators.

Inmarsat in early 2010 introduced a hand-held telephone for the first time in its history. The goal was to occupy the low end of the market with a phone that cost half the price of equipment sold by competitor Iridium Communications of McLean, Va.

Inmarsat said that it has now sold 50,000 ISatPhone Pro handsets and is closing in on its target of a 10 percent market share by mid-2012. Inmarsat estimates the global market for satellite handsets at around 600,000 units.

Pearce said the company would be focusing on increasing the revenue it generates per handset, moving closer to the Iridium customer base before competitor Globalstar of Covington, La., recovers from a partial failure of its low-orbiting constellation and fields a second-generation system by 2013.

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