back on air defenses we may have created an equivalent opportunity for the Soviets with bombers.

The orange on this chart represents the high altitute radar coverage we have today, the red represents the low altitude cover. As you can see, it does not present much of a challenge to the Soviet planner and I do not think any of us in the air defense business question for a moment the ability of the Soviets-if they chose-to avoid radar detection and perhaps conduct no warning bomber strikes against our forces.

Senator WARNER. Well, in a sense, do we have a national line there that can be circumvented?

General BROWN. If it is a national line, Mr. Chairman, it is a very leaky national line.

Senator WARNER. That proves to be somewhat leaky.

General BROWN. Back in the heyday of air defense we had picket ships, Texas towers, and a great number of airborne early warning radar aircraft. All of those things disappeared and today we are left

with only these microwave radars. That is the only warning we have today, the 200-mile range microwave radars that are so widely spaced that there is no question that the Soviets would have no difficulty underflying them.

For my part, I have served on both sides of that fence. I spent a lot of my career in air defense. I also commanded two SAC bomber wings and I assure you if I put my SAC hat on, that is not much of a challenge.

OTH BACKSCATTER RADAR

The first step on the road back is, as Mr. Gardner pointed out, the deployment of the over-the-horizon Backscatter radar which will give us an all-altitude bomber detection capability out to about 2,000 miles. OTH-B will give us the tactical warning that will introduce enough uncertainty into the equation. We think it is important that the Soviet planner will not have the certainty he has today that he get through. Senator WARNER. Do you run exercises where SAC is trying to penetrate that system?

General BROWN. Yes, sir.

Senator WARNER. And those penetrations are successful?

General BROWN. Well, in order to insure that the crews get sufficient training, SAC flies high enough that they will be detected. There is no point in conducting low altitude exercises.

Senator WARNER. You know how they will come out.

General BROWN. Yes, sir. Now, when we introduce the AWACS we are to conduct low altitude training and low altitude parts of exercises. But there still are not nearly enough AWACS to be able to do that except throughout a small portion of an air defense exercise.

The AWACS, of course, does an excellent job of long-range lowaltitude detection. The problem, of course, is you cannot maintain a barrier with the AWACS exclusively because it would be terribly expensive. It would take the gross national product to maintain an AWACS barrier around North America day in and day out.

OTH-B DEPLOYMENT

So, the first step on the way back, as I indicated, is the deployment of the OTH-B. We have in the program now an east coast and a west coast deployment. Ultimately, we may want to deploy one looking south. You notice, that leaves the northern portion open. OTH-B does not work looking to the north because of disturbance caused by the Aurora. We looked at two alternatives, space-based radar and modernizing the current DEW line.

We have spent a great deal of time looking at space-based radar and finally have come reluctantly to the conclusion that it is simply not going to be available in this decade. So, we have opted to go with enhancing the DEW line. The DEW line today is old, is getting increasingly expensive and difficult to maintain. We have to do something about it.

IMPROVED DEW LINE AND OTHB

If we do this in combination with the OTH-B we will then have recreated a belt of tactical warning around North America that we think is critical.

The second element of the joint United States-Canadian air defense policy statement was to control access to North American air space. Those microwave radars do not do a very good job of tactical warning, but they are required to control access to North American air space. They are depicted here.

We are also in the process of replacing the old blockhouses that have been in the air defense system since the late 1950's with new, modern, computers in region operation control centers. The first one of those has just reached its initial operational capability on March 1, and the balance of the system will be completed this year.