PARIS — Satellite ground communications manufacturer Comtech Telecommunications is sticking with its earlier revenue and gross-profit forecasts for 2012 despite what it says are signs that pressure on U.S. government spending, its primary source of revenue, is increasing on all fronts.

In particular, the company told investors, its biggest microsatellite contract, with the U.S. Naval Research Laboratory, now appears under threat of cancellation.

Melville, N.Y.-based Comtech’s AeroAstro division is building a satellite platform, or skeletal structure, for a star-mapping satellite called Joint Milli-Arcsecond Pathfinder Survey, or JMAPS, under two contracts with a combined value of $43.4 million. The satellite was to have been launched in 2015.

Comtech had hoped that this contract would pave the way for future work for its microsatellite division. Company Chief Executive Fred Kornberg, in a Dec. 9 conference call with investors, said he is still hopeful that a tight budget environment will cause U.S. government agencies to seek out smaller, less expensive satellites such as those that AeroAstro can build.

But JMAPS is in trouble. “As a result of the extreme pressures on our U.S. government customer to reduce its spending, we believe that additional bookings for our large microsatellite contract have become less certain,” Comtech said in a Dec. 8 filing with the U.S. Securities and Exchange Commission (SEC).

Kornberg said Comtech is already certain of receiving the expected JMAPS revenue in 2012 and early 2013. Further work is uncertain, but he said he remains confident that “the customer will eventually find the funds to complete it. It was just a warning.”

The microsatellite work was to have been a growth relay as Comtech transitions its business following the loss of its two showcase U.S. Army contracts, the Movement Tracking System (MTS) and the Blue Force Tracking (BFT)-1 work that together have been central to Comtech’s financial performance for the past decade.

The U.S. Army selected ViaSat Corp. of Carlsbad, Calif., for the second-generation BFT work, called BFT-2, and is gradually winding down its work with Comtech. Still undetermined is how fast the wind-down will occur, and how much “sustainment” work on MTS and BFT-1 the Army will request Comtech to perform in the coming three to five years.

In the conference call, Kornberg said Comtech is still negotiating with the Army on the kind and amount of MTS and BFT-1 work Comtech will do. Comtech has said that, depending on what the Army decides, the company may inaugurate a new pricing system for Comtech-owned intellectual property used in MTS and BFT-1. This would compensate the company for the possible loss of the contract to provide the Army with commercial satellite capacity as part of the hardware delivery contract.

The Army has said it may secure its own satellite bandwidth, a decision that would further reduce Comtech’s revenue stream.

Kornberg said Comtech technology could be integrated into the BFT-2 network. But BFT-2 technology also could be applied to the Comtech hardware. It is unclear which way the Army will go, he said.

Comtech revenue for the three months ending Oct. 31, the first quarter of the company’s fiscal year, from MTS and BFT-1 was $25.7 million, compared with $95.8 million in the same period a year earlier. As of Oct 31, Comtech had $27.1 million in MTS and BFT-1 work remaining in its firm backlog.

The company’s total revenue for the quarter was $113.4 million, down from $178.2 million a year ago. Operating income was 13.9 percent of sales, dragged down by the RF Microwave Amplifiers division, which for the past couple of years has showed much lower profitability than the Telecommunications Transmission and Mobile Data Communications divisions.

Comtech Chief Financial Officer Michael D. Porcelain said the company’s overall performance for the three months ending Oct. 31 was better than expected. The problem is that the U.S. government budget environment, plus softness in some of Comtech’s other markets, makes it difficult to predict how the coming months will develop.

For now, Comtech is sticking with its earlier forecast that total revenue will be between $400 million and $430 million, with EBITDA, or earnings before interest, taxes, depreciation and amortization, at about 17.5 percent of revenue.

A bright spot, Kornberg said, is the company’s 500-watt Ka-band tube amplifier for high-throughput broadband satellites. Satellites of this type are just now entering the commercial market in Europe and North America, and represent a high-growth area in an otherwise static overall satellite manufacturing market

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