The Inmarsat-4 F2, one of the largest and most powerful communications satellites ever built, has had its launch bumped to Tuesday.
The spacecraft will deliver broadband from the Arctic to the Antarctic
The six-tonne UK-built craft is due to be lofted by a Zenit-3SL rocket from a floating platform in the Pacific Ocean.
It should have flown on Saturday but a software glitch led to an automated halt in the countdown sequence.
Flight controllers say they are now happy to go for a Tuesday launch after investigating the technical problem.
Lift-off is now scheduled at the opening of a 29-minute window at 1407 GMT. Inmarsat-4 F2 is the second of three satellites designed to improve global communications systems.
The first satellite, which covers most of Europe, Africa, the Middle East, Asia and the Indian Ocean, was launched from Cape Canaveral in March.
The second will improve and extend communications across South America, most of North America, the Atlantic Ocean and part of the Pacific Ocean.
The two satellites will support the London-based sat-com Inmarsat company's global broadband network, BGan.
The Sea Launch system uses a converted oil rig
Their onboard technology is designed to allow people to set up virtual offices anywhere around the world via high-speed broadband connections and new 3G phone technology.
The satellites offer "broadband for a mobile planet", says Inmarsat chief operating officer Michael Butler. Those set to benefit include business travellers, disaster relief workers and journalists.
The spacecraft, each the size of a London bus, should continue functioning for about 15 years. They were built largely at the EADS-Astrium facilities in Stevenage and Portsmouth, UK.
The Inmarsat-4 F2 is going up from waters close to Kiritimati (Christmas Island) on the equator.
It is using the innovative Sea Launch system, which employs a converted oil drilling platform as a launch pad. It is moved into position from its California base.
Sea Launch is a joint venture between American, Russian, Ukrainian and Norwegian companies.