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Showing results for tags 'dawn'.
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Hey all, so I've been trying to build a mars tranfer vehicle somewhat in the vein of Hermes (from The Martian). For me, it's an 80 ton, crewed, ion propelled spacecraft. Unfortunately, when I got it assembled and fueled in orbit, I discovered that my mod install had reduced the thrust of the engines from 2 kN to 0.25 N which is 8000 times less thrust, and KER told me a 10 m/s burn would take 4 hours and change (8 engines). I am obviously going to have to rethink my plan, but that's actually not my main point of interest. \ All this got me wondering, how would a real world ion rocket leave earth orbit for an interplanetary transfer? I am very experienced with using multiple perigee kicks to make low thrust escapes, but the thrust of real life ions is SO low that this isn't possible. Even if I halved the mass of my rocket to 40t and tripled the number of engines, it'd still be more than half an hour for 10 m/s. At that rate, it'd take more than 300 kicks to reach escape velocity. I know that all real world ion spacecraft to date have been lauched into heliocentric orbits using chemical rockets, so I'm not sure it's actually possible to use such a low thrust system for earth escape. There are however, several hypothetical vehicles, both fictional and real concept designs, that do appear to exclusively use ion propulsion once in orbit. Does anyone know what kind of trajectory would be used? The only one I can think of is a very long spiral up to very high orbit, and from there on to deep space. However, I imagine this would eat up an absurd amount of dV, so it doesn't seem like a good option for anything except maybe a solar sail vehicle. Ion drives in stock are time consuming, but you can basically treat them the same way you would small chemical rocket engines like the LV-1. With realistic ion drives though, I don't have the first clue how to use them. Thoughts? Ideas? -
Hello again, fellow Kerbalnauts, I've returned after a long slumber to bring to you a brand new shuttle that I've been developing over the past couple of days Endeavour - https://drive.google.com/open?id=0B_ZkNlM8j7rjR25kd2hraDNzX1k Mass - 410 tons Part count - ~290 Height - 35m Width - 12.6m Length - 21.2m ACTION GROUPS - 1 - Toggle Bay Doors Best way to fly it, that I've noticed, is that as soon as you launch, the craft wants to pull west at about 5 m/s within 10 seconds, so pull 5 degrees east. Once you lose the boosters, you'll be going about 270- 310 m/s and 6.5 km up. at that point, you will notice your velocity dropping just a little bit. DO NOT PANIC, it goes away pretty fast. At the altitude of 20 km and about 450 - 500 m/s, pull to 40 degrees east , once at 28-30 km, roll 180 degrees so the large tank is under you, closer to the ground. Once that happens, go to map view to monitor your Ap (Apogee) , once it's around 65-80 km, go back to the shuttle and reduce engines to 2/3rd power, and burn BELOW PERIAPSIS NODE. You need the horizontal velocity more than vertical velocity at this point. You will run out of fuel at around 2.1 km/s. Nose down, and while the shuttle's still moving, jettison the main tank and start the OMS engines and burn for a few seconds to get away from the big tank. Time warp to about 2 minutes to Ap, and start up the OMS to push to orbit. Great, you're in orbit, and probably wondering how to get down. Easy! just point your OMS in retrograde direction and fire when you're 90-100 degrees west of the space center in perspective to Kerbin. Point your shuttle up at about 25-40 degrees while in atmosphere to aero break. (Do not go above 40, or you'll flat spin at orbital speed, NOT pretty) The shuttle has a very low stall speed, it's about 45 m/s. so make sure you land the thing Anyways, hope you guys enjoy my masterpiece! pics - (just realized I misspelled Endeavour as Endeveror)
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Please post your craft using dawn ion drives. Why did you choose dawn over something like nerv? Is this a craft built "for fun" or is it a career game workhorse? I'd love to hear all about your design decisions and engineering choices. (if this repeats a thread, please post link? Happy to just continue conversation there.)
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