A Russian rocket carrying a US-made telecommunications satellite has plunged into the Pacific Ocean shortly after launch.
Intelsat-27 was to have provided mobile broadband and video services
The Zenit-3SL rocket, which was being operated from a floating pad south of the Hawaiian islands, failed 40 seconds after the lift-off at 06:59 GMT.
The Intelsat-27 satellite was due to be positioned over the Atlantic to provide services to the Americas and Europe.
Officials say no-one was hurt as a result of the incident.
Staff from the Sea Launch company, which organised the launch, direct all missions from a support vessel that sits at a safe distance of about 6.5km uprange of the platform.
The firm said it would establish a review board to determine what went wrong.
"We are very disappointed with the outcome of the launch and offer our sincere regrets to our customer, Intelsat, and their spacecraft provider, Boeing," Kjell Karlsen, president of Sea Launch AG, said in a statement.
"The cause of the failure is unknown, but we are evaluating it and working closely with Intelsat, Boeing, Energia Logistics Ltd and our Zenit-3SL suppliers. We will do everything reasonably possible to recover from this unexpected and unfortunate event."
Sea Launch had not long returned from Chapter 11 bankruptcy protection.
A spectacular rocket failure on its converted oil rig in 2007 forced the firm to restructure its finances as orders slowed and debts mounted.
It re-emerged in 2011 and had lofted four satellites successfully from the Odyssey platform before Friday's loss.
The rig-cum-pad and its command ship are based at Long Beach, California.
For a mission, the pair move south to the equator at 154 degrees West Longitude.
An equatorial launch location gives a rocket a boost from the Earth's rotation, meaning it can lift heavier payloads into orbit.
Sea Launch is owned now by a Russian-led consortium headed by Energia Overseas Ltd, and is headquartered in Bern, Switzerland.
The commercial market for launching large geostationary telecommunications satellites is intensively competitive.
It has been dominated for several years by the European Ariane rocket, operated by Arianespace, and the Russian Proton vehicle, which is sold by International Launch Services (although the latter has experienced a number of failures of its own recently).
Once the cause of Friday's loss is identified and any necessary corrective action taken, Sea Launch will need to re-instil confidence in the market that its product is a good one.
The Ukrainian-Russian Zenit-3SL vehicle has a generally good reliability record.
A modified version, the Zenit-3SLB, is operated from land, flying out of the Baikonur Cosmodrome in Kazakhstan. The most recent of these launches was at the end of 2011.
Launch contracts from the Luxembourg-based Intelsat company had been integral to Sea Launch's return to business after bankruptcy protection.
Intelsat-27, which weighed some 6.2 tonnes at launch, was to have provided direct-to-home TV services and mobile broadband connections.