On This Day: First Spacewalk Under a Shuttle

"It looks like this big patient is cured," Astronaut Stephen Robinson

On this day in 2005, Discovery astronaut Stephen K. Robinson became the first person to do a spacewalk underneath a space shuttle orbiter.

Mission managers sent Robinson under Discovery's belly because they had concerns that a pair of protruding gap fillers, bookmark-like strips of cloth impregnated with ceramic, could disrupt the aerodynamics of the orbiter during reentry and affect the shuttle’s temperature.

Robinson, mounted on a robotic arm controlled by fellow STS-114 astronauts Wendy Lawrence and James Kelly, was able to pull out the fillers by hand. Gap fillers were used to prevent tiles from scraping against one another and to protect the orbiter by filling in those narrow gaps in its heat shield. There are thousands of gap fillers on the bottom of each space shuttle.

Take a closer look at Discovery’s tiles at the Steven F. Udvar-Hazy Center in Chantilly, Virginia. And in Washington, DC, see one of the gap fillers that Robinson removed in the Moving Beyond Earth gallery.