A new Pentagon study warns that losing access to Russian-made rocket engines would have a "significant impact" on the U.S.'s military space program, a Pentagon spokeswoman confirmed.
The engines power the Atlas V rockets that launch U.S. military satellites into space, and losing them would delay as many as 31 missions and cost the U.S. as much as $5 billion, according to the study.
"The department has been briefed on the findings and recommendations of the RD-180 Engine Study and is working with interagency stakeholders to evaluate the way ahead. At this point, no decisions have been made," Maureen Schumann, a Pentagon spokeswoman, told The Hill.
Lawmakers say the U.S. should not be relying on Russian rocket engines for such sensitive national security missions.
On May 13, Russian Deputy Prime Minister Dmitry Rogozin said he would ban exports of the engines.
There is currently no alternative to the engines, but the pending 2015 House Defense bill would devote $220 million to developing an alternative U.S.-made engine by 2019.
According to Space News, the Pentagon report recommends accelerating the current schedule of Russian-engine purchases.
"Actions must be taken in [fiscal year 2014] to mitigate current risk and preserve future options," said a summary of the report obtained by Space News.
Deliveries of the engines began speeding up last month.
—This report was updated at 11:25 a.m.