“Yes. But we’re inflating it with thirty-three cubic yards of water.”
“Water? You’re putting twenty-eight tons of water in orbit?”
“For the experiment, yes. Is that a problem?”
“That’s over seven times what the Dragon capsule can deliver to ISS.”
“Oh? Cool.”
“How many trips will it take you?”
“That’s proprietary, General. Is there a higher incidence of microdebris in any particular orbit?”
“The stuff we know about also has the bigger debris mixed in. Trackable. That’s why we know about it. Twenty-eight tons? That’s huge.”
“It’s a little bigger than your average spy satellite, but not much. What are those, twenty tons?”
“You know this from direct observation?”
“Wikipedia. Look, I’d like to put up my test sphere tomorrow. I was thinking out about five hundred klicks. Above the ISS but below the Iridium constellation. Perhaps a straight equatorial, zero-inclination orbit. You want to check that out and I can touch base with Sergeant Mertens before I begin?”
“Twenty-eight tons of water?”
“And change. I’ll check in with Agatha tomorrow.”
“Right. Jesus. Twenty-eight tons?”
THIRTY
Cent: 4,800 Joules
I picked up the twelve-foot sphere from Fran Wilde of BlimpWerks. The porthole’s aluminum frame was only ten inches across but they had it sealed and clamped into the fabric.
“We tested it at twenty PSI,” she said. “It was tight as a drum after twelve hours.”
I hefted the entire roll. “How did you get it so flat?”
“We pumped it out, down to a couple of psi. Compared to out here—” She waved her hand through the air. “—it’s a ‘vacuum,’ but when you’re up there it will probably expand without you doing anything.”
I hefted the bag. By my calculations, the cloth alone weighed forty-seven pounds. The stainless steel inflation valve and the porthole with its half-inch-thick polycarbonate window and aluminum frame added another seven.
“So the flange anchoring system worked out?” They’d been worried about that. Apart from fill valves, they had no experience in bonding metal fixtures into their envelopes. Luckily lots of work on that problem had been done by others.
Ms. Wilde said, “Between our fabric reinforcement and this combination of toothed grips, compression gaskets, and sealant, I think we’ve got it solved.”
“How’s the big guy coming?”
“We don’t take delivery of the outer port until the end of the week, but we did a full-assembly low-pressure inflation test with an aluminum hatch in its place.”
“Oh? All the ports in?”
“Every one. We pumped the inner sphere to three psi over and the outer at two psi.”
“Not exactly a leak test.”
“No. Just an alignment test to make sure the inner flanges all matched up with the outer ones and that we had a uniform gap all the way around.”
“And?”
“Three feet plus or minus three inches and we think the variability will shrink once you get gravity out of the mix.”
“Very nice.” I slapped the bundle in my arms. “Let’s see how it flies.”
* * *
Agatha confirmed that a five-hundred-kilometer equatorial orbit with a thirty-five-degree mean anomaly at midnight Zulu would be clear of any operational or derelict spacecraft and would cross the fringe of the Kosmos 2551/Iridium 33 cloud in a week.
Ms. Wilde was correct about the sphere’s behavior once I got it into orbit. It may have only had a few psi of air in the tightly rolled folds but it was several orders of magnitude more pressure than was outside.
To keep it manageable while I refined the orbit to match Agatha’s parameters, I’d wrapped the bundle several times around with a nylon cargo strap. As soon as I was in orbit, the cloth bulged out at the ends and from between the straps, but stayed mostly contained.
Once I was in the groove, I pulled open the Velcro closure and let it loose.
It expanded, quickly at first, then slowing as the pressure dropped with the volume increase and the stiffness and mass of the fabric became a factor. By the end of a minute, though, it was a sphere, though there were still wrinkles in the fabric and it easily dimpled when I pushed a finger into it.
I backed off and admired the whole. It was highly reflective silver with an almost painful highlight at the angle of maximum reflection. The occluded side, in shadow, was still lit by reflected earthlight.
The Apex Orbital Logo incorporating Space Girl predominated, with the zeppelin-shaped BlimpWerks logo above and off to the side. Both were repeated on the opposite hemisphere. They’d done them in gold Mylar with a black trim and fused them to the aluminized Mylar outer coating with an adhesive they said would survive wide temperature swings.
Right. Time to see inside.
I moved to the porthole, flipped up the sun visor, and looked within. No surprise, I saw nothing but black, but I’d brought a flashlight, an upper-end disposable that we thought would survive vacuum. I pressed it against the polycarbonate and switched it on.
The interior nylon layer was an unremarkable gray, but I could see well enough to jump within and I did.
The automated pressure valve on my oxygen feed didn’t react because the interior was so close to vacuum as to make no difference. The port was pointed toward Earth and, after my eyes adjusted, it provided all the light I needed.
I jumped away.
I appeared in a defunct drilling yard in South Texas where we were renting a brand-new, never-used frac tank, a large open-topped, rectangular steel tank with a five-hundred-barrel capacity. This was the equivalent of seventy-seven cubic yards, twice what the sphere could hold.
Dad was standing on the catwalk landing at one end, dumping bags of chopped bamboo and synthetic-wool fibers down into the tank. He was wearing a wet suit and a dust mask and I could tell he was sweating up a storm because the fibers were sticking to his forehead and neck.
I jumped up onto the catwalk and he threw his last empty bag onto a pile on the ground, saying loudly, “That’s the last of that.”
The tank was three-quarters full, filled earlier when he twinned to the local municipal water tower, but the fibers were floating on the surface, matted.
“Time to mix. You should try and twin to your target.”
He vaulted over the railing, splashing down into the water, then twinned from there to five feet above the surface of the water at the other end of the tank. The tank went from calm and matted to a roiling torrent as the liquid flowed through him to plunge back down, sucking the fibers under the surface and thoroughly mixing them into the fresh water.
Right. My turn.
My first attempt at twinning was several meters away from the sphere. The helmet purge valve buzzed from the pressure drop. I was immediately surrounded by fog as the hot, humid air rushed through me into space, the moisture flashed to ice crystals, and the BlimpWerks sphere was actually blown away from me.
I stopped twinning in orbit, and the helmet vented all the way down to 4.9 psi.
I jumped closer, and then into the interior of the sphere and twinned again. The walls moved away slightly and I heard a thump as they fully inflated, pressurized to one atmosphere. The pressure valve on my oxygen buzzed, bringing my relative helmet pressure up, and I stopped again, still in the sphere.
It was weird. I knew that I could actually take off my helmet in here. Well, until the walls started getting punctured by micrometeorites. I twinned again, but to vacuum, to outside the sphere, and my helmet buzzed again, venting.
My first thought was that the sphere would collapse, like it had when the BlimpWerks people pumped the air out in their factory, but it didn’t. It wasn’t the vacuum pulling in that had caused that, but the greater air pressure outside pushing in. When the outside vacuum matches the inside the sphere stayed “inflated.”
I jumped back
to Texas, tank side. Dad was back on the catwalk, dripping, but he’d taken off the dust mask.
“All mixed,” he said, and held up a glass jar filled with liquid. It was mostly clear but white and gray fibers floated uniformly through the mix.
I held up my thumb and he dumped it back in. I took a good look at the tank below before returning to the interior of the sphere.
I twinned to under the surface, crouched at the bottom of the tank, wondering how long it would take the water to flow into the interior of the sphere.
It was practically instantaneous, water flowing through the Cent-shaped hole (in all directions) with an orbital vacuum pulling it through. I untwinned, still in the tank, and jumped up to the catwalk. I felt the water draining out of the weave of the suit, out of my long underwear, but, in this heat and humidity, there was hardly any cooling.
Dad raised his eyebrows at me and I raised my thumb again.
I wanted to see how it was doing. I was half afraid it had split open as the water rushed in, but I was mindful of Cory’s warning about not taking the suit into orbit while it was wet.
Dad went back into the tank, and twinned, draining out the last of the water/fiber slurry.
I went ahead and shut down my oxygen, purged the helmet, and took it off.
“Where’d you put the leftovers?” I asked him when he reemerged.
“The input side of the local sewage-treatment plant. They’ll filter it and the fiber will end up in compost.”
* * *
I didn’t get back to the sphere for twenty-four hours. Cory wanted the suit to dry thoroughly, and he hadn’t done a close-up examination for wear and deterioration in over a month.
When I appeared in orbit, the sphere was not split open. It was not a spreading cloud of water vapor and ice crystal.
It was tight, the wrinkled cloth smoothed out, the logos more prominent. When I pushed against it, to test how taut the fabric was stretched, there was hardly any deformation. I moved away and it seemed to stay there. Okay, Newton’s third law—equal and opposite reaction—but twenty-eight tons was 350 times more mass than me and the suit, so I moved 350 times faster away from our point of contact than it did.
The sphere was spinning slowly, about five revolutions per minute, and I positioned myself in its shadow and studied the rim, looking for any jets of water vapor and ice backlit by the sun.
After several moments I concluded there weren’t any. A close examination of the surface didn’t yield any obvious impacts, so I moved to the aluminum and polycarbonate porthole and installed the monitor.
The package was a used four-inch Android cell phone, fully charged, but with all the radios turned off. The only thing it was doing was running a seismometer app that used the phone’s accelerometers to monitor vibration and displacement. I attached it to the port using a spring bracket that hooked into opposite sides of the aluminum frame and pressed the back of the phone firmly against the polycarbonate. To finish, I shaded it with a tent of ordinary aluminum foil, anchored around the perimeter of the port’s aluminum frame with a twisted piece of copper wire.
Lastly, I took some video, myself in the foreground. This wasn’t one of those selfies at the end of my arm. I now had a “tripod” to use when I wanted a stationary vantage point. In this case it was an extra mounting bracket to snap the camera onto. That, in turn, had two collapsible fiberglass cross pieces snapped into it. I could position this “cross” in space, pointed in the direction I wanted, and let go. Just like the ice skater spreading her arms, this slowed down any tendency of the camera to rotate.
It wasn’t perfect, but it was easy to get the camera pointing in the correct direction for minutes at a time, and the poles folded down to store in a thin pocket on my left outer thigh.
Tara groaned and fussed when I asked her about the appropriate language for a press release, then took it over, using up her evening off to edit the video and post it and the press release.
* * *
It took five days to weave the first suit, but Cory was being extremely careful, triple checking every step and documenting everything. They went through several powered/relaxed to unpowered/clenched cycles before they put it on the life-mode simulator.
Cory was quite pleased. “Consistent and sufficient. Variation is under four hundred pascals and nothing less than twenty-nine point nine kilopascals.”
“Let’s try it in orbit,” I said.
Cory said, “No!” It was almost a shout.
I blinked.
He cleared his throat. “I mean, we are a long way from that step. We need to check the performance with the pressure-sensor unitard, we need to cycle it at least a hundred times to make sure it’s behaving consistently.” He looked at me sideways. “This time we’re doing it properly. No shortcuts.”
My lips twitched.
“Can you get another suit made in the remaining time?”
“I have material for four more.”
“This one took five days.”
He said, “We were being very careful with the first one. Actual construction is about seven hours per suit. We’ll go ahead and finish this batch.”
“Five new suits? And the life-support backpacks? Helmets?”
“We ordered the helmets from the original manufacturer, but I’ve outsourced the visor assembly and the life-support backpacks. We’re adding some safety monitors for oxygen and carbon dioxide partial pressures and an ear clip for blood oxygenation and pulse. Oh, and helmet pressure.”
“Display? Audible alarm?”
Cory nodded. “Both, I think. Telemetry if I can arrange it, but that depends on what comms we end up with. All the satphone providers can handle data but I don’t think we can use Iridium outside of LEO.”
“Don’t forget local comms. We have more than one suit, we can start doing multiperson missions.”
“Exactly,” he said and tapped himself on the chest.
I shivered. I’d been thinking Dad—maybe Mom. The people who could survive a catastrophic failure of the suit. If I were in orbit with someone who couldn’t teleport away at need, I’d have to stay very close. “Better make that redundant comms.”
* * *
By the end of the week amateur astrophotographers were posting pictures of the sphere, a tiny shining speck just big enough to see as circular, with phases of illumination like the moon.
I’d found one point of impact, a frozen plug sealing a triangular hole a half inch across. According to the seismometer app, we’d had fifteen impacts total, but one had been clearly larger than the others, a sharp spike and movement that lasted for some minutes as the shockwave bounced back and forth through the watery interior of the sphere.
The other collisions registered as smaller spikes and, despite substantial searching, I couldn’t find the holes.
At the end of the second week, we’d registered another twenty-five impacts, but really hadn’t lost any appreciable water, though one of the impacts produced a hole nearly two inches across. You could see the fibers matted in the icy plug and I spent extra time watching how it behaved in full sun, even going so far as to halt the rotation of the sphere to keep it in full sun at least forty-five minutes.
It evolved, changing shape slightly and though I detected some vapor streaming away after its longest solar exposure (fifty-two minutes, terminator to terminator) it hadn’t let go, but seemed to grow thicker, melting and refreezing on the outside like a scab that keeps getting picked at.
I went back to trying deliberate punctures but it took a lot more force to stab the icepick through the BlimpWerks fabric than it had the ice bag, probably because of the Kevlar layer. I finally managed it by adding sixteen-feet-per-second motion toward the sphere, about the speed you’d get from falling off a four-foot ledge on Earth, and punching the icepick into it at impact.
Only did it once. It hurt.
The only advantage of this deliberate hole was I could find the point of puncture. The hole still sealed immediately and it didn?
??t tell us any more than the earlier experiments with the ice bags.
What else could I try?
* * *
Dad stared at me. “You want what?”
“A gun. Well, a bullet, but a fast bullet. Just one. And something to shoot it with.”
“Ah. This is for the sphere?”
“Yeah. It will give us a known velocity and we can video the impact.”
“Uh. But you’ll fire it in a vacuum.”
“Yeah.”
He went off and talked to someone. When I next saw him he had a rifle and a box of ammo. “This is about as fast as it gets, for commercial off-the-shelf. The consensus seems to be that, as long as the rifle doesn’t have time to heat up or cool down too much, it will be just like firing a rifle in the atmosphere.”
“Ah. Expansion and contraction of the metal?”
“Yeah. Also, too hot and the primer or propellant might ignite on their own.”
That was a scary thought, but it would definitely take time for either to happen. “How fast is it? How much mass?”
He handed me a sheet of paper. “One thousand four hundred two meters per second. Seventy-five grains.”
“Grains? What’s grains?”
“Grains. Wheat, barley. One of the oldest measurements.” At my expression, he got out his phone and Googled it.
“An English Penny, which is called the Sterling, round without clipping, shall weigh Thirty-two Grains of Wheat dry in the midst of the Ear.”
“Great. How many cubits a second does this bullet go?”
Dad relented. “Fifteen point four three two three six grains to the gram.” He used the calculator app on his phone. “Round it to four point nine grams.”
I did the calculations later while I was killing time prebreathing. The bullet’s energy of impact would be north of forty-eight hundred joules. A more typical orbital collision was nine times faster. Kosmos 2251 collided with Iridium 33 at over 11,699 meters per second. At those speeds, the 4.9 gram bullet would impart over 335 thousand joules, the energy of a third of a stick of dynamite exploding.
Premission, I set the camera at a lower resolution to enable a higher frame rate: 120 frames per second, to capture as much of the event as possible. Once I was suited up, I took the rifle out to West Texas and fired it a few times from different positions. With the helmet on I couldn’t hold it against my shoulder and aim down the sights but I could still roughly hit the center of my target, an eight-foot stretch of arroyo wall, from thirty feet. It kicked a bit, but the weight of the rifle and the rubber stock recoil pad on the butt absorbed much of it.