More-secure MX systems studied

The Congressional Office of Technology Assessment has identified five ways to provide the new MX missile with reasonable chances of surviving a Soviet attack. New methods of basing the MX are being considered, because the present hardened missile silos are believed to be increasingly vulnerable due to the improved accuracy of Soviet missiles.

According to the OTA, the five feasible methods are:

* A multiple-protective shelter, which involves hiding the MX among a larger cluster of shelters so the Soviet Union would have to aim at all the shelters to attack all the missiles. This method, chosen by the Carter administration, is now being developed by the Air Force.

* A low-altitude antiballistic-missile system to defend the bases.

* Launching of the MX under attack so the missiles could be used before the Soviet Union could destroy them.

* Basing of the MX on small submarines.

* Basing of the missile on large, wide-body aircraft.

"All offer reasonable prospects for feasibility and survivability," the study said, "but each of these has serious risks and drawbacks, and it is believed that choosing which risks and drawbacks are most tolerable is a judgment which cannot be made on technical grounds alone."