The United States is taking a hard look at its aging air defense system -- designed to detect and neutralize Soviet bombers. Without major improvements in the US early-warning system, defense experts say that current and expected improvements in the Soviet Union's manned bombers and cruise missiles will leave the US increasingly vulnerable to a surprise nuclear strike by Soviet aircraft.
"The Soviet Union has the potential to carry out an essentially 'no warning' air attack . . . against key [US] strategic installations," declared the Air Force chief of staff, Gen. Lew Allen, during recent hearings on continental air defense held by the House Armed Services Committee at the urging of a committee member, Rep. Ike Skelton (D) of Missouri.
As the congressman sees it, US air defenses are "made up of outdated and ineffective interceptor planes, a radar system that is full of holes, and a nonexistent surface-to-air missile system."
Defense officials do not take issue with his analysis. The nation's air defenses are in perilous state, they admit.
The reason? "By 1960 it became clear that the Soviet Union did not intend to deploy large numbers of long-range aircraft and that the predominant threat to the continental US was shifting to Soviet ballistic missiles," observed Richard Delauer, undersecretary of defense for research and engineering, at the recent hearings.
Added General Allen. "With the advent of the intercontinental ballistic missile, the basic character of the strategic threat has changed dramatically, prompting major shifts in US atmospheric defense policy."
As a result, the air defense system was allowed to fall into disrepair, they say.
One source familiar with ground-based air defense systems says that there never was an appreciable Soviet bomber threat to the US in the 1950s and 1960s. He adds that the much-vaunted TU-22M (code-named "Backfire" by NATO) is essentially a theater weapon and, as such, constitutes little threat to the US today.
But others disagree. They point out that in 1966 the Soviet Union possessed a total of 210 TU-95 Bears and Myasishchev M-4s (or Bisons in NATO terminology).
They add that there is no doubt that the Backfire has an intercontinental capability: Its maximum unrefueled combat range is 5,000 miles, which is expected to improve as its engines are enhanced. According to the widely respected magazine Aviation Week & Space Technology, the Soviet Union is developing two new bombers and upgrading the Backfire.
Pointing out that the Kremlin has continued to modernize its bomber and cruise missile capability, though not to the degree it has modernized its ICBMs) , the NORAD commander, Lt. Gen. James Hartinger, stresses that the US "cannot afford to give Soviet war gamers an attractive option in a bomber scenario."
General Allen insists that the Soviet Union is expanding its strategic bomber capabilities with air-launched cruise missiles and deploying a growing number of Backfires. He says that 100 of the bombers have been deployed so far and that 30 are being added yearly. "Of equal concern is the fact that the Soviets are evidently following our lead and developing a long-range cruise missile and a cruise missile carrier," he told the House air defense hearing July 22.
Some 20 years ago, Soviet bombers such as the Tupolev Tu-95 (code-named "Bear" by NATO) would have encountered formidable air defenses had they attempted to breach US airspace.
strings of long-range readers, the best-known survivor being the Distant Early Warning (DEW) Line, were designed to detect assaulting aircraft as they swept over the Arctic Ocean and down across Canada.
The DEW Line, a radar, computer, and communications network at the uttermost reaches of the North American continent, constituted the outher alert perimeter and consists of 81 stations sretching from the Aleutian Islands to Iceland via Canada and Greenland. It began operation in 1958, the year after the US and Canada integrated their air defense efforts by establishing the North American Air Defense Command (NORAD), now known as the North American Aerospace Defense Command.
Today even the Air Force admits the DEW Line is full of holes. Of 408 warning and surveillance radars that once probed North American skies, only 110 are left, says General Allen.
Old and limited, they are only capable of detecting bombers and cruise missiles at a distance of some 200 nautical miles. And even at this short range , as General Hartinger observed recently, "the radar can only see aircraft at medium to high altitudes. At low altitudes there are miles of coastline where bombers can penetrate our airspace and, once inside, roam freely, since we have no interior radars."
In short, the DEW Line could do little to prevent Soviet bombers from attacking the nation's command, control, and communications centers (such as NORAD's headquarters deep in Cheyenne Mountain outside Colorado Springs, Colo.) as well as its land-based missiles and B-52 bombers.
Both Representatives Skelton and the Air Force point out that with its key command, control, and communications centers knocked out, and its strategic retalitory forces badly mauled, the US would be exceedingly vulnerablt to a Soviet ICBM strike.
The DEW Line is not the only feature of US air defenses to have been degraded over the years. Its assigned fighter force has shrunk dramatically.
"In the 1960s our American air defense had 2,600 interceptor fighter planes," says Skelton. "Today we have about 275 and these are dangerously outdated."
The bulk of NORAD's current interceptors force is made up of 10 squadrons of F-106 Delta Darts, an improved version of the F-102 Delta Dagger, which entered squadron service in 1959 and is flown both by Air Force and Air National Guard units. According to General Allen, the F-106 lacks the capability "to counter enemy aircraft and cruise missiles ingressing at low altitudes."
While NORAD's fighter resources waned, its anti-air-craft missiles disappeared. Some 1,000 Nike-Hercules and Hawk anti-aircraft missile batteries that defended US cities were eliminated in April 1979. Likewise, Bomarc anti-aircraft missiles, deployed at Air Force bases near the Canadian border, have since vanished.
Alarmed by the Soviet bomber threat to the US, the Air Force planst to deploy over-the-horizon backscatter (OTH-B) radar systems, which surpass conventional line-of-sight radars by bouncing radio waves off the ionosphere. By this means it can provide an all-altitude bomber detection capability for a distance of some 2,000 nautical miles.
Because the northern lights tend to degrade the performance of a north-facing OTH-B system, the Air Force may decide to upgrade the DEW Line to provide all-altitude radar coverage or switch to a space-based radar.