Astronauts aboard the International Space Station used a pair of robot arms to install a pallet of equipment on Sunday, but when break-time came they may have found long lines at the bathrooms, Reuters reported.
With a record 13 people aboard the station, the main toilet broke down, sending astronauts scrambling to the use backup commodes on the Russian side of the station and aboard the visiting U.S. shuttle Endeavour.
"Put an 'Out-of-Service' note on the WHC (waste and hygiene compartment)," Mission Control's Hal Getselman told a crewmember after a fruitless attempt at repairs.
The commode, which is connected to the station's wastewater-recycling system, had been the crew's main bathroom. NASA was limiting shuttle toilet use because it cannot dump the wastewater overboard, as is customary during flight.
Wastewater dumps could contaminate the station's newly installed platform for science experiments.
The porch-like facility was mounted on the front of the station's Kibo laboratory during a spacewalk Saturday. It will be used to hold experiments that need to be exposed to the open environment of space.
"For right now, having all (shuttle crewmembers) using the shuttle toilet is not going to be an issue," station flight director Brian Smith said.
If the toilet cannot be repaired within about six days, it could become a more serious matter, Smith added. "We don't yet know the extent of the problem," he said.