Rama 2 by Arthur C. Clarke and Gentry Lee

General O’Toole put down the template and rubbed his eyes. He had read the sermon before—right before his meeting with the pope in Rome, in fact —but somehow it had not seemed as significant then as it did now. So which are you, Rama? he thought. A threat to Courtney Bothwell or a herald of Christ’s second coming?

During the hour before breakfast General O’Toole was still vacillating. He genuinely did not know what his decision would be. Weighing heavily upon him was the fact that he had been given an explicit order by his command­ing officer. O’Toole was well aware that he had sworn, when he had received his commission, not only to follow orders, but also to protect the Courtney Bothwells of the planet. Did he have any evidence that this particular order was so immoral that he should abrogate his oath?

As long as he thought of Rama as only a machine, it was not too difficult for General O’Toole to countenance its destruction. His action would not, after all, kill any Ramans. But what was it that Wakefield had said? That the Raman spaceship was probably more intelligent than any living creatures on Earth, including human beings? And shouldn’t superior machine intelli­gence have a special place among God’s creations, perhaps even above lower life forms?

Eventually General O’Toole succumbed to fatigue. He simply had no energy left to deal with the unending stream of questions without answers. He reluctantly decided to cease his internal debate and prepared to imple­ment his orders.

His first action was to rememorize his RQ code, the specific string of fifty integers between zero and nine that was known only by him and the proces­sors inside the nuclear weapons. O’Toole had personally entered his code and checked that it had been properly stored in each of the weapons before the Newton mission had been launched from Earth. The string of digits was long to minimize the probability of its being duplicated by a repetitive, electronic search routine. Each of the Newton military officers had been counseled to derive a sequence that met two criteria: The code should be almost impossible to forget and should not be something straightforward, like all the phone numbers in the family, that an outside party might figure out easily from the personnel files.

For sentimental reasons, O’Toole had wanted nine of the numbers in his code to be his birthdate, 3-29-42, and the birthdate of his wife, 2-7-46. He knew that any decryption specialist would immediately look for such obvious selections, so the general resolved to hide the birthdates in the fifty digits. But what about the other forty-one digits? That particular number, forty-one, had intrigued O’Toole ever since a beer and pizza party during his sophomore year at MIT. One of his associates then, a brilliant young num­ber theorist whose name he had long forgotten, had told O’Toole in the middle of a drunken discussion that forty-one was a “very special number, the initial integer in the longest continuous string of quadratic primes.”

O’Toole never fully comprehended what exactly was meant by the expres­sion “quadratic prime.” However, he did understand, and was fascinated by, the fact that the string 41, 43,47, 53, 61, 71, 83,97, where each successive number was computed by increasing the difference from the previous num­ber by two, resulted in exactly forty consecutive prime numbers. The se­quence of primes ended only when the forty-first number in the string turned out to be a nonprime, namely 41 X 41 = 1681. This little known piece of information O’Toole had shared only one time in his life, with his wife Kathleen on her forty-first birthday, and he had received such a lacklus­ter response that he had never told anybody about it again,

But it was perfect for his secret code, particularly if he disguised it prop­erly. To build his fifty-digit number, General O’Toole first constructed a sequence of forty-one digits, each coming from the sum of the first two digits in the corresponding term in the special quadratic prime sequence beginning with 41. Thus “5” was the initial digit, representing 41, followed by “7” for 43, “1” for 47 (4 + 7 = 11 and then truncate), “8” for 53, etc. O’Toole next scattered the numbers of the two birthdates using an inverse Fibonacci sequence (34, 21,13,8, 5, 3, 2,1,1) to define the locations of the nine new integers in the original forty-one-digit string.

It was not easy to commit the sequence to memory, but the general did not want to write it down and carry it with him to the activation process. If his code were written down, then anyone could use it, with or without his permission, and his option to change his mind again would be precluded. Once he had rememorized the sequence, O’Toole destroyed all his computa­tions and went to the dining room to have breakfast with the rest of the cosmonauts.

“Here’s a copy of my code for you, Franceses, and one for you, Irina, and the final one goes to Hiro Yamanaka. Sorry, Janos,” Admiral Heilmann said with a big smile, “but I’m all out of bullets. Maybe General O’Toole will let you enter his code into one of the bombs.”

“It’s all right, Herr Admiral,” Janos said wryly. “Some privileges in life I can do without.”

Heilmann was making a big production out of activating the nuclear weapons, He had had his fifty-digit number printed out multiple times and had enjoyed explaining to the other cosmonauts how clever he had been in the conception of his code. Now, with uncharacteristic flair, he was allowing the rest of the crew to participate in the process.

Franceses loved it. It was definitely good television. It occurred to O’Toole that Francesca had probably suggested such a staging to Heilmann, but the general didn’t spend much time thinking about it. O’Toole was too busy being astonished by how calm he himself had become. After his long and agonizing soul-searching, he was apparently going to perform his duty with­out qualms.

Admiral Heilmann became confused during the entering of his code (he admitted that he was nervous) and temporarily lost track of where he was in his sequence. The system designers had foreseen this possibility and had installed two lights, one green and one red, right above the numerical key­boards on the side of the bomb. After every tenth digit one of the two lights would illuminate, indicating whether or not the previous decade of code was a successful match. The safety committee had expressed concern that this “extra” feature compromised the system (it would be easier to decrypt five ten-digit strings than one fifty-digit string), but repeated human engineering tests prior to launch had shown that the lights were necessary.

At the end of his second decade of digits, Heilmann was greeted by the flashing red light. ‘I’ve done something wrong,” he said, his embarrassment obvious.

“Louder,” shouted Francesca from where she was filming. She had neatly framed the ceremony so that both the weapons and the pods appeared in the picture.

“I’ve made a mistake,” Admiral Heilmann proclaimed. “All this noise has distracted me. I must wait thirty seconds before I can start again.”

After Heilmann had successfully completed his code, Dr. Brown entered the activation code on the second weapon. He seemed almost bored; cer­tainly he didn’t push the keyboard with anything approaching enthusiasm. Irina Turgenyev activated the third bomb. She made a short but passionate comment underscoring her belief that the destruction of Rama was abso­lutely essential

Neither Hiro Yamanaka nor Francesca said anything at all. Francesca, however, did impress the rest of the crew by doing her first thirty digits from memory. Considering that she had supposedly never seen Hermann’s code until an hour earlier, and had not been alone for more than two minutes since then, her feat was quite remarkable.

Next it was General O’Toole’s turn. Smiling comfortably, he walked easily up to the first weapon. The other cosmonauts applauded, both showing their respect for the general and acknowledging his struggle. He asked everyone please to be quiet, explaining that he had committed his whole sequence to memory. Then O’Toole entered the first decade of digits.

He stopped for a second as the green light flashed. In that instant an image flashed into his mind of one of the frescoes on the second floor of the shrine of St. Michael in Rome. A young man in a blue robe, his eyes uplifted to the heavens, was standing on the steps of the Victor Emmanuel Monu­ment, preaching to an appreciative multitude. General O’Toole beard a voice, loudly and distinctly. The voice said “No.”

The general spun around quickly. “Did anybody say anything?” he said, staring at the other cosmonauts. They shook their heads. Befuddled, O’Toole turned back to the bomb. He tried to remember the second decade of digits. But it was no good. His heart was racing at breakneck speed. His mind kept saying, over and over again, What was that voice? His resolve to perform his duty had vanished.