The launch of a private US spacecraft has been aborted after last-minute technical concerns. SpaceX's Dragon capsule was due to be the first non-government craft to try and reach the International Space Station.
US firm SpaceX blamed a technical issue with one of the Dragon cargo capsule's nine engines on Saturday for its failure to launch from NASA's Kennedy Space Station in Florida.
The spacecraft had been due to lift off at 4:55 a.m. before it was aborted with seconds to go.
"The initiation sequence had started, but there was a cut-off," said NASA commentator George Diller.
A SpaceX spokesman said engineers would look into the cause of the technical fault.
"We detected something was wrong with one of the limits" on one of the rocket's nine engines, said the spokesman on SpaceX's live broadcast of the event.
A NASA official said the launch would be attempted again at 3:44 a.m. on Tuesday.
It was due to embark on a three-day flight to the International Space Station (ISS) and undertake several complex docking maneuvres designed to establish it could safely dock on the orbiting station. On the fourth day it was to attempt to attach to the outpost.
The unmanned rocket was intended to become the first privately built spacecraft to attempt to dock with the ISS. SpaceX is one of several US companies competing to take over the job of delivering cargo to the space station for NASA.
These private firms ultimately hope to restore the US goal of sending human travellers to space by 2015.
ccp/tm (dpa, AFP, Reuters)