American Satellite Co., trying to boost its position in the telecommunications industry, has arranged a $350 million unsecured loan to enable the 8-year-old company to launch its own satellite system.

The loan -- one of the largest unsecured loans ever extended to a domestic satellite carrier -- has been heralded by ASC officials as a significant step for the company, which is a joint venture between Fairchild Industries and Continental Telecom Inc.

The loan, arranged by the Bank of America NT&SA, will enable ASC to quadruple its present satellite capacity and will, for the first time, give the company its own satellite system to provide private, specialized telephone networks to large corporations and government agencies.

Under the loan, ASC plans to launch its own system of three satellites -- with one acting as a spare. The first launch is scheduled for three years from now on the space shuttle.

"The primary purpose of the loan is to acquire a space segment of our own," explained Lee M. Paschall, ASC's president. "Our growth projections show that we need to acquire our own satellite system" to meet the increasing demand for satellite services.

The company's assets total $141 million, and ASC predicts they will triple within the next four years to more than $500 million.