A crucial antenna on the space shuttle Discovery failed to operate on Monday when it reached orbit, complicating docking procedures with the International Space Station, according to Nasa.
The US space agency said the loss of the Ku-band communications antenna was no cause for alarm as the shuttle had other methods of communicating with the ground and multiple back-up systems for the radar system used for docking.
"The dish-shaped antenna is used for high data rate communications with the ground, including television, and for the shuttle's radar system that is used during rendezvous with the International Space Station," the statement said.
"Discovery can safely rendezvous and dock with the station and successfully complete all of its planned mission objectives without use of the Ku-Band antenna, if needed."
The shuttle also has S-band and UHF antennae that can transmit voice and data information on different wavelengths to Nasa officials at mission control in Houston, Texas.
The International Space Station has its own Ku-band system for transmitting television images to the ground and that can be used to transmit views of the shuttle after it has docked, Nasa said.
"Flight controllers are continuing to troubleshoot the problem with Discovery's Ku-band antenna while also formulating plans to conduct the mission without use of the shuttle Ku system if necessary," the statement said.
Nasa said the Ku antenna is also normally used for inspections on the second day of missions to determine if there has been any damage to the shuttle reaching orbit.
"If the Ku still is not working tomorrow, the crew will record all of the inspection video and play it back after docking with the station, using the station's Ku antenna," the space agency said.
"The crew will monitor the video in real time tomorrow and will note the time stamps of any areas of concern."
Discovery blasted off on Monday towards the International Space Station, for a historic mission that put more women in orbit than ever before and two Japanese astronauts in space simultaneously for the first time.
Nasa had earlier described Monday's dawn launch as nearly "picture perfect" with officials expressing satisfaction about the relative absence of debris that might have risked damaging the shuttle.
Discovery's arrival at the International Space Station is tentatively scheduled for today and will be one of the final missions for the shuttle programme, which will be shuttered later this year.