The thing is that after the "cooling" of relations with our country, the Americans began to build their own transport system at an accelerated pace, so that in the future they would not be dependent on Russia. The leaders were SpaceX and Boeing, which created the Crew Dragon and Starliner spacecraft, respectively. However, during the testing of promising ships every now and then problems arise, and the terms of the manned mission are constantly delayed.
In particular, during the testing of the Crew Dragon emergency rescue system, the latter simply exploded. After that, the head of SpaceX Corporation, Ilon Mask, began to be asked a lot of “uncomfortable” questions about spending budget funds. In turn, the functionary promised to send the first astronauts to the ISS next year.
Despite Musk’s assurances, NASA was still “nervous” and turned to Roskosmos with a request to find additional space for them on the Soyuz spacecraft. However, our country refused.
At the same time, the reason for the negative response was by no means “strained relations”, but a banal lack of places. The thing is that the construction of one "Union" takes 2,5 - 3 years. That is why all contracts are signed for several years in advance, and Russia has repeatedly warned its American colleagues about this. Now, an additional NASA astronaut flight in 2020 can take place only if our astronauts give way to them. But this option is completely excluded, as it will entail the failure of the Russian space program.
In this case, the Americans can only hope that SpaceX and Boeing will fulfill their promises and finish work on their own ships next year. Otherwise, NASA will again have to “beg” Congress to extend the contract with Roskosmos, which will not be easy.
It is worth recalling that congressmen have repeatedly tried to introduce a ban on the supply of our RD-180 engines in the United States. However, the decision was constantly delayed due to the lack of replacement for Russian units.
And everything would be fine, if not for another piquant detail. It is the RD-180 that should be used to launch the promising Boeing Starliner ship.