With Russia threatening to end its participation in the International Space Station (ISS) program and possibly even removing one of its major components from the orbiting space station after 2020, some have questioned whether the US can continue its $3 billion a year commitment to the ISS program beyond 2020.
Originally, the US had planned to decommission the ISS after 2016 in order to utilized those funds for the Constellation program which was supposed to place American astronauts back on the surface of the Moon before the end of the decade. But the Obama administration decided to end the lunar program in order to continue the ISS program. But now thanks to tensions with Russia over the Ukraine, the future of the ISS is cloudy.
Congress, however, decided that America needed to develop a heavy lift vehicle (the SLS) in order to enable American to have the lifting capability to deploy human spacecraft destined for the Moon and Mars. But the ISS could also provide America with the means to quickly and cheaply replace the ISS with a new generation of larger and cheaper private and SLS derived space stations.