CAPE CANAVERAL, Fla. — SpaceX delayed its second astronaut flight by a day because of high wind and weather conditions that could jeopardize the recovery and recycling of the rocket booster, pushing the launch to Sunday.

Friday’s postponement news came after SpaceX chief Elon Musk disclosed he had gotten mixed test results for COVID-19 and was awaiting the outcome of a more definitive test.

NASA Administrator Jim Bridenstine said anyone testing positive for COVID-19 must quarantine under NASA policy and remain isolated. Officials said contact tracing by SpaceX found no link between Musk and any personnel in close touch with the four astronauts, who remain cleared for flight.

It wasn’t immediately known if Musk would be allowed at the Kennedy Space Center launching site even if later tests came up negative.

Musk said via Twitter that he tested positive for coronavirus, then negative twice, then positive again. He said he wasn’t feeling too well the past few days — sniffles, cough, low fever — but currently had no symptoms.

“So ‘Elon Musk Tests Negative for Covid’ is an equally correct title,” he tweeted.

Musk said his first tests were rapid tests, and he was awaiting the results of lab tests. The 15-minute rapid tests are less sensitive than the lab tests, which taken longer to process.

NASA and SpaceX representatives wouldn’t say where Musk was Friday, although officials confirmed he was not at Kennedy. His company is based in Southern California, where he makes his home. He was inside Kennedy’s Launch Control last May for SpaceX’s first astronaut flight last May.

NASA Turned Over Space Station Ferry Trips to SpaceX and Boeing

Four astronauts — three Americans and one Japanese — are scheduled to rocket to the International Space Station on Sunday night.

“NASA and SpaceX are going to work through it together and come to the right conclusion,” Bridenstine told reporters. “Our astronauts have been in quarantine for weeks and they should not have had contact with anybody (outside their tested inner circle). They should be in good shape.”

Bridenstine said it was too early to know if any changes will be necessary in the final stages of the countdown.

One of the test pilots on SpaceX’s first astronaut flight, Doug Hurley, said he’s certain Musk will be involved with the launch — regardless of where he is.

“Knowing Elon the way I do, they will figure out a way for him to be very much connected,” Hurley told The Associated Press from Houston.

The upcoming crew flight comes just three months after the end of the test flight with Hurley and Bob Behnken, both NASA astronauts. The four are going up for a full space station stay of five to six months. They will be replaced in the spring by yet another crew launched by SpaceX. The company reuses rocket boosters and this one was expected to be used again in the spring.

NASA turned over space station ferry trips to SpaceX and Boeing, which has yet to launch anyone, following the retirement of the shuttle fleet in 2011. The space agency is looking to save big by no longer having to buy seats on Russian Soyuz capsules for U.S. astronauts. The last ticket, used by a NASA astronaut launched from Kazakhstan in October, cost $90 million.