Attendees take pictures of the Crew Dragon spacecraft during the NASA Commercial Crew Program (CCP) astronaut visit at the Space Exploration Technologies Corp. headquarters in California.

SpaceX has had six employees test positive for COVID-19 as of Monday, according to an internal company memo seen by CNBC.

Elon Musk's space company has limited the number of employees physically working at its facilities, like others in the industry. But SpaceX operations have continued after it was deemed "mission essential" by the Department of Defense. A Pentagon letter allows companies working national security contracts to continue work, even if state governments enforce shelter-in-place orders.

The SpaceX memo noted that one of the employees recently identified has self-isolated. The company has also previously directed employees who may have been exposed to self-isolate, a precautionary measure it took after the company's first employee case last month.

SpaceX did not respond to CNBC requests for comment.

NASA, like the Pentagon, has also determined that its upcoming SpaceX Demo-2 launch is mission essential. NASA Administrator Jim Bridenstine told CNBC last week that, despite the coronavirus crisis, his agency and SpaceX are still aiming for late May to launch Demo-2. The mission will be the first time SpaceX sends astronauts to space.