SpaceCorp (7 page)

“It’s actually a wooden spaceship,” Monica said.

“She means nanocellulose,” Mack said.

“We don’t care if it’s
papier mâché
if you can get it flying in a year,” Hank said.

Mack blushed, “Well, we’ll have to see.”

Hank turned to the room. “Folks, as most of you remember, six months ago, the Iranian Space Agency attempted to shoot down a derelict Centaur upper stage. The
Shahab-7
rocket missed a direct hit, but the proximity fuse set off a large warhead of between one and two tonnes of high explosive as it passed by. The blast was sufficient to knock the Centaur into a new orbit where it subsequently scored a direct hit on the
SSS Von Braun
. The entire station was destroyed. 110 members of her 737-person crew were killed instantly in the impact area. Of the 627 personnel who successfully made pod ejections, 54 were killed by debris impacts while the pods were jockeying for their reentry positions. Two pods—20 personnel—burned up during faulty reentry. Four pods made land touchdowns resulting in twelve more dead. One pod was lost at sea—never recovered. The final butcher’s bill for that disaster was 226 people. 511 survivors, two of whom are here in this room.” Hank gestured toward Mack and Monica, who both nodded at the quiet applause.

“As much as we mourn the loss of our friends,” Hank continued, “we still have a business to run, and quite frankly, we need to get that station replaced fast and in a hurry. We cannot afford the three-year construction time of conventional aluminum stations. Mack and his team have been working on a new idea for the last eight years that he says is now space-ready. I’ve seen it and I think it has merit, not just because he can get it ready to receive customers in a year, but his new design is far more survivable than anything we’ve put up before. So with no further ado, Mack show us what you got.”

Mack put on his headset and pulled the visor over his eyes. The rest of the room followed suit. There were some gasps when a few of the audience weren’t prepared for a space-walking astronaut’s view of the new station.

“We set this up so it will seem like it’s a single individual following me around the station without the inconvenience of have to go through airlocks and get in and out of space suits. All you have to do is relax and let me tow you around.”

Mack stood before his virtual audience holding a piece of clear nanocellulose. “For those of you unfamiliar with nanocellulose, the tensile strength is about the same as aluminum; stiffness about like Kevlar
^®
. Its strength to weight ratio is eight times that of stainless steel. Unlike the metals however, it also makes a pretty good foam, allowing us to build up large structures in foam-filled honeycomb. Originally nanocellulose came from wood pulp until we figured out how to get algae to make it—the trees liked that.” He paused for laughter but there was none. “Okay, bad joke. Anyway, with the algae subject to radiation damage in LEO we were limited to making nanocellulose parts on the ground and shipping them—and all their bulk—into space with an endless train of shuttle flights. Well, we fixed that. We now have rad-hard algae that can be farmed in space. In other words, we start construction with an algae tank in space. One side is clear with a UV filter and always faces the sun. Once we get a farm in place, all we have to do is send up water and dry ice—both of which are pretty dense and compact compared to spacecraft structures. We can make a space station with less than a tenth of the sorties we’d need for a conventional structure.”

“How’d you manage to get them rad-hard?”

“Good question! We borrowed the recuperative powers of
Deinococcus radiodurans
, aka ‘Conan the Bacterium.’ All DNA is equally susceptible to radiation damage and all organisms have, to some extent, the ability to repair that damage. This little guy happens to excel on the repair end. He can tolerate an acute dose of 500,000 rems of radiation without so much as a sunburn. 500 rems is enough to kill a human in a couple of weeks.”

“So your algae are genetically modified?”

“‘Have to be or they wouldn’t make nanocellulose, but let’s table that for now. We’ll start with a top-down view. You’ll notice the form factor is similar to a conventional metal-hulled structure, but with the new nanocellulose construction, it’s only a quarter of the mass. The outer ring is a standard kilometer in diameter by 250 meters thick and 250 meters deep. It rotates at the standard 1.34 RPM for about a full g at the outermost deck. Outside hull walls are thicker than their metal counterparts—twenty meters—because the nanocellulose is a lot lighter. That extra thickness gives us the ability to absorb a more severe impact than an aluminum hull.”

He maneuvered over to a large honeycomb block two meters long by a meter wide. “This is our basic building block. Nanocellulose walls are 10 centimeters thick. The interior cavity is filled with nanocellulose foam. The nobs and indentations allow the blocks to snap together. We use shims for alignment and then after everything is where we want it, we seal the spaces with a wet nanocellulose derivative we call ‘space glue’ using high-pressure syringes. The needle goes into this sprue hole and the glue travels along these channels. Under high pressure, the glue will leak out along the channels to fill the thin space between the blocks. Since we’re in the vacuum of space, we are assured a complete fill every time—we’ve tested that. Anyway, once assembled the exterior gets a coat of reflective foil to help with temperature stability. And we also have a network of cooling pipes to maintain thermal stability as the hull rotates.

“When a typical piece of debris impacts the hull, it’s usually absorbed in the foam. The friction heat makes it self-sealing. Come on over to our ‘firing range.’”

Mack pulled out a pistol and brandished it about. “This little gadget is my virtual debris shooter—I can set a few dials and launch an object of any size, mass, and velocity I choose. Let’s try a small one first, say, a 25-mm steel ball and 40,000 kilometers per hour.” He aimed and fired at a typical foam-filled honeycomb brick. A small hole appeared at the front facet. He rotated the brick showing an exit hole on the opposite side.

“It went right through! How’s that gonna help?” a voice asked from the audience.

“That’s right, just as it would have with an aluminum outer hull. So come on over here where we have ten layers of wall stacked up duplicating the 20-meter thickness of the outer wall. We capitalized on the lightness of the material to make a thicker, more bulletproof hull.” He showed the audience a cross section that traced the projectile path. It stopped at three meters. “That same shot would have gone six meters through a standard aluminum hull. Notice how the projectile path is sealed behind the projectile. It’s airtight and needs no repairs.”

“How big a projectile can it stop?”

“That of course depends on impact velocity, but using the 40 kilo-klick standard, we can stop a 75-mm steel shot in twenty meters. Even bigger if they’re slower. And if you do suffer a full penetration, all you have to do is inject it with foam and cap either end with solid nano and it’s sealed. You can affect such a repair manually from inside the hull without having to program a robot mission on the outside of the hull.”

“How is it on Centaur upper stages?” another voice asked.

“A Centaur upper stage traveling at a closing speed of 40,000 kmph will pass through the entire station doing catastrophic damage. There is no way to stop something that big and that fast. And there is no way to predict all the variations of a glancing blow at lower speeds. So for those kinds of hazards we have a different solution.”

Mack led them through the ring to the interior where they were flanked by giant spokes 150 meters thick. The ends of each spoke were chamfered to match the 250-meter thickness of the ring and the 400-meter depth of the central hub.

“Notice the central hub is quite a bit larger than it is on conventional space stations. And there are no instruments allowed in the hub as on conventional craft. Instead the middle of the hub is filled with liquid hydrogen tanks that provide propellant for nuclear thermal rockets mounted at the top and bottom of the hub. Eight nuclear rockets are mounted at the top and bottom of the hub, four up and four down for improved evasive maneuvers and significant orbit changes. Fuel rods are 93 percent enriched U-235 and are good for 20 to 30 years depending on the maneuvering duty cycle. Primary propellant is LH
₂
however this can be augmented with LOX injected into the nozzle as a thrust quadrupling ‘afterburner.’ All LH
₂
and LOX tanks are mounted inside the hub between the rocket arrays. Replacements are modular—we bring up full cartridges, insert them into place, and send the empties back for refilling. All together, we can generate a million newtons in either direction—four million with LOX augmentation.”

“How much is that in dog-years?” someone asked. There were several chuckles from the crowd.

Mack smiled. “I assume you mean, how fast can it accelerate? With LH
₂
only, we’re good for 0.025 g—about 0.25 meters per second squared. And quadrupling the thrust with LOX gives us four times that or 0.1 g—about a meter per second squared. On a conventional space station, you can only barely feel orbital maneuvers—the stations are too big and the thrust too small. On one of these stations—you’ll feel it.”

“How fast does it take to bring these engines up to full thrust?”

“All eight engines are kept ‘warm’ as they generate electric power for the ship though a Brayton cycle reactor. It’s just a matter of throwing a few switches to shift from power to thrust. Under normal circumstances there’d be hours of check outs and preflight inspections, but I’m assuming an emergent situation here. So we’re talking less than thirty seconds in practical terms.”

“And the LOX augmentation?”

“A few more switches. Another twenty or thirty seconds.” He paused to let his audience process the data. “Ladies and gentlemen, I’m not going to tell you we can skip out of the way of any old bolt from the blue. But with just a few minutes of early warning, we can outmaneuver any incoming projectile large enough to do us serious harm.”

“What about a
maneuvering
projectile?” It was the same voice that asked about genetically modified algae. With a virtual audience of faceless avatars, he couldn’t tell who was speaking.

This time Mack paused for more than a few seconds. “Do you mean to say that someone might deliberately try to shoot us down? Like with a missile of some sort?”

“Yeah, something like that.”

“We have no plans for active countermeasures at this time. However, if someone can show me that I’m being shortsighted, I’ll be happy to reconsider.”

C
HAPTER
F
OUR

Sunset that night …

The Cafeteria Balcony Overlooking the Pacific at Vandenberg

Mack and Monica were seated at a table at the western edge of the balcony, the better to have an unobstructed view of the sun setting over the Pacific. Mack had used one of his reward chits to get a bottle of the local Merlot to share. He’d topped off their glasses half an hour ago and now they were trying to make the last drops last a few minutes longer.

“Hey, Mack, you two gonna be awhile?”

“Yeah, Cindy. You want us to kill the lights and lock up?”

“Thanks.” She brought over a half-filled carafe of the house Merlot. “Here, you guys can finish this.” Cindy was a somewhat plump, fiftyish, sandy blonde with an affectation for bright red lipstick. She’d ‘remed out’ on a space station fifteen years ago working in the galley. She still wore her radiation dosimeter on a chain around her neck, probably as a badge to let everyone know she hadn’t always been a groundie. Like a lot of crew-turned-groundie, she’d drifted for a bit, eventually coming to wait tables at the V-berg Café. “People need to eat,” she’d said, “And I need to know what’s going to happen next.”

“So what do you think?” Monica asked after Cindy left. She’d pulled an empty chair over so she could rest her feet on it while she leaned back to savor the last embers of the sun. Her chair was close to Mack’s.

Mack was leaning forward resting on his forearms and twirling the wine around inside his glass. “I dunno. They want to get a new station flying in a year so they know they need a new idea... but this might be a little
too
new for this crowd.”

Monica reached over and put her right hand on top of Mack’s left forearm. “
This
from the fellow who invented and delivered the new space shuttle system when he was barely out of graduate school?”

He smiled looking down as he covered her hand and gave it a squeeze. “You know, if they green-light this crazy scheme, you’ll be spending a lot of time up there.”

“You mean we’ll be apart?” she asked.

He blushed, “Yeah… I guess that’s what I mean.” He leaned back in his chair so they could hold hands.

“It’s not like I’ll be gone for the whole year. I’m a yo-yo, not crew.”

“I know.” He looked down at their hands while she tilted her head a bit to see him out of the corner of her eye.

“Something else?” she asked.

“I was thinking about asking you to move in.”

She arched her eyebrows and looked heavenward, “Listen to you! Sleeping together for two months and I’m supposed to move in!”

“It’s not such a bad idea. I’ve got a lot of room—they always give me a pretty big place because of the shuttle work, and it’s close to the lab and the mock-up hangar.”

“You want me to be a groundie.” Her flat tone made it impossible to tell if that was a question or a statement.

“Groundie? Oh, no, no. I wouldn’t ask you to do that… I mean you’re an astronaut. You were meant to be in space.”

She looked at him carefully. “This isn’t about Royce, is it?”

He shrugged, “No, I don’t think so.”