Delta-v, page 18
“Right. For the first time in my life I heard silence. I want to hear it again. Space sounds like paradise to me.”
JUNE 16, 2033
Mission control manager Gabriel Lacroix walked to the front of a darkened classroom. His forty asteroid-mining trainees filled out the seats. A hologram of the solar system instantiated in midair and zoomed in on Earth. The continents, oceans, and swirling clouds of Earth passed by, but the view continued into the vastness of space—until eventually a lonely rock resolved out in the void.
Lacroix said, “This is the reason we are all here. . . .”
The ash-colored chunk of rock continued to grow until the hologram filled the available floor space. It was an asteroid, shaped like a crude spinning top, with a pronounced ridge running around its equator. Its surface was littered with boulders, and there was one especially large boulder protruding near its north pole—like a fortress—that was alternately obscured and revealed as the hologram slowly rotated.
“Asteroid 162173 Ryugu.” A label faded in as he said it. “Discovered in 1999, it is a rare C- and G-type near-Earth asteroid. Roughly 900 meters in diameter and 450 million tons in mass, it contains tens of millions of tons of nickel, iron, cobalt, nitrogen, ammonia, and water—worth an estimated 106 billion US dollars.”
Whistles throughout the room.
“In 2018 the Japanese Aerospace Exploration Agency’s Hayabusa2 probe visited Ryugu and remained for nearly a year. It obtained the detailed scans and images you see here, and it also gathered a sample of the asteroid’s regolith, which it returned to Earth in 2020—dropping a capsule into the Australian desert.”
Detailed photographs of black, almost coal-colored, dust materialized in front of the asteroid.
“This sample confirmed that Ryugu is composed of carbonaceous chondrite—which contains volatiles in the form of mineral hydrates, which can be readily transformed into water vapor.”
Lacroix examined the faces of the trainees. “And water will be the single most valuable commodity in the early days of space exploration—creating air to breathe, fuel for rockets, and in sustaining human, animal, and plant life. However, Ryugu also contains other vital resources—ammonia, nitrogen, and metals. What makes these resources so valuable is their trajectory above Earth’s gravity well. . . .”
The hologram panned away from Ryugu and zoomed in toward Earth once more. “Even with today’s reusable launch systems, it currently costs seventeen hundred dollars per kilogram to lift a payload into low Earth orbit.”
A holographic rocket barely climbed off the Earth.
“It costs over twice this amount to lift a kilo of payload to a geostationary transfer orbit—or GTO—36,000 kilometers above Earth.”
The same rocket burned a tenth of the way to the Moon.
“That is because at present we need to bring all the fuel required for any space voyage up from Earth’s surface. This is why placing anything into orbit around the Moon costs at least 6.6 million dollars per ton.”
Lacroix looked out at the trainees. “Building truly useful structures in deep space—on the order of a million tons or more—from Earth-sourced materials would require investments of seven or eight trillion US dollars. And that is just to lift the materials. It does not include cost of R and D, design, and construction. Catalyst Corporation believes it can do better.”
The hologram zoomed out to encompass the Earth, the Moon, and the tiny, labeled dot of Ryugu. “Due to its low gravity, mined resources from Ryugu, by contrast, could be returned to cislunar space for as little as a kilometer per second of delta-v. And in situ production can provide the fuel necessary.”
An animation showed a robot tug departing Ryugu on a long, looping trajectory around the Sun, and then doing a brief burn before being captured in a Moon orbit years later.
“That is half the acceleration required to lift materials from the Moon’s surface. By cost-effectively shipping millions of tons of resources from Ryugu into a lunar DRO, Catalyst Corporation aims to drastically reduce construction and refueling costs in cislunar space—in the process kick-starting a booming cislunar commodity exchange.”
Lacroix examined his audience. “But how do we begin?”
The hologram then zoomed in toward the Moon and a 3D model of Catalyst Corporation’s hypothetical mining ship in orbit there—its radial arms folded in preparation for a burn. The trainees had all grown familiar with the spacecraft in the training mock-up over the past month. The holographic ship fired its engines, sending it on a trajectory to intercept the passing asteroid Ryugu.
“Our training program has been predicated on the need for a crew of eight miners to depart from lunar orbit and rendezvous with Ryugu on its next close approach.”
The hologram zoomed in to show the spacecraft arrive in the shadow of the asteroid.
“There, the crew will conduct robot-assisted mining operations for a period of approximately four years.”
The assembled trainees murmured among themselves. Tighe looked to Morra sitting next to him. Their expressions said it all: Four years?
The hologram showed the Earth and Ryugu revolving around the Sun several times until they came into close proximity again.
“After which a relief crew will arrive from Earth and the original crew will return home, having mined 8,000 tons of resources—which is approximately one-third the entire mass that humanity has launched into space thus far. Those resources will have been sent back toward a lunar DRO via robotic tugs at regular intervals on slow low-delta-v trajectories—meaning that the crew will arrive back on Earth before most of their shipments show up in cislunar space.”
Murmured discussions spread throughout the room.
Tighe had to admit it was a polished presentation, but how expensive were computer graphics, after all? No doubt Joyce intended the video to hook investors. Having a crew of “trained” asteroid miners who believed in the mission would no doubt come in handy during press conferences and investor road shows. That didn’t mean any of it would ever turn into an actual space mission—much less a four-year mission in deep space.
Lacroix studied the faces of his audience. “I see many of you have concerns. Questions. But let us talk about how we will mine Ryugu. . . .”
The hologram zoomed close to the asteroid, rotating slowly along its ridge-like equator. “All terrestrial methods are inadequate to the task of mining in space.” Lacroix pointed at the equatorial bulge. “Ryugu is more like a pile of gravel in free fall than it is a solid object. Forceful methods at excavation would result in scattering the material in microgravity. Even assuming you can gather the regolith, how do you differentiate and refine the various useful materials in microgravity?”
Lacroix gazed out at the trainees. “The answer is optical mining—utilizing concentrated sunlight to harvest and process material.”
The hologram panned to show four robotic spacecraft mounted on brackets on the mining ship’s spine. Each of the machines had twin parabolic reflectors that dominated its profile like huge round ears.
“Over the next three months, with the aid of VR and AR simulators, you will become proficient in the maintenance and support of the APIS optical mining system.”
The hologram dissolved to show an elevation of one such machine. The scale indicated it was nearly 50 meters wide.
“The heart of the APIS system is the Honey Bee—a robotic craft originally designed to autonomously identify, bag, and process small asteroids up to 10 meters in diameter. We intend to use it on boulders plucked from Ryugu’s surface. To harvest those boulders, Catalyst Corporation plans to adapt NASA’s canceled Asteroid Redirect Mission hardware. . . .”
Another robotic hologram appeared next to the Honey Bee, and this new machine looked like a three-legged spider, with 18-meter-long legs fashioned out of metal triangles. Twin circular solar panels were attached to its smaller hexagonal body.
“We’re calling this the Asteroid Retrieval System—or ARS. In the low gravity of Ryugu, the ARS can move boulders up to 10 meters in diameter away from the surface and into a terminator orbit. There, the Honey Bees can bag them. . . .”
A holographic animation now showed cube sats scanning the asteroid’s surface, highlighting a candidate boulder. An ARS robot launched from the mother ship, extending three long legs as it descended to the surface, eventually standing over the boulder. It then drilled into the rock with smaller, mandible-like arms, clamped down, and pushed off the asteroid, its legs curled around the boulder.
As the ARS rose above Ryugu’s horizon, the Sun illuminated it, and the robot released its prize. A Honey Bee optical mining rig then rendezvoused with the floating boulder, expanding what looked like a large fumigation bag to enclose it. The bag cinched shut, and the Honey Bee then focused its twin solar collectors toward the Sun.
Lacroix looked out at the trainees. “Your job will be to help these robotic systems do their job. This will require a detailed understanding of their technical specifications and maintenance. Let us begin. . . .”
JULY 8, 2033
An axis trainer occupied one wall. This was a vertical framework of concentric rings mounted in gimbals. Set within the rings and secured at the waist and feet was a ruggedized space suit, burnt orange in color, ribbed with thick padding, and set with carbon fiber plates. The suit looked like a cross between a federal prison uniform and bomb disposal armor. The spherical helmet was especially odd; where a normal helmet had a visor, this one was instead an opaque shell. The entire surface of the helmet was studded with dozens of black nodules set in rows.
Tighe and the other trainees stood at ease, wearing white LCVGs (liquid cooling and ventilation garments) resembling long johns. The formfitting bodysuits were lined with water tubes to distribute heat, the nozzles for which emerged at the waistline.
An instructor with a South African accent paced the floor in front of them like a drill sergeant. “What you see before you is the Mark V Extravehicular Mobility Unit—or EMU. Also called a clam suit. . . .”
The instructor made a circular gesture, and two assistants swiveled the EMU on the axis trainer so its back now faced the trainees. The suit’s primary life support pack was surrounded by a rectangular docking collar. One of the assistants opened the pack like a hatchway, revealing the suit’s interior.
“In microgravity, you climb in and out of the EMU while it is docked to the side of the spacecraft. You then close and seal the hatch before undocking from the ship.” He studied the faces of the trainees. “Can anyone tell me why this design is necessary for asteroid-mining operations?”
By now the trainees knew better than to raise their hands.
After a pause the instructor answered for them. “Because asteroid dust is an extreme biohazard. It must never get inside your ship. Asteroid regolith is five times finer than talcum powder, with particles as sharp as broken glass. If breathed in, they can enter your bloodstream directly—resulting in death. If taken into the lungs, they can penetrate deep enough to cause silicosis—stone grinder’s disease—resulting in death. Regolith also sticks to and shorts out circuit boards and jams valves and seals—causing equipment failures that can also lead to death.”
The instructor now had their full attention. “But asteroid regolith is just one of the dangers you will face during extravehicular activity—which you will hereafter refer to as EVA. . . .”
To Tighe’s surprise one of the assistants put in earplugs and withdrew a semiautomatic pistol from a nearby box. He chambered a round while the other assistant pivoted the suit to face forward again.
The instructor barked, “Cover your ears!”
The trainees complied.
The assistant took aim at the suit and fired once at point-blank range. The bullet put a divot in the chest plate. Everyone uncovered their ears again, and the assistants rotated the suit once more to show that the round had not penetrated.
“The EMU’s Kevlar-laminate armor is capable of stopping even high-caliber rifle rounds traveling 1,700 miles per hour. In deep space it might even protect you from a micrometeorite the size of a grain of sand traveling twenty times faster.
“Now let’s talk about the biggest and most constant danger you will face while on EVA: ionizing radiation—galactic cosmic rays. . . .”
* * *
—
Three weeks later and Tighe had mastered every aspect of the Mark V EMU. He found the precise physical tasks required to prepare for a space walk similar to those for a cave dive. The clam suit’s primary life support system was essentially a high-end rebreather, much like the Se7en series rebreathers he’d used for years. However, unlike with water-diving equipment, a space walker had to provide not just breathing gas but also atmospheric pressure across the entire body.
Space suits were pressurized to just a third of an atmosphere to prevent them from becoming a balloon that paralyzed the wearer. However, ambient air at such low pressure lacked sufficient oxygen to breathe, and for this reason pure oxygen was used.
Prior to any space walk, he’d need to prebreathe oxygen at normal pressure for a couple of hours to eliminate the nitrogen in his bloodstream—which would otherwise bubble out of his blood like a shaken-up soda can in the reduced-pressure environment and cause the bends.
Here, too, Tighe’s diving expertise had direct application to his new profession, and he was soon able to coach fellow trainees.
The first time the instructors winched Tighe into the clam suit’s hatchway, he removed his oxygen mask before wriggling into the suit’s immobilizing embrace and poked his head up into the dark helmet. The clam suit hatch shut and sealed behind him with a hiss.
He felt like he’d stuck his head inside a stew pot. It was completely dark until glowing text appeared—an integrated crystal display. When he turned his head, the integrated crystal turned with him—although the helmet itself did not. No matter which way he turned his head, the crystal pane encompassed his entire field of vision.
On Earth the suit weighed 200 kilos, and he had to push down feelings of claustrophobia as he stared into the opaque helmet wall.
He heard a voice in his ear. “Tighe, commence suit power-up.”
“Roger that.” Tighe followed the steps of the suit’s power-up procedure, tapping at virtual interfaces with his heavy arms. Soon he heard a whirring sound, followed by the suit pressure dropping. His ears popped as oxygen flowed down over his face. It was invigorating. Cooling water now also flowed through his LCVG, conveying the sensation that he’d just lowered himself into a pool of water.
His display crystal sprang to life, boot loaders scrolling past. Then suddenly the world opened up around him—as if he weren’t wearing any helmet at all. Tighe glanced left, then right, and was stunned by the utter reality of the view.
“Holy shit . . .”
The helmet had simply disappeared.
The instructor shouted at Tighe from nearby. “The headgear you are wearing renders itself invisible to the wearer. The plenoptic apertures—those nodes arrayed outside the helmet—gather light fields from all around the helmet and the EMU’s software stitches them together into a cohesive panorama. This technology gives you unprecedented situational awareness while on EVA.” The instructor continued: “In the event of system failure, you access the legacy visor here. . . .” He lifted the opaque front faceplate like a shutter, revealing a clear visor beneath.
Tighe was barely listening to the instructor as he gazed around the room in wonder.
AUGUST 18, 2033
Tighe and Jin opened the Hab 1 airlock in the training mock-up and climbed up into Transfer Tunnel 1. Dressed in their lightweight blue pressure suits, they moved quickly, sealing the hatch behind them. Then they both looked up.
The 2-meter-wide tunnel rose 106 meters above them—the hatchway to the Central Hab barely visible. Electrical, data, and plumbing conduits ran to vanishing points along three sides, with composite ladder rungs rising on the fourth side.
Even after months of training in the mock-up, it still amazed Tighe that the company had gone to the effort of building a full-scale replica of their tenuous spaceship deep within the Antarctic ice—like a bug in amber.
As in the real design, the laminate-walled transfer tunnel had no atmosphere. However, here on Earth, gravity was in full force the entire length of the transfer tunnel; on the real spaceship, gravity would reduce proportionately as one “ascended” toward the Central Hab. Starting out at 1 g, you’d experience a half g at 50 meters, a quarter g at 75 meters, and so on.
Instead of an elevator, which would add significant mass and maintenance headaches, the crew ascended each of the ship’s three radial tunnels by hooking their suit harnesses to carabiners on a steel cable. A twenty-volt planetary gear winch allowed them to traverse the tunnel in five minutes. Here on Earth, they were forbidden from using the ladder to speed things up—too dangerous.
Tighe and Jin clipped their harnesses into a braid of carabiners at the end of the cable, then used a virtual UI to activate the winch.
As they slowly rose from the Hab 1 airlock, Tighe said, “You ever do training like this at the CNSA?”
Jin shook his head. “No one has built a ship such as this.”
“I’m surprised. Spinning a spaceship to create artificial gravity makes sense.”
“Only if the radius of rotation is at least 200 meters. Otherwise, the Coriolis effect can sicken the occupants. Imagine gravity changing dramatically whenever you sit or stand up.”
Tighe looked upward. “This tunnel isn’t 200 meters.”
Jin looked up as well. “A 106-meter radius could be endured with training, but launching a ship even this size into space would require tens of billions of dollars. Too expensive.”
“It’s a shame.”
