Retired astronaut Buzz Aldrin married his “longtime love,” Anca Faur, on his 93rd birthday on Friday.

Aldrin is known for being the second person to ever step foot on the moon, after Neil Armstrong, per CNN.

“On my 93rd birthday & the day I will also be honored by Living Legends of Aviation I am pleased to announce that my longtime love Dr. Anca Faur & I have tied the knot. We were joined in holy matrimony in a small private ceremony in Los Angeles & are as excited as eloping teenagers,” Aldrin wrote on Twitter.

Faur, 63, has a doctorate in chemical engineering and works as the executive vice president of Buzz Aldrin Ventures LLC, per the BBC. The couple have been in a relationship for more than four years, and spend time together with each other’s families, according to Aldrin’s Twitter.

This is the fourth time the astronaut has been married, People magazine reported.

Aldrin’s first wedding was in 1954, when he married Joan Archer. They stayed married until 1974 and had two children together.

He married his second wife, Beverly Van Zile, in 1975. They were married for three years.

A decade later, Aldrin married Lois Driggs Cannon. They were together for 24 years and got a divorce in 2012.

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Who is Buzz Aldrin?

Born Edwin E. Aldrin Jr., he legally changed his name to Buzz Aldrin during the early 1980s, according to Aldrin’s website.

Aldrin is one of only 12 people to ever step foot on the moon. He piloted the Apollo 11 spacecraft in 1969 and became the second person to step foot on the moon after Armstrong, per the BBC.

According to the Deseret News, Aldrin wrote a book titled “Mission to Mars” and is an advocate for sending a manned mission to Mars.