Doohan had been suffering from pneumonia and Alzheimer's disease

A portion of Doohan's ashes, along with 200 others, were launched from a site in New Mexico on 28 April.

The rocket reached its planned altitude of 72.7 miles (117 kms) before coming down in a nearby mountainous area.

Operator Space Services Inc said the craft had locator beacons, but that bad weather had hampered the search.

Doohan played Scotty, the Enterprise's straight-talking engineer, in the original TV series and several movies.

Recovery operation

He died aged 85 in 2005 after suffering from Alzheimers for several years.

Also on the flight were the ashes of astronaut L Gordon Cooper, one of the first men into space.

Space Services offer several types of memorial flights, including putting remains into orbit or sending them into space before returning them to earth.

A company spokesman said: "The terrain is very mountainous; it's not somewhere that you can walk or drive to. My understanding is that it will take some time to get up there."

"They know the general location, and we have the utmost confidence that they will recover it."