WASHINGTON — Satellite hardware builder SpaceQuest Ltd. entered the space-based services market with the launch of two ship tracking satellites last year, and has contracted to launch two more satellites for the constellation in December, a company official said.

Fairfax, Va.-based SpaceQuest claims to be the only firm in the world with a global space-based Automatic Identification System (AIS) capability, and two more satellites will allow it to deliver even more-precise ship tracking data, according to Dino Lorenzini, the company’s chairman and chief executive. The company plans to launch two additional pairs of satellites in 2011 and 2012.

SpaceQuest was founded in 1994 by Lorenzini and Mark Kanawati, and has delivered satellite platforms, GPS receivers, communications payloads and other space-hardware systems to a variety of government, commercial and academic customers.

The company saw a growing market for machine-to-machine messaging and AIS data transmission so it financed the construction and launch of the AprizeSat-3 and AprizeSat-4 satellites with retained earnings and home equity loans, Lorenzini said in an interview. The satellites were lofted in July 2009 as secondary payloads on a Russian Dnepr rocket out of Kazakhstan. The next two satellites will also launch on a Dnepr, a converted ballistic missile.

AIS originally was conceived as a way for ships to avoid collisions by providing data on other ships in the immediate vicinity. Any ship weighing more than 300 tons is required by the United Nations to carry an AIS transmitter, which sends out a signal every six seconds with information including the ship’s position, direction, speed and contents. Nations also use AIS data to monitor which ships are approaching their coastlines.

The U.S. Coast Guard has a need for a space-based AIS capability to track ships in the middle of the oceans. The service contracted with Orbcomm Inc. of Fort Lee, N.J., to put AIS receivers on six satellites that were launched in 2008. Four of these satellites failed on orbit, but the other two are providing operational AIS data to the Coast Guard and Navy, Orbcomm spokeswoman Jennifer Lattif said in an e-mailed response to questions. These satellites are in inclined orbits that provide coverage between 65 degrees north and 65 degrees south latitude.

Orbcomm is building at least 18 satellites for its next-generation constellation of two-way messaging spacecraft, each of which will have an AIS receiver. The first few of these satellites are slated for launch between December 2010 and March 2011, Lattif said. Other firms have also announced plans to launch AIS satellites.

SpaceQuest’s 13-kilogram AIS spacecraft are in near sun-synchronous polar orbits that circle the globe 14 times each day. From this orbit, the constellation covers any given mid-latitude region four or five times a day, Lorenzini said. The satellites are collecting some 460,000 AIS transmissions from 22,000 ships each day. The number of AIS transmissions collected each day should well exceed  1 million after the two new satellites are on orbit, he said.

SpaceQuest has only one customer now paying for AIS data, but it hopes a larger constellation with more-frequent revisits will attract more business from government and commercial customers, Lorenzini said. The company is looking for partners to integrate its AIS data with other information and create customized screen displays, which will be more valuable to customers than raw data, Lorenzini said.

“The thing we find most interesting is the commodity traders, who are very interested in knowing about the flow of energy around the world,” he said. “There’s a lot of work being done all the time looking at ships leaving and arriving at various ports, and this gives them some additional insight.”

In addition to tracking ships, SpaceQuest hopes to market other capabilities, such as monitoring the levels of propane tanks. There are about 17 million propane tanks in the United States, and many of them are monitored manually by dispatched workers, Lorenzini said. Sensors could be installed on propane tanks that transmit fuel level information up to SpaceQuest’s satellites, which would relay that information to a ground station and automatically send a message to the customer.

“We’ve analyzed some of the data from our propane tank partners, and on average the tanks are still 55 percent filled when they go to fill them,” he said. “To be able to get down to 15 or 20 percent with confidence will enable them to make fewer trips.”

The company estimates it needs $3 million to $5 million to launch the service on a large scale, and it is still looking for an investment partner.