other words."
"But you didn't shoot that fast."
"We didn't have to, sir," Gregory replied. "The limiting factor at present is the targeting software. That's being worked on. The purpose of this test was to evaluate part of the software package. We know that these lasers work. We've had them here for the past three years. The laser beams are converged on a mirror about fifty meters that way"-he pointed-"and converted into a single beam."
"They have to be-I mean, the beams all have to be exactly in tune, right?"
"Technically it's called a Phased-Array Laser. All the beams have to be perfectly in phase," Gregory answered.
"How the hell do you do that?" Ryan paused. "Don't bother, I probably wouldn't understand it anyway. Okay, we have the beam hitting the downside mirror "
"The mirror is the special part. It's composed of thousands of segments, and every segment is controlled by a piezoelectric chip. That's called 'adaptive optics.' We send an interrogation beam to the mirror-this one was on the shuttle-and get a reading on atmospheric distortion. The way the atmosphere bends the beam is analyzed by computer. Then the mirror corrects for the distortion, and we fire the real shot. The mirror on the shuttle also has adaptive optics. It collects and focuses the beam, and sends it off to the 'Flying Cloud' satellite mirror. That mirror refocuses the beam on the targets. Zap!"
"That simple?" Ryan shook his head. It was simple enough that over the previous nineteen years, forty billion dollars had gone into basic research, in twenty separate fields, just to run this one test.
"We did have to iron out a few little details," Gregory acknowledged. These little details would take another five or more years, and he neither knew nor cared how many additional billions. What mattered to him was that the goal was now actually in sight. Tea Clipper wasn't a blue-sky project anymore, not after this system test.
"And you're the guy who made the breakthrough on the targeting system. You figured a way for the beam to provide its own targeting information."
"Something like that," the General answered for the kid. "Dr. Ryan, that part of the system is classified highly enough that we will not discuss it further without written authorization."
"General, the purpose in my being here is to evaluate this program relative to Soviet efforts along similar lines. If you want my people to tell you what the Russians are up to, I have to know what the hell we're supposed to look for!"
This did not elicit a reply. Jack shrugged and reached inside his coat. He handed the General an envelope. Major Gregory looked on in puzzlement. "You still don't like it," Ryan observed after the officer folded the letter away.
"No, sir, I don't."
Ryan spoke with a voice colder than the New Mexico night. "General, when I was in the Marine Corps, they never told me that I was supposed to like my orders, just that I was supposed to obey them." That almost set the General off, and Jack added: "I really am on your side, sir."
"You may continue, Major Gregory," General Parks said after a moment.
"I call the algorithm 'Fan Dance,'" Gregory began. The General almost smiled in spite of himself. Gregory could not have known anything about Sally Rand.
"That's all?" Ryan said again when the youngster finished, and he knew that every computer expert in Project Tea Clipper must have asked himself the same thing: Why didn't I think of that! No wonder they all say that Gregory is a genius. He'd made a crucial breakthrough in laser technology at Stony Brook, then one in software design. "But that's simple!"
"Yes, sir, but it took over two years to make it work, and a Cray-2 computer to make it work fast enough to matter. We still need a little more work, but after we analyze what went wrong tonight, another four or five months, maybe, and we got it knocked."
"Next step, then?"
"Building a five-megajoule laser. Another team is close to that already. Then we gang up twenty of them, and we can send out a hundred-megajoule pulse, twenty times per second, and hit any target we want. The impact energy then will be on the order of, say, twenty to thirty kilograms of explosives."
"And that'll kill any missile anybody can make "
"Yes, sir." Major Gregory smiled.
"What you're telling me is, the thing-Tea Clipper works.
"We've validated the system architecture," the General corrected Ryan. "It's been a long haul since we started looking at this system. Five