The FAA on Sept 30 said SpaceX had to investigate why the second stage of its Falcon 9 malfunctioned after a Nasa astronaut mission, grounding the launch vehicle for the third time in three months.

The malfunction caused the booster to fall into a region of the Pacific Ocean outside of the designated safety zone the FAA approved.

The FAA also said Friday it closed the SpaceX-led investigations for the Falcon 9 mishaps that occurred with Starlink missions in July and August.

On Sunday, the FAA said SpaceX’s workhorse Falcon 9 rocket could return to flight solely for a mission on Monday for the European Space Agency’s Hera spacecraft from Florida.

Separately, Reuters reported this week the FAA could approve a licence for the launch of SpaceX’s Starship 5 as soon as this month. Starship 5 is the fifth test launch of the company’s rocket which it calls Starship.

The Starship spacecraft and Super Heavy rocket are a fully reusable system designed to carry crew and cargo to Earth orbit, the Moon and beyond.

Last month, the FAA said it did not expect a determination on a licence before late November. SpaceX said Monday Starship’s fifth flight test could launch as soon as Sunday, pending regulatory approval.

The FAA has repeatedly said it did not expect to decide on a licence until late November. On Tuesday it said only that it was still reviewing the proposed mission and would make a decision “once SpaceX has met all licensing requirements”.

SpaceX CEO Elon Musk has harshly criticised the FAA, including for proposing a US$633,000 fine for SpaceX over launch issues and for the delay in approving the licence for Starship 5, which the company says has been ready to launch since August. Musk has called for the resignation of FAA administrator Mike Whitaker and threatened to sue the agency.