maltesh

A potential simplification; Since both departure planet and target planet are orbiting the same body, you can use Kepler's third law to find the ratio of the transfer time to the period of the destination planet without calculating the periods explicitly, or using the gravitational parameter in that particular step.

So yeah, gave it a shot. Basic asparagus-staged setup, with a nova punch 2M RCS tank that I wound up mostly ignoring. Went for an orbital radius that isn't on the chart, either; 150 million km or 1 AU, and circularized. I then ran the numbers to try to figure out where Kerbin would need to be for me to burn for a return. T THe result I got was that Kerbin needed to be about 29 degrees ahead of my current position, so I eyeballed it, and burned to Hohmann back down. One Kerbin year out, I knew I had a problem. Kerbin was at my Periapsis, but it would get there about eight days before my spacecraft did. What I should have done at that point was to speed up (pushing out my periapsis and apoapsis), then burn in the Radial- direction (pulling in my periapsis back onto Kerbin's orbit) to bring the intercept time down to one Kerbin Period. I did not do this thing. As a result, Keerbin got to my periapsis eight days before my spacecraft, and I was Krakening too violently to try to circularize on an inside track. Neverthelless, transfer time was about 700 days, and I was eyeballing it without being able to veiw my orbit from directly above Kerbol. Missing by eight days is pretty good in my book.

Fair enough. Still, I'd balk at spending nearly two hours at 100k time running the nearly 20 years that would be the average catch-up time for an inside-track attempt on a planet 20million km from Kerbol, and assuming an SOI the same size as Kerbin, assuming you didn't go for a specifically-timed launch window. Said launch windows, for a planet 20 million km out, would occur about every 241 days. Hohmann transfer time: 73 days.

I suspect you'd be shocked by how long riding the inside/outside track can take given interplanetary distances and the typical size of planetary SOIs, even given 100k time accelleration. And the farther out the planet, the flatter the rotation curve, and longer the periods, so the slower this will go.

I'd expect a planet to be at least a hundred times further from Kerbin than Minmus at closest approach, and would wager on it being significantly further.. At any rate. here: https://docs.google.com/document/d/1IX6ykVb0xifBrB4BRFDpqPO6kjYiLvOcEo3zwmZL0sQ/edit Note that the angle produced will only really work for circular and near-circular orbits of the destination objects, and even for those, you're still going to have to do some maneuvering to find that SOI on final approach. I would recommend that any potential planetary explorers do the "Leave the Kerbin SOI, orbit Kerbol at least once, then return to Kerbin" mission to get a feel for what finding a planetary SOI at interplanetary distances will be like, using the current instrumentation.

Reaching all the targets seem pretty fairly doable in KSP, even without triggering the fuel bug. The hardest circularization target from Kerbin's 13 million km orbit would be the Venus sized orbit, assuming a Hohmann transfer. It should be noted that a Hohmann trasfer to the Neptune orbit will take more than a day on 100,000x speed. Enough fuel to land and return, aye, that'd be quite tricky without fuel or personell transfer.

Yes, many people have gotten farther, it's pretty much a matter of how long you're willing to let the flight continue. In the current version of the game, there is no place else to go. There is nothing else in the universe to put an exterior boundary on the Kerbin SOI, so you will never leave it on your current course. You are pretty close to your hyperbolic excess velocity for your described orbit and if you don't decelerate, your velocity will never fall below 16,394 m/s. Edit: Not saying your achievement isn't impressive, though. By my calculations, if your ship didn't leave the Kerbin SOI moving at about 12km/s, it almost certainly was capable of doing so. (Assuming you didn't bi-elliptic sundive, that is)

Okay, here we go, using two separate Elliptical Orbits. h1 is the average of the periapsis and apoapsis altitudes on Orbit 1. Semimajor axis of orbit 1 is h1 + r h2 is the average of the periapsis and apoapsis altitudes on Orbit 2. Semimajor axis of orbit 2 is h2 +r p1 is the period of orbit 1. p2 is the period of orbit 2. Using Kepler's Third Law of planetary motion, Units don't matter at this point, as long as you use the same units for all distance values, and the same units for all time values. Units will matter later. And now we solve for r. That will work. And if you follow the link above, and plug in the appropriate numbers, you'll get an answer. In fact, you'll get three answers, two of which are complex numbers, and one of which is a real number, which will be the radius of your planet. Let's say you don't want to directly solve for r because all the radicals give you a headache and/or your calculator/spreadsheet deals poorly with imaginary numbers. Let's use Newton's Method, instead. (Hello, calculus, how have you been?) Let's define a reasonable guess at the radius of the planet as r0. We'll define two functions: and And using newton's method... So if you put in your initial estimate, r0, you'll get r1, which will be a value closer to the actual radius. Put in r1, you get r2 and so on. In a few iterations, you'll have a good, solid value for the radius. This is probably more work than you wanted to do, admittedly. At any rate, once you've got the radius, you can find the semimajor axis of one of the orbits. a = h1 + r And knowing the period (p) of that same orbit... (It is now extremely important that all length units be in meters, and all time units be in seconds, so do the appropriate conversions if you haven't yet.) We can find the standard gravitational parameter, μ . Divide μ by the Newtonian Gravitational Constant , G = 6.67 x 10-11 Nm2/kg2 and you'll have the mass.

I almost invariably go with tripod landing gear, but I also tend to design for as wide a footprint as I can, for that higher stability. This was my most recent nearly-stock Mun lander stage: I suspect I could have landed it nearly anywhere on the Mun without worrying about local slope. In retrospect, I should have brought more fuel, as the half-tanks turned out to not be enough for even my standard maximum-efficiency return, and I had to go to the RCS to bring them back. Regardless, I would say test-deploy your lander on the pad without a lifter, and mount those legs as high as you can without risking engine damage. You can mount landing legs on the stock radial engines; this will also help to spread the wide footprint. Could have putthe legs a bit higher on the body, though.

You don't have to use circular orbits. You can use two elliptical orbits instead. (Which, because of the way the map screen works in the paid version, means you can do it easily with one spacecraft, and besides, nothing manually flown in KSP winds up in a true circular orbit, anyway.) Knowing the period and apse altitudes of two different orbits allows you to solve for the radius. Knowing the radius allows you to solve for the mass. When I have more time, I'll sit down and rerun through the math for that. As I recall, I think the first part required me to solve a cubic equation, and I wound up going to Wolfram Alpha for that when measuring Kerbol. Edit: Thinking about it further, a reasonable person would probably use a numerical method such as Newtons's Method or the Secant method to solve for the first part. The closed-form result is a lengthy nightmare.

You'd probably have to be moving faster than Kerbin escape velocity to not bleed off enough velocity to deorbit at 30km (assuming you didn't do a powered orbit, as above) It's also possible to put things into stable, unpowered orbits as low as about 22km above Kerbin...if they never get taken off rails. This is easily achievable with persistence file editing, but since the game doesn't let you save while in the atmosphere, I am hard-pressed to think of a flight plan that will leave a spacecraft in Kerbin orbit with an apoapsis that low. Possibly ejecting pilotable debris and ending the current flight before atmospheric drag slows the new spacecraft too much.

"Munrise" doesn't measure 90 degrees. In LKO, the Mun rises at approximately 30 degrees below horizontal, or about 60 degrees from the direction directly towards the center of Kerbin.

If you're going for the Hohmann Transfer, figuring the angle is fairly easy for objects in circular orbits. You've just got to remember Kepler's Third Law. Define at as the semimajor axis of your transfer orbit, equal to (starting orbital altitude + final orbital altitude + diameter of body being orbited by everything)/2. Define af as the semimajor axis of the orbit of your target object. tf =0.5 * (at/af)1.5 (Edited to fix mistake in calculation) tf is the fraction of your target's orbital period that will pass during your Hohmann Transfer travel time. Your transfer window is thus when your target object is tf of its orbital period away from the point directly opposite your starting point. For instance, Hohmann transferring from the Mun to Minmus, tf = 0.25, and you should launch directly into a Hohmann transfer when Minmus will have to travel 90 degrees along its orbit to get to a point directly opposite Kerbin from where the Mun is at your time of launch.

Because of the way orbital periods work, you can use the Munrise Burn Method to get you to Minmus. Basic Elements of Munrise Burn: 1. Get into eastward Low Kerbin Orbit (aim for about 100km circular orbit, but the method is extremely forgiving with the Mun) 2. Wait for the Mun to rise over the horizon. 3. Burn in your direction of velocity o until your apoapsis is on or about the Mun\'s orbit. 4. Coast to apoapsis, and wait. The Mun will be along shortly and sweep you into its large SOI. It\'s basically the most fuel-efficient method to get you to the Mun, and puts your spacecraft on the surface (assuming you know what to do from there) in about 7-9 hours from launch. The MinmusRise burn is basically the same; you only need to be going about 80 m/s faster to put your apoapsis in the range of Minmus\' orbit than you do in the Munrise Burn, and 1. Get into eastward Low Kerbin Orbit 2. Wait for the Minmus to rise over the horizon. 3. Burn in your direction of velocity until your apoapsis is at Minmus\' orbital radius. 4. Coast to halfway out or so, and do a plane-change that puts your apoapsis on Minmus\' orbit. You may also need to adjust your velocity a bit to find the intercept, but with v0.15\'s patched conics, it will be fairly obvious when you do. 5. Coast the rest of the way, get swept up into Minmus\' SOI, and land. Thus is ultimately both more time-efficient (putting you on Minmus in about 2 days from launch), and fuel efficient than using a Munar slingshot. As mentioned before, you only need about 80 m/s more to burn into a Minmus intercept than you do into a Munar intercept from LKO, and if by some miracle, you don\'t manage to spend more than that in delta-V adjusting your Munar flyby trajectory to give your exit path an apoapsis Minmus orbit, you /will/ spend more than that in delta-V circularizing at Minmus\' orbit As for why I advocate doing the plane-change late in the transfer; The faster you\'re moving, the harder an orbital plane change is, and the farther out you are, the slower your spacecraft\'s moving, and at 30,000 km over Kerbin, you\'re moving pretty darned slow. You don\'t have to orbit in the same plane as Minmus to intercept it, you just have to cross the plane at a point where Minmus is at the time you cross it.

The altimeter already does that.

Nrml+ only points your spacecraft north if your orbit around an object is counterclockwise when viewed from above north pole the Mun, and your orbit is near-equatorial. Most of my orbital insertions around the Mun and nearly all of my mechjeb-assisted orbital insertions to Minmus result in orbits that are going in clockwise directions when seen from above the north pole about those moons; in that case, Nmrl+ points in a southernly direction. If you were to take your right hand, and curl the fingers in the direction you\'re travelling in your orbit, and stick your thumb out, your thumb points in the general direction of Nrml+

I\'m sorry, I can\'t tell from your response, and don\'t want to assume. Did you attempt the provided control experiment? Edit: Figured I\'d try myself, full-on-burns, all the time, using a spacecraft that consisted of just the last stage of yours, As I neither have your .craft file, nor am I particularly good at flying spaceplanes, starting from a 100km circular orbit to take advantage of the Oberth Effect. Waited until I crossed the Midnight line, and did a full on burn until my projected escape path put me into an orbit with an apoapsis of 19GM from Kerbol. I then coasted out to that apoapsis and circularized, again with full on burns. Fuel at start 400, fuel at end, 117.1. A little over 2/3 of a tank of fuel. Could have gone far farther, and circularized much higher. Probably could have escaped Kerbol.

Take the same spacecraft, and put it in a low circular orbit around Kerbin (~100km or so). Wait until you cross the midnight line, and then burn prograde. Keep burning until the patched conics show that your eventual apoapsis in Kerbol orbit will be at 19Gm. Then shut off the engines, coast out of the Kerbin SOI, into the Kerbol orbit, out to the 19Gm apoapsis, and circularize. Compare how much fuel you have when you do so . Edit: Admittedly the rather egregious low-throttle fuel-efficiency bug will muddle the results significantly, if triggered. It\'s capable of eking dozens of km/s of delta-V out of a single fuel tank.

I think stuff on rails will happily orbit at any altitude higher than ~21km over Kerbin. Perhaps I\'ll try editing an atmospheric Impossisat into a 25-30 km Kerbin orbit.

Kerbal abuse is a serious problem that afflicts thousands of players daily. You can help. Abuse more Kerbals today.

I would not be surprised if at least one of the planets in the update is perfectly placed at UT = 0.0 for a Hohmann Transfer from Kerbin. All the planets of the solar system orbit very close to the ecliptic plane. Significant plane changes at several km/s velocity are /extremely/ fuel-expensive.

To put your spacecraft in orbit within Minmus\' SOI, REF = 3. A detailed discussion of KSP orbital parameters is in the Google Doc linked in my signature.

Getting close enough to Kerbol that you can circularize and use the Planetrise burn method is ridiculously fuel-expensive. You\'d be looking at circularizing at about 10,000 km altitude over Kerbol, and you\'d need a spacecraft capable of over 120km/s of delta-V to circularize that low, and burn out of that orbit again.

Gravitationally slingshotting around the Mun is not worth it for interplanetary travel. To get the best velocity increase benefit for a gravitational slingshot you have to be moving very slowly relative to the Mun, because the velocity you get from a gravitational slingshot comes from the Mun bending your travel direction closer to its travel direction when you pass through its SOI. If you are moving slowly enough to get a decent gravitational boost from the Mun, you\'ve also let Kerbin\'s gravity drag rob you of a heck of a lot of the velocity that you could have carried out of the Kerbin SOI by doing all your burning in LKO and taking advantage of the Oberth effect there. As a result, you\'ll wind up using more fuel by going for the Munar slingshot. Munar slingshots are good for getting to points in the Kerbin SOI or in very nearby Kerbol Orbit when on a razor-edge fuel budget, and not much else.

Your engines are too far from the Kerbal. If you brought them closer (like, say, half the height of a Kerbal above his head), he\'d pop in short order. The game deletes any flying/falling object that is deep in the atmosphere of Kerbin (below about 21 km) and more than 2.5 km from the active spacecraft. One of the big new engines can easily toss a Kerbal about 4 km, so you need quickly switch to the Kerbal before he leaves that range if you\'re firing them from the launchpad.