The Soviet Union may be overreacting to the US strategic defense and space shuttle programs for political purposes -- describing them as a threat to Mother Russia itself and not as benign as President Reagan asserts. But there could be good reasons for the Kremlin's concern.
The United States is researching and testing military systems that could eventually be used to attack ground targets from space, according to knowledgeable sources with years of government and private experience in the field. Such systems include lasers and high-energy kinetic weapons.
In fact, some experts say, technologies being developed for defensive purposes could be available for space-to-ground attack missions before they are ready to intercept Soviet ballistic missiles -- and perhaps even if they never can.
In coming months, one of the Pentagon's secret shuttle missions, called ``Teal Ruby,'' will test an infrared sensor's ability to look down from space and find aircraft and cruise missiles. The planned testing of other systems with the potential for detecting and striking ground targets, says a well-connected source with years of experience in military space projects, is ``probably one of the most sensitive aspects'' of the shuttle program.
``One of the things you have to realize is that a very small kinetic-energy device impacting from orbit releases tremendous energy,'' said this source. ``Look at what meteorites have done in the past. We're not talking about peanuts here.''
``On kinetic energy, I do know that it is possible to hit targets on Earth,'' this source continued. ``I can't say much about it, but I do know of ongoing research programs. So I believe the Soviets have reason to be paranoid about it.''
Speaking of Defense Department work on nonnuclear strategic weapons, says another source with considerable government and industry experience, ``there's some really sensitive things going on in this area.''
The Soviets themselves, while behind the US technologically, have also been working for such space-to-ground attack capabilities. Years ago they deployed something called FOBS (fractional orbital bombardment system), designed to send nuclear weapons into partial orbit around the South Pole, then bring them out of orbit for ballistic attack. The system was very inaccurate, however, and was apparently scrapped.
Some US officials have said they think that more recentlythe Soviets may have aimed ground-based lasers at US satellites. If so, Soviet officials presumably must believe that lasers could be pointed and focused in the opposite direction as well.
Officials working on the Strategic Defense Initiative (SDI) program say defending against aircraft (as well as cruise missiles) with space-based lasers would be easier then countering ballistic missile warheads. Lowell Wood of the Lawrence Livermore National Laboratory and Lt. Gen. James Abrahamson, director of the SDI office, have made such assertions in recent months.
If true, critics of the President's ``star wars'' program warn, it would be even easier to threaten targets on earth, especially relatively ``soft'' ones like command-and-control facilities, power networks, or ships.
``It's something to take seriously,'' said William Kincade, senior associate with the Carnegie Endowment for International Peace.
``If you solved the challenging problem of getting the energy [for high-powered lasers] into space, but fell short of getting the information systems necessary to hit ballistic missiles,'' Dr. Kincade added, ``then you might consider the possibility of using that energy beam on other targets where the timing and accuracy were not so devilishly difficult to achieve.''
With very high-speed rounds fired en masse from low-Earth orbit, other experts say, it is at least theoretically possible to fragment heavy concrete missile silos and destroy ICBMs before they are launched.
``Something that's going 17,000 miles per hour in low-Earth orbit has tremendous kinetic energy,'' said John Pike of the Federation of American Scientists. ``If you were to . . . drop it down in the atmosphere so that it retained most of its velocity, it could go through hundreds of feet of dirt and dozens of feet of concrete.''
For some time, Air Force officials have spoken of the need for a ``transatmospheric vehicle,'' a craft able to fly in the atmosphere as well as in space for quick-reaction reconnaissance and attack missions anywhere in the world. According to Air Force Magazine (a private publication), the Pentagon is to decide in 1988 whether to proceed with prototype development of such a vehicle.
Such ideas were being explored by the Pentagon long before President Reagan launched his strategic defense program 22 months ago. And US Air Force doctrine includes being able to hit targets on Earth from space.
All of this is years away from potential deployment, it is generally agreed, and many very challenging technological problems remain.