The United States military's space program could see more than 30 missions delayed for an average of three and a half years each if Russia follows through with its threat to ban exports of the RD-180 rocket engines used for launching satellites, according to a Pentagon report obtained by SpaceNews. The Pentagon reportedly also found that, in a worst-case scenario, the delays may cost the US as much as $5 billion. In a best-case scenario, the numbers drop to nine missions delayed by around two years each and a loss of $2.5 billion.

The US 'needs to develop a domestic engine'Russia's Deputy Prime Minister said the ban would be going into place earlier this month, but SpaceNews reports that the government is yet to see signs that it's been put in place. While that remains the case, the Pentagon suggests accelerating the pace at which RD-180s are purchased to increase the remaining US stock. Right now, there are reportedly only 15 of the engines left between the military's rocket contractors, United Launch Alliance and RD Amross.

The Pentagon reportedly also found that speeding up production of a US-made engine that's in the works from United Launch Alliance would not be able to avoid the delays. Nonetheless, it noted that the US "needs to develop a domestic engine." Elon Musk and SpaceX, of course, would be happy to provide that. SpaceX is currently suing the government over what it alleges is a monopoly being granting to United Launch Alliance. Should the government begin to choose SpaceX, Musk claims that it would save the US over $1 billion each year. Should United Launch Alliance become an unviable option as engine supplies dwindle, it may well have to shop around.