In the middeck of Endeavour, in the Orbiter Processing Facility, Center Director Jim Kennedy (far left) watches as a technician gets ready to lower himself through the LiOH door into the Environmental Control and Life Support System (ECLSS) bay. LiOH refers to lithium hydroxide, canisters of which are stored in the ECLSS bay under the middeck floor. During flight, cabin air from the cabin fan is ducted to two LiOH canisters, where carbon dioxide is removed and activated charcoal removes odors and trace contaminants. Kennedy is taking an opportunity to learn first-hand what workers are doing to enable Return to Flight. Endeavour is in an Orbiter Major Modification period.