Amidst Russia’s current involvement in Ukraine, United Launch Alliance (ULA) — a 50-50 joint venture owned by Lockheed Martin and The Boeing Company — has signed commercial contracts with multiple American companies to explore alternative rocket engine concepts to the current Russian-based models.

The contracted companies have signed on to “investigate next-generation liquid oxygen/hydrocarbon first stage propulsion concepts,” according to a release.

In collaboration with ULA, each company will conduct technical feasibility analysis, develop high fidelity plans, identify schedule, cost and technical risks, as well as cost estimates to meet aggressive recurring cost targets. All concepts will support a first launch by 2019.

Reuters reported:

The U.S. Defense Department, spurred by growing concerns over Russia’s actions in Ukraine, has said it wants to end its dependency on Russian engines to power rockets that launch national security satellites into space.

“ULA has a number of very promising alternatives and we are working with the very best propulsion companies in America,” said Dr. George Sowers, ULA’s vice president of Advanced Programs, and lead for the propulsion study. “There are many exciting advanced technologies that are mature and can be used to enhance our capabilities and our competitiveness.”