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Authors: Robert L. Forward

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BOOK: Dragon's Egg
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“I am almost positive that the scruff is being picked up by just one of the four antenna wires,” she said eagerly. “If I could get the engineers to switch the data collection mode to read each antenna separately …”

“Nyet!” boomed Professor Sawlinski. “Paying the Deep Space Network to point their antennas to a given spacecraft to collect a one hour prearranged data dump is expensive enough. Do you realize how much it costs to send a command to a spacecraft?”

She started to speak, but Sawlinski cut her off as he dropped his recently acquired “American Professor” image and reverted to his autocratic old school Russian stance.
“Nyet! Nyet! Nyet!”
he said as he turned his back on her and switched on his computer console. “
Do svidaniya
, Mademoiselle Carnot.”

Jacqueline started to speak, but realized that the interview was over. She seethed inwardly, but finally decided to leave and take her frustrations out on the
computer. At least he had transferred the money to her account before he had turned her off. Quietly closing the door behind her, she made her way downstairs to the computer console room.

“I wonder how much a command change really does cost?” she thought as she made her way down the steps. “I will go out to Jet Propulsion Laboratories, talk to the Deep Space Network engineers and find out if it is as expensive as he thinks it is.”

With the computer glad to see her again, now that she had money in her account, she read in the figures that she had laboriously extracted the previous evening. She then ran an analysis of the collected data. The peaks in the power spectral density curve were still in four families. The four lowest peaks were the fundamental orbital frequencies of the four black holes, while the higher harmonics were evidence of the slight ellipticity of the orbits. The basic pattern had not changed for decades. Although the black holes were orbiting in the interior of the Sun where the densities were hundreds and thousands of times greater than water, as far as the ultra-dense black holes were concerned, they were orbiting in a near vacuum.

She searched carefully between the four lowest spikes, but could find no evidence of another peak. She had the computer repeat her search, and it came up with three two-sigma candidates, but they looked like noise to her and a quick check with a random half-data set proved her right. She was through for the time being, for a data dump was not scheduled for another week. But while she was on the computer, she decided to have another look at the noise problem.

She first wrote a program to extract the noisy portions from the data sets, then to find the maximum of the amplitude of the scruff (which was a hard concept for the computer to grasp), then to plot the phase of the scruff maximum with respect to the position of the
Sun. In the process, she learned that the spin rate of the satellite had increased slightly in the past years, somehow gaining angular momentum from the solar wind and light pressure.

Further examination of the drift of the phase and some calculations of the orientation of the spacecraft with respect to the Sun found that the peak in the scruff stayed constant with respect to the distant stars.

“That means that whatever the source of the noise, it is outside the Solar System!” Jacqueline exclaimed.

Then she realized that she had never asked herself what the “scruff” really looked like. On the hardcopy printout of the reconstituted analog signal from the spacecraft, the scruff just looked like random fuzz. She cleared the screen and called up the latest data dump. The curve of the low frequency radio readout wound its familiar way across the screen. She stopped it as she came to the maximum of the scruff. The scruff was so strong in this section that it often saturated the screen.

She called on a section of the data analysis program that she had seldom used before, and a small section of the data was expanded on the screen. The hours-long humps that were the subject of her thesis were now stretched out so much that only a portion of one of them could fit into the screen. The scruff now dominated the screen and looked as noisy and nasty as ever. She called for another expansion, and the computer activated an override warning circuit.




Jacqueline hesitated slightly, then hit the confirm key. Immediately a set of almost random dots filled the
screen. The short-term variation from point to point was strong, but the general amplitude level seemed to rise and fall slowly, with a period of many minutes.

Again, she called on the computer to carry out an operation on the data that she had never used before. She had been interested solely in the variations of the data with periods of weeks to days. Now she asked it to carry out a harmonic analysis with periods of seconds. Again the computer complained.




There was no hesitation this time: Jacqueline had hit the confirm key long before the computer had printed its objections. The spectral analysis plot flashed on the screen. There was a large spike around one Hertz that represented the one per second data digitalization rate, but at 0.005 Hertz there was a strong spike, indicating a periodic fluctuation with a 200-second period. However, the 200-second variation could have been caused by a beating between the one Hertz data sampling rate of the spacecraft and some high frequency oscillation that was close to some harmonic of the sampling rate. Jacqueline felt from the behavior of the data that a high frequency variation was causing the scruff, but it would be hard to prove it with the spacecraft sampling rate set at one sample per second.

Jacqueline, her enthusiasm finally exhausted by confusion and sleepiness, dropped the hardcopy printouts of the data into Professor Sawlinski’s mailbox and went off to bed. She again had a dream about flying above the Solar System, only this time she was whirling around rapidly. She awoke feeling dizzy, then went back to sleep to dream ordinary, quickly forgotten dreams.

After awakening the next day, Jacqueline went by Professor Sawlinski’s office. His door was open, and her data sheets were spread out on his desk. He was talking with Professor Cologne, the astrophysicist.

“This high frequency scruff is definitely not random noise, for there is evidence of a strong periodicity of 199 milliseconds, or a little over five cycles per second. The beating between the 199-millisecond pulsations and the one-Hertz data sampling rate gives it the 200-second beat pattern. However, it is not a 200-second fluctuation because the engineering interruptions in the science data are not exactly an even number of seconds long, and the 200-second beat starts with a new phase after each engineering readout. If you take enough data, and do an analysis of it, you find the 199-millisecond periodicity.”

As he spoke, Professor Sawlinski held up Jacqueline’s printout. Professor Cologne studied it briefly, then returned it with the comment, “It has all the earmarks of a pulsar, but there just isn’t any known pulsar of that frequency. I would suspect the spacecraft somehow has found a way to become a low frequency radio oscillator.”

Professor Sawlinski saw her standing in the door. “Ah, Jacqueline, come in. I was just showing Professor Cologne our latest data. I have decided that we ought to arrange to have the data digitalization rate increased to at least ten times per second, so we can obtain a better idea of the time varying nature of these pulsations.”

“But the cost …” Jacqueline interjected.

“Yes, it will cost some money, but by the time the computer billing gets to us, we will be well into the new planning year,” he replied. “Could you visit the JPL people and arrange for the change?”

Nom de Dieu
!” muttered Jacqueline under her
breath. “First, not enough money, and now plenty of money.”

Aloud, she replied, “Yes, Professor Sawlinski. Do you also want to try reading out the antennas sequentially?”

he replied brusquely. “How many times must I remind you, only change one parameter at a time in an experiment!”

“Yes, Professor,” she said, and practically bowed her way out of the office.

Once in the hall, she found herself automatically heading down the stairs to the computer room. She stopped and started to turn back to go to JPL, but then she decided to spend a little more time learning how the spacecraft command system operated. She felt that perhaps she could not only satisfy Professor Sawlinski, but also her own curiosity.

After a few hours spent browsing through the engineering handbooks, she smiled and headed up the stairs, where she caught the CalTech jitney bus to JPL. Sawlinski’s name moved her swiftly through the administrative maze and she shortly was assigned to Donald Niven, one of the JPL project managers.

When she walked into the office she had been directed to, she saw a chunky young man with neatly trimmed dark hair and the slacks, sports coat, and tie that seemed to be the professional uniform of the engineers at JPL. She guessed that he was in his late twenties. She had thought that a project manager would be someone older, but as their conversation proceeded, she could tell from his cool, calm, methodical questions that, despite his age, he had acquired years of experience in the Deep Space Network organization. Their discussion was half technical, half financial.

“So the length or complexity of the command has almost no bearing on the cost?” she asked.

“That’s right,” Donald said. “So that groups like
yours could plan their expenditures, we worked out a standard rate for each command cycle.”

“Suppose a command has a series of steps in it?” she asked.

“As long as the steps are something for the spacecraft computer to go through and do not involve us, then the charge is the same for one or ten steps,” he replied. “What do you have in mind?”

Jacqueline got out her program sheets. Donald swung his computer console around so they could both look at it. He typed in the code for the OE spacecraft operations manual.

“The first thing I want to do is to increase the low frequency radio data digitalization rate to its maximum,” she said. “Then, after a week of high rate data collection, I want to have the data taken alternately with the four antennas, each one taking data for one minute at a time. After that, I want to have the X-ray telescope reactivated. It has a one-degree field of view, and I want it to scan between these two angles at a rate of one degree per day.” Jacqueline handed over the sheet of paper and he took it.

“I see these are in spacecraft coordinates,” he said, his opinion of the young woman increasing with every second. “Thanks for taking the trouble to convert them for me.”

“It was no trouble,” she replied calmly. “I have been living with that spacecraft so long that I practically think like it.”

Together they worked out the command procedure, and Donald transferred it to the programming section. The computer would actually do the programming, but the programmers had to take the computer result through several tests to make sure that some bugs had not crept into the computer simulation in the decades since the spacecraft had been launched.

“I’ll give you a call when the command is ready,”
Donald said. “It’ll be a few days before the formal procedure is finished. Fortunately, I don’t think we will have any trouble getting permission from the sponsoring agency. Although the experiment package was built by ESA, the spacecraft itself was built by the Russians, so the authority for command changes rests with the Soviet Academy of Science, and Professor Sawlinski’s name should be good enough for them. Do you have a telephone number where I can reach you?”


As the days passed, Jacqueline and Donald spent many hours poring over the command time line. It was a long sequence, with even longer delays in it.

“Why can’t we leave the low frequency radio on high digitalization rate while the X-ray telescope is scanning?” Jacqueline asked. “That way, if the X-ray telescope picks up something unusual, we can check the low frequency radio to see if the scruff is active.”

Donald paged the screen to the section describing the operational characteristics of the low frequency radio digitalization block. “The X-ray telescope uses a lot of power, especially when it is in the scanning mode,” he said. “I’m afraid that, because of the age of the radioisotope power generators, the voltage on the power bus will drop so much that the low frequency radio digitalization will blank out if we ask it to keep operating at its highest rate.”

“How fast can it operate?” Jacqueline asked.

“Well,” Donald said as he looked through the table, “it was minimum-voltage designed for an upper rate of eight times a second, and we have it pushed all the way to sixteen times per second. With the low voltage on the bus, we ought to come back to either eight or four times per second.”

“Leave it sixteen times a second,” said Jacqueline firmly. “No data is preferable to poor data.”

Donald looked at her with a slightly bewildered expression as if he were seeing past her pretty face for the first time. He started to protest, but decided against it and made the short change in the command sequence as she wanted it.

Slowly the command was assembled. Jacqueline and Donald worked on it periodically during the day when Donald was charging to Sawlinski’s account. They also talked about it over lunch and in the evenings, when Sawlinski’s budget received an extra dividend of Donald’s time.


Donald lay back on the grass of the recently mowed lawn of the Griffith Park Observatory. It was Saturday and a pleasant evening lay before him. First, a visit to the early show at the planetarium where he would see the highly touted Holorama show. Then an evening under the stars at the Greek Theater down the hill to listen to the Star Crushers, the latest sensation in popular music. And, to go with it all, a fascinating and beautiful, but perplexing, girl.

The Sun had set and Donald’s mind wandered up into the lightly star-sprinkled sky as it had been doing ever since he was a little child and he and his father would go out into the back yard in the evening to look at the stars. Occasionally they would both be rewarded by the quick slash of a meteor or the slow progression of a satellite. Donald knew that since those days, his life had been fixed. He wanted to go to the stars!

BOOK: Dragon's Egg
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