The panel called not only for private shuttle operation but also for an end to the ban on commercial payloads.

Ariane 1, launched in 1979, brought mostly commercial payloads into orbit from 1984 onward.

Other experts said the nation would be better served by relying more on unmanned vehicles for launching commercial, scientific and military payloads.

Then, the shuttles had a more central role in delivering payloads - commercial, scientific and military - into space than today.

At the time of its launch, it was the heaviest commercial payload to be launched by a Proton.

As a result, private communications satellites and other commercial payloads have a lower priority than those of the Defense Department or of scientists.

Of 500 Atlas rockets launched since the 1950's, 13 have carried commercial payloads.

Three American aerospace companies are vying to sell the services of their unmanned rockets for commercial payloads and some government missions.

The company collapsed three years later, before sending a single commercial payload into orbit.

It has been carefully designed to drive down the cost of lofting commercial payloads.