Thruster glitches and helium leaks can't stop Boeing's Starliner astronaut test flight — but why are they happening?

A metallic capsule is seen, looking very tiny against the backdrop of Earth.

When NASA astronauts tried to dock Boeing's first crewed Starliner spacecraft at the International Space Station Thursday (June 6), they had to wait. 

Five aft thrusters on the Starliner service module were out. And that was after flight controllers found workarounds for two new helium leaks on the spacecraft on top of one it already had. Also, its cooling system was using more water than expected, and another helium leak would be detected later after Starliner docked with the space station.