PARIS — A data center financed by three of the world’s largest commercial satellite fleet operators to coordinate satellite maneuvers and broadcasts to avoid orbital collisions and signal interference is scheduled to begin full operations the week of April 11.

The Space Data Association (SDA), founded by Intelsat and SES of Luxembourg, and Inmarsat of London, has not yet achieved the support of as many other satellite operators as had been expected at this point.

But SDA Chairman Stewart Sanders said four other operators — Paradigm Secure Communications of Britain, which owns Britain’s military telecommunications satellites; Star One of Brazil; EchoStar of Englewood, Colo.; and low-orbiting Earth observation satellite operator GeoEye Inc. of Dulles, Va. — have taken steps to assure they will become part of the SDA effort shortly following its entry into operations.

Sanders, who is senior vice president for engineering at SES, said in an April 6 interview that SDA representatives are continuing to make presentations to individual satellite operators, some of which are still worried that SDA participation means giving away corporate secrets.

Such worries are unnecessary, said Sanders, who pointed to the fact that SES, Intelsat and Inmarsat are themselves competitors.

Located in the Isle of Man and created in 2009, SDA in 2010 contracted with Analytical Graphics Inc. (AGI) to create the Space Data Center database. Exton, Pa.-based AGI subsequently transferred to SDA a program called Socrates that AGI had been managing since 2008 through AGI’s Center for Space Standards and Innovation division.

With the Socrates data added, SDA’s database now includes information on nearly 200 satellites in geostationary orbit owned by 13 operators, with the three founding members accounting for half of these. The database also includes more than 100 satellites in low Earth orbit owned by seven companies, including the 66-satellite constellation operated by Iridium Communications of McLean, Va.

The AGI software is similar to products produced by other companies, including Integral Systems of Columbia, Md., that enable operators to identify the location of frequency interference, most of which is accidental. A second goal of SDA is to reduce the likelihood of an in-orbit collision by acting as a clearinghouse for operators to notify other operators of a planned in-orbit maneuver.

Paul Welsh, AGI vice president for business development, said in an April 6 interview that the recent months-long uncontrolled drift by the Intelsat Galaxy 15 satellite is an example of why SDA is needed.

While the Galaxy 15 episode was well known to all satellite operators in the geostationary arc 36,000 kilometers over the equator, and to the U.S. Defense Department’s Space Surveillance Network of ground-based radars, the data produced on its whereabouts was often faulty.

“We found discontinuities in about 15 percent of the TLE [two-line element] data produced by the Defense Department,” Welsh said. Most of the problems, he said, resulted when the Space Surveillance Network mistook the Galaxy 15 satellite for one of the satellites whose orbital station Galaxy 15 was traversing as it wandered, uncontrolled, along the geostationary belt.

Intelsat and SES worked together to craft maneuvers that permitted Galaxy 15, whose C-band broadcast payload was still active, to cross other satellites’ terrain with little or no interference with these satellites’ broadcasts.

Welsh said he is confident that many commercial and government operators who have remained hesitant to join SDA will become members once AGI transfers control of the operational database to SDA in mid-April.

“Once everybody sees it is operational, and that it does not require the use of sensitive data, you will see SDA adding members,” Welsh said.

Managers from Paris-based Eutelsat, which after Intelsat and SES is the third-largest commercial fleet operator in terms of revenue, have said they will join SDA. Other notable absences up to now are Telesat of Canada, DirecTV Group of Los Angeles, the Russian Satellite Communications Co., the Indian Space Research Organisation and China’s direct-broadcast satellite operator, China DBSat.

The U.S. Air Force is also absent. Richard W. McKinney, deputy undersecretary for space programs at the Air Force, said the U.S. government has a favorable view of SDA but is still sorting out a policy on whether to join and what information to put into the database.

Sanders said SDA’s goal is to better manage the physical space in orbit — meaning traffic management, especially in low orbit but also in higher geostationary orbit — and to reduce the amount of frequency interference that occurs.

Cost, Sanders said, should not be an issue. Now that the founding members have undertaken the startup charges, operating the Space Data Center will cost less than $2 million per year, he said.

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