The US Air Force formally kicked off a contest for the development of new rocket propulsion systems which would replace Russian-built RD-180 engines, Lieutenant General Samuel Greaves, Chief of the Air Force's Space and Missiles Systems Center, said on Wednesday.

The RD-180 engine used for powering the Atlas 5 rocket has no US-made analogues so far.

According to the general, the program will be implemented using a public-private partnership. The government hopes do divide $160 million in contracts between four bidders by September 2015. The bidders are required to use their own funds to cover at least a third of the prototypes. Initial proposals are due by June 23.

Among main contenders are United Launch Alliance (ULA, a joint venture by Lockheed Martin Corp and Boeing), SpaceX and Aerojet Rocketdyne Holdings Inc.

On December 2014, the US House of Representatives adopted Senator John McCain-sponsored amendment which presumes ending US reliance on the RD-180 engine by 2019.

The amendment does not cover the contract between ULA and Russia's Energomash which is due to expire by 2019. It was also reported that the Congress unveiled $220 million for the development of new US-built rocket engines.

In March, the US government announced it would start taking bids for ending US reliance on Russian rocket engines. The competition will cover 28 launches planned for 2020-2024.

Source: Sputnik News