Sirius could file for bankruptcy as early as Tuesday

— -- While the satellite radio company said it has exchanged $172.5 million of debt maturing in December for new debt due in 2011, it still has about $175 million coming due Sunday.

A bankruptcy filing for Sirius would give it the right to terminate contracts with on-air talent, such as Martha Stewart and Howard Stern, who has a five-year, $500 million deal. A Chapter 11 filing also could crimp Sirius' growth because subscribers might shy away from a company in bankruptcy.

Sirius has nearly 20 million listeners and provides a wide range of music, sports and talk radio.

Analysts said they don't believe DirecTV would want a satellite radio business or its satellites. DirecTV, the nation's largest satellite TV company, has launched new satellites and is focusing on enhancing its TV service.

Sirius and Liberty declined to comment.

The struggle over Sirius brings together three strong personalities: Malone, Ergen and Sirius CEO Mel Karmazin.

It also renews the adversarial relationship between Karmazin and Ergen. In 2004, when Karmazin was head of Viacom and in a dispute with Ergen over the fees Dish had to pay to carry Viacom channels, Dish published Karmazin's home phone number and told subscribers to call him.