PARIS — Mobile satellite services provider Globalstar is entering a make-or-break period during which it is counting on new satellites to generate sufficient revenue to pay off debts associated with the billion-dollar second-generation constellation, according to company and industry officials.

The Covington, La.-based company, which in the past three years has become expert at walking the high wire, has slashed expenses sufficiently to report a gross profit for the three months ending Dec. 31.

It has succeeded in deferring payment to its ground infrastructure suppliers, Hughes Network Systems and Ericsson, in return for paying interest on the outstanding balance, and has renegotiated the bank loan that is the centerpiece of its financing.

But key payment milestones begin arriving March 30 for the Hughes contract, and June 28 for the Ericsson work, Globalstar said in a March 13 filing to the U.S. Securities and Exchange Commission (SEC).

Just as urgent for Globalstar is placing its new satellites into service to restore the company’s two-way voice subscription base.

Eighteen of the 24 second-generation satellites under contract have been launched. Anthony J. Navarra, president of the company’s global operations, said during a March 12 conference call with investors that all 18 should be in final operating position by late this summer.

The fourth and final batch of six satellites is tentatively scheduled for launch in August or September aboard a single Soyuz rocket operated by Europe’s Arianespace launch consortium from the Baikonur Cosmodrome spaceport in Kazakhstan.

The timing of this launch depends in part on whether Globalstar and its satellite prime contractor, Thales Alenia Space of France and Italy, are able to develop a software patch to overcome a momentum-wheel defect affecting several satellites launched in 2010 and 2011.

Globalstar Chairman Jay Monroe said the momentum-wheel issue has not affected the six satellites launched in December. Monroe’s New Orleans-based Thermo Capital Partners investment group has kept Globalstar afloat in recent years as it has lost subscribers because of radiation-caused degradation of its first-generation satellites.

“We will implement the [momentum-wheel] fix in the next six months,” Monroe said during the conference call.

A big question for Globalstar is how many subscribers to the voice service will return once the second-generation constellation is capable of providing reliable coverage. Monroe said the company should be able to offer a call completion rate of 80 to 90 percent once the current 18 satellites are in final position.

In the conference call and the SEC filing, Globalstar told investors that its current cash on hand — $10 million as of Dec. 31 — plus a $46 million account provided by Thermo and a rise in cash flow from the return of voice subscribers will be sufficient to meet the company’s financial obligations for 2012.

Globalstar’s revenue in 2011 was $72.8 million, up 7 percent from 2010. Operating expenses in 2011 totaled $146 million.

The company’s revenue growth “should really pick up steam in 2012 and be really robust in 2013 with the new constellation,” Monroe said March 14 at the Satellite 2012 conference in Washington, organized by Access Intelligence LLC.

While a delay in the launch of the final six satellites to late 2012 could reduce the amount of voice revenue the company generates in 2012, it also would push out Globalstar’s first principal payment on its $586.3 million in bank debt.

Ninety-five percent of that sum was guaranteed by France’s export-credit agency, Coface, which supported Globalstar to generate work in France for Thales Alenia Space and launch-related work for Evry, France-based Arianespace.

Under the terms of the Coface-backed facility, which has been renegotiated several times, Globalstar must begin repaying the principal either eight months after the last launch of six satellites or on June 30, 2013 — whichever comes first.

Investments in an upgraded ground infrastructure for the second-generation satellites, plus construction of at least six more spacecraft, will require Globalstar to raise fresh equity or debt.

For the next couple of years, Globalstar is counting on eight first-generation satellites launched in 2007 to continue functioning at full strength alongside the 24 second-generation spacecraft. Eventually, however, these eight satellites are likely to show the same radiation-caused erosion of voice service as the 28 other first-generation satellites, which were launched around 2000.

While the first-generation satellites continue to provide data service, notably with Globalstar’s popular Spot GPS Messenger hand-held device, the monthly revenue from data subscribers is only half of what voice subscribers pay on average.

Globalstar and Thales Alenia Space have entered arbitration proceedings over whether the satellite builder is obliged to build more spacecraft under terms agreed to in a contract that Globalstar insists remains valid. Thales Alenia Space argues that the contract was terminated.

Monroe said the arbitration panel is expected to deliver a ruling “in the near future.”

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