by Cixin Liu
The discussion grew heated. The assembled experts tore into the idea like a pack of hungry wolves presented with a piece of fresh meat.
Wade slammed the table again. “Enough! Don’t get bogged down on details right now. We’re not evaluating feasibility; rather, we’re trying to figure out if it’s worthwhile to study the idea’s feasibility. Focus on big-picture barriers.”
After a brief silence, Vadimov said, “The best thing about this proposal is that it’s easy to get started.”
Everyone immediately caught on to Vadimov’s meaning. The first step in Cheng Xin’s plan involved launching a large number of nuclear bombs into orbit around the Earth. Not only did humanity possess such technology, the bombs were already on launch vehicles: the ICBMs in service could easily be repurposed for this use. American Peacekeepers, Russian Topols, and Chinese Dongfengs could all directly launch their payloads into near-Earth orbits. Even intermediate-range ballistic missiles, if retrofitted with booster rockets, could do the job. Compared to the post-Crisis nuclear disarmament plans that required destroying the missiles, this plan would be far cheaper.
“Excellent. For now, let’s pause our discussion of Cheng Xin’s en-route propulsion idea. Any other proposals?” Wade looked around the room.
A few seemed to want to speak up, but finally decided to remain quiet. None of them thought their own ideas could compete with Cheng Xin’s. Eventually, everyone’s eyes focused on her again, but this time, the meaning was completely different.
“We’ll meet twice more to brainstorm and see if we can come up with a few more options. But we might as well get started on the feasibility study for en-route propulsion. We’ll need a code name.”
“Since the probe’s velocity would go up a level each time a bomb explodes, it’s a bit like climbing a flight of stairs,” Vadimov said. “I suggest we call it the Staircase Program. Besides the requirement of a final velocity exceeding one percent of lightspeed, another parameter to keep in mind is the mass of the probe.”
“A radiation sail can be made very thin and light. Based on the current state of material sciences, we can make a sail of about fifty square kilometers and limit the mass to about fifty kilograms. That should be big enough.” The speaker was a Russian expert who had once directed a failed solar sail experiment.
“Then the key will be the mass of the probe itself.”
Everyone’s eyes turned to another man in the room, the chief designer of the Cassini-Huygens probe.
“If we include some basic sensors and take into account the necessary antenna and radioisotope power source to transmit information back from the Oort Cloud, about two to three thousand kilograms ought to do it.”
“No!” Vadimov shook his head. “It has to be like Cheng Xin said: light as a feather.”
“If we stick with the most basic sensors, maybe one thousand kilograms would be enough. I can’t guarantee that’s going to succeed—you’re giving me almost nothing to work with.”
“You’re going to have to make it work,” said Wade. “Including the sail, the entire probe cannot exceed one metric ton in mass. We’ll devote the strength of the entire human race to propel one thousand kilograms. Let’s hope that’s light enough.”
During the next week, Cheng Xin slept only on airplanes. As part of a task force led by Vadimov, she shuttled back and forth between the space agencies of the US, China, Russia, and Europe to coordinate the feasibility study of the Staircase Program. During that week, Cheng Xin got to travel to more places than she had in her life up to that point, but she didn’t get to do any sightseeing except through the windows of cars and conference rooms.
At first, they had thought they could get all the space agencies to do a combined feasibility study, but that turned out to be an impossible political exercise. In the end, each space agency performed an independent analysis. The advantage of this approach was that the four studies could be compared to get a more accurate result, but it also meant that the PIA had to do a lot more work. Cheng Xin worked harder on this project than anything in her professional career—it was her baby, after all.
The four feasibility studies quickly reached preliminary conclusions, which were very similar to each other. The good news was that the area of the radiation sail could be shrunk to twenty-five square kilometers, and with even more advanced materials, the mass of the sail could be reduced to twenty kilograms.
Then came some very bad news: In order to reach the required speed of 1 percent of lightspeed, the mass for the entire probe assembly had to be reduced by 80 percent—to only 200 kilograms. Subtracting the mass reserved for the sail left only 180 kilograms for sensors and communication devices.
Wade’s expression didn’t change. “Don’t be sad. I have even worse news: At the last session of the PDC, the resolution proposing the Staircase Program was voted down.”
Of the seven permanent members of the PDC, four voted no. Their reasons were surprisingly similar. In contrast to the technical staff of the PIA with background in spaceflight, the delegates were not interested in the propulsion technology. They objected that the probe’s intelligence value was too limited—in the words of the American representative, “practically nil.”
This was because the proposed probe had no way to decelerate. Even taking into account the fact that the Trisolaran Fleet would be decelerating, the probe and the fleet would pass by each other at a relative speed of around 5 percent of lightspeed (assuming the probe wasn’t captured by the fleet). The window for gathering intelligence would be extremely small. Since the small mass of the probe made active sensors such as radar impractical, the probe was limited to passive sensing, mainly of electromagnetic signals. Given the advanced state of Trisolaran technology, it was almost certain that the enemy would not be using electromagnetic radiation, but media such as neutrinos or gravitational waves—techniques beyond the current state of human technology.
Moreover, due to the presence of sophons, the plan for sending a probe would be completely transparent to the enemy, making its chances of successfully gathering any valuable intelligence nonexistent. Considering the enormous investment required to implement such a plan, the benefits were too minuscule. Most of the plan’s value was purely symbolic, and the great powers were simply insufficiently interested. The other three permanent members of the PDC voted yes only because they were interested in the propulsion technology.
“And the PDC is right,” said Wade.
Everyone silently mourned the Staircase Program. Cheng Xin was the most disappointed, but she comforted herself that as a young person with no record of achievements, having gotten this far on her first original idea wasn’t too bad. Certainly, she had exceeded her own expectations.
“Ms. Cheng, you look unhappy,” Wade said. “Apparently you think we’re going to back off from the Staircase Program.”
Everyone now stared at Wade, speechless.
“We’re not going to stop.” Wade stood up and paced around the conference room. “From now on, whether it’s the Staircase Program or any other plan, you do not stop until I tell you to stop. Understand?” He dropped his habitual indifferent tone and screamed like a crazed wild animal. “We’re going to advance! Advance! We’ll stop at nothing to advance!”
Wade was standing right behind Cheng Xin. She felt as if a volcano had erupted behind her, and she cringed and almost screamed herself.
“What’s our next step?” asked Vadimov.
“We’re going to send a person.”
Wade had resumed his calm, emotionless voice. Still in shock at his explosion, it took a while before those in the room understood what Wade meant. He wasn’t talking about sending someone to the PDC, but out of the Solar System. He was proposing sending a live scout to the bleak, frigid Oort Cloud one light-year away to spy on the Trisolaran Fleet.
Wade kicked the leg of the conference table and sent his chair flying backwards so that he could sit behind everyone as they continued to discuss. But no one spoke. It was a rep
eat of the meeting a week ago when he had first brought up the idea of sending a probe to the Trisolaran Fleet. Everyone tried to chew over his words and unravel the riddle. Shortly, they came to see that the idea wasn’t as ridiculous as it seemed at first.
Hibernation was a relatively mature technology. A person could complete the voyage in suspended animation. Assuming the person weighed 70 kilograms, that left 110 kilograms for the hibernation equipment and the hull—which would resemble a coffin. But what then? Two centuries later, when the probe met the Trisolaran Fleet, how would they wake this person up, and what could he or she do?
These thoughts revolved inside the heads of everyone present, but no one spoke up. But Wade seemed to be reading everyone’s minds.
“We need to send a representative of humanity into the heart of the enemy,” he said.
“This would require the Trisolaran Fleet to capture the probe,” Vadimov said. “And to keep our spy.”
“This is very likely.” Wade looked up. “Isn’t it?” Those inside the conference understood that he was speaking to the sophons hovering around them like ghosts. Four light-years away, on that distant world, other invisible beings were also “attending” their meeting. The presence of the sophons was something that people tended to forget. When they remembered it, besides fright, they also felt a kind of insignificance, as though they were a swarm of ants under the magnifying glass of some playful, cruel child. It was very difficult to maintain confidence when one realized that whatever plans one came up with would be known by the enemy long before they were even explained to the supervisor. Humanity had to struggle to adjust to this kind of warfare, in which they were completely transparent to the enemy.
But now, Wade seemed to have changed the situation slightly. In his scenario, the enemy’s knowledge of the plan was an advantage. The Trisolarans would know every detail about the trajectory of the probe, and could easily intercept it. Even though the sophons allowed the Trisolarans to learn about humanity, surely they would still be interested in capturing a live specimen for up-close study.
In traditional intelligence warfare, sending a spy whose identity was known to the enemy was a meaningless gesture. But this war was different. Sending a representative of humanity into the Trisolaran Fleet was, by itself, a valiant gesture, and it made no difference that the Trisolarans would know the individual’s identity ahead of time. The PIA didn’t even need to figure out what the spy had to do once he or she got there: As long as the person could be safely and successfully inserted into the fleet, the possibilities were endless. Given that the Trisolarans were transparent in thought and vulnerable to stratagems, Wade’s idea became even more attractive.
We need to send a representative of humanity into the heart of the enemy.
Excerpt from A Past Outside of Time Hibernation: Man Walks for the First Time Through Time
A new technology can transform society, but when the technology is in its infancy, very few people can see its full potential. For example, when the computer was first invented, it was merely a tool for increasing efficiency, and some thought five computers would be enough for the entire world. Artificial hibernation was the same. Before it was a reality, people just thought it would provide an opportunity for patients with terminal illnesses to seek a cure in the future. If they thought further, it would appear to be useful for interstellar voyages. But as soon as it became real, if one examined it through the lens of sociology, one could see that it would completely change the face of human civilization.
All this was based on a single idea: Tomorrow will be better.
This was a relatively new faith, a product of the last few centuries before the Crisis. Previously, such an idea of progress would have been laughable. Medieval Europe was materially impoverished compared to the Classical Rome of a thousand years earlier, and was more intellectually repressed. In China, the lives of the people were worse during the Wei, Jin, and Southern and Northern Dynasties compared to the earlier Han Dynasty, and the Yuan and Ming Dynasties were much worse than the earlier Tang and Song Dynasties. But after the Industrial Revolution, progress became a constant feature of society, and humanity’s faith in the future grew stronger.
This faith reached its apex on the eve of the Trisolar Crisis. The Cold War had been over for some time, and though problems such as environmental degradation persisted, they were merely unpleasant. The material comforts of life improved at a rapid pace, and the trend seemed to accelerate. If one surveyed people about visions of the future, they might give different answers for how things would be in ten years, but few would doubt that in another hundred years, humanity would be living in paradise. It was easy to believe such a thing: They could just compare their own lives with the lives of their ancestors a hundred years earlier!
If hibernation were possible, why would you linger in the present?
When examined from the perspective of sociology, the biotechnology breakthrough of human cloning was far less complicated than hibernation. Cloning raised moral questions, but they mostly troubled those with a moral view influenced by Christianity. The troubles brought about by hibernation, on the other hand, were practical, and affected the entire human race. Once the technology was successfully commercialized, those who could afford it would use it to skip to paradise, while the rest of humanity would have to stay behind in the comparatively depressing present to construct that paradise for them. But even more worrisome was the greatest lure provided by the future: the end of death.
As modern biology advanced apace, people began to believe that death’s end would be achievable in one or two more centuries. If so, those who chose hibernation were taking the first steps on the staircase to life everlasting. For the first time in history, Death itself was no longer fair. The consequences were unimaginable.
The situation was akin to the dire conditions of post-Crisis Escapism. Later, historians would call it Early Escapism or Time Escapism. Thus, even pre-Crisis, governments around the world suppressed hibernation technology more zealously than cloning technology.
But the Trisolar Crisis changed everything. In a single night, the paradise of the future turned into a hell on Earth. Even for terminal patients, the future no longer appealed: By the time they woke up, perhaps the world would be bathed in a sea of fire, and they wouldn’t even be able to find an aspirin.
Thus, after the Crisis, hibernation was allowed to develop without constraints. Soon, the technology became commercially viable, and the human race possessed the first tool that allowed them to traverse large swaths of time.
Crisis Era, Years 1–4 Cheng Xin
Cheng Xin went to Sanya on Hainan Island to research hibernation.
This tropical island seemed an incongruous site for the largest hibernation research center, which was operated by the Chinese Academy of Medical Sciences. While it was the middle of winter on the mainland, spring ruled here.
The hibernation center was a white building hidden behind lush vegetation. About a dozen test subjects inside engaged in experimental, short-term hibernation. So far, no one had been put into hibernation with the intent of crossing the centuries.
Cheng Xin first asked whether it was possible to shrink the equipment necessary to support hibernation down to one hundred kilograms.
The director of the research center laughed. “One hundred kilograms? You’d be lucky getting it down to one hundred metric tons!”
The director was exaggerating, but only slightly. He showed Cheng Xin around the center, and Cheng Xin learned that artificial hibernation didn’t exactly match its public image. For one thing, it didn’t involve ultra-low temperatures. The procedure replaced the blood in the body with an antifreeze cryoprotectant, then brought the body temperature down to minus-fifty-degrees Celsius. Relying on an external cardiopulmonary bypass system, the body’s organs maintained an extremely low level of biological activity. “It’s like standby mode on a computer,” said the director. The entire system—hibernation tank, life-support system, cooling eq
uipment—weighed about three metric tons.
As Cheng Xin discussed possible ways to miniaturize the hibernation setup with the center’s technical staff, she was startled by a realization: If the body’s temperature must be maintained around minus-fifty-degrees Celsius, then in the frigid conditions of outer space, the hibernation chamber needed to be heated, not cooled. In the long journey through trans-Neptunian space in particular, outside temperature would be close to absolute zero. In contrast, minus-fifty-degrees Celsius was like the inside of a furnace. Considering that the journey would take one to two centuries, the most practicable solution was radioisotope heating. The director’s claim of one hundred metric tons was thus not too far from the truth.
Cheng Xin returned to PIA Headquarters and gave her report. After synthesizing all relevant research results, the staff again sank into depression. But this time, they gazed at Wade with hope.
“What are you all looking at? I’m not God!” Wade surveyed the conference room. “Why do you think your countries sent you here? To collect a paycheck and to give me bad news? I don’t have a solution. Finding a solution is your job!” He kicked the leg of the conference table, and his chair slid back farther than ever. Ignoring the conference room’s non-smoking rule, he lit up a cigar.
The attendees turned their attention back to the new hibernation experts in the room. None of them said anything, but they made no effort to disguise the anger and frustration of professionals faced with ignorant zealots who were asking for the impossible.
“Maybe...” Cheng Xin looked around hesitantly. She was still unused to MD.
“Advance! We stop at nothing to advance!” Wade spewed smoke at her along with the words.