The Pentagon will review rocket launches by Elon Musk's SpaceX, it has said.
The certification that allows the company to send launch vehicles into space will be reviewed to check that the US Air Force complied with the requisite guidelines, investigators said in a memo.
“Our objective is to determine whether the U.S. Air Force complied with the Launch Services New Entrant Certification Guide when certifying the launch system design for the Evolved Expendable Launch Vehicle-class SpaceX Falcon 9 and Falcon Heavy launch vehicles,” wrote US Department Of Defense Deputy Inspector General Michael Roark.
SpaceX successfully launched its first national security space mission for the US in December. One of its rockets carried a military navigation satellite into space from Florida's Cape Canaveral, marking a major moment for Mr Musk's company.
The US government hopes that many space missions will eventually be taken over by private companies such as SpaceX and its competitors, with the hope that it could make launches cheaper.
The review comes at a difficult time for SpaceX, which said last month that it would sack about 10 per cent of its more than 6,000 employees. It said then that it was facing "extraordinarily difficult challenges".
The memo to SpaceX – which requested to speak to someone familiar with the certification, and said investigations would begin in February – did not say why specifically the new review had been launched, or whether there was any likelihood that the certification itself would be changed.