DENVER -- Martin Marietta Corp.'s mammoth Denver facility is quietly becoming a national center for an exotic new technology that would detonate nuclear bombs in space in an attempt to destroy incoming missiles.

Engineers at the facility are working on two separate contracts to develop critical components of the weapons systems. The work is part of the Strategic Defense Initiative program, which is designed to create a technological shield to protect the United States and its allies from Soviet nuclear missiles.

Under the larger of the two programs, Martin Marietta, which is based in Bethesda, Md., is studying ways to design a weapon that would harness the power of a nuclear explosion to create an enormously powerful laser beam.

Specifically, it is working on the complex challenge of creating an effective guidance system that would track missiles and aim the laser beam with pinpoint accuracy.

Called the nuclear-powered X-ray laser, the weapon would set off a nuclear explosion and use the energy it produced to create an X-ray laser beam. While X-rays are invisible, they are still a form of light, and the rays from the beam would reach their targets almost instantaneously.

The weapons could be put in permanent orbit, ready to respond instantly if a missile launch was detected. But the idea of an orbiting nuclear arsenal would almost certainly be politically unpopular, so engineers are looking at the possibility of using hypervelocity rockets based either on land or on submarines to launch the systems.

Once the system was in space it would have to find the Soviet missiles, calculate their speed and trajectory, and trigger the explosion. The weapon would include a series of rods that would direct and focus the laser beams.

The X-ray laser device itself would be operational for less than a millionth of a second after the explosion. But by that time, the powerful laser beam would be zooming toward its target. When it hit the missile the energy from the beam would not cause an explosion, but would simply smash the metal, said Hugh DeWitt, a physicist at the federal government's Lawrence Livermore Laboratory in Berkeley, Calif.

Martin Marietta's $5.7 million contract, awarded a few months ago, calls for the company to spend 18 months doing initial design studies for the system, concentrating on the aiming mechanism, said Ed Vaughn, a spokesman for the Army Strategic Defense Command in Huntsville, Ala. The contract includes an option for an additional $14.4 million during a second 18-month period.

Martin Marietta has been developing expertise in the area of aiming "Star Wars" weapons for some time now. The company opened a $9.2 million facility dedicated to the technology in November 1985. The company's Rapid Retargeting Precision Pointing facility is designed to conduct both computer simulations and actual tests of certain elements of space-based defense systems.

The laboratory was set up in order to refine the aiming of both laser weapons and kinetic energy weapons, which are nonexplosive projectiles that shoot toward their targets at such blinding speeds that they can destroy missiles through sheer impact.

Under a separate contract, Martin Marietta has done some initial design work on the kinetic energy weapons as well.

Meanwhile, the company recently won a $5.1 million contract to develop aiming components for a nuclear hypervelocity pellet system. The system would set off a nuclear explosion in space that would hurl millions of small pellets at incoming missiles.

The weapon could be used to destroy the missiles themselves, but its primary purpose would be to demolish the thousands of decoys that would be expected to accompany a nuclear missile attac