A US space capsule that could help get humans to Mars is due to make its maiden flight later, the BBC reports.
Orion will be launched on a Delta rocket out of Cape Canaveral in Florida on a short journey above the Earth to test key technologies.
The conical vessel is reminiscent of the Apollo command ships that took men to the Moon in the 1960s and 1970s, but bigger and with cutting-edge systems.
Given that this is a first outing, there will be no people aboard.
Nonetheless, the US space agency describes the demonstration as a major event.
“This is huge; Thursday is a giant day for us,” said Nasa administrator Charlie Bolden.
Lift-off is scheduled to occur at 07:05 local time (12:05 GMT), depending on the weather and the technical readiness of all involved.