The astronauts working aboard the International Space Station had an extremely busy weekend in space with spacewalks and shuttle inspection on the docket.  NASA currently has four spacewalks scheduled over the 14-day duration shuttle Endeavour will be in space.

Shuttle Endeavour's Rick Mastracchio and Dave Williams recently conducted a six-hour spacewalk to install a new truss on the ISS.  The new gyroscope had to be installed after the previous one unexpectedly stopped operating normally.  The gyroscopes installed on the ISS help it maintain and stabilize a position in space.

Another spacewalk will take place tomorrow morning, while the final spacewalk will take place on Friday, August 17.

NASA recently inspected the 3-inch-by-3-inch gouge located on the underside of the shuttle Endeavour, trying to determine the depth and seriousness of it.  The U.S. space agency will continue to examine the gouge, also thinking about using one of the remaining space walks to repair the shuttle.

The Streptococcus pneumoniae Expression of Genes in Space (SPEGIS) mission -- which launched aboard shuttle Endeavour over the weekend -- aims to discover what effects space has on bacteria.  Scientists and researchers believe sending it into the harsh environment of space will help them further learn details about the pesky pathogen.

The Streptococcus pneumoniae, or pneumococcus, can be found in the "upper respiratory tract of approximately 40 percent of the healthy human population."  S. pneumoniae commonly causes pneumonia, bacterial meningitis and middle ear infections.