According to a complaint filed June 20 with the U.S. District Court for the Eastern District of Virginia in Alexandria, Orbital accuses Denver-based ULA of illegally preventing the open-market sale of the RD-180, and monopolizing the launch-services market regarding some satellites in violation of U.S. antitrust laws. Orbital is located in Dulles, Virginia

This suit furthers Orbital’s disagreement with ULA over the Russian-made RD-180 engine, which is imported to the United States. by a company called RD AMROSS, a joint venture of United Technologies Corp. of Hartford, Connecticut, and NPO Energomash of Moscow, which manufactures the engine.

Orbital requested that a federal judge strike down an exclusivity agreement ULA has with its engine supplier, RD AMROSS. Orbital also requested that the court enforce ULA pay Orbital at least $515 million. The outcome could add up to significantly more than $1.5 billion, for damages as a result of ULA’s alleged monopolization of “launch systems and services used for medium-class payload missions,” according to court papers. Orbital wants the case to go before a jury.

United Technologies Corp.’s recently divested rocket propulsion division is the original U.S. partner in RD AMROSS. The joint venture has not yet conveyed as part of that transaction.

This is due to an exclusivity agreement decades ago with Lockheed Martin, one of ULA’s two parent companies along with Boeing Co., RD AMROSS is only permitted to sell the RD-180 to ULA. Lockheed Martin, which needed a main engine for its new line of Atlas rockets, helped fund the RD-180’s development.

Currently Orbital is using 40-year old AJ-26 also known as NK-33 engines remnants from the Soviet Union’s abandoned 1970′s effort to send cosmonauts to the moon. Aerojet Rocketdyne has been refurbishing the engines for use on Antares.

Orbital is concerned about the limited supply of the engines as well as corrosion that has occurred over the past four decades. Aerojet Rocketdyne reported an agreement with a Russian company to reinitiate production on the engines providing Orbital will sign a contract to do so.