A federal judge March 20 dismissed Orbital Sciences’ [ORB] anti-trust lawsuit against 

United Launch Alliance (ULA) and RD AMROSS after the three parties requested dismissal the day prior.

Orbital said in a filing with the United States Securities and Exchange Commission (SEC) that it agreed to dismiss, without prejudice, its antitrust lawsuit against ULA and RD AMROSS over access to the Russian-made RD-180 rocket engine. The parties will now attempt to negotiate a business resolution for Orbital’s access to the RD-180, subject to all necessary approvals from the U.S. and Russian governments. If a mutually agreeable resolution is not reached, Orbital will have the option to refile its lawsuit.

Orbital last summer sued ULA and RD AMROSS, alleging anti-competitive practices in its quest to acquire the RD-180, which is manufactured by NPO Energomash and distributed in the United States by RD AMROSS, a joint venture of NPO Energomash andUnited Technologies Corp. [UTX] Orbital wants to break into the medium-lift launch market and saw the RD-180 as its best bet for the long term.

Orbital said in its filing that over the last year the company has conducted three successful launches of its Antares medium-class rocket, which uses liquid propulsion engines in its first stage. The Antares currently uses Aerojet-Kuznetsov AJ-26 engines and Orbital has purchased a sufficient supply of those engines for launches through 2016. For future launches after 2016, Orbital said it is considering other engines, including the RD-180. The AJ-26 is developed by Russia’s Kuznetsov and Aerojet Rocketdyne, a division of GenCorp [GY].

The Federal Trade Commission (FTC) last year began an investigation into potential anti-competitive practices on behalf of ULA and RD AMROSS related to the RD-180 and whether an agreement between the two companies for the engine’s exclusive supply is preventing other companies, like Orbital, from competing for space launch services, particularly medium-lift. The FTC doesn’t comment on the status of ongoing investigations and a spokeswoman declined comment.

Orbital CEO David Thompson told sister publication Defense Daily that the company has three plans in place to enter the medium lift market. Two of them depend on Russian engines, the NK-33 and the RD-180, and a third, which he didn’t specify.

ULA is a joint venture of Lockheed Martin [LMT] and Boeing [BA].