Veteran NASA astronaut Leroy Chiao will replace William S.
McArthur, Jr., as the commander of Expedition 9, the next
mission aboard the International Space Station.

The change in crew assignment is a result of a temporary
medical issue related to McArthur’s qualification for this long
duration flight. Because of medical privacy considerations, no
information about McArthur’s condition will be made public.

As a member of the Expedition 9 backup crew, Chiao has been
training alongside McArthur for months. Chiao joins Russian
Flight Engineer and Soyuz Commander Valery I. Tokarev for the
six-month mission. The Expedition 9 crew is scheduled for
launch aboard a Soyuz spacecraft in April. European Space
Agency astronaut Andre Kuipers is the Board Engineer rounding
out the three-member Soyuz crew. Kuipers returns to Earth with
Expedition 8.

“This is a temporary medical issue for Bill,” said Astronaut
Office Chief Kent Rominger. “Because we are very cautious in
our approach to crew health, we train backups for this kind of
situation. We plan to assign Bill to another flight in the near
future,” he said.

“Obviously, I’m disappointed I won’t fly on the Expedition 9
mission, but I understand the necessity of the medical criteria
that are in place for long-duration space flight,” McArthur
said. “I know that Leroy will ensure all of the Expedition 9
objectives are met, and I look forward to flying soon on
another Space Station mission.”

For information about Chiao and McArthur, visit:

For more information about the International Space Station,