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Pecan

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Everything posted by Pecan

  1. To be honest, I usually let MJ do the mundane things so I'd just put Pe at the required altitude too, most of the time. That's different to what's efficient though - extreme cases make the extreme case (reductio ad absurdum); take a direct transfer from Kerbin to Moho, target orbit 750km for a Scansat satellite, as a fairly common/plausible example. With a direct transfer to Moho, and Pe set to 750km, you're going to be tearing in with your flight-path hardly deflected by Moho's gravity. Needs a huge, long, injection burn to slow you down enough to capture (which is why Moho's considered hard-ish). Set Pe to 7.5km, say, and your flight-path will be deflected by (IIRC and again it depends on the exact intercept) nearly 90-degrees before you do anything else. Yes, you're travelling relatively faster, because you have fallen that much closer, but the dV to close the orbit and capture is much less (quite apart from having more time in which to do it, since gravity-deflection is extending the time until your Moho escape - which is down to patched conics). Because your Pe is already very low you get maximum Oberth when you burn to create and lower your Ap. Since the Ap is 100 times your Pe there is also a lot less work to do than if you were circularising low-down. Circularising low, then raising Ap and re-circularising is indeed a bad idea. Now, with the point that you have not circularised low, you transfer to Ap and finally circularise. Two burns - the major braking manoeuvre being done with the maximum benefit or gravity-assist and Oberth. That plus minor circularisation burn is, I believe, much less than the capture unassisted by gravity. TL;DR Sooooo - if you want to do a direct transfer to Moho, and don't use Moho's gravity to the full, you are effectively doing a sun-relative Kerbin altitude to Moho altitude Hohmann transfer and both burns (lower Pe, circularise) are pretty big. Using Moho to gravity-brake you have less of a burn to do and maximum benefit of Oberth.
  2. Thank you for the testing - now we all have your experience to add as well :-)
  3. Well, gentlemen, y'all must feel mighty clever with all that evilootion theory, but we all know, 'cause it says in the holy book of readme that Kerbals were created by the great HarvesteR, praise be upon his keyboard. He made the light and the dark, the planets and moons and Kerbals in just four years. Now if you don't straighten yo'sells up and get to the church of KSC he might about crash and burn yo' rockets. Make sure it ain't yo' ass he Harvestin'.
  4. People join KSC to forget ... The past is past, they have new lives in space ... I've forgotten the rest.
  5. i) The further from the target you can make adjustments, the better. ii) The closer you approach a body the stronger its gravity will affect you. iii) Hitting mountains is a 'bad thing' (unless they've been really naughty and deserve it) So right from the start, aim for as low a Pe around the target as you can cope with without screaming. This maximises the amount your flight-path will be deflected by the body and Oberth. At Pe burn to lower your Ap to the comfortable altitude you actually want to settle into. At Ap, circularise.
  6. The rate at which you can pitch-over through the gravity turn is fairly constant (bear with me) and so is the dV needed to get to orbit. Your ascent path is therefore primarily dictated by a vehicle's TWR: 1. With low TWR (1.1 - 1.3, say) you climb relatively slowly, can be pitched-over almost to the horizon quite low and will put a lot of thrust into building horizontal speed at the same time as building Ap. By the time you, eventually, get to Ap this leaves little extra speed required for circularistation, and a short burn. The trick is, of course, not to get too horizontal too soon and waste too much time in thick, draggy atmosphere. 2. With hight TWR (1.8+) you will climb quickly, with little time to pitch-over without flipping completely. Your Ap is therefore developed early, but you're left having to build a large amount of horizontal velocity and a big circularisation burn. The trick is, not to "go straight up and turn right". Somewhere between the two is the optimal gravity turn for any particular vehicle. Significant proportions of this forum, other KSP information and the time we all spend, is dedicated to trying to find it. Rocket science ^^.
  7. Alright, time to 'fess up - I think di/anhedral looks cool, so I use it a fair amount. For the minimal benefit though, the biggest headache is then getting the CoT (axis) from wing-mounted engines back in the right place. Veeltch, for yours the engine nacelles, etc. snap to that position; tilt the wings and you'll have to fiddle about with the offset tool instead. Your call whether it is worth it.
  8. I've been using 580m/s for Mun for a long time, thanks to http://i.imgur.com/NKZhU57.png, which I usually found fitted my piloting style (or otherwise) better than the one given by the OP. For up to date information, the best-checked that I'm aware of is http://forum.kerbalspaceprogram.com/threads/96985-1-0-4-WAC-s-Delta-V-Map-continued-2-1-%28Aug-13th%29-Swash-transition, although I haven't been many places far in 1.0.4 yet. I'd say they are correct, but need more information to know why they aren't working for you. Three immediate points are - i) What does MJ say the dV is? It and KER sometimes disagree, ii) My low Mun orbit is 8 - 10km, so you might want to start from lower, iii) What's the TWR? If it's less than about 2 relative to any particular body MJ can have a hard time landing.
  9. There are already a couple of threads about this you might like to read: http://forum.kerbalspaceprogram.com/threads/129763-How-exactly-do-radiators-work-Can-I-use-them-to-help-with-aerobraking http://forum.kerbalspaceprogram.com/threads/131295-Heat-Radiators%28-%29
  10. Yep, like the others I'd still give the 'honours' to Eve. You're not alone in finding out that Tylo is not just another step, like the other planets and moons though - the two of them definitely stand out.
  11. I'm using it in 1.0.4 and have found no problems with it.
  12. Surely not; "We choose to do these things ... not because they are easy ... but because they are hard"? *grin*
  13. Arrows won't help in the slightest, this is a problem of people not reading the manual. Which, of course, is a problem of not having a manual. Hey Squad! You know that manual I've written? The one you can't decide whether to give me screenshot copyright-clearance for? (*whisper* well actually, contracts aren't covered in that one - and they never will be if you stop me publishing!)
  14. The greater the difference in altitude between your station's orbit and your shuttle's "phasing orbit" the quicker the lower will catch up with the higher. I'd never bother to wait days (!) in LKO for a rendezvous, using a at least 75km separation in LKO (75km/150km). Changes to orbital altitude of these magnitudes only take about 100m/s dV and usually mean docking within a few hours rather than days. Look at it this way - in less than three days you could do a flyby of Mun and more or less pick where on the station's orbit you want to rendezvous rather than just waiting for 'the' right time. On the other hand, of course, that's closer to 1km/s dV so I don't recommend it (although this would make sense if you needed to do a big plane-change at the same time). When to burn, it all depends on the phase angle between the vehicles (just like optimal interplanetary transfers). Using rough figures for my example orbit altitudes: First find the orbital periods: 75km, orbital period = 31m 150km, orbital period = 36m The transit during a Hohmann transfer for rendezvous will take half an orbit, or half the average time of the two orbital periods: Average orbital period = 33.5m Transit time = (33.5m / 2) 16.75m (Transfer dV = ~59m/s * 2 = 118m/s) So, if you're transferring the lower-orbit vehicle to the higher target: The target will complete (16.75m / 36m) 0.47 of its orbit during your transit Which means you want to start when the target is (0.47 * 360) 167.5 degrees from the rendezvous-point Or, more simply, (180 - 167.5) 12.5 degrees ahead of you Alternatively, transferring the higher-orbit vehicle to the lower target: The target will complete (16.75m / 31m) 0.54 of its orbit during your transit Which means you want to start when the target is (0.54 * 360) 194.5 degrees from the rendezvous-point Or, more simply, (194.5 - 180) 14.5 degrees behind you And if I hadn't used such rough figures we might have got 13.5 degrees for both of them, but what the hell - who can 'see' 13.5 degrees by eye?! 15 degrees (1/6th of 90 degrees) is close enough and not too hard to judge by eye, so create the manoeuvre node for there and jiggle it until it fits (technical term). [sorry Slashy, but sometimes I'd rather look and see if it's close-enough than do the maths properly.] Of course, this might just be an easyish way for me because I'm a navigator and used to picturing 90 degrees, 60 degrees, 45 degrees, 30 degrees, 15 degrees (the difference between 45 and 30 also being 15)
  15. The most fundamental factor in 'shuttle' design for KSP is "Just about any other way is easier, and most of them are more efficient too."
  16. Congratulations. Once you get your head around how to design it does add a lot :-) That's the important thing. And remember, when you need a break you always have the option of just slapping some outrageous construction together and watching what happens.
  17. Because you know he'll use this as just one side-booster to a 'proper' Whackovian monster once he's happy :-) Wait 'til we see the core stack!
  18. It's certainly worth doing small launches because we all have to start somewhere. Learning how the physics of flight and space work, in KSP, is hard enough anyway though - so don't dump all the extra complications of career mode on yourself. I'm almost exciusively a sandbox player but science mode is arguably the best for beginners, if they are overwhelmed with sandbox choice, since you unlock components at your own pace. Career mode is just ... no, why would you? ... until you know what you're doing with the other stuff.
  19. Aye, there's the rub. You want "a" stage or vehicle to go through space to Moho. Design it to go to Moho, through space. You then want a launch vehicle that will deliver it to orbit in the first place. Design it to go to orbit, through atmosphere. Those things are very different and require different engines. Some are great for working in a vacuum but they usually lack thrust (LV-N or Ion) so are useless for lifting all the mass of a large vehicle into orbit. The KR-2L has both vacuum efficiency and thrust, but uses huge amounts of fuel at sea level. Other engines, however, are very good at launching things but not efficient in space. Separate stages. Separate vehicles. Separate engines. Once you've chosen your engine you might find you need more thrust than one can provide so, then, it might be worth clustering them. Do yourself a favour too - install the KER or MJ mods so you can see deltaV and TWR stats for your vehicles. Squad won't give them to us in stock because 'some beginners might be overwhelmed by the numbers' but as soon as you start designing vehicles, instead of just throwing stuff at the sky to see what stays up, you need the figures. KER is probably the most popular but MJ can also double as an autopilot for various functions.
  20. You get all the height/speed/distance awards even if you don't take them as contracts. People were previously annoyed because you would have to just do one tiny step at a time, not there's no point. My first science/career is on the pad, because you don't have any parts worth taking anywhere else. Second a 'hopper' with the flea engine, just to get away from KSC and pick up some different biome science. Third to orbit, lots of EVAs all the way around, land. Fourth, science probe to Mun - although you may well be able to pick up some easy test, science from space and tourist contracts by then too. I never bother with anything other than 'landed' (ie; on the pad) test contracts unless it's for something I was planning to do anyway. I never bother with EVA surveys (use waypoint manager mod if you want to do those) and hardly ever with the crew report ones either; again unless they happen to be where I was going. In essence, career mode is science mode unless you strap down the rewards a lot. Kerbin science isn't worth it and money is never really an issue - Go Lunar ASAP!
  21. I have associated it with the river ever since I saw its name.
  22. Doh, I still haven't answered the the proper question, have I! So far I haven't found any useful boosters that burn-out, stop going up and fall back to the ground before my vehicles are more than 23km away (or whatever the distance is). Definitely something best for horizontal takeoff, I would think, as they don't have so far to fall so are on the ground again quickly.
  23. Has a new version of KSP, built on a new version of Unity, that knows anything about Directx12, been released while I wasn't looking? (It was asked and speculated about a while ago, although I can only find a reddit link, off hand: https://www.reddit.com/r/KerbalSpaceProgram/comments/3f00gz/with_windows_10_and_directx12_around_the_corner/) ninja'd - serves me right for trying to find the link.
  24. Pilot -> SAS -> retrograde? Works for me, but then on the rare occasions I'm doing suborbital I'll be jettisoning all but the pod, parachute and science module.
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