The company's billionaire CEO has previously described it as the "holy grail" of space travel.
According to a NASA statement, the heat shield attached to the Crew Dragon spacecraft meant to take the next crew of astronauts to the International Space Station in September as part of the Crew-5 mission has a big problem.
It is necessary to replace it to keep astronauts safe.
When the heat shield was put through the landing loads, it did not pass, according to Steve Stich, NASA commercial crew program manager.
We knew we couldn't go forward and fly that heat shield because of the damage we could see from that test.
It is a rare instance of a piece of SpaceX hardware showing serious wear and tear after being in the air for a while, and shows just how intense the reentering atmosphere can be on the company's materials.
The news came just after NASA denied rumors about a damaged heat shield on the AX-1 spaceship that splashed down last month.
The thermal protection system material itself is replaced on every single crewed mission and therefore shouldn't be a problem, as the agency clarified at the time.
A re-enactment of a spaceship is a must for increasing our ability to explore the universe. Do you want to fly a craft that had a major mechanical test failure when you get to do it?
Boeing's attempt to compete with SpaceX is even more difficult than we thought.