An advisory group of NASA is concerned over the possibility of the International Space Station (ISS) becoming inaccessible, with Boeing and SpaceX experiencing any delays in the completion of their scheduled commercial crew vehicles by 2018. The members of the NASA Advisory Council held a meeting on July 28, 2016 in Cleveland to discuss the matter.

The apprehensions are over the fact that NASA will not be left with any way to send its crew to the ISS in the case of both the companies’ failure to receive certification for their respective vehicles by the end of 2018, because by this time the existing agreement of NASA with Russia, which offers seats to NASA astronauts on its Soyuz spacecraft, will get expired.

The Interim Chairman of the Council’s Human Exploration and Operations Committee, Wayne Hale, explained to the council that the time schedules of both the companies entail the completion of vehicles by 2018 for sending NASA’s crew to the ISS, but the margin in those schedules is extremely little. “Human spaceflight development programs invariably suffer schedules slips due to their technical complexity, and integration of commercial providers into government service adds further obstacles,” said Hale.

He added that for this reason, it is practical to presuppose that there might be delays from the schedule in post-certification missions. During a committee meeting on July 26, 2016, the schedules submitted by the companies revealed that Boeing’s certification review, which is the final step prior to operational flights, will be completed in May 2018.

SpaceX’s certification review is set to take place in October 2017. Meanwhile, SpaceX bagged an order from NASA for a second post-certification mission on July 29, 2016, which is the fourth such mission awarded by NASA to Boeing and SpaceX, entailing transportation of crew to and from the ISS.