"Faiths And Fuels, Part 9"
Tana B'Khenna
5th Zaru-Toru, Y.C. 807
Research Board, The Foundry
Rivi throws herself on the bunk next to me. "This is... Mad. They call whacking a tank with a hammer and pre-thinned fault lines a successful test..."
I shudder as the image of the fuel tank flying through the air fills my mind. "Yeah. I'm getting second thoughts."
She sighs. "I think we should get back to the Archive. There must be better solutions tried."
I look out the tent. "But... I don't know. The thing is, sure we could incorporate the Archive. But would it mean as much to just copy what they did?" I point out the tent. "It might well be terrifying and dangerous, but this is all ours. And I think that counts for something."
She stares. "They've buried people, Tana."
I think about the fuel tank. "I know. Nine dead, twenty retired, I heard too." I sigh. "But maybe that itself is a reason to do things our own way. We take our time, we do things right... We learn our lessons."
She shrugs. "We could learn lessons more easily through the Archive."
I lie on my back. "But is that the right way though? Is one mission and then done the way we should go?"
She rolls to face me. "What I think is that we have the opportunity to understand how they did it, and learn from them."
I look out the tent again. "But we would miss out on this... We'd trade further growth as a people for a quick turnaround. And I think more risk... I think that we should treat it as four missions, not one."
She stares. "But it is one mission."
I shake my head. "No. Launchpad to orbit of the homeworld. Homeworld outbound. Landing. Return. Each stage has different challenges, and each one could be done with dedicated vehicles to give each mission the best chance possible."
"With so much more to go wrong though." She shrugs. "And besides, the Council have basically already agreed we'll be leading what comes after... a one off mission sets us going for our destiny much quicker."
"I know they'll ultimately make the decision. But, if we have dedicated vehicles for each stage, we could maximise the potential for safely completing each stage." I get up, put some bowls on the floor. "Look. Remember the numbers on the board that they worked out?"
"Yeah."
I jot down the equations. "So, they began with the estimates of our world's size. And they worked out how fast we'd need to travel to sustain that, right?"
She nods. "Yeah."
"So, the momentum exchange principle means some mass is ejected so that the mass we want to keep to complete the mission gets there - fuel mass times velocity is equal to rocket mass times velocity."
"Yeah. Your point is? I mean, we build a rocket, burn it's fuel, get there, come back."
I shake my head. "I don't think we can do it with one rocket, Rivi." I draw a table. "Follow my logic here. How much rocket do you think we'll need?"
She sits up. Pauses. "At least two people. And their survival equipment. And a box for all that to go in."
I smile. "Want to chuck a number on that mass?"
She yawns. "Four to one relative to each person, say."
"So we are at ten of us as our starting point, right?"
She nods. "Go on."
"And that goes at ten thousand strides a moment."
She gulps. "And Tori is not confident of finding a rocket that does ten thousand strides a moment."
I nod. "Exactly. Lets say we only have a thousand strides a moment. That means we need ten times the fuel of what we want to move. And at this point, we have just our habitation module and our bubble of fuel."
She nods. "Two very unrealistic assumptions."
I nod. "And so, we need fuel containers, we need a module separation system for evacuation when this thing goes wrong, and we need it all in a fairing that holds shape against much faster airflow."
She sucks in air. "I see where you are going with this now. I mean, if we need say... twice as much mass in total rocket before fuel as we do in habitation module, and ten times as much fuel as total rocket mass..."
I gulp. "And the tank mass increases with the more fuel we need, and then the fuel mass itself increases with the amount of fuel we need..."
She gulps too. "And the engines have to get bigger and more powerful to lift it all up."
"Exactly. And at this point, we've only just gotten to orbit and our hypothetical rocket already is a huge fuel tank with a very small habitation module on the top of it."
"And those big engines we needed on the launchpad will be so powerful that they'll be uncontrollable once we are down to the massively reduced mass in orbit."
I nod. "So, I think we need to think of having stages to our rocket. We can put parachutes on fuel tanks, and as they drain and get used up, we detatch them."
She leans in, nodding fast. "We'd have to get rid of them, we can't keep lifting drained tanks... And yeah, worst case they are going to be really big tanks, we need to make sure they land safely."
Visions of massive tanks squashing buildings run through my mind. "Or at least give people time to get out of the way."
She stands. "And eventually we get rid of engines too, and use smaller engines for a subsequent stage."
"Yes! And a big chunk of rocket too."
I look at the equations. She looks out the tent. "We really need to know how fast those rockets they are testing go."
