Frederf
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Everything posted by Frederf
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I've always wondered what the most efficient orbit is that is atmo-crossing that takes the least dV to make into my desired orbit. If I wanted to get 200x200km it's probably best to boost into some 22x800km monstrosity and use less dV to circularize by a non-pro-retro burn to shuffle my eccentricity.
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Deadly Re-entry and Ferram Aerospace Research
Frederf replied to Enigma179's topic in KSP1 Gameplay Questions and Tutorials
I just recently did testing with FAR/DRE on a sample unmanned Mk. I pod and chute. A probe body was along for the ride in order to provide control. Previously I did have problems with FAR not slowing the craft for suitable recovery. With more recent versions (955 is what I'm testing right now to see if it's changed) I discovered I had a wide-ish window for reentry up to Munar energies. I attempted minimum orbit (60-70k) and Munar schemes and all had acceptable windows. I found that during Munar reentry my acceptable periapsis was 0-34km bounded by G tolerance and aerobraking limits respectively. The most shield I ever used was about 60% (I recall 108/250 left) and was never a limiting factor on these profiles. Perhaps double brake profiles or higher energies would reach the shield material quantity limits. Firstly I noticed a large difference in drag depending on orientation. Second I noticed a small ~5 degree cone of stability around the blunt attitude and another larger one around the pointy attitude. A zone of repulsion exceeded reaction wheel strength at significant Q loadings. The consequences of being on the wrong side of the fence too late into the reentry are obvious. At 30km I had a no-bounce profile with no more than 4.5Gs. Approaching 34km I had a significant balloon in altitude to 66km which used more shield material and lessened G loading. Toying with this limit with minimal onboard battery life was beneficial but risky. Lift (which I think FAR 9551 addresses) offered surprisingly significant control. Not much experimentation was done regarding trajectory control by lift but L/Ds of no less than 8 were recorded. -
Kethane Pack 0.9.2 - New cinematic trailer! - 1.0 compatibility update
Frederf replied to Majiir's topic in KSP1 Mod Releases
Is it really the case that you can convert 1kg of Kethane into >1kg of other resource? -
Economical descent profile for Mun landing?
Frederf replied to jadoo1989's topic in KSP1 Gameplay Questions and Tutorials
I think you missed the part where I said "negative propellant flow rate" meaning as you burn fuel is being added. This allows the ascent with magic adding fuel to be a time reversal of landing with normal disappearing fuel. I only forgot about the fact that the Mun spins the same way in both but it should be a minor effect. -
Delta-V question in relation to thrust
Frederf replied to SlinkyBlue's topic in KSP1 Gameplay Questions and Tutorials
Highest mass fraction and specific impulse always result in highest dV (per configuration). The optimization comes from the fact that different performance rockets need different amounts of dV to do the same mission. A TWR of 1.01 means that it'll take more dV to lift off from Kerbin than a TWR of 2 or so. The TWR 1.01 might have 500 more dV but it might take 1000 more dV to get into orbit in that configuration. Even orbital maneuvers suffer at very low TWRs because you can't give your impulse at the better points in the path due to Oberth. -
Economical descent profile for Mun landing?
Frederf replied to jadoo1989's topic in KSP1 Gameplay Questions and Tutorials
The optimum descent profile is the time-reversed optimum ascent profile with a negative propellant flow rate. It'll look mostly like a good takeoff in reverse. However that's hard to do without teh maths so I found a method that's nearly as good ad a lot easier. The idea is to place your periapsis about 3-5km above your intended landing site. Upon approaching your landing site (how far determined by TWR) you should be near your 3-5 km close scrape height. Burn retrograde with enough radial positive component to cancel any falling but not enough to gain height. As you decelerate pitch up more and more to direct more of your thrust to maintaining altitude. When you're over the landing site and your horizontal speed is manageable then let down at 10-30 m/s vertically until close and land per normal. I budget about 60 seconds hover time (Mun's gravity times 60 = hover dV) for the landing. -
Pretzels... knot food... get it?
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I just can't seem to dock.
Frederf replied to Anizer's topic in KSP1 Gameplay Questions and Tutorials
I recommend at 500m you close quite deliberately, something like 10 meters per second for every kilometer separation. This puts you on a "hundred seconds" collision. Do it again when you're most of the way there and repeat. 100 seconds collision speed will get smaller as you get closer. At 100m or so, stop, then dock. Slower docking closures are nice if you want to think about the orbital mechanics in the proper sophisticated way. If you just want to focus on "I'm going toward it" then you can't take too long. -
[0.20] ModuleManager 1.3 - for all your stock-modding needs
Frederf replied to ialdabaoth's topic in KSP1 Mod Releases
Textures are likely the largest source of RAM usage. -
I just can't seem to dock.
Frederf replied to Anizer's topic in KSP1 Gameplay Questions and Tutorials
This sounds like what early Gemini docking problems were encountered. If your target is on the prograde side of you then burning toward it is burning prograde into a high, slower orbit. You increase the separation instead of closing it. The problem if your target is turning so more straight line speed isn't the answer. Ignore where the target is now and focus on where the target will be in the future and then maneuver to arrive at that time and place. -
[0.20] ModuleManager 1.3 - for all your stock-modding needs
Frederf replied to ialdabaoth's topic in KSP1 Mod Releases
Ooooooo. That's clever. If not loading a part means lowering the memory footprint having a simple text-only "part library management" tool is possible. -
[1.3.1] Ferram Aerospace Research: v0.15.9.1 "Liepmann" 4/2/18
Frederf replied to ferram4's topic in KSP1 Mod Releases
A small feature request. Is it possible to code in a simple ARI helper that can be turned on/off like the pitch damper and yaw damper?- 14,073 replies
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Kethane Pack 0.9.2 - New cinematic trailer! - 1.0 compatibility update
Frederf replied to Majiir's topic in KSP1 Mod Releases
I just noticed that there is a .cfg file that defines the geometry and distribution of Ke deposits. I'm sorely tempted to go in and edit it to be a little harder at least for the Mun. -
No, it's not. If you orbit at 23,001m+ then you will continue to do so if you depart the craft. The path is cyclical and permanent unless it intersects a set litho+atmo object. Overheating, aero drag, collisions with other craft, etc. aren't a factor. Decay factor might be based on overall drag averaged over 360x180 rotation or even in a single orientation. It wouldn't have to be remotely precise for 99% of craft to be believable. tristian brings up an interesting idea about pre-determined unloaded craft fates that could really enhance unloaded craft modeling. With some cheap one-time calculations some valuable craft behaviors can be realized.
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I just can't seem to dock.
Frederf replied to Anizer's topic in KSP1 Gameplay Questions and Tutorials
Docking is putting two metal plates together. This is a rendezvous problem. Your two craft look to be in very similar orbits. I bet you can get a rendezvous under 500m and kill relative velocity for under 50 m/s dV. Target the other craft and cancel relative inclination at the next node. Let's turn a 3D problem into a 2D problem. You can think of various orbits as highways in the sky. If you need to catch a craft ahead of you you need to take the fast lane. Speed and path are the same thing. If you need a different speed then you need a different path. Targeting the destination vessel you should see 1 or 2 closest approach marker sets if your orbits cross once or twice respectively. The spread in the marker set is your projected positions at the moment your vessel crosses the target's orbit. If the target has already passed the intersection point then you need to get there faster. Getting there faster means taking the faster path which is a lower orbit. Alternately if you arrive too soon you need to get a high/slow orbit to delay. -
Rewrite the part descriptions
Frederf replied to ddavis425's topic in KSP1 Suggestions & Development Discussion
The part stats are already pretty crowded and loaded in the flight scene too which is the time for brevity. Already I right click on a pod and the stats page goes off the screen behind the navball. I like the humorous flavor text but the descriptions are getting very long and often at the expense of knowing what it is the thing does. -
DRE has part damage based on heat/acceleration which can be fixed in IVA. It shouldn't in stock except for broken wheels.
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Command Module question :
Frederf replied to Herbin's topic in KSP1 Gameplay Questions and Tutorials
Four I think. You can choose your crew before liftoff including empty seats. From the space center click on the launch facility (runway or pad) and it'll give you those options. -
That's sort of bad. I spent at least an hour practicing simple airplane flight and no time elapsed at all if I choose the most convenient option? Actually getting time to elapse in KSP is such a chore.
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Does revert roll back time as well?