Such a large increase would probably also drive Government customers to use conventional rockets to launch their payloads.

The second method uses the laser to help expel mass from the spacecraft as in a conventional rocket.

The mission is expected to cost $152 million, including $42 million for the conventional rocket used to fire the spacecraft away from Earth, project officials said.

It would take conventional rockets at least seven months to reach Mars.

The phaseout of all conventional rockets left the nation virtually grounded after the Challenger disaster in 1986.

The space plane, launched by a conventional expendable rocket, would supplement the shuttle but not replace it.

They argued that the tubes seemed designed for use in conventional military rockets.

As you well know, Iraq has declared these efforts to have been in connection with a program to reverse-engineer conventional rockets.

The Pentagon has decided to use conventional rockets instead of shuttles for most of its secret missions.

However, this approach requires lifting hundreds or even thousands of tons on conventional rockets, an expensive proposition.