WASHINGTON — A gritty battle for dominance may be about to erupt in the rarefied atmosphere where communications satellites orbit the Earth.

Monday's official announcement that two high-tech moguls want to use low-orbiting satellites to launch a $9-billion global communications system adds a major new player to the increasingly competitive market for global communications services.

Bill Gates, co-founder of Microsoft Corp., the world's biggest computer software company, and Craig McCaw, chairman of giant McCaw Cellular Communications, unveiled their plans to form a new company called Teledesic Corp. Teledesic will seek government authority to use radio waves to deliver wireless calling, video conferencing and other advanced services to people around the world.

But Teledesic is not alone. The National Aeronautics and Space Administration, Motorola Inc., Hughes Aircraft Co. and at least four other companies have already asked the Federal Communications Commission for approval to offer new telecommunications services over parts of the same precious radio spectrum sought by Teledesic.

"The whole issue of licensing has not been resolved," said Michael D. Kennedy, director of regulatory relations for Motorola, which is a major investor in the Iridium Project, a $3.3-billion effort to build a global portable cellular telephone network using 66 satellites to transmit signals.

"One more party now has to be reckoned with, but we're confident that there's sufficient airspace to accommodate all existing requests," countered Tom W. Davidson, a Washington communications lawyer who is shepherding Teledesic's applications through the FCC.

The radio airwaves have emerged as a key battleground amid the rapid development of new technologies such as high-definition television, digital radio and wireless telephone services.

The new satellite services will compete with cable and fiber-optic phone lines for markets as the so-called information highway takes shape.

Interest in the radio spectrum is so high that the federal government estimates it can raise between $7 billion and $10 billion by auctioning space on it for the next generation of wireless telephone services alone.

As for the radio spectrum sought by Teledesic and others, the FCC has asked for industry comments on negotiating a resolution on how to divide up the limited space.