Apollo 11 moonwalker Buzz Aldrin is expected to be noticeably absent from a gala kicking off a yearlong celebration of the 50-year anniversary of the first moon landing even though his foundation is a sponsor and he usually is the star attraction.

Organisers haven't heard one way or another if Aldrin is attending Saturday evening's Apollo Celebration Gala at the Kennedy Space Center in Florida, but they expect him to be a no-show.

Aldrin's expected absence comes just a month after he sued two of his adult children and a former business manager, accusing them of misusing his credit cards, transferring money from an account, and slandering him by saying he has dementia.

Just weeks before, his children, Andrew and Jan, had filed a petition claiming their 88-year-old father was suffering from memory loss, delusions, paranoia, and confusion.

Andrew and Jan Aldrin, as well as business manager Christina Korp, are on the foundation's board and were expected to be at Saturday evening's gala.

"We haven't heard one way or another," Jeff Carr, a spokesman for the foundation, said on Friday about Buzz Aldrin. "At this point, it's a little too late to include him in the program. He hasn't reached out or let anybody know his plans."

The black-tie gala held under a Saturn V rocket at the Kennedy Space Center features a panel discussion by astronauts, an awards ceremony and an auction of space memorabilia. Tickets range from $US750 to $US2500 per person.

Aldrin, along with Neil Armstrong and Michael Collins, was part of the Apollo 11 mission that landed the first two humans on the moon on July 20, 1969.