Arenamontanus provides: :) http://www.flickr.com/photos/arenamontanus/sets/72157624693618421/with/4... Remember to thank him if you get the chance, He did the math and chose the pretty colors. Those are not tables they're graphs called porkchop plots. Look [url=http://en.wikipedia.org/wiki/Porkchop_plot]at this wiki[/url] to learn how to read them if you can't figure it out at first. Like Tyrnis says, if you want to have a table (or porkchop) of travel times you have to decide when you're leaving because that determines where everything is when you arrive. I forget the year A-mont. chose for his plots but it makes a huge difference. Jupiter has an 12 year solar orbit and Saturn's is 32 (iirc) so if you use these graphs you're using these positions for the outer system and effectively declaring what year it is. [edit] also he might have used the mean distance. I don't recall.[] see also; http://www.eclipsephase.com/travel-time-how-long-does-it-take http://www.eclipsephase.com/faceted_search/results/DIY%20space%20travel (the main travel time thread) http://www.projectrho.com/rocket/ (Atomic rockets; massive Geekgasm for the uninitiated rocketeer) http://www.fourmilab.ch/cgi-bin/Solar (an electronic orory of the solar system highly recommended) http://clowder.net/hop/railroad/sched.html (Cosmic train schedule will explain EP's earth/mars, Earth lunar, Earth/mars/main belt cycler ships) http://lunaf.com/english/live-data/saturn-moons-position/ (a map of the orbits of moons arround Saturn) http://www.braeunig.us/space/orbmech.htm (a more in-depth look at orbital mechanics) http://www.clowder.net/hop/railroad/deltaveemap.html (A whimsical look at the minimum amount of fuel it will take to get arround the inner system using [url=http://en.wikipedia.org/wiki/Hohman_transfer_orbit]Hohman Transfer Orbits[/url] looks like you have some reading to do. Say, when you're done would you mind comming back here and explaining it all to me? ;)

At the table, I generally say it takes 1 month per AU, round up, and leave it at that.

JSnead gave the numbers he calculated for the ships in the core book earlier, and they make physical sense. I have them in my tables in the naval document. One cannot just divide the distance with the delta-v, since 1) there is an (de)acceleration period, 2) roughly half of the delta-v needs to be used for launch, half for slowing. Still, I earlier calculated that the acceleration burns even to max velocity are on the order of hours, so for most trips they are negligible.

Just to muddle things, capture orbits seem to be much better choice than Hohmann transfer orbits if you can aerobrake/aerocapture. EDIT: So you could blow 90% of your delta-v on acceleration, aerocapture/aerobrake at destination, and use the 10% to get to your refueling station. It's likely to be significantly faster, especially for longer trips.

Jaberwo wrote:

Correct me if I'm wrong, but wouldn't using all you delta v during short phases and the end and the beginning of the journey mean that your spacecraft has an extremly big power output? What I just typed into my calculator: delta v = 200km/s Travel Time Mercury Luna (day 50): about 10 days Insignificant time of acceleration: 1 day = 86400 seconds delta v for acceleration: 100km/s Kinetic Energy of ship after accel (asuming a mass of 1,000,000kg): 0.5*1000mt*(100km/s)² = 5*10^15 J Enegy/time = Power = 58 GW = cooling problems for a 1000mt ship? I don't understand all of this enough to have too much faith in my calculations though. Maybe this is too short for the accel/decel time to be insignificant?

That's a very good observation. It's actually worse than that - the propulsive efficiency of a fusion rocket is like 1/7000th. So your power output is actually 7000 times that number. [img]http://upload.wikimedia.org/wikipedia/commons/4/45/Propulsive_efficiency... Notice the efficiency dropping off as exhaust speed increases. A 1 MeV neutron is about 14,000km/sec, so a proton is going to be in that neighborhood too. The reason cooling wouldn't be an issue is because the heat is being continuously dumped out of the rocket. This is one of the reasons He-3/He-3 fusion is favored; because it is such an "engineering friendly" fusion process. The entirety of the output is ionized He-4 particles and protons, which can easily be directed by powerful magnets. You can either directly slow down the He-4 particles with your magnets (generating electricity) or just use the magnets to make sure the (very hot) particles get expelled in the right direction. Presumably the fusion drive would also have fancy near perfect x-ray mirrors (to bounce the x-rays back and forth to reheat the plasma) inside it because He-3/He-3 fusion actually creates more energy as x-rays than it does as charged particles. It does show that even a minor breakdown in your fusion magnetic containment would cause big problems - you'd only be able to thrust up to the amount your ship could shed heat at that point, which is going to be some fraction of 406 terawatts (58GWx7000) (also this assumes the x-ray leakage isn't a big deal). So Eclipse Phase fusion rocket ships must be engineered to be able to prevent the vast majority of that 406 terawatts from impinging on the ship itself at all. EDIT: I just realized, the fusion rockets are supposed to have 1/20th of a gravity of accel, right? That's about .49 meters/sec/sec - so a 100km/sec velocity is going to take about 50,000 seconds. EDIT2: My example also assumes the ship runs purely on fusion fragments. That's probably incorrect - a 1000 tonne ship likely say 50% propellant. Mix that with the fusion output to increase your propulsive efficiency. Get something better than 1/7000th. Also has an effect on your delta-v calcs because you are losing mass in the form of propellant as you go.

I have been working on a warship for EP, but I have spent so much time on the design that I forgot most of the calculations by now, but they all made sense back then... I just realised that my ship has a similar power level but the thrust is just so much lower. I should probably just present what I have and let you guys check the numbers: http://eclipsephase.com/warship

...someone's already done the work for roleplayers. On RPGNow.com, where in fact you can also get all the EP .pdf's (and where I discovered EP in the first place), there are several resources for sci-fi gamers to make the science a little more tangible or 'hard': This tome will make it easier for you to incorporate 'hard science' into your EP gaming (or any sci-fi gaming for that matter - and would probably be unwelcome in a Star Wars game): http://www.rpgnow.com/product/100018/The-Pumpkin-Suit%27s-Manual%3A-Easy... This one will help you Gatecrashers with making up new alien worlds: http://www.rpgnow.com/product/100391/The-GM%27s-Planet-Building-Handbook Solutions for combat in three dimensions, whether in space, zero-gee or other: http://www.rpgnow.com/product/80714/Three-Dimensional-Combat-Solutions Also available on RPGNow.com are tilesets, map creators, printable paper model kits and even soundtracks and maps for sci-fi settings, all on the cheap. Explore.