BERLIN (AP) — Friction between the United States and Russia over Ukraine won’t spell the end of the International Space Station, the head of NASA said Monday, dismissing concerns that one of the world’s most prestigious scientific endeavors could fall victim to political disagreement.

The comments by NASA Administrator Charles Bolden come a week after Russia warned that it could cease cooperating with the U.S. on the project after 2020. Although Japan, Europe and Canada are also members, all currently depend on Russian Soyuz capsules to take astronauts to the space station since NASA retired its shuttle fleet.