US Air Force Secretary Deborah Lee James stated that the US air force is working with Congress to ease restrictions on the use of Russian RD-180 rocket engines.

The US air force is working with Congress to ease restrictions on using Russian RD-180 rocket engines, US Air Force Secretary Deborah Lee James stated on Wednesday.

In 2014, Congress passed a law requiring the United States to develop a domestically produced next-generation rocket propulsion system by 2019 in order to eliminate reliance on the Russian RD-180 rocket engines.

"We are trying to work this through with Congress to essentially give us a little bit more leeway either allow us to use a few more [RD-180] engines for a few more years until we can get this developmental program completed," Lee James said.

She added that the US military believes a new engine will be developed in less than a decade, but that still falls short of the deadline requested by Congress.

The US government is currently looking to award contracts to manufacturers to expedite the replacement of the RD-180 engine.

US lawmakers are also looking into the domestic development of entirely new generation of space launch vehicles in partnership with private companies including SpaceX, Boeing and Lockheed Martin.