SpaceX, Boeing face delays and technical challenges as they work to restore human spaceflight for NASA

NASA’s bold experiment to rely on contractors to provide a taxi service for its astronauts to the International Space Station is running into troubles that could delay the first flights and leave the space agency without a way to get its astronauts to the orbiting laboratory.

In prepared testimony submitted to a congressional hearing on the status of the program, the Government Accountability Office said ongoing “delays and uncertain final certification dates raise questions about whether the United States will have uninterrupted access to the [space station] after 2019.”