 The Stars are not Far, Mars Mission 2071. |
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 Nov 5 2006, 08:04 PM
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#26
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Prime Runner  Group: Banned Posts: 3,732 Joined: 1-September 05 From: Prague, Czech Republic Member No.: 7,665  |
You are quite correct about the 10^16. I misplaced a zero while multiplying large numbers. Sorry about that. As to whether it's more feasible to go in 5 months, I don't know. If you accelerate at 1/10th of a G instead of 1 G you get there in 6 months instead of 2 days, and you use up 110th the fuel. But is that economical with Shadowrun technology? People don't survive well at 1/10th gravity for half a year. They really don't. Which means that you'd need some sort of elaborate life support system running continously for the entire period. Probably involving keeping everyone in vats or centrifugingthem for artificial gravity. So really, you have to ask yourself which is more expensive: keeping a team alive in space for half a year (maintaining their bodily functions, supplying food, clean water, artificial gravity stimulus, waste disposal, etc.) or supplying an extra 70 megatons of power for your fusion engine. And honestly, when we compare the costs of life support to the costs of deuterium, I'm really not seeing the advantage for the slow ships. I don't think that a slow route is economically feasible, while with SR tech, a fast one is. People can jolly well just eat Cliffbars for 2 days - 6 months requires a whole thing. Seriously, Fusion reactors produce a lot of energy if you can get them to "not explode". A Kilogram of He3 and 2/3 of a kilogram of D can potentially output 6x10^14 Joules - which would cover our energy needs in less than the mass of a Troll. The fuel really seriously isn't a problem. The problem is using that fuel in such a manner that you don't all die - and SR has already handwaved that particular problem away. -Frank |
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Nov 5 2006, 09:02 PM
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#27
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Shadow Cartographer Group: Members Posts: 3,737 Joined: 2-June 06 From: Secret Tunnels under the UK (South West) Member No.: 8,636 |
Neither of us can put a price on life-support systems on a space ship in 2070 in a fictional universe, or costs of He3 that might well have been mined and shipped from the lunar surface. Given the energy costs in accelerating and decelerating the ship in the way you describe, which would run a million people's homes for an afternoon, I personally think the life-support approach would be less. But there's nothing in your figures that wrecks internal consistency with the rest of the setting and cannon backs up efficient fusion power, so I guess the real answer is whatever the GM's imagination demands. :D When your players get back, do us a favour and put us out of our misery about those fucking dragon bones, will you? ;) |
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Nov 5 2006, 09:51 PM
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#28
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Moving Target Group: Members Posts: 281 Joined: 9-September 06 Member No.: 9,346 |
The UCAS government has just confirmed that what you thought were Dragon Bones was actually a weather baloon. |
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Nov 5 2006, 11:57 PM
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#29
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ghostrider Group: Retired Admins Posts: 4,196 Joined: 16-May 04 Member No.: 6,333 |
Oh man. Can we see another "YotC" length/style supplement come from this? It might actually lead me to buy a SR4 book. :D
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Nov 6 2006, 01:18 AM
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#30
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Moving Target Group: Members Posts: 340 Joined: 18-September 06 From: Chicago (CZ) Member No.: 9,422 |
Get the hell out its dragon bones! Just like you UCAS governmental types to hide what you know from the public. When are you going to let us know about area 54 and Roswell New Mexico? Yeah I bet the azzies are going to say something about that one arent they?
:D |
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Nov 6 2006, 01:21 AM
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#31
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Moving Target Group: Members Posts: 281 Joined: 9-September 06 Member No.: 9,346 |
....
Johnson. We have a problem. Bring the Neuroneutralizers. And more weather baloon footage. |
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Nov 6 2006, 01:26 AM
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#32
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Runner Group: Members Posts: 2,598 Joined: 15-March 03 From: Hong Kong Member No.: 4,253 |
You can take a look at Atomic Rockets for the description of a lot of proposed spacecraft drives.
There's also the possible reactionless drive |
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Nov 6 2006, 02:32 AM
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#33
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Midnight Toker Group: Members Posts: 7,686 Joined: 4-July 04 From: Zombie Drop Bear Santa's Workshop Member No.: 6,456 |
Never forget Burnsides Advice: Friends Don't Let Friends Use Reactionless Drives In Their Universes. This isn't because reactionless drives are unbelievable or infeasible. This is because they give any and every 2-bit suicide bomber the ability to shatter planets with the equivalent of a rowboat. Edit:But really, if you want to get to Mars fast, just summon a spirit with Movement, Guard, and Innate spell:Levitate, Blood Invoke it, and feed it a few hundred lab rats. Lets say you've got a 100,000 kg pressurized box without engines (engines are unnecessary in this scheme) and including crew weight. A blood spirit who has been fed 200 white lab rats (6 essence each) will be able to get 600 successes at threshold 500 on a force 1188 (1200-12) spell for a movement rate of 118,800 m/ct or 39,600m/s. Add Movement to this and the vessel will have a movement rate of of 47,044,800m/s. It takes 12 boxes of damage from the background count but shrgs them off with several hundred resistance successes. The trip between Earth and Mars takes less than half an hour without any fuel costs (aside from the lab rats and the initial sapient sacrifice). The Guard power even eliminates the need for a box or protective gear. The levitation spells and movement power could be applied to the astronauts individually and the guard power will take care of little details like oxygen and deadly radiation. Since an astronaut in comfortable street clothes is likely to weigh less than 200 kilograms they can increase their travel speed to 282,286,800m/s 5 more rats will let them break lightspeed. Edit2: Really, forget about manned missions. There could be tours leaving every 15 minutes. No hassle, no fuss, and no long lines. Mommy and Daddy Wageslave should have no trouble taking little Timmy on one of Aztechnology's Mars tours. With no safety gear to worry about, no annoying airport security, and a round-trip travel time of less than a second, there is a killing to be made in Mars tourism. The best part is that nothing can possibly go wrong unless the summoner dies (or a tour party is attacked by a similarly imbued blood spirit) |
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Nov 6 2006, 05:14 AM
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#34
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Neophyte Runner Group: Members Posts: 2,458 Joined: 22-March 03 From: I am a figment of my own imagination. Member No.: 4,302 |
The official stance of this office is that the dragon bones, dragons themselves, Elvis, the entire town of Roswell, and Tina Turner's legs are in fact swamp gas. You may carry on with your life now citizen, and sleep well. |
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Nov 6 2006, 05:42 AM
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#35
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Running Target Group: Members Posts: 1,206 Joined: 9-July 06 From: Fresno, CA Member No.: 8,856 |
First of all by Fuel I mean reaction mass, it could be water or spotted owles, all it has to have is mass.
Well claiming that you could use some sort of super particle accellerator to create the velocity for the reaction mass is inconsistant with the technology presented in the current game usiverse. If you could accellerate reaction mass to velocities high enough to create the kind of accelleration you're recomending with mere hundreds of kilograms of mass you'd also be able to put that kind of technology into propelling projectiles from guns and we don't see anything like that anywhere else in the SR world. There are two keys to thrust. Thrust from a action reaction no matter how the power comes follows: Thrust = -u * dm/dt Where thrust is positive because dm/dt is negative (The rocket is losing mass), and u is the velocity of the propellant (Like I said, it could be water or dead mob capos.) So if you want to reduce dm/dt you have to increase u. You say that we can write in a future tech that allows us to do whatever we like with u, but I argue that if you can make a interplanitary engine that can create those kind of propellant velocities it would have ramifications that are visible in the terestrial technologies and that does not appear in SR as we see it. |
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Nov 6 2006, 06:01 AM
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#36
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Moving Target Group: Members Posts: 906 Joined: 16-October 06 Member No.: 9,630 |
You'd spin the crew comartment of the ship. The crew's quarters and recreation section could be in a cylinder that would spin at about 2 rpm (possibly more if the crew had bio/cyberware instailed to fight off the effects of Coriolis.) This would generate some gravity. At least a an exercise room spining at a higher rate say 6 or 7 rpm.
If you could some how ignore the effects of Coriolis you could duplicate earth's gravity on a ship 18 meters wide by spining at about 14 rpm. (that would leave a normal unmodified human on the "ground" puking) The center of the ship which would still be weightless would contain much of the important power equipment and life support, as well as the engine room at the back and the bridge towards the front. |
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Nov 6 2006, 06:10 AM
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#37
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Running Target Group: Members Posts: 1,206 Joined: 9-July 06 From: Fresno, CA Member No.: 8,856 |
Also le t me give you an idea of the unreasonableness of assuming a reaction mass velocity from a plasma engine having any speed you like:
The temperature at the core of the sun is: 1.36E+07 K(wiki) The average energy of a particle based on temperature is 3/2 K T Where K is boltzman's constant: K = 1.3807E-23 J / K So the average energy of a particle in a plasma as hot as the core sun is: 2.817E-16 J A proton has mass near enough to 1u = 1.66054E-27 kg. E = mv^2 non relativistic, so v = sqrt(E/m) in this case v = 4.12E+05 m/s. Thrust = -u dm/dt, and we assume we bottle the sun then to get a 100,000 kg ship to accelerate at 9.8 m/s then dm/dt would have to be 2.38 kg/second. For 345600 seconds going two days there and two back? Granted as the ship loses mass you can decrease dm/dt and still get the same acceleration. But if you want to do it on a mere 1000 kg of reaction mass? And I would still argue that the core of the sun is not a feasable estimate for the core of a plasma jet. |
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Nov 6 2006, 06:15 AM
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#38
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Prime Runner Group: Banned Posts: 3,732 Joined: 1-September 05 From: Prague, Czech Republic Member No.: 7,665 |
Shadowrun Thor Shots are mass driver based, you actually do have large scale space-based hyperaccelerators that are used in war. Shadowrun's game universe already has that and has for some time (they were first discussed I think in Paradise: Lost). You don't have it in hand held weapons, but that's not particularly germaine to a discussion about a 100 tonne object with a fusion reactor that is in space.
Wow. That's amazingly not meaningful to this discussion. In fact, you've just proved that rocketry is impossible because the temperature of the exhaust of the space shuttle is only 3600 degrees Kelvin. That means that by your calculations it would require the launching of some 23 tonnes of fuel every second just to keep the space shuttle stationary. And it would - if hypothetically the exhaust didn't also have a directional kinetic push in addition to its raw heat derived particle speed. But it does have that, which is where the vast majority of the impetus comes from. You aren't just heating things up and then opening a door for plasma to osmosis out of - you're charging it up with directional kinetic energy and then firing it backwards. -Frank |
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Nov 6 2006, 10:51 AM
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#39
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Moving Target Group: Members Posts: 530 Joined: 11-June 05 Member No.: 7,441 |
Well hell, in that case, let's burn off a kilo of mass in a Plank Time! Problem solved! (I keed, I keeed!) |
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Nov 6 2006, 11:14 AM
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#40
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Moving Target Group: Members Posts: 394 Joined: 19-May 03 From: In your base eating your food. Member No.: 4,607 |
Very funny :sleepy: . You and I both know they're closing the blood spirit loophole that never should have been created in the first place. Oh and we're not launching from groundside on Earth, that's just nuts. We're going up the well to meet the ship and then doing orbit to orbit. But first, training in Antartica! Those suit warmers better damn well work. I hate the cold. :) This is the reason I play Shadowrun. Tres cool epic runs like this. |
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Nov 6 2006, 03:28 PM
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#41
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Moving Target Group: Members Posts: 340 Joined: 18-September 06 From: Chicago (CZ) Member No.: 9,422 |
Ahh so it is the dragon who plans to go retreive the dragon bones and he had his S-K space facilities to do the training. Now I understand why target wastelands was put into print.
Lightbright you crafty and wacky elf I should have saw that one comming when the ruins in antartica were mentioned along with the name of Loffy and lightbright but thats a big hole of a connection to make but now it makes sense. So then when mars gets as close as it can get to earth were going to have another space race campain (like year of the commet). I scan you and dig it. |
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Nov 6 2006, 04:17 PM
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#42
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Moving Target Group: Members Posts: 749 Joined: 28-July 05 Member No.: 7,526 |
and bringing the topic to SR products again, where can I get information on space related technology, property, and resources? (Satellites, habitats, moon bases, terrestrial lift complexes...) Is it all in Target: Wastelands?
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Nov 6 2006, 04:24 PM
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#43
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Prime Runner Group: Banned Posts: 3,732 Joined: 1-September 05 From: Prague, Czech Republic Member No.: 7,665 |
Pretty much, though there is also some in SotA: 2064 (Mars Probe successful) and Street Magic. The stable orbital platforms have weak manaspheres generated by specially engineered plants. This allows you to use magic there without explosive decompression. Mobile units such as asteroid miners and transports, don't stick around in one area long enough for that to happen. -Frank |
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Nov 6 2006, 04:26 PM
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#44
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Running Target Group: Members Posts: 1,206 Joined: 9-July 06 From: Fresno, CA Member No.: 8,856 |
Well actually if you follow my calculations the space shuttle would need about 2,110 kg/s dm/dt in order to maintain stationary… (If exaust is 3,600K) If you want 3g of acceleration at launch you use 6,330 kg/s In fact the space shuttle uses closer to 10,000 kg/s of reaction mass at launch. Yes, it uses something on the order of a million kg of fuel in the first two minutes. So I’d say not too bad for a back of the envelope calculation. Not to mention the process errs on the conservative side.
What the heck do you mean by directional kinetic push? If you mean that we will first heat your plasma, then run it thorough some sort of accelerator? A sort of spaceship sized linear accelerator? I still contend that the world of SR does not indicate that this type technology. Now if you want a space race it would be way more reasonable to assume a smaller ship than would be necessary to contain the amount of reaction mass you’re talking about. If you want constant acceleration accept something much more like a few percent of one gravity. While you’re trying to boost a ridiculous amount of reaction mass into space someone else will send up a small ship and accelerate at a constant a few percent of what you’re proposing and make it in a couple months. Basically, 2 days is ridiculous, it would be way more acceptable to assume a couple months, and that the medical technology of the Cyber world of SR would make it reasonable for the astronauts to make the trip and not be atrophied weaklings with heart failure at the end. And don’t forget all this is assuming that you don’t land on Mars and want to boost off again, or somehow stay long enough to prepare sufficient reaction mass to take off again. |
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Nov 6 2006, 04:35 PM
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#45
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Moving Target Group: Members Posts: 340 Joined: 18-September 06 From: Chicago (CZ) Member No.: 9,422 |
most of it yeah. Wake of the commet is probably another good one to look into but mainly target wastelands
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Nov 6 2006, 04:44 PM
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#46
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Prime Runner Group: Banned Posts: 3,732 Joined: 1-September 05 From: Prague, Czech Republic Member No.: 7,665 |
Yes. And the Space Shuttle is over 2 million kilograms, not 100,000. So your calculations would call for it requiring over 120,000 kg per second. You're off by an order of magnitude, and we haven't even taken into account that this is happening in-atmosphere, where friction is a big problem. -Frank |
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Nov 6 2006, 04:51 PM
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#47
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Running Target Group: Members Posts: 1,206 Joined: 9-July 06 From: Fresno, CA Member No.: 8,856 |
Okay, you want it line by line:
K = 1.38E-23 J/K T = 3600 K E = (3/2)KT = 7.46E-20 J 1u = 1.66E-27 kg KE = 1/2 m v^2 = 3/2 KT v = sqrt(3KT/m)=9467m/s Thrust (Force = Mass * Accelleration) = 2,000,000 kg (Space Shuttle on Platform) * 30 m/s^2 = 60,000,000 N Thrust = -v * dm/dt Dm/dt = Thrust / -v = 60,000,000N / 9467m/s = 6331 kg/s So I’m not off by an order of magnitude, not even close. |
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Nov 6 2006, 05:09 PM
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#48
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Running Target Group: Members Posts: 1,150 Joined: 19-December 05 From: Rhein-Ruhr Megaplex Member No.: 8,081 |
Using today's possible technology, it seems sweat deal to launch a several million ton spaceship into earth orbit with less than 5 kilotons of fuel. Especially if you don't particularly care about the environment. Alltough, thinking about it, to bring a similar paylod to orbit would require about a million or more space shuttle starts, which also wouldn't be very easy on the environment...
(source:Project Orion) |
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Nov 6 2006, 05:28 PM
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#49
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Prime Runner Group: Banned Posts: 3,732 Joined: 1-September 05 From: Prague, Czech Republic Member No.: 7,665 |
Sorry Demerzel, I was way too generous with your calculations.
According to your calcs, a 100 tonne object would need over 2 kilos of ejecta per second per G at 10^7 Kelvin, with a linear relationship with temperature. The ejecta of the space shuttle is less than 1/1000th that temperature, so it would need 1000 times that per G of acceleration every second. So our 100 tonne object would need to fire over 2 tonnes every second for 1 G. Let's bring this into the general case. That's 2% of mass per second per G. A Space Shuttle Launch lasts eight and a half minutes (510 seconds) and has about 3 Gs of acceleration. That would be 510 seconds losing 6% of total mass each second. So the payload, as a percentage of the original load + fuel, would therefore be .94^510 - or approximately 1 gram of shuttle for every 50 million tonnes of fuel. Congratulations, you just disproved rocketry. :rolleyes: I'm going to stop checking your math because it's obviously wrong. -Frank |
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Nov 6 2006, 05:49 PM
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#50
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Moving Target Group: Members Posts: 340 Joined: 18-September 06 From: Chicago (CZ) Member No.: 9,422 |
I think someone just got served
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