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Koichi Wakata (twice)
Rex J. Walheim (thrice)
Shannon Walker
Carl E. Walz
Mary E. Weber
James D. Wetherbee (twice)
Douglas H. Wheelock (twice)
Peggy A. Whitson (twice)
Terrence W. Wilcutt
Dafydd Williams
Jeffrey N. Williams (thrice)
Sunita L. Williams (twice)
Barry E. Wilmore
Stephanie D. Wilson (thrice)
Peter J.K. Wisoff
David A. Wolf (twice)Read more about this topic: List Of International Space Station Visitors