1

Aerobraking

Three astronauts huddled around the stuck cable winch attached to Annex 5’s aerobrake, repairing the mechanism while the background stars wheeled slowly in a circle. Commander Seiji Takada watched the scene intently on a screen in front of him, but kept an eye on the clock and several monitors as well. No one had thought three astronauts would take four hours on a simple winch mechanism.

“How about annex three?” he asked Clara Forsyth, the day officer on the bridge.

“It’ll be secured in another twenty minutes. The plumbing won’t drain on the third level.”

“These annexes are more trouble than they’re worth,” Seiji growled. “They should vent the leftover in thirty minutes; we can’t delay separation much longer.”

“It’s the sewer line. If they vent it, the remaining sewage will dry out and it’ll be very difficult to remove.”

“It’s that, or let the entire structure burn up.”

There was a crackle over the radio. “We got it!” announced Robert Wairimu. “Prepare to activate the winch!”

“Acknowledged; on your word, Robert,” replied Seiji, suddenly alert. He watched the three astronauts slowly back away from winch. Since they were standing on top of the aerobrake, Columbus 8’s rotation pushed them downward against it, so they were able to walk slowly away from the stuck equipment.

“Okay, give her a rip,” said Robert.

Seiji pushed some buttons and the winch sprung alive. The annex, ten meters in diameter and ten meters high, its top three floors deflated and airless, began to compress slowly against the first floor.

“It’s working!” exclaimed Seiji. “You did it, guys! Congratulations!”

“It’s looking good,” agreed Robert.

They all watched, either on the screen or outside in person. The six winches worked intentionally slowly, pulling the top of the annex downward into the shadow of the fourteen-meter aerobrake, millimeter by millimeter. After fifteen minutes the winches finished their work. Seiji pushed some on-screen icons and the winches successfully locked.

“We have full lock,” exclaimed Seiji. “Thanks, guys; come on inside. Job well done.”

“Thanks, Commander,” the three astronauts chorused, and they turned toward the airlock. Seiji turned to Clara. “Well, annex five is secured.”

“Three will be, don’t worry,” she replied.

Seiji’s attaché—a combination computer and videophone—beeped with an incoming connection. He looked at the screen and saw that Governor Will Elliott himself was calling. “Toru, activate the call,” he said to the attaché. The screen flashed alive with Elliott’s face.

“Hi, Seiji, just thought I’d check in with you to make sure all is well up there. We’re ready for your arrival; five shuttles are already in orbit and the sixth one goes up right after aerobraking is complete.” Elliott tended to talk in long blocks; he was used to calls to Earth that involved long time delays.

“Thanks for calling, Will. It’s nice to be so close that we can have an ordinary conversation! Annexes 3 and 5 have given us some trouble, but five is now stowed for arrival and three will be shortly. The other four annexes are stowed and ready. Except for the repair people and the pilots, everyone is out of the annexes and in the interplanetary transit vehicles. Separation is scheduled for . . . twenty-six minutes.”

“Annex three is now stowed,” reported Clara.

“I heard that,” said Will. “I’m glad to hear everything’s ready. I was getting worried! Clearly, a lot of work is needed to get these annexes functionally nominally. We cut some corners developing them, knowing we would be flying them in groups so there would be plenty of people around to repair them. They potentially help a lot to reduce the costs of interplanetary flight. So thanks for all your work, and please convey my gratitude to your team as well.”

“I will, of course. We’ll get all six of them to you, don’t worry.”

“Good. I’m not worried at all, really. You’ll be in our thoughts and prayers, Commander.”

“Thank you, Governor.”

“Goodbye.”

“Goodbye.” Takada closed the circuit and turned back to the work at hand. The bridge now had five people on duty; two had arrived during the call. Clara started to call around to the other five ITVs or Interplanetary Transit Vehicles—the Sabaeus, Hellas, Ausonia, Gangis, Coprates, and Tithonium—and to the two Mars shuttles—the Apollonaris and the Ascraeus—making up Columbus 8 to verify that someone was on the bridge of each and prepared to run it. As the readiness of each was confirmed, Clara turned over the life support functioning to it. Seiji watched and listened; all was going normally.

Right on time, Seiji gave the despin command. Columbus 8 had already been slowed to 1/4 revolution per minute from its usual 5 revolutions, which had decreased its gravity to a maximum of about two percent of terrestrial gravity. Such miniscule gravity was useful only to create a sense of up and down and to make the bathroom work, though barely. The Columbus 8 complex consisted of an axial unit twenty meters long and six meters in diameter that served as a zero-gravity gymnasium; it was a single, large, open recreational space. At one end an aerobrake, a heat shield ten meters in diameter, was attached; the opposite end had their main antennas. The axial unit had two rings of four docking adaptors each. The first ring had Interplanetary Transit Annexes 1, 2, 3, and 4 docked to it; their aerobrakes each had a single docking collar embedded in their center, and docked to each annex was an ITV, the Sabaeus, Syrtis, Ausonia, and Gangis. The second ring of docking adaptors had two annexes, numbers five and six, docked, and their ITVs, the Coprates and Tithonium; the two other docking adaptors in the rear ring had the Mars shuttles Apollonaris and Ascreus attached. Their final ITV, the Hellas, was docked to the far end of the axial unit via a docking port in the aerobrake and served as zero-gravity housing for those who wanted to live and sleep in zero-gee. Thus Columbus 8 crudely resembled two sets of spokes attached together. It had been assembled at Gateway Station, between the earth and the moon, starting almost a year ago, and had left Gateway four months and five days ago. It had proved to be a comfortable and reasonably spacious accommodation for 72 persons.

It took about fifteen minutes of gradual work to stop Columbus 8’s rotation completely. Gravity ebbed away and soon was gone. That accomplished, Seiji began to give each ITV and shuttle permission to undock; finally, the annexes themselves were undocked, leaving the central cylinder naked. It had been purged of its air during the separation phase and was now empty. The winches had already been tested, so Clara activated them and they watched the axial unit compress down to a safe size behind its aerobrake. An hour after they started the separation maneuver, Columbus 8 was no more; it was replaced by sixteen separate vehicles, each with a pilot, a copilot, a maneuvering unit, and an aerobrake. Except for skeleton crews in the annexes and shuttles, everyone was in the seven ITVs, which provided tight but comfortable accommodation for two or three days.

Now the more complex phase of the mission began. Seiji and the bridge crew became mission control as each of the vehicles—including the Syrtis, the ITV in which they were located—prepared to fire its engines. Each of the sixteen vehicles had to hit the Martian atmosphere at the same angle in roughly the same place at roughly the same time, but they could not be too close to each other. Each vehicle had a specific flight plan that had to be executed exactly. Meanwhile, Aurorae Outpost on Mars provided radar and radio doppler data that confirmed the position of each vehicle and audited the entire procedure to make sure everything was done exactly right.

One by one, each vehicle fired its engine briefly in a specified direction to impart a few tens of meters per second of velocity. That was all that was needed to guarantee separation, for they had twenty hours before they reached Mars.

Twenty hours of relative peace and quiet while teams on Mars and in shuttles orbiting the planet reviewed emergency plans. Twenty hours of zero gravity, drinking water and eating food in tubes and washing with wet cloths, and patiently waiting. Twenty hours of ordinary work for about half the hundred fifty human beings on Mars.

Just after dawn, the first vehicles began to encounter the Martian atmosphere several hundred kilometers west and slightly north of Aurorae Outpost. For those who rose early enough, the streaks of light crossing the sky from west to east were fascinating to see, but worrisome. Sparks sometimes rolled off the aerobrakes and the smoke contrail occasionally wavered slightly. At closest approach, the glowing aerobrake could be clearly made out with the naked eye through the slightly opaque bubbles the Marsians lived in; the vehicles dove to within ten kilometers of the surface to encounter air thick enough to slow them, and the closest point was just twenty kilometers north of the Outpost, where a collection of surface vehicles stood ready to race to any wreckage that might result. The personnel on Columbus 8 briefly experienced decelerations as high as three gees. Then the vehicles, in their straight line through the curve of air, began to rise away from the surface, and in less than a minute they were in space again. The two-minute encounter had slowed them from almost 8 kilometers per second to 5 kilometers per second, putting the vehicles in a one-sol (Martian day) elliptical orbit that always remained roughly above Aurorae Outpost. In that orbit was Embarcadero, their interplanetary arrival and departure facility, which had ITVs, an ion engine, remote manipulator arms, fuel tanks, and three Lifters—unmanned fuel tugs based at Phobos and Deimos—all useful in emergency situations. The Ascreus and the Apollonaris awaited in the orbit as well

“Marshall, Lizzie, you won’t see a lot of me for the next few days,” Will reminded his kids over a quick lunch at “the patio,” their main cafeteria in Yalta Biome.

“Dad, you already told us!” said Lizzie rolling her eyes. Ethel put her hand on her daughter to reminder her to listen.

“We’ll have some people down here by sunset, right dad?” asked Marshall.

“Yes; the five tourists and four special visitors are coming down in the Apollonaris in about three hours. We just cleared them for landing before I came here for lunch.”

“So, everything went well this morning?” asked Ethel.

“Perfectly. The new aerobrakes on the annexes performed as expected. All sixteen vehicles are right on target.”

“When will we have the annexes? I want to see one of them, they sound cool,” said Marshall.

Will chuckled. “The technology’s cool, but I don’t think they’ll look that special, Marshall. The first step is to bring together the pieces of Columbus 8 to Embarcadero; they’re up to a hundred kilometers apart, still. The axial module will be attached to Embarcadero in about twelve hours and then the ITVs will dock to it, which will give everyone space to walk or float around in. Embarcadero will spin to 1 revolution per minute, which will generate about a tenth of a gee, enough for toilets and showers—”

“But how will people come and go?” asked Marshall.

“Embarcadero will stop rotating three times a sol for about an hour each, for docking and undocking. Mars shuttles will bring half the crew here right away, while the other half works on the annexes—”

“And that’s complicated!” interrupted Marshall.

“Well, it might be, but we hope it won’t be,” replied Will. “Each annex has a flexible 4.5 tonne meteoroid shell and a triple-thick, 4.5 tonne pressure shell, with life support equipment and some cargo located inside. We have to squeeze down the pressure shell inside the meteoroid shell, secure it at a certain size and configuration with cables, then literally unzip the meteoroid shell, pull the pressure shell out, and transfer the pressure shell to the six-meter diameter cargo bay of the Mars shuttle. Not an easy task to accomplish on a pressure shell that’s originally ten meters in diameter, but it is a flexible plastic fabric, and we’ll have the rigid outer meteoroid shell to push against. If we can’t accomplish that task using special equipment and old-fashioned muscle, a shuttle can fly to Deimos with the annex sticking out of the cargo bay, because the slight gravity of the moons should make the task easier.”

“It’d be a waste of fuel, though,” said Ethel.

“And time. We’ll see. Then the shuttle will land with the annex, refuel, and go back up with cargo for Earth. The remaining folks at Embarcadero will transfer gold, argon, nitrogen, and other Mars surface cargo to mounting points inside the meteoroid shell, which is still attached to its aerobrake and its navigational and maneuvering systems. Once everything’s ready, lifters will push them on a trajectory that will take them past Venus and on back to Earth next summer. Then the shuttles will come back here with the last crewmembers.”

“Why can’t they fly straight back to Earth?” asked Lizzie.

Will shook his head. “Mars and Earth are no longer aligned right for that. It’ll be two years before a direct flight will be possible again. But Venus is in a perfect position to bend the trajectory back to Earth.”

“It’s really amazing we can do something this complex,” said Ethel. “This is not like anything we’ve attempted before.”

“It’s an order of magnitude more complicated than Columbus 7,” agreed Will. “But we’ve developed fifteen years of experience with the Mars shuttles; we know what they can do. Embarcadero has more equipment than ever before. And we have people here that are incredibly good with orbital rendezvous and cargo transfer. Let’s hope we don’t blow it.”

“There’s always an element of luck in these things,” agreed Ethel. “The big danger is a collision between vehicles; there are a lot of them in a compact part of space. And I suppose the untried part of the plan is the annexes, since they’re new.”

“If they prove too difficult to pack into the shuttles, we can always fly them down here with landing engines and parachutes,” replied Will.

“Say Will, where do you think this will lead?” asked Skip, who was seated at the next table.

“You mean, Columbus 9 or Columbus 10?” He shrugged. “This approach is getting pretty complicated. We have eight shuttles here on Mars and in the next six weeks we have to fly sixteen shuttle missions. We can’t afford any accidents. I think we have to develop a good, reliable landing system to bring the annexes down and spare the shuttles, or build a new, bigger shuttle. But right now, politics being what they are, and with the depression still growing, I can’t see us getting money for a new transportation system.”

“No, that’s not in the cards,” agreed Skip. “But could the current system double in size?”

“Maybe, especially if we don’t fly more ITVs; they have to be sent back to Earth. We might have to split the arriving fleet into two complexes, and send the annex aerobrakes back to Earth over a longer period of time, so we can spread out the workload on the shuttles. Maybe we can improve the shuttles’ reliability enough to fly them more often before they have to be repaired. And Embarcadero has to get bigger to accommodate larger missions and their possibly larger emergencies.”

“The more people we can fly here each time, the cheaper it’ll be,” added Ethel. “If this world’s going to grow, we need a breakthrough in propulsion and in the cost of transportation.”

“That’s for sure,” agreed Skip.

Will turned to his lunch; he had to eat quickly and get back to the control area. He kept one ear on the conversation about Lizzie’s subtraction homework and Ethel explanation to Marshall about how she was making plastic chairs for the arrivals. At the next table, Skip and Brian engaged in their usual political exchange, Skip attacking the White House for its import restrictions and the consequent trade war with the rest of the world and Brian insisting that nothing else could protect an economy massively damaged by the terrorist computer virus attack and the small terrorist nuclear explosion over Houston. Érico Lopes, their left-wing Brazilian, occasionally offered light-hearted support to Skip, though he was more interested in helping his almost three year old son with his lunch. Roger occasionally encouraged Brian, though he was sitting with his family as well and was no longer fired up to argue politics. Others sat and listened; about fifty of the hundred people in the outpost were seated at their usual spots on the patio.

Before heading back to Mars Control, Will turned to Érico. “Any news about Fuel Plant number 2?”

“Eliseo says they’ll have it fixed by tomorrow. It was one of those trivial mechanical breakdowns that people can fix easily, but robots can’t fix in ten years.”

“So I gathered. But since no one will be back to Phobos for nine months after December, I wanted to be sure it’s fixed.”

“Understandable. I’m glad we’re getting a third unit; both units are acting up. They’re too old.”

“Same with the units on Deimos. Let’s hope they make it until Columbus 9.” Will turned back to his family. He apologized that he had to go and took his tray to the return area. Then he headed across the patio to the table with Alexandra and Yevgeny Lescov on his way to Mars Control. The two of them looked a bit sad, but Will didn’t make anything of it. “Yevgeny, any developments with the gold shipments?”

“No. We’ve still got fifteen extra people running equipment, and that’ll continue until the end of next month. Cassini Outpost has a shipment scheduled to arrive here November 29.”

“The last sol before the last launch. How much?”

“They hope it’ll have sixteen tonnes.”

“Sixteen!” Will was surprised. “And the total for the columbiad will be?”

“Two hundred eighty-eight tonnes.”

“Wow.”

“The value of gold fell a bit this sol, but it was still $2,400 an ounce.”

“But the value of the dollar is half what it should be. We’re talking about $1,200 per ounce based on last year’s currency—old dollars—or 1,000 euros per ounce, or thirty-three million euros per tonne. So we’ve mined almost 10 billion euros of gold.”

“That’s why the stock of Muller Mining, Consolidated, and Siberco has gone through the ceiling,” said Yevgeny. “Thank God we put half of our savings in their stock several years ago. Our net value has increased about ten times.”

“Ours, too. Their stocks are practically the only ones performing well, now; in fact, I suspect a stock bubble. I’d sell a lot of the stock early next year.” He turned to Alexandra. “And Colorado?”

“Oh, it’ll be ready.” She didn’t sound very enthusiastic. “We’ll be cutting the rye-38 crop tomorrow and plowing under the roots. The soil tests indicate the rye-38 has removed most of the cadmium and selenium and reduced the lead below serious levels. We’ll be able to plant fruit trees and some vegetables next week.”

“And the foundations for the housing?”

“The work left is minor. As soon as the annex pressure shells arrive, we can start to set them up. We’ll keep up with the arrival rate just fine.”

“Good.” Will looked at her closer. “Are you feeling well?”

“No; I apologize I didn’t explain, but I’ve been under the weather lately. I took off this morning, but I’m feeling better now. Eve saw me this morning; don’t worry.”

“A virus?”

“Something like that.” Alexandra waved her hand dismissively and Will wasn’t sure whether she was dismissing the virus or him.

“Okay, get better. Let me know if there are any developments.”

“Oh, don’t worry.”

Will waved goodbye. He headed across the biome to the airlock leading toward Riviera and Colorado. Yevgeny turned to Alexandra. “Maybe we should tell Will. He can give good advice.”

“No, I don’t think I want his advice. I know what it’ll be.”

“Well, so do I.”

“Yevgeny, it’s my body!”

“Dear, I know, but it’s our decision.”

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