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Landing/Takeoff from earth?

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Fri, 2012-12-07 12:18
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mkn mkn's picture
Landing/Takeoff from earth?
Hey all, making the jump from lurker to poster here, looking for advice on handling space travel in game. My understanding is that the various orbital shuttles are metallic hydrogen rockets (I'd never heard of this til I picked up EP... will wikipedia very soon). Let's say, for instance, that I'm in orbit around Earth, with a fully fueled shuttle. I can buy that they could deorbit, and then perform a powered (tail first) landing--SpaceX is already experimenting with this for large booster stages. But I'm not sure I can handwave the same ship *taking off* and boosting to a stable orbit without refueling--especially on large bodies with dense atmosphere (earth just being the most notable example, since we all know how hard it is to get off *this* big floating rock). It just feels sort of too Buck Rogers to me... and any physics wonks playing will grumble that the same shuttle should be able to boost off Luna, perform a high velocity transfer to Mars, take a little picnic on Phobos, and land on the red planet with the same amount of fuel. I don't want to get into calculating Delta-v and doing real life rocket science while playing EP--am I just overthinking things? My first thought is that the first example (of landing and taking off on earth in a single stage) might require a specially modified shuttle, with every bit of excess mass cut away--so that it must dock with a mothership if you want to stay alive in it for any length of time--and probably cut the max passengers in half. Also--any advice on a quick fudge for deciding the duration of a space voyage? Rimward has a little table, but again, my group includes engineers (I went to art school, ha ha) and pulling a generic number out of a hat might poop on the verisimilitude a little bit. I did find a web app that can calculate real life distances between many different bodies (in a straight line).
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“Man is an artifact designed for space travel. He is not designed to remain in his present biologic state any more than a tadpole is designed to remain a tadpole.” -William S. Burroughs
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Fri, 2012-12-07 14:39
Undocking Undocking's picture
Well, using a LLOTV or SLOTV
Well, using a LLOTV or SLOTV at high-velocity will be enough to land and take off from Earth: "High velocity configuration allows the vehicle to land and take off against on Venus or Earth without refuelling and for rapid transport between nearby habitats"; "Using a small LOTV with a hydrogen-oxygen engine to take off and land from Venus or for other high velocity uses is exceptionally cramped and allows for absolutely no room for error"(EP 348,349). You could have a variant LOTV that allows for (your party size) to be in high velocity. This assumes that you don't take the Kilimanjaro space elevator. Tell your PCs to mind the kill-sats.
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Fri, 2012-12-07 14:43
RustedPantheress RustedPantheress's picture
Well, let's be frank about it
Well, let's be frank about it: most mass transfer from Earth to Orbit took place using a space elevator. And most shuttles were (IMHO) space planes (so you took a plane, modified it for space, and stuck an appropriate rocket engine up its ass). Of course, in EP, nobody goes to earth anymore. So, most shuttles are built for the following conditions: Low gravity, and very little in the way of atmosphere. Now, let's look at some other things: In most cases, anything less than 1.5million KM away, you're going to egocast. LOTVs are designed for less than 100,000km distance (although that can be stretched, depending on your astrogator). My advice: if you don't want to handle the space travel, then don't. Just use egocasting, or have one of your players handle the math.
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Somebody is using bad science! Snark, facts, snark. Your body is corrupted: Cool, do more science to it. Your mind is warped: That's nice, want a cookie? What do we say to the God of Death? Not today!
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Fri, 2012-12-07 16:03
mkn mkn's picture
I guess I'm looking for a way
I guess I'm looking for a way to use spacecraft in-game that reflects some of the realities of space travel without requiring anyone (even RL engineers) to haul out a scientific calculator. Just curious if anyone else has played with this in their house rules. For example--'maximum range' is sort of a mushy concept for a spaceship. Especially if the party is traveling as infomorphs, or in hibernation, to a destination with no nearby egocaster, a year in deep space might be tolerable/necessary--or they might be able to get there much faster than a full "ship" that needs to haul around a hab for biomorphs. Maybe an abstract "delta=v" stat? A transfer from earth orbit to Luna might cost 2 units. Double the delta-v you spend, and you can get there twice as fast--and vice versa. Every ship has different delta-v based on size, tankage, drive type, etc. I see the PC's in the role of mission planners rather than rocket jocks--it's another field where they can make mistakes, screw up, and have to deal with the consequences (or reap the rewards). I'm very pleased that EP de-emphasizes traditional space travel, but I've got a few scenarios where a little nail-biting/mission planning might add to the suspense--it'd be a shame to have so much detail in resolving hacking, combat, nano hardware, and so on, and treat the spacecraft as a pure background element.
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“Man is an artifact designed for space travel. He is not designed to remain in his present biologic state any more than a tadpole is designed to remain a tadpole.” -William S. Burroughs
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Fri, 2012-12-07 16:13
Jaberwo Jaberwo's picture
http://iopscience.iop.org
This has been quite useful for our games: http://www.transhuman.talktalk.net/ts/TSTravTime.htm On page 6 this document (http://iopscience.iop.org/1742-6596/215/1/012194/pdf/1742-6596_215_1_012...) presents a rocket that can lift off earth and carry 25tons of payload, while using abput 24tons of MH as fuel and propellant. Don't know about the accuracy of these figures, but it seems to be from a respectable journal.
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Fri, 2012-12-07 16:36
Undocking Undocking's picture
Space-Travel as Plot Device
mkn wrote:
I guess I'm looking for a way to use spacecraft in-game that reflects some of the realities of space travel without requiring anyone (even RL engineers) to haul out a scientific calculator. Just curious if anyone else has played with this in their house rules.
In the Neptune/Fringe game I'm running space travel works in the 'speed-of-plot'. It takes them where they need to be when you want them to be there. Tell the group they have enough to leave Luna, land on Earth, take off from Earth, and return to Luna. If they want to do anything more than that there will be problems. If you don't want anyone taking out a calculator, then don't let anyone and do it as an abstract with your own judgement. If the PCs want to plan out their flight, have them make Pilot (Spacecraft) rolls to determine their idea of what seems reasonable to accomplish with the ship provided and fuel available.
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