The VoidQ

[HanleyTucks]

I am writing to tell you more than you want to know about MTU, which I call The Void.

This was inspired by another thread. Essentially it comes from the fact that in Books 1-3 there are a lot of blanks. Books 1-3 mention everything which existed in 1977, like slugthrowing firearms and blades of various kinds, some drugs - and lasers. As for the rest... well, starships, they mention Jump drives and liquid hydrogen fuel, and power plants - but wait... are these fusion powered burning the hydrogen or some isotope? Fission-powered using the hydrogen as reaction mass? Some sort of high-tech batteries? A Dune Navigator in a box who subsists by drinking liquid hydrogen? Something else? It doesn't say! You fill in the blanks!

In CT Books 1-3, you fill in the blanks.

.... but note that these are tailsitter-oriented craft with appropriate acceleration couches.

That is why IMTU craft are tailsitters. It makes takeoff and landing more... interesting.

Of course, IMTU the drives are essentially Epstein drives, which I have run essentially as described in this blog article. Essentially there's a fusion reaction done 200m or so from the back of the ship. This for something like the Rocinante however is a 100TW reaction, which is equivalent to a 24kT nuclear explosion every second (hey, it's 5-6 times the entire current 18TW energy output of the human race). Unless someone dug a 300m well under each ship's landing pad, the reaction couldn't actually happen (the pellets would just hit the ground and fizzle) and the locals wouldn't appreciate it if it did.

And so they use a regular fusion reactor's heat to turn water or liquid hydrogen into plasma and chuck it out the back. This is more like 334GW or 80t of TNT going off every second, which at about 4 times the power of Saturn V's first stage and so is more plausible. You still don't want to be anywhere nearby when it takes off, though - I believe they cleared the Saturn V launch area for a mile around, though the sound was more of an issue than the radiative heat.

So, reaction mass heated to plasma goes out the back for takeoff, once they reach 100km or so (on an Earthlike world) they change over to the torch drive - the pellets ping out the back, the lasers ignite them, bang!

In addition, stealing ruthlessly from the Torchship trilogy, I have said that after the AI Wars drove humanity out of Sol and its neighbourhood, computers above TL7 or so are essentially banned. This means that your Travellers get to use cathode ray tube screens with green writing, star charts, tabulated data, and slide rules.

In addition, the rules of physics remain in play. Therefore this stupendous energy must go somewhere. During launch with the secondary (water reaction mass) drive most of the heat is dispersed by exhaust, but in spaceflight, it must go somewhere - and so they deploy radiators. Yes, this does cause complications with space combat.

And now, because I have neither shame nor mercy, I will subject you to the flavour fic which I would never put into any game. Sensible people will stop reading now. This is the appropriate playlist to have in the background as you read.

 

[HanleyTucks]

622-101, Röntgen E965641-6 Ag Ga NI Ri Nav
City of William, Port Conrad
View attachment 1880

• FCV Jabberwocky, Type Z fusion cargo ship, 400 metric tonnes displacement
• Captain Corialanus XIAO ♀
• Pilot Rice NGULI ♂
• Navigator Miley JEN ♀
• Engineer Denne TAMMY ?
• Purser Earon JENSKIN ♂
• Passenger Lipaul Morgonz & Dog Blue
• Cargo: Grain 20t, Liquor 20t

Captain Xiao was with the navigator, looking at charts under the bright light shining through the dome, as the Purser came thunking up the ladder from below. She turned to him, putting the navigational calculations down. "Jenskin - Mr Purser, is all the cargo loaded and secured?"
"Ma'am."
"Show me the manifest, please..." she flicked through the pages. "20 tonnes grain - is that in their usual drums?"
"Yes, ma'am."
"Check the seals on those, last time we were here they were sloppy and it got out and jammed up the vents." He nodded. "And 20 of liquor - do make sure that's well-secured, really nobody should miss a bottle or two, but they get upset when the seals are broken."
"Ma'am." The purser was sweating now.
"Are you alright, Mr Purser?"
"Sorry, ma'am. It's just this planet, ma'am. The 1.25 gees. It makes my balls hurt."
The navigator sniggered, and the captain raised an eyebrow. "We'll be underway soon enough. Now - the passengers?"
"Just the one, ma'am, that businessman going to Lorenz. Well, and his dog."
"I thought we had three?"
"We did, ma'am, but they came down with the narc. It's this dense atmosphere, ma'am. Down the Trophy Valley it's even worse. Then when they went to hospital some idiot local doctor took them back up too quickly and they got the bends. They'll be weeks to recover."
"You refunded them their passage, I assume?"
"Yes ma'am, minus the deposit."
"Good." She handed him back the manifest, "See to that grain and the passenger," and turned to the wall and picked up a handset. "Engineering, this is the bridge, report."
"Engineering. Reactor is at 10%, landing gear deployed, cargo lock closed, airlock closed, radiators retracted, gunports closed, fuel 22t, life support optimal."

"Very good. Prepare for takeoff in 30." She hung up, and turned again to the navigator. "Conditions still good?"
"The weather is good. Atmospheric pressure 1.55 bar, local temperature 305 Kelvin, wind is 130 degrees at 30 kilometres an hour, no rain forecast today, we're good for takeoff."
"Alright. This gas giant you were talking about. Run me though it again, Jen."
"Ma'am. Since there was no fuel here, we've not enough to Jump, let alone enter a gravity well on the other side. Röentgen is in the fourth orbit, and the system's only gas giant is in the ninth orbit. We might make it there on a straight run but it'd take us two weeks. There's one rock and three dwarf ice planets between here and there, and the seventh one happens to be in a good spot about now for a gravity assist, if we use that we trim it to 10 days. No atmosphere so it's an easy one."
"And the gas giant?"
"The locals call it Anna, for some reason. It's busy - 13 large moons and 59 small ones, and it's got a wicked radiation belt. It's most of the way to being a brown dwarf. Skimming will be tricky, our magnetic bottle should keep the radiation off us if we're in full burn, though - depends if it's a stormy one. I'll have a better idea as we get closer. The locals have only optical telescopes here, no satellites, so I couldn't get good observations of it - but this large outer moon will be a good target. There's an old scout base there, abandoned but it's got a working navigational beacon."

"Very well." She checked her watch. "Nguli - Pilot, are you prepped?"
"Ma'am. Assuming normal takeoff profile into low orbit, maximum dynamic pressure will be at about 28km."
"That's high."
"It's this mud they call an atmosphere."
The captain grunted. "Twenty-five minutes. Confirm launch window with spaceport control."
"There is no spaceport control, remember, ma'am," the bearded pilot gestured out the window to the blasted patch of concrete with its deep ditch, two kilometres across to the half-buried warehouse, "just the local cops."
"Well then tell them what time to get out of the way."

Xiao turned and slid down the ladder with the spacer's practiced ease, into the galley. She glanced around approvingly and saw that everything was secured, and then went down another ladder to what was generously called the ship's cabins. Bunks were set into the wall, with a door sliding down from above, and cupboards set into the walls for crew belongings. They were doubled up, one on top of the other, but with the spaces larger than on a naval ship, here at least they could sit up without banging their heads and sliding down a wall. Xiao studiously ignored the fact that the bunk of the navigator was made up but never slept in, and that discarded women's underwear was in the purser's bunk. Across the small common area from these four bunks were the two staterooms, one being the twin of the crew quarters, and the other being a full room - the space for four bunks occupied by only one, and a desk and two chairs - her room.

View attachment 1882

Down the ladder once more took her to the cargo space, where the Purser Jenskin was finishing sweeping up, pushing the seal on plastic barrels down and swearing to himself, "You were right ma'am, these stocky hairy bastards are sloppy, so much for Teutonic efficiency." In this cargo space she could now feel the thrum of the reactor - or rather, the thousand vibrations per second of the superconducting magnets containing the fusion reaction. Already the heat was building up, but with the dense wet atmosphere of Röntgen to take it away, there was no need for radiators - so long as they got under way soon.

Past the cargo lock and down though the final ladder and into engineering she went, where she found the engineer, Tammy, middle-aged, pudgy, and of indeterminate gender - Xiao had never thought to ask, and it had never come up. Tammy was tapping on a dial. "All good?"
"Hmm? Oh yes, ma'am, just watching the mass flow here. For the secondary drive. It's been a bit uneven lately."
"Anything to worry about?"
"No. Maybe just a stutter or two on the way up."
"Very well." She checked her watch. "We launch in 11."
"Ma'am," Tammy nodded and looked back at the dial.

Xiao climbed all the way up through all the levels back to the bridge, where she slid into her chair, and kicked it back for takeoff, looking out of the dome straight up into the deep blue sky of Röntgen. To her front right was the pilot, her front left the navigator, both with their couches tilted back for takeoff. She flicked a switch on her arm rest. "All hands, all hands, this is the captain. Six to liftoff. Secure all, I say again, secure all. Passengers... er, passenger to couch. Purser, secure passengers. Sedate the dog."

Acknowledgements came back. A distant shuffle, a protest and animal yelp was heard. Xiao hoped that was the dog and not the passenger. The pilot spoke to someone on the radio, "6 minutes guys, better clear out the damn way," and chortled. He sensed a slight furrowing of eyebrows from the captain, cleared his throat and focused on the green writing scrolling up on his screen. The moments ticked by. This was the hardest part for Xiao, the moments before liftoff. She always had an irrational fear she'd flick the switch and nothing would happen. She sweat a little.

 

[HanleyTucks]

"Three minutes. All hands, couches. Bridge to engineering, prepare for secondary engine start."
"Aye, preparing for engine start."
A clunk shuddeed through the ship as the secondary engine valves opened, flooding them with liquid hydrogen. Tiny wisps of vapour could be seen even up around the dome. She glanced at her screen and dials.
"One minute, bridge to engineering, engine start, control to me." There was no technical reason the engineer could not start the launch, and logically it would be the pilot, but the captain flicking the "go" switch was an old, old tradition.
"Aye, engine start." A low hum was heard through the ship, and Xiao fancied she could feel the heat of the reactor - she couldn't, of course, but she always felt that. She grasped the joystick to her left and flicked the cover off the switch on top, and rested her thumb gently on the switch.

View attachment 1881

"Time," the pilot said quietly, and Xiao flicked the switch. There was no rumble yet as with the old chemical boosters some ships still used, only a slight tremble as more liquid hydrogen started flowing past the fusion reactor, heating to thousands of degrees and surging out the back as plasma. The ship shifted slightly and creaked, and slowly the planet's 1.25 gravities had the acceleration of the ship added to them. The plasma briefly scorched the granite and glassy surface of the landing pad until the ship was clear.

Now with three and a half gravities of acceleration the ship roared into the sky. The passenger and crew were pressed into the couch, Xiao felt as though a heavy set of hands were pushing on her chest. Oddly, she remembered she had forgotten to go the toilet first. Her face was pulled back by the extra acceleration, and a little drool escaped from the corner of one mouth, but nobody looked pretty during high gee manouevres.
"8,000 metres," called the pilot, "9,000... 10... 12... 14..."
"Retract... landing gear," said Xiao, stuggling to get breath.
"Landing gear retract, aye," and more thunks and clunks as the long heavy legs folded into the ship and their ports closed. The ship turned slightly.

A minute went by as the ship climbed higher, one hundred kilograms a second of liquid hydrogen being heat into plasma pushing them up into the sky. The ship shook a little, buffeted by the atmosphere.
"Approaching max Q," said Nguli, calmly, apparently unperturbed by the acceleration, "throttling back." The roaring subsided somewhat and they felt a relatively light two-and-a-half gees. Then the ship began shaking with a rhythmic thumping, "Damnit, resonance... misjudged..." he eased back slightly more and the resonance subsided. Moments passed.
"50 kilometres, throttling back up." And they were slammed back into their couches again.
"65 kilometres, ma'am, for the pri -"
"It's 110 for this atmosphere," grunted out the navigator Jen.
"I know that," said Nguli, a little testily. He'd forgotten.

Another minute and, "110, ma'am."
"Very well," said Xiao, flicking a switch near her shoulder, "You have control."
"Aye, captain. Rightyo, bridge to engineering - time to rock 'n roll."
"Pilot?"
"Sigh. You guys," he grunted through four gees of acceleration, "are no fun. On my mark, disengage secondary drive."
"Acknowledged."
"Five... four... three... two... one... mark!"

A clunk was heard and the flow of liquid hydrogen stopped, and so did the secondary engines. Xiao's heart jumped into her throat and her stomach did gyrations as the acceleration stopped. Her dark greying hair floated up around her head, except for the hair stuck there with sweat. She wiped the drool from the corner of her mouth.

The pilot spoke again, "Engineering, engage primary drive."

"Engaged." The pilot flicked one switch after another, and the ship's reactor kicked up a gear and a magnetic field folded out behind the ship as it started falling, deuterium and tralphium tanks opened and started venting their pellets into the railguns firing them out the back at several kilometres per second, then as the laser began pulsing, the ship juddered with the first impacts of the exploding plasma it was still falling backwards into, then the moments of falling were gone as all were slammed back into their couches once more, those all the way down at Port Conrad could see a bright bloom in the sky which quickly resolved into a bright moving star visible even in day.

As the ship rose on its plume of plasma which was moving at a significant fraction of the speed of light, the pilot began curving the ship around to come into orbit. In a few minutes, its speed moving forward matched its speed still falling back towards the planet so that as it fell it would never fall to ground.

"Engines disengaging," said the pilot, flicked more switches, and the primary engine stopped. Again came that sick feeling in the stomach, and hair floating free. "We're in orbit, ma'am." Xiao always felt her face bloat and the pressure in her eyes straight away with zero gee. Nguli glanced at a screen, "180 by 320, should be stable for at least a week. Radar says this orbit clear."
"Very well. Engineering, this is bridge. Deploy radiators."
"Radiators deploying, ma'am."
Thunks and clunks throughout the ship as the heat radiators deployed, without which the heat from the reactor would soon cook everyone in the ship. Further clunks.
"Radiators deployed, ma'am", said Pilot Nguli, checking his dials.

"Very well." She toggled the comms, "this is the captain, all hands, all hands, we are in orbit. We will remain here for 60 minutes while preparing navigation. Check your gear and get something to eat, and Jen," she said, unclipping herself from the couch and floating free from it, "you come over here, and bring your sextant and slide rule. We've got some maths to do."

Jen reached over herself to unclip, paused and grinned, and flicked on the comms. "Bridge to purser."
"Purser."
"I hope your balls are alright."
Exasperated swearing could be heard from below as the navigator sniggered.

Down at Port Conrad, the sound of the ship's primary fusion drive engaging finally reached them. Long after the ship had gone out of sight, they heard the boom and rumble of the Jabberwocky.

 

[Diveguy]

Nicely written. Thank you for sharing.