“Curve it! Send it up steeply at the start, then level it out once it’s up in thinner atmosphere so it stays below satellite altitudes.”
“Makes construction a lot harder. There’ll also be lateral accelerations going around the curve and they’ll try to pull up on the base of the tower. That’ll try to lift the foundation out of the ground, a tensile stress that’s poorly tolerated by rock. We could do it, but, trust us, a better foundation with a shorter tower that only applies compression would be better.”
Dergraf rolled his eyes and opened his mouth, but Eckels broke in to forestall him, “Hold on Alston, let’s hear what the Staze people have to say about your other near-Earth suggestions.” He nodded at Prakant.
Prakant said, “We actually agree with Dr. Dergraf’s first and fourth points that building more habitat and research space in orbit is low-hanging fruit. In fact, we’ve already ordered what we call a ‘blimp’ aimed at such a goal. Our hundred-meter-long, fifty-meter-diameter blimps start with a blimp shape that’s formed in heavy-duty aluminized Mylar. We plan to launch such a Mylar blimp in a collapsed state, blow it up with a little air pressure, temporarily staze the space within it, then blow it up a little more and permanently staze the new, outer, layer that forms. Once the temporary Stade in the interior disappears, we’ll be left with a Stade shell around a large multi-utility space. We’ll zip the Mylar off and use it to form another Stade blimp. Each blimp will have fittings on the ends with airlocks to the outside, automatic doors to isolate episodes of pressure loss, and connections to the next blimp. If we slightly angle the connecting fittings, we could chain sixty-three of the blimps together so they’ll form a ring two kilometers in diameter and 6.3 kilometers in circumference. If we rotated the ring at 0.95 revolutions per minute, we’d have Earth-normal gravity in the living and hydroponic farming quarters. Spokes will lead to the central axis where we’d attach more, non-rotating, blimp modules for weightless activities, research, and manufacturing. We’re hoping to attach that central axis to ISS2 to provide some continuity with what’s already up there.”
Dave Tomas said, “How are you planning to un-zip and re-zip this Mylar blimp in space? Don’t assume it’s a trivial problem. Spacesuits are extraordinarily clumsy and materials perform bizarrely in a vacuum where they’re subject to intermittent doses of extreme heat and cold.”
Prakant grimaced, “We’re worried about that too. We’ve developed some waldo-type robots we’re hoping can do the work in space, but plan B is to send up an even bigger blimp that we’ll blow up and use as a shirtsleeves-environment-work-space for making the blimps I previously described.” He paused for a moment, then indicated Kaem. “Mr. Seba’s had some ideas regarding Dr. Dergraf’s second suggestion, the space telescope. Perhaps he could explain those?”
“Sure,” Eckels said. “But please keep it brief, I’d like to move on to our discussion of the Mars mission.”
Seba said, “I’ve been surprised no astronomy groups have come to us to request a Stade reflector telescope. It seems to me to be the perfect material, completely reflecting all wavelengths from VLF radio to ultra-high frequency gamma. Nothing can damage it and it doesn’t get dirty since nothing sticks to it. It should be fairly easy to build a major improvement over the James Webb Telescope, or any other telescope as well. Just build a mold for a single hexagon, then send it up to the new space habitat. Cast as many Stade hexagons as you like and bolt them together. You could build a telescope, hundreds or even thousands of meters in diameter if you wanted. Since the Stade would be massless it’d be easy to reorient it in any direction you wanted.”
Taking a breath, Seba continued. “As to Dr. Eckels’ third point, we think going to the moon before going to Mars makes more sense than a long launcher in Florida. You’d launch to the Moon from either Virginia or Florida on Earth. There you’d build living and workspace using the same kind of Mylar blimps we talked about for space habitat. Once you’d established a workforce, you’d put a super-launcher up there. There’s no atmosphere to impede the launch and transmit loud sounds. It shouldn’t be a problem to find good rock for a foundation. You can use the same sets of molds we use for putting up towers here on earth. If you put up a 1,000-kilometer launcher on the moon and ran it at sixty gravities acceleration, you could send spacecraft out at almost 123,000 kilometers per hour and reach Mars in 25 days. Build another launcher near the top of Olympus Mons on Mars to send them back. The atmosphere on Mars at an elevation 2.5 times that of Mt. Everest is pretty close to vacuum.”
Dergraf barked a laugh, “That’s all well and good, but how the hell do you think you’re going to stop when you arrive at Mars going that speed? It’s going to have to have a huge rocket engine and enough fuel to slow it down anyway. I don’t think the physics of going that fast is going to work out to any great benefit.”
“That’s another reason to launch from the Moon,” Seba said, undaunted. “We won’t be limited to craft that can be launched through the atmosphere.” He dumped sugar packets out of a bowl on the table and lifted the bowl and a pencil off the table. He held them up with the pencil pointing out of the bottom of the bowl. He said, “Picture a long skinny spacecraft,” he waggled the pencil, “with a huge Stade bowl at one end. You can’t launch it out of the atmosphere, there’s too much resistance. But, with a small hole passing through the middle of the bowl for the launch tower, you could launch it off the Moon. The huge bowl doesn’t slow you down at launch because it’s massless and there’s no air. Once you’re in motion, you could turn the bowl to the sun and use it as a solar sail to get a little more speed. When you get to Mars you use it as a drogue to slow yourself down in the atmosphere. Same thing when you get back to Earth.”
Stunned, Eckels stared at the bowl and pencil in disbelief. Could that work?! he wondered. After a moment, he thought, Of course, it would. It’d take planning and study and testing, but it’d definitely work.
Eckels thought Dergraf looked stunned as well. I think he’s irritated because he no longer feels like the smartest man in the room.
A smirk formed on Dergraf’s face, said, “I don’t think the acceleration provided by a solar sail’s going to mean diddly when you’re already going 123,000 kph.”
Seba shrugged, “No, it won’t, but you’ve already got the bowl there, ready to use as a drogue when it comes time to stop. It could act as a massive telescope if you needed one. You could think of the light sail idea mostly as a backup way to get back home in case of disaster. Say you missed your pass through the Martian atmosphere and shot right on by. Then you burned all your rocket’s fuel trying to stop and were still going hell-for-leather out toward the asteroids, you might really be happy you had a solar sail you could use to get back to the inner system. Remember, you can go into stasis, so even if it took decades to get back using the sail, that’d be better than just keeping on going…” He’d paused a moment, and Eckels opened his mouth to speak but before he or anyone else could interject, Seba shrugged and said, “Or you could just keep going on out to the stars…”
Dergraf ignored the star-shot suggestion, rolling his eyes, “I think I’d be hoping someone would send a rescue mission so I got back to Earth before the next ice age.”
Seba grinned at him, “Granted.” He looked at Eckels. “That brings me to another Stade device you might want to consider adding to NASA’s portfolio. You may be aware that Dr. Medness at the University of Maryland has achieved proton-boron fusion using a chirped laser and a Stade fixture. Most of what’s written about it is in regard to how it’s a clean energy source free of the neutron radiation that comes from nuclear fission or hydrogen fusion. Also, about deriving electricity directly from the stream of charged alpha particles p-B fusion emits, without having to generate steam to run a turbine. However, you could also directly use that stream of alpha particles as rocket exhaust. One mole of boron and hydrogen weighs 11.8 grams, but when it’s fused it releases 840 gigajoules, or 233 megawatt-hours of power. That’s the same amo
unt of energy as 200 tons of TNT.
“With that much power, those alpha particles would be ejected at an exhaust speed of 12,000 kilometers per second or four percent of the speed of light. The thrust produced by fusing 11.8 grams of p-B per second would be 141,600 Newtons. That’s enough to accelerate a 100 metric ton spacecraft at 0.143 gravities. Most of us think of 0.143 gravities as a pretty low acceleration, but if you accelerate steadily at that rate, you’d achieve 1.13% of the speed of light in 4 weeks. That kind of speed puts the outer planets within reasonable reach. The acceleration would be increasing as the mass of your vessel decreased with fuel consumption. If fifty of the 100 tonnes of that ship were proton-boron fuel, it’d run the drive for 49 days, so you’d have sufficient fuel to slow you down at the other end when you consider the reduction in mass. You could also slow down by plunging through an atmosphere using the Stade drogue on your ship.
“Or, to consider a trip to Mars again; if you launched a fusion rocket from your tower on the Moon at 123,000 kph and added that 0.143 gravity acceleration for half the journey and decelerated for the second half of the trip, you’d get to Mars in less than six days. That’d only burn about six tonnes of proton-boron fuel so you could have a ninety-four-tonne payload.”
Rubbing his forehead, Eckels settled back into his chair, thinking about how, at the beginning of the meeting, he’d thought he’d befuddled the people from Staze with his bold vision. Instead, he found himself disconcerted by the scope of the strategy they’d presented. Desperate to get back in control of the meeting, he said, “It sounds like this could generate enough speed to let us send a mission to another star.”
Looking surprised, Seba said, “I think, trying for the stars, we’d still be subject to the tyranny of the rocket equation. Let’s see…” He sat back and stared into the distance a moment, then said, “I guess it’d be doable, but if we start with a hundred metric ton spaceship burning one mole or 11.8 grams of hydrogen-boron per second, which would be one metric ton per day, and planned to burn ninety-four tonnes to accelerate toward Alpha Centauri, saving one tonne to maneuver a five-tonne package on arrival… You’d accelerate at an average of 0.3 gravities since your craft would lose most of its weight during acceleration. That’d achieve a velocity of 7.9% of the speed of light. That wouldn’t be fast enough for relativistic time dilation to make much of a difference. It’d take fifty-four years to get there which, thankfully, would go by in the blink of an eye if you were in stasis the whole time. When you got there, you’d have to find an atmosphere to crash into to slow yourself down, then hope there was something interesting to do since you’d be completely out of touch with Earth.” He shook his head, “I surely wouldn’t want to go myself.” He brightened, “Maybe a robotic mission would be worth sending?”
Eckels blinked, “What if there wasn’t a suitable planetary atmosphere to slow you?”
Seba shrugged, “Probably should figure that out before you leave, using that massive Stade orbital telescope that replaces the James Webb. You could always drogue through the stellar atmosphere to stop. However, if there isn’t a planet with an atmosphere to visit I’m not sure why you’d go in the first place?”
Feeling brain-strained, Eckels said, “Um, is there a working model of this fusion rocket?”
Seba looked surprised, “Oh, no sir. I’ve run the numbers but I suspect inefficiencies will keep it from working as well as the numbers predict. We’ll need to build one before we’ll know for sure. We have a lot of other stuff on our plate so we haven’t been pursuing it, thinking surely someone else would. If NASA wants to work on it with us, I can look into it deeper.”
Eckels nodded, “Please do. Depending on what you find, I’ll get a team working on a funding proposal.”
***
Brad Medness took a call from Kaem Seba, worried the guy was going to want some kind of payment or quid pro quo for the free Stade fixtures Seba’s people built for Brad when he was proving out the proton-boron fusion system.
Instead, Seba said, “Hi, Dr. Medness. We’ve been talking to NASA and I started wondering whether you’d considered using your fusion system as a rocket engine?”
“What?” he asked reflexively. “No. Are you thinking that you could use fusion electrical power to run an ion engine or something?”
“Um, no. Just exhaust the alpha particles from the proton-boron fusion out a nozzle and call that your rocket.”
“Hmmm,” Medness said, thinking. “I’d have to run some numbers to see if it would generate significant thrust.”
“It should,” Seba said, cheerfully. He read off the rocket equation to Medness, “To save you looking it up yourself.”
“I know NASA has deep pockets,” Medness said, “but before I spend a lot of time on this, can you make sure they’d be willing to spend a hundred million for a fusion reactor?”
“A hundred million?!” Seba said in consternation. “Is that for a reactor and lasers, fully set up as a rocket with the nozzle and control systems?”
“No, just for the reactor.”
“Why so much?!”
“Well, as you probably know, the University’s the majority owner of its faculty member’s inventions. They want to get back the money they put into the research.”
“But surely they could make more money by pricing it affordably! Selling it cheaper would bring in a lot more sales. Sell a thousand reactors for a million dollars each, rather than one for a hundred million?”
Medness chuckled at Seba’s naiveté. “When you’ve patented a product everyone wants and no one else can make, you’d just as well charge as much as the market can possibly bear, hadn’t you?”
“I disagree,” Seba said slowly. “When it has the potential to markedly improve the world as a whole by eliminating our dependence on fossil fuels, I think you have a moral obligation to make them safe and affordable. Selling them for as much as the market can bear violates the dictum of ‘doing no evil.’ Besides, I still think you could make more money at a reasonable price.”
“Oh, come on, young Seba,” Medness said with a laugh, thinking of other babes in the woods who’d urged him to consider similar soft-hearted strategies. “You need to join the grown-up world. We’re following the dictum of ‘look out for number one.’”
“I predict you’re going to regret taking that path, sir.”
“I’m gonna laugh all the way to the bank, young Seba,” Medness said cheerfully. He wasn’t surprised when Seba said goodbye and ended the call.
~~~
Back in Virginia, Kaem Seba looked around at the group of young engineers who’d been sitting around the table listening in while he talked to Medness on speaker.
One of the people at the table, Arturo Ortiz, Staze’s newly acquired nuclear engineer, wondered whether the conversation he’d just heard meant the job he’d just started had already come to an end.
But Seba was smiling. He said, “Well that’s a setback.” His eyes turned to Arturo and he said, “Team, let me introduce Dr. Arturo Ortiz. He’s got an undergraduate degree in nuclear engineering and a shiny new Ph.D. in nuclear physics. His Ph.D. thesis displayed a brilliant conceptual grasp of fusion.” Seba’s eyes drilled into Arturo’s, “You ready to try to turn your concepts into reality?”
Arturo nodded, unaccountably nervous. What’s going on? he wondered. Seba’s about the same age I am. Even if he supposedly came up with the theory stasis is based on, he couldn’t figure out how to build a working model by himself. I should not be intimidated by him! After all, he’s only got an undergraduate degree in general physics. Arturo shook himself and asked, “What are you thinking we’re going to do, uh…?” Arturo stopped himself before he said, “sir” to Seba. It just seemed inappropriate to “sir” someone with less education than he had. He continued, “Will Staze spend the money to buy Medness’s reactors at that price?”
“No,” Seba said with a little laugh. “I think we can build a reactor that doesn’t depend on the principles in the Medness
reactor. But if we can’t, remember he can’t build his reactor without us either. So, he’s only going to be able to sell one of those hundred-million-dollar reactors.”
“What? Why would he need us?”
Seba smiled, “His reactor’s built out of Stade. We can charge him a hundred million to build his reactor for him, see how he likes being on the other side of that kind of negotiation. But I don’t think it’ll come to that.” Dropping that issue, he looked around the table. “Now, one of this team’s tasks is to get Medness’s patent application and read it so we’ll know what’s covered and what’s not. Let’s just assume we can’t use laser-driven ponderomotive acceleration of protons into a target. What alternatives can you suggest?”
Arturo blinked, “Alternatives?”
“Yes,” Seba said. He didn’t sound impatient but he did look a little disappointed. “Other ways to achieve proton-boron fusion.”
“Well…” Arturo paused waiting for inspiration, “magnetic confinement hasn’t been able to achieve deuterium-tritium fusion and D-T’s much easier than proton-boron, so… that seems like a fruitless avenue…”
“Agreed,” Seba said. “One of the things you’re going to hear over and over here, Arturo, is ‘stop to think what advantages Stade might give you…’” he trailed off, looking hard at Arturo.
Arturo was wondering whether he should insist on being addressed by his title but suddenly realized he’d better get his mind on the business at hand. “Um, I’m not sure what advantages it might provide?”
The look Seba gave him made Arturo realize he had something much more important than whether he was being called “doctor” to worry about. Like whether I’m going to keep this job! It seemed impossible that someone who had graduated at the top of his class from MIT, then got a Ph.D. with a thesis that was stirring significant interest in the world of nuclear physics, might need to worry about his job in his first week, but he knew Staze could and did hire nothing but the best. I may not be all that special here, he suddenly realized.
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