capi3101

Loads today - got a Joolian encounter with my pathfinder probe, but the encounter is two million klicks out and its only got 123 m/s of delta-V left. Might have to settle for just a close pass on that one. Launched another probe towards Eeloo - got within 400,000 kilometers of it, still no encounter. Hell Kraken ate both of my craft headed for Duna; that was annoying as hell. At least, I think it was the Hell Kraken - it had most of that one's characteristics. What really sucks is that I had one of those down to a 16,000 kilometer pass...

I've used a combination of a Skipper with four LV-T30s set radially on the bottom of Tail Connectors as a Mainsail substitute - it'd actually be a superior combination if it didn't weigh so much more (slightly more thrust, much improved Isp). Yeah, I love Skippers too. Part count matters for me, though; trust me on that one.

Yeah - what you've got there is a variant on a "Phallus 7" (if you'll forgive me for being crude) - a long and narrow rocket with a very high center of gravity. Most folks design a lander like that (Chute, Mk-1 Command Pod, FL-T400 tank and LV-909 with 3-4 lander legs) for their first trek out; this one's larger of course, but essentially the same idea. The problem is in the design; it's easy to tip this kind of rocket over. Here's how I'd go about fixing it: 1) Dump the big RCS tank - I'd wager you're not using that much RCS anyway. If you're not comfortable with doing away with RCS completely, I'd humbly submit you use 4-6 of the small Roundified tanks (read: I recommend zero, two at the most if you must have some). You'll save mass (and therefore improve your delta-V). 2) Consider swapping out the Mk1-2 Command Pod for three Mk1 Lander Cans. Again, there's a mass savings there. 3) Here's my key suggestion - swap out the X200-32 tank for four X200-8 tanks, and set each one radially outboard of the X200-16 as low as you can attach them. Place your lander legs on those tanks, and run fuel lines from those outboard tanks to the central tank. That widens and shortens your stack while keeping the same amount of fuel. I'd also humbly suggest getting closer to the Mün's surface before you burn to deorbit. You can safely orbit as low as 14 km above the surface, and you won't pick up as much velocity in the process of your deorbit. You'll still have to burn a good deal to bring your horizontal velocity to zero (you've got a heavy ship there, that's unavoidable), but it should save you some gas. You only need about 850-1000 m/s of delta-V to make it back to Kerbin from the Münar surface (assuming you acheive Münar orbit first). Assuming you dump the RCS tanks, your "bingo fuel" level is therefore just over 200 liquid fuel units; if you go below 210, hit space or plan to not return from the Münar surface with that flight. With the RCS tank, "bingo fuel" is 300 fuel units. If I'm doing the math right, you start with 2430 - so it won't look like you've got that much left either way. Good news is that you don't need all that much.

And that's helpful to me...........how? My apologies for the 'tude; it's been a rough day.

I figured as much. Had to try, right? Calls for a change of plan... Been trying to figure out how to get out there; so far my attempts to solicit a flat delta-V target for Vall for the transfer stage from the KSP community have met with the usual "well, here's my craft, it's more awesome than yours" responses. I suppose the whole point of a challenge is the fact that you can do it however you wish and it's supposed to be, you know, challenging. Still...

Ah - okay...looking back at your lander design, I see that you've got a very basic craft (what I sometimes call a "Phallus 7", if you'll forgive me for being crude). Most folks start off with a design like that - a Mk16 Chute, a Mk1 Pod, an FL-T400, an LV-909, three or four lander legs and a ladder (with panels and batts later as they started to be required). With that design, your "bingo fuel" level is 80 Liquid Fuel Units remaining; once you're there, hit space or plan on not returning from the Mün. Don't start a steady burn until you're around 5,000 meters. Better yet, go IVA and watch your radar altimeter gauge. When it starts to twitch, you're 2500 meters over the surface. Keep your speed around 100 until you're a thousand meters AGL, then start burning. 1 m/s per ten meters AGL is a good rough guesstimate as to where you want your speed, at least until you get a better feel for your craft. Be sure to use the radar altimeter - your stage screen altimeter is practically useless when it comes to landing (as you no doubt know because you say you've stuck the landing before). Now, since you've got fuel lines, let me make a suggestion: ditch the FL-T400 in favor of an FL-T200 centerline with three more FL-T200s outboard, attached radially. Run fuel lines from those outboard tanks to the centerline tank and attach your lander legs to those outboard tanks (use two lander legs if you wish). There are a couple of net effects there: 1) You've effectively doubled the amount of fuel you had available to you (basically you've got the same amount now as an FL-T800, the long small tank) 2) You've widened and shortened your craft, which means it will be less prone to tip over on you when you land. As undulating as the terrain is on Mün that can be very important.

Ten million dollar question then - what if you have a craft that lands like a lander, but then you put the lander legs up and - surprise! - it's a rover too...

No, there are no restrictions on the lifter (for once). Just the total mission payload - I don't play with Kethane, so I'm limited to a total mission payload of 320 tonnes. Sounds like a lot until you consider that the fuel to get out to Vall has to be included in that figure. I happened to do this last night in a different save game - I set up a craft that would deliver six satellites to Jool, with the intent that each satellite would then make its way to one of Jool's moons (except for one, which would remain in Jool's orbit). The original craft would then plunge into Jool's atmosphere. My first real try at using Protractor. I think I mucked it up - burned with theta and adjusted phi at zero along the prograde until the closest pass number for Jool started going back up again, then killed it - my apoapsis at that time was somewhere in the neighborhood of Dres's orbit, with no Jool encounter indicated at all... I do understand that the most Kerbal solution is to just go for it; I'd still like a target range of figures that doesn't vary by over 7,000 m/s.

That 2.2 TWR you read about was referring to Kerbin launch only - it corresponds to an ascent along the terminal velocity curve, which is important because it optimizes fuel efficiency during the launch. Once you're up in space, TWR takes a back seat to delta-V in its level of importance; up there you need to be efficient, not (necessarily) fast.

Sent a probe delivery system out in the direction of Jool this evening using Protractor for the first time. Don't know if I'm going to make it yet or not.

Howdy, all. I'm going to be doing an entry soon for the Vall Exploration Challenge. Biggest problem I've got right now (as per my signature's salad bar) is that I've never been out towards Jool before. Now ordinarily, I'd just play it conservative and build a transfer stage that has double the amount of delta-V that it would take to get out there according to the delta-V maps (~14,000 m/s), but the challenge in this case has a mass limit that I'm adhering to, and the amount of payload mass I'm calculating is quite a good deal lower than I'd like it to be (just shy of fifty tonnes, but a I know I'll be hauling 35 tonnes of probe landers with me, that leaves precious little for the obligatory "manned lander with as many Kerbals aboard as you can muster" requirement. Especially if I want to bring along a 'hound for good measure. So, Joolian veterans: 1) How much delta-V does a trip to Vall and back really take? 1915 for the Jool intercept, 2630 to orbit Jool at 150km with inbound aerobraking possible, 1970 for the Vall intercept, then 790 for a 15k Vall orbit - that's what the delta-V map says - for 7,305 total. Since I can aerobrake inbound, does that become 4675 instead? The trip back is also really getting me; I've read you can make it back to Kerbin with just 2800 or so. 2) How should I go about handling the transfer? I've heard you can aerobrake at Jool to put your orbit near Vall's; how much delta-V does that save? There's too much variance in the numbers - I'm getting anywhere from 7500-14600 m/s; the lower it is, the more payload I can bring. So what exactly should I plan for? Any and all assistance is appreciated. And before anyone says anything, I don't use Mechjeb and won't until I return a Kerbal from Eve. I do however use KER and Protractor, and I am aware of the aerobraking calculator website.

Now, now, we all know the cake is a lie......

Tell me this now...my probe is still on its way out towards Jool...... Hoping to get this one wrapped up over the weekend; the Vall Challenge has started to distract me.

Ah - a trainer lander. I remember those from my demo days... Yes, you can upright the craft, but it's tricky; I'd definitely recommend a quicksave first. Turn SAS off, then fold up your gear. Follow celem's advice and use RCS to get it upright. If you've got four RCS blocks on that pod, you should have sufficient thrust available to do it. Next time you build a Mün lander, use four FL-T100 tanks instead of an FL-T400. Set one center, three outboard, stick your lander legs on the outboard tanks and hook fuel lines going from the outboard tanks to the center. You'll widen and shorten your stack that way, which means you'll be less prone to tipovers like that one. Plus it's the same amount of mass - no change in TWR, no change in available delta-V that way.

I don't use MechJeb personally - but I plan to install it if I ever successfully return a Kerbal from Eve. I'd suggest you use it for whatever parts of the game you find tedious to do by hand, and not use it for whatever parts of the game you find fun. I've also heard folks have had issues with its calculation of launch windows and that it occasionally botches landings; I wouldn't use it for stuff I know I could do better by hand. I use KER for readouts already; some of the autopilots in MechJeb (like the ones that reorient your ship for radial and normal burns) look very attractive. And don't be afraid to ask questions - the only dumb question is the one left unasked.

Built an automated probe lander/rover combo to take out to Vall. Drove it around on Kerbin, even flew it to the top of the VAB and drove around up there a bit. It's a bit heavier than I'd like and its steering is more than slightly over-responsive, but I think it'll do the trick. I should probably mention that the intent is to send ten of those things in that general direction. My first trip to the Jool system... I must say I hate the very small rover wheels. Did a Minmus mission, for Science! Not as much as I'd hoped!!! On the plus side, I've finished unlocking all the Tier 5 techs. At this point I need to make a beeline for Mainsails and PB-NUKs.

OP: I'll have to check your math on your delta-V; for now I'll take your word for it. Presumably you've used atmospheric Isp for the bottom two stages and vacuum Isp for the top two, right? So...flight profile. Straight up to 10k, then 45 degrees elevation on course 090 and then follow the navball as it comes down. When you're more than 55 seconds to apoapsis, burn along the horizon until your projected apoapsis is where you want it. kill your burn, wait until your craft is above 70k, then plan a maneuver at apoapsis that will circularize the periapsis. All the while keeping the craft's gee meter near the top of the green zone and throttling back as necessary (to keep the craft around that magic 2.2 TWR). Start your burn for circularization when the time to the maneuver node equals half the total time of the burn; minus a second or two is still fine. Is your flight profile to orbit anywhere close to that?

The intercept nodes indicate the positions of the controlled craft and its target at the point at which they will have their closest approach to one another in their respective orbits. They will only show up if the orbital paths of the two craft come within close proximity to one another, which is why you need an -apsis of the control craft to be somewhere in the neighborhood of the orbit of the target craft. Now (and here's the kicker), it doesn't really matter where along the target craft's path the control craft's -apsis is, it just matters that it's there. You can't adjust the intercept nodes if you can't see them or if the game doesn't recognize them.

Debating as to how early I want to go at the moment. I've been trying to finish up the Constellation Challenge, so my career game has actually been lagging - I only unlocked nukes last night. Should I go ahead and max out the tech tree first, or just go? Might be really interesting to just go, what with the Skipper being the most powerful engine I have available. Strike that - my initial plans call for RTGs and they're a final tier tech. Going to have to do some more Mün missions, looks like.

Check the brakes - when I can't get a rover to move, that's usually the problem. If the brakes are off, make sure the wheels are getting power. If they are, try putting the controls into docking mode and hold down the "W" key on the keyboard. If nothing happens then, well......time to try SCE to AUX.

Here's how I'd handle that situation: assuming A is the source/control craft and B is the target craft. First, I'm assuming the nodes are zeroed out - that's very important. If the ascending/descending node is not zero, a burn needs to take place to make it that way. Assuming both craft are on a course where east (090) is prograde, a northward burn at the descending node or a southward burn at the ascending node will do the trick. Zero is where you want it; if you can manage to get it to say "NaN", you're right on the money. I'd then push A's apoapsis on up to 110k (i.e. roughly the same altitude as B's orbit). You should then get the intercept chevrons. Plan at the apoapsis next to push the periapsis down closer to Kerbin and watch what that does to the intercept point. If it shortens it, great - just make sure you haven't pushed your periapsis below 70k (the edge of the atmosphere). If it lengthens it, then go the other direction (I'll tell you right now that that shouldn't happen). Do the same thing at periapsis - adjust the apoapsis. At some point while you're doing all this you'll get close and find a "break even point", where it won't decrease any more; that's where you plan to burn. Expect to muck it up - H/N on RCS does wonders for fixing that sort of thing. If after a while you find planning nodes at neither the apoapsis or periapsis helps, try one somewhere in between.

Here - this may be helpful. It's out of date, but there at least information on what the distinction used to be. In RL, a Reaction Wheel is essentially just a gyroscope. When the craft needs to turn, electric motors change the orientation of one of the three axes on which it is spinning; the effect of precession then works on the entire spacecraft as an "equal and opposite" reaction (i.e. Newton's Third Law). The end result is that the gyroscope returns to its original equilibrium, while the spacecraft's orientation has changed. To experience the effect of precession yourself, take a bicycle wheel and grab it by any handhold you can place along its spinning axis. Hold it so that it is upright - parallel with your body (I suppose perpendicular would work too but parallel's easier on your body). Get somebody else to get that wheel spinning - get it going as fast as possible. Once the wheel's spinning, try to turn it; you'll experience a definite counter-force that will try to turn the wheel back to its original position. You can hold it in the new position, but it takes constant force. That's precession, it's how a gyroscope works, and in turn it's what a Reaction Wheel in KSP is based upon. You mean the Large ASAS module, right? Both the Inline Reaction Wheel and Inline Advanced Stabilizer (i.e. the old SAS and ASAS modules) have the same mass - and yes, the Large ASAS module is less massive for some odd reason. All three work the same way nowadays, and with the inclusion of SAS capabilities with the command pods, all three are legacy parts - largely redundant.

Münar midlands for science!! Unlocked enough now that I finally have NERVAs. Duna, here we come. Been seriously neglecting my career game, what with all the stuff I've been doing for the Constellation Program challenge. Speaking of, I also reviewed my sandbox flights in progress to see if I had anything else to do before warping to the next Duna transfer window to wrap up my Constellation entry. Protractor's telling me I've got a Jool window coming up first, so I'm thinking of getting something ready there. I could use a practice run out that way, to say......oh, Vall maybe.

The distinction between the two (SAS and ASAS) went away in 0.21; right now there is no functional difference between the two. That will change in later versions, no doubt.

The surface atmosphere on Duna is roughly the same as it is on Kerbin at 10,000 m, when most folks make their gravity turns. So in general, you're okay to begin your gravity turn as soon as you're maybe 1,000-2,000 m up at most (high enough so that you know you're not going to fly into terrain). Turn in the general direction of your return stage's orbit around Duna (or 090 if you're going for direct ascent). Shoot for no lower than 50k. 1,300 m/s; otherwise it's just like a launch from Kerbin.