Solar Sailer

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Solar Sailer Page 4

by Stephan Besik


  Chaz smiled ironically. “You know, it would be a lot cheaper to have kids than to spend your dough on a Moon colony. I’ll bet Charity’s got a dozen hottie girl friends, any one of which would love to help you spend your money on them- and their babies.”

  Aman looked disgusted. “Yeah, right. Like going through a few divorces would be cheaper.” He smiled and shook his head. “No, thanks. If I find someone special, well, I might change my mind. But not right now. I’d rather beg for money for a worthy cause. I think I’ll take the Moon.”

  Steam Turbines

  Wallace was feeling much better about the project after the last few days. The meeting about Moon problems had been a bit scary; he hadn’t really thought much about what his ship was going to do once it was operational. It helped to know that Aman and Chaz were thinking about that and had another team working the problem.

  Things were starting to come together. For a while his regeneration idea for the moonship engines had almost turned to dust. He couldn’t find companies that made high performance turbines at the scale he needed that could use ammonia as the working fluid. Most regeneration facilities were far too big to fit on the ship, as well. The customers for such things were big organizations trying to save on costs to really big ones like power companies. Not much market for regeneration for one-megawatt plants. Especially not regeneration based on ammonia.

  Then he’d found a company that made small regeneration steam turbines for everything from small farms to middling-sized factories. They weren’t perfect for his needs but they were close. He had taken Albert Sanchez, his chief engineer, and Suzette Thompson, his chief mathematician, along to visit the company. They had talked over the possibilities with the folks there and he had waved a little money under their noses. It helped that a big money guy like Treble was funding them. The turbines that he wanted for the ship would have to be high performance, lightweight, and highly reliable. Just the kind of expensive little toys the engineers at the company loved to have someone else pay for. Now Wallace just had to bring in Klaus to make sure these guys didn’t rob him blind.

  Aman Talks Politics

  Aman had never met the Secretary General but he needed a multinational authority to control the Moon, and the United Nations was as multinational as it got. He was a little surprised that it had been fairly easy to arrange an appointment with her. But then, money tended to talk even when it wasn’t crossing any palms.

  The Secretary General rose and reached across her desk to shake hands. “Mr. Treble. I don’t think we have met.”

  “You’re correct, Madam Secretary General, I’m sure we haven’t. Thank you for extending the privilege to me.”

  “I am frankly surprised, Mr. Treble. Your reputation precedes you and there is little of the diplomat that I can see. What brings you to me?”

  Aman took a deep breath. A lot rode on this meeting and he wanted to get it right.

  “About a year ago, a young man sent a proposal to my foundation that we elected to fund. After a year of progress I believe that the young man will soon succeed in an endeavor that will have a profound impact on the future of humanity.

  While the project is not yet complete, it is likely that in two years we will demonstrate the availability of low-cost, high-speed travel to the Moon. Perhaps of more importance, we will soon begin development of a craft of greater capabilities that will enable humans to travel to Venus in a fraction of the time required by other means. Like our lunar ships, the interplanetary ships we intend to build will also operate at considerably lower cost than anything now available.”

  The Secretary General knew little about space treaties, but she did know that at the moment the Moon Treaty and the Outer Space Treaty were little more than pieces of paper. With the exception of the ban on nuclear weapons in space, they were of little practical use. As the Americans would say, they were nothing more than apple pie and motherhood. They were that way for a reason; at the time the Moon Treaty was written only the USA, the UK and the then- USSR had any interest in the Moon, and only one was demonstrating the capability to get there. Since then no one had found a strong reason for establishing a permanent colony up there, or even a good reason to return. As for the Space Treaty, there were many signatories but the treaty had yet to be tested. As long as there were no human beings anywhere except on Earth and manned space travel was prohibitively expensive the Space Treaty worked. What would happen if someone found a reason and economic means to establish a colony on the Moon or some other place in the Solar System? How was ownership going to work on a distant rock that no one really owned? She frowned a little. Had Treble found a good reason to go back? Would getting there faster and cheaper make a difference?

  “What does this have to do with the United Nations, Mr. Treble?”

  “We intend to establish a permanent colony on the Moon, ma’am, as a stepping stone for trips to Mars and Venus. We recognize the problem with any one of the major powers controlling the Moon. If a single nation takes control, there is a pretty good chance that a major power shooting war will start. We don’t want to be the cause of that, and we don’t want to be fought over.

  It seems to us that the U.N. is the best alternative to any of the major powers. I think that we need a few things. First, we need a document covering governance of non-Earth territories that addresses the needs of any colonies, research stations, or other settlements that may be established in the near future. That has to include some means of establishing ownership of parcels of land peacefully. Second, I think we need some police or similar organization to act as a sort of trip line in case one of the major powers decides they want to take any Lunar settlements by force. Third, we need a judiciary to make decisions in cases of crime, civil disputes, and possible violations of our governing document.”

  The Secretary General interrupted, “What about a legislature?”

  “We will need that, too, but right now any colony we build will likely be rather small, almost certainly too small to require a legislature. My foundation will implement our corporate behavior policies but I think we will also plan on limited-charter town meetings for self-governance for a while. Meetings that all inhabitants of the Moon will attend by some means. The first colony will be more a research station than anything else, and a research station with a fairly narrow purpose: providing a detailed assessment of the resource situation on the Moon and finding locations suitable for a permanent colony that will be more than a tourist attraction.”

  The Secretary-General turned her chair and stared at a large bookcase against her office wall for a while, digesting what she had been told. She turned back to address Aman.

  “I don’t think we can help you very much with your plan. Much as I’d like to be of assistance, the permanent members on the Security Council are quite unlikely to allow anything meaningful to come out of my office. With the exception of Earth orbital satellites, there is no profit motive for activities in space and therefore no interest. There has been no evidence that establishment of permanent habitations on the Moon will be little more than curiosities for the foreseeable future. Of course, if you do demonstrate that colonization of the Moon will someday be profitable, the major powers will scrap over rights like dogs over a bone.

  There is also the strategic argument against permanent habitation. Once there, a colony on the Moon could be a valuable military asset, a place from which to launch high-velocity weapons toward Earth. The Space Treaty forbids nuclear weapons but variants of conventional weapons such as kinetic weapons are not mentioned. The major powers on the Security Council have become experts in cold war. They do their fighting on other people’s property to insulate their own people from most of the violence. The Moon would be a great place to fight over because of its possible strategic significance and complete or nearly so lack of innocent victims. That is, assuming that your project demonstrates that the Moon can become a relatively inexpensive orbital bombardment platform.”

  Aman shook his head. “We thin
k that hauling strategic weapons up to the Moon, even with our new technology, will not be cost effective any time soon. We also think that the amount of warning a nation will have if someone attempts an orbital bombardment will give the target a fair amount of time to prepare, and particularly a lot of time to counterattack with Earth-based nuclear weapons.

  On your first point, however, that’s why we need some form of political shelter. The technology exists to make the Moon readily accessible. Whether or not it’s our group, someone will implement existing technology to get to the Moon quickly and cheaply. If that happens in a political vacuum the major powers will turn the Moon into a bone to fight over, as you suggest. That’s why it’s necessary to fill that vacuum with something that will keep them at bay. At the least they will have to think twice if we have some political cover in place.”

  The Secretary General swung her chair away from Aman again. Not a patient man, Aman waited patiently as the Secretary General stared out her window. At last she turned back again.

  “Do you think that getting to the Moon will produce a significant return?” She grimaced. “Of course you do. Otherwise you wouldn’t be here.” She leaned forward a little.

  “I can’t do much for you officially, but give me a day or two to think this over. I think there may be a way we can work together on this a bit and solve both our problems. I may get a decent agreement on space activities and fill a potentially troublesome gap. You will get the cover you need to keep the big dogs at bay.” She smiled and rose from her chair. “And now I must end this meeting. You’ve taken the little bit of free time that I have in this job and given me an excuse to fill all of it.”

  She offered her hand to Aman, who rose and shook it. He smiled. “Thank you, Madam Secretary General. I am sure any assistance from you will be worth the wait.”

  Albert’s Bad News

  “It isn’t going to work.”

  Wallace looked at Albert Sanchez, his principal engineer, with a look that could kill. He was in no mood to be told that his ship wasn’t going to work.

  “What do you mean it isn’t going to work?”

  Albert shrugged and waved his hands. “I mean it isn’t going to work. It looks like there are two problems. First, we can’t get the half-moon sails into orbit. We looked at the biggest cargo carrier out there and the rocket diameter is too small to handle a large segment of the frame arc. We’d have to break each sail edge down into four pieces, maybe more, and trying to put them together again in space is going to be difficult. If it works at all without human hands-on. And for each join point we have to add we’ll weaken the frame and make it heavier. It may be really expensive even if we can do it, because we would probably have to dedicate a whole cargo run to the outer frame sections alone.”

  The design of the ship currently ahead in the development process included two sails. Each sail was a large half circle, the two halves separated by a space for the ship’s hull. The outer edges of the half circles were lightweight metal arcs that supported the outside edge of each solar sail. The half-circle design was intended to provide strong support for the solar panels while keeping the weight of the ship’s sail frames as low as possible. An arc was stronger than a straight edge of the same material.

  Whether or not the half-circle sail frame was the best design, it couldn’t easily be taken into orbit by the existing cargo carriers. They simply weren’t large enough in diameter to hold a length of curved aluminum big enough to keep assembly of the sail frames in space easy. Then there was the loss of the original weight advantage and the possible weakening of the frame.

  The base of each sail was a long, straight mast that spanned the diameter of the sail. The main masts were fifty meters long and were attached to a massive (in space terms) axis that connected them both. The hull of the ship sat at the center of the axis, inside a gimbal that enabled the hull of the ship to change direction relative to the sails.

  Overall the ship looked like a huge letter H inside a broken circle. The H was made up of the ship’s hull and gimbal and the two masts. Each half circle was divided in two by a spar that stuck out of the center of its mast. The sail frames were split by what the team had come to call the spars of the ship, hollow aluminum tubes that spanned the radius of each semicircle from the center point of its mast to the outer ring. The spars stored the very thin material of the solar sails when the ship was at rest. When no power was being drawn by ship’s systems the fabric of the sails was completely tucked away, folded like an old Asian hand fan inside their spars. This was done to keep the sails from accumulating heat from the sun’s rays when the sails weren’t generating electricity. The spars contained the electrical cables that powered the sail motors and cables bringing power back from the sails. When the ship was under way, each side of the H formed a large solid semicircle of fabric like two hand fans that had been popped open. At least, that had been the plan.

  Albert continued on. “We’re also beginning to think that the solar panels are going to take a beating because of the switching we might have to do. As you know, part of the solution to the heating problems in the solar panels and the engines is to turn off the electricity by retracting the sails into the spars. It looks like opening and closing the fans frequently to turn power on and off will cause a lot of wear. The alternative is to slow down the switching, but it might have to be so slow that we can’t really use it. Maybe the regen system will take care of the cooling problem, but if it doesn’t and we have to open and fold the sails frequently we’re sunk.”

  Wallace sat back in his chair, looking tired and frustrated. “So are we back to the drawing board? What about the window shade design that we started? Was that a flop, or did we abandon it just because we wanted to get the sail weight down?”

  Albert shrugged. “We ditched it to get the weight down. It looked like it was going to be quite a bit heavier no matter how we put it together. But we have to get the frame up there. And that might still be a nonstarter because we run the risk of not being able to shut down without causing a lot of wear in the panel. We have to try something else.”

  Wallace nodded. “It doesn’t matter how much better the circular frame design is, and we’re likely to have to switch power on and off frequently to let the plasma motors cool and the sails from accumulating heat.” He thought for a moment and then made the decision. “Okay, let’s backtrack and try the window shade arrangement. Maybe there’s something we can do to keep the weight down. Whether or not it’s heavy, it will almost certainly be easier to ship and assemble just because the frame parts are straight. It’s also going to be quite a bit faster to open and close the sails if we have to do it.”

  Albert nodded. “Will do. It might not be so bad. It’s only the sail structure that has to be redesigned. I don’t think we’re going to have to rework much if anything of the payload.”

  Wallace frowned as he went back to work. “I sure hope not.”

  As it turned out there were some advantages to the window shade design that weren’t immediately obvious. As Albert and his team worked on the redesign it looked like there were some good things about a rectangular design that hadn’t been taken into consideration.

  Perhaps most important was the cost. The standard type of solar panel fabric was made in rectangular sheets. Material for a rectangular sail would be almost an off-the-shelf item. For the circular sail the solar panel material had to be cut into arc slices like pieces of pie, which meant additional cost for custom sail parts. The change in cost wasn’t small, either. There were virtually no other customers ordering pie slice-shaped solar panels and all the costs for development, setup, and fabrication had to be borne by one customer (their moonship project) and by the first set of sails. The difference in cost between rectangular and arc sections of sail material was nearly a factor of five. Although the sails were not the most expensive part of the ship, no part of the ship was cheap and the change in cost alone was dramatic enough to call into question the original idea of fan-shaped s
olar sails.

  It turned out that the engineering of the new system was also easier to understand. The new system was quite similar to an electrically driven horizontal window shade and there were plenty of those around to look at and play with. There were some differences in the solar sails to be sure, but the fundamentals were similar.

  The new design consisted of two large rectangles, each forty meters “high” and twenty-five meters wide, for an area of a bit over two thousand square meters. The newest variety of panel fabric was lightweight, sturdy, and highly efficient, and two thousand square meters would generate over one megawatt of power. Each sail was a frame of aluminum tubing that formed the edges of the sail, with strips of solar panel running across the width of the frame. The team called the long tubes masts and the short tubes that formed the top and bottom of the sail its spars. In addition to the spars at the top and bottom, there was a spar in the middle of each long section of sail. The center spar broke each sail in two and contained additional “up” and “down” motors, so that there were four sails that could be independently operated.

  The solar panels were fastened together in long rolls, with wiring at the top of each section of a standard width of solar panel. Small motors at the top and bottom of each sail were used to roll up or pull down a solar panel window shade. (Motors had to pull down and draw up the window shade; there was no gravity to pull the sails down.) When the solar sails were inactive they were rolled up into a cylinder at the “top” of the two top sails and at the “bottom” of the bottom sails; when they were deployed to generate electricity they rolled out to form a flat surface between the top and bottom of each sail frame. A series of wires running from each rollup cylinder of each sail carried electric current to the inside mast where it was routed to the ship’s systems and the plasma engines.

 

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