Sounding suspicious, Lee said, “Go ahead.”
“Okay, say we’ve got our tripod going up to about sixteen kilometers with the limb that aims up to the southeast going on up to a hundred kilometers of altitude. If it’s angled upward at forty-five degrees that gives you a rail that’s 141 kilometers long, okay so far?”
Lee nodded.
“Now, instead of a 141-kilometer linear motor, we have a group of ordinary rotating electric motors mounted on the rail at about an altitude of 8,000 feet. That way people down on the ground won’t be bothered by the noise.”
Doubtfully, Lee said, “And how are regular electric motors going to launch a spaceship?”
Kaem smiled at her. “Chain and sprocket.”
She blinked, “What?!”
“We use a Stade bicycle chain that runs from the bottom to the top and then back down again. We’re talking about a 282-kilometer chain. It’d be a massive problem if we made it out of ordinary materials. But we’re making it out of weightless, massless, non-stretchy Stade. We hook our spacecraft to the chain down at the bottom, then power up those rotary motors that’re sitting up at 8,000 feet. I found some currently available motors that’re capable of 18,000 rpm, so if we have them turning 4.5-meter diameter sprockets they’d be able to accelerate our spacecraft up over four kilometers per second.” He frowned, “Though to do that in the 141-kilometer length of our rail, they’d have to accelerate at six gravities. That’s not very comfortable and it’s still not the seven kps we’d need for low Earth orbit.”
Looking dubious when he first spoke of a chain and sprocket drive, Lee’s eyes had begun to sparkle as he explained. Now she appeared positively enthusiastic. “That’s okay! Space-Gen’s boosters only achieve velocities of about 3.4 kps by 85-kilometers of altitude. The second stage takes over from there. If our elevator gets them up to 4 kps and 100-kilometers of altitude we’d be in great shape. We’re going to have to have something like Space-Gen’s second-stage rocket to establish the orbit we want anyway. And,” she smiled broadly, “second stages are way cheaper than first stages.”
“Oh,” Kaem said. “Well, we’d only have to accelerate at a little over 4 gravities to get to 3.4 kps. Or, we could put up a 200-kilometer-long, 100-kilometer-high elevator at a 30-degree angle and get to 3.44 kps accelerating at just 3 gravities.”
Lee gave him a look. “Damn, I wish I could work numbers like that in my head.”
Kaem shrugged, “It’s not that hard. You just…” he trailed off when Lee exploded into laughter.
“‘Not that hard,’” Lee quoted, still giggling. “Arya may not get it, but I just love your sense of humor.”
~~~
Lee waved him away, so Kaem moved on to talk to Norm. Taking a seat next to the engineer, he said, “I hear you’re working on how to label our Stades. I’d like to say thanks. I keep worrying about it but never getting around to doing anything about it.”
Norm nodded. “Yeah, I’m embarrassed to say I never thought about it. But it only took a little consideration to realize it’s really important.”
“How’re you thinking to do it?”
He shrugged, “My first reaction was that it’d be simpler to do something like a barcode, or a QR code, or an RFID, or a USB receptacle, but I kept coming back to Arya’s point that format compatibility could be a real problem mere decades from now, much less centuries.”
Kaem nodded, “Over millennia, ordinary language might be unstable too. Out at that distance, I was thinking that we needed an image of a dead body to warn the future when a Stade has something toxic in it. Now I’m realizing that if we put a picture of someone sick on Simone’s Stade, representing her, someone in the future might think it meant whatever was in her Stade was radioactive or poisonous.”
Norm said, “Her Stade’s only set for a century.”
“Yeah, but there’re going to be more sick people coming in. Some might choose to travel farther into the future.”
Norm got a distant look in his eye. “Thinking about this is… hard. Do you have any solutions?”
Kaem shook his head. “Not really. I was thinking that the box should be mounted with the opening on the long side of the sheets of paper. The important info should be on sheets of Stade that could be pivoted out on a Stade pin through their corners. That way if the paper degraded or someone threw it away, the Stade sheets would still be there because they couldn’t be pulled out.”
Nodding thoughtfully, Norm said, “The Stade sheets would need to be shorter than the box to allow room for the corner to pivot up out.”
“Any idea how you’re going to print text and images in Stade?” Kaem asked.
Norm looked surprised, “Just have the same company that does our molds do it. They could mill the letters into one side of a mold for one of our sheets of Stade.”
Kaem grimaced. “That’s expensive, and worse, it takes a long time. I’m thinking something like a laser cutter to cut images and text in millimeter thick plastic sheets, then using Gunnar’s Mylar pressed up against it to form the Stades out of the plastic. They’d have defects where the laser cutter had removed the plastic.”
Kaem
