cantab

Linkay? Note that this isn't exactly the same as a "regular" gravity assist, and that ITN-style transfers are not possible in Kerbal Space Program since it doesn't implement n-body gravity.

Claw pretty much covered it. Reaction wheel placement doesn't matter for overall control effectiveness (though it may matter for deformation of the ship, I'm not sure). Overall mass distribution does matter, and I just checked that with my Reaction wheel test ship. Four fuel tanks in a line, two full and two empty, turns more slowly if the end ones are full than if the two middle ones are full. And of course a typical rocket will roll under reaction wheel torque far more readily than it will pitch or yaw.

Yup, two reaction wheels gives twice the torque as one. For how quickly that torque turns you, it's more complicated, look up moment of inertia. The more mass, and also the further it is from the centre of mass, the harder.

We have a thread for showing what you did in KSP today. We have a whole forum for mission reports. Sorry, but this is just bragging, plain and simple.

Yeah, probes need electricity to control the rocket. (Manned ships don't, though they still need it for reaction wheel torque). One control you do get without having electricity though is enabling and disabling batteries, including the integrated batteries in probe cores. You can use this to "hibernate" your probes or provide an emergency backup battery. I quickly knocked up a Munar lander impactor using this technique and no power but that in the Stayputnik. Launched it with an S1 SRB for the first stage, kept the battery off except for the duration of five burns (ascent, circularisation, transfer, capture-deorbit, and landing slowing the impact speed). Of course, it's simpler and safer to put some solar panels on. But I suppose if you've unlocked the Stayputnik but not the panels in a career game you might try the hibernation approach.

Yeah, there's no orbital decay in KSP, atmopsheres stop hard at their edge which is just below 70km up for Kerbin. Nudging the station when docking is the likely cause. If you want you can always do a little stationkeeping to put it back in your desired orbit.

The challenge says it has to be at the top of the rocket. On the other hand having the rocket start out on its side or upside down, then right itself, would presumably be allowed here.

You have to balance out the extra delta-V per unit mass obtained with ion engines against the delta-V lost from not taking full advantage of the Oberth effect. And then throw in player time issue from potential long burns and part count issues from the lack of a big ion engine. More efficient, I believe, would be to do things the other way round. Use an ion engine for a series of periapsis kicks, getting the most out of the Oberth effect and raising the apoapsis each time. When departing LKO, this means getting around 950 m/s of dV out of the ions. Then use a chemical or nuclear engine for the final ejection and transfer burn, since that needs to be completed in one pass and the ions don't have the thrust. On arrival, reverse the procedure, using the chemical or nuke engine to just barely capture then the ion to change your orbit to what you want. I'd want an autopilot for that kind of stuff mind you.

In reality they are, and it was proven by Isaac Newton. http://en.wikipedia.org/wiki/Shell_theorem That said, the instability isn't "ball on a hill" unstable, but "ball on a table" unstable. If it moves, you can push it back. Of course pushing it back without breaking it up may be easier said than done.

I believe the lowest safe orbit around Gilly is 7 km up, so 20 km from the centre, giving a circumference of 126 km. The longest stock part currently is the S1 SRB, at 15 metres. You would thus need 8,400 of them to make your ring. Maybe not completely impossible, but probably beyond most computers. So you're going to need mod parts as well as modding the physics range. Remember, it's generally good to have a crack at the Challenge yourself before posting it here, to get a feel as to whether it's feasible.

No they don't. Not unless we want stock KSP to be as hard as Real Solar System KSP is. The engines only arguably need to be balanced with each other.

It may not be related, but I've got a subtle acceleration on one of my probes. Just made the ejection burn for a Mun flyby, and my Mun periapsis creeps lower by about a metre every second. Only when physics is running, so not in timewarp or the tracking station. It's very steady, not like the jitter that's common with wobbly ships. There's a chance I quicksaved with engines running slightly, but they seem off when I reload it and the acceleration continues when they're definitely shut down. I've done every change I can on the craft in terms of enabling and disabling things, as well as rotating the probe, and making and loading a new quicksave, of course closing and restarting the game, copying either quicksave to persistent.sfs, uninstalling Precise Node, running either 32-bit or 64-bit KSP (I'm on Linux), wiping my settings.cfg, and still this phantom acceleration is there.

Way off As discussed, even the E classes would just be awesome shooting stars for the night sky watchers.

Are you choosing "control from here" on suitable parts? For main engine burns it helps to have a probe core near the engines. For docking, you want to control from the docking port in question. This is especially, but not only, an issue for multi-part ships with sections docked together. Are you going really slowly? That'll make the navbal more susceptible to jitter. And, of course, have you tried closing and reopening the game? There are some other bugs that's been known to fix.

Not much today. Mainly just messing about with some lifter ideas, but the game crashed before I could test one of them And now I'm thinking of getting MechJeb for testing these things properly since I'm inconsistent with my ascents.

The Advanced Grabbing Unit is the proper name for the claw, btw.

If you will only make major burns with the lander attached, angle your engines slightly so they point through the CoM of the whole combination. If you're using multiple engines, you could probably keep balance with manual adjustment of the thrust limiters, since you only need to worry about two states: lander and no lander. You can adjust said limiters in-flight on liquid engines. Whatever your solution, you'll make things easier the closer to the centreline you can get your lander. For example if most of your ship uses 2.5 m parts, consider putting a 1.25m tank in the stack and attaching the lander to that.

I think scoring in Duna Apollo style had a cap on rover count. That should be instated, or an alternative might be to score for only as many rovers as you land Kerbals. Also, we have effectively 45 points lost for using nukes, since they're listed twice, that should be fixed. And some other scoring suggestions: Penalty for each stage dropped, not counting the lander or science probes, after leaving Kerbin's SOI. To discourage use of a multi-stage CSM, and missions that keep the launcher's third stage to help with Moho orbit insertion, since that's not how Apollo did it. Bonus for hitting Moho with the third stage, like the later Apollo missions did, but only if it was dropped before leaving Kerbin's SOI. Bonus for making a direct transfer to Moho, as opposed to a longer route that uses eg an Eve gravity assist. Bonus for landing somewhere with an amenable temperature (if surface temperature varies between day and night) or near the terminator where the temperature would be amenable (if the temperature in-game doesn't reflect the day/night cycle).

Either add a third docking port to the radial boosters allowing a tug to shift them, or use a claw-equipped tug to do the same, or mount the manouvering equipment on decouplers or docking ports then jettison it afterwards.

The solution to this is to increase your conic patch limit in the config file. If you want to do any sort of gravity assist travel that's essential.I somehow forgot before, but as it happens I did recently set up a Munar gravity assist onto a Eve assist to ultimately reach Moho. I only went by the Mun for the science, otherwise it really wouldn't have been worth it: it saved about 80 m/s from a 1020 m/s ejection burn, at the cost of spending ages setting things up right. And by ages I mean several hours of working with Precise Node and alexmoon's launch window planner, and this after I'd already worked out the desired transfer orbit and only needed to add in the Mun flyby.

What calculator and what values did you put in? Because I used http://impact.ese.ic.ac.uk/, and a 36 metre diameter dense rocky asteroid, weighing ~70,000 metric tons so much heavier even than our class Es, coming in at 17 km/s, would explode in the upper atmosphere with a force of about 2 Megatons TNT. Even directly below the explosion there would be no damage from the blast, it's far enough away. The worst that could happen is fragments denting the odd car or house.Remember that the real-world ARM is not a mission to deflect a killer asteroid, but to tow and study a small harmless one. Heck, I believe anything bigger than an A or maybe a B class is way beyond what NASA are considering moving - but then NASA do have to pay for their rockets.

PhysicsSignificance = 1 in the configuration file.

Was it really much better before ARM? We already had the 48-7S on everything small and a lot of things not small, the Mainsail as the heavy lift engine, the LV-N streets ahead for big interplanetary ships (unless you have the patience of a saint in which case you use the ion engine), asparagus as the One True Staging, I could probably go on.

Just look at a delta-V map. From LKO there's very little difference in what you need for the Mun and for Minmus, so there's very little delta-V that can be saved. In the wider solar system the differences are bigger, likewise I believe in the Jool system. And if you want to make a big inclination change a gravity assist gives big savings. Why not try what I did. Throw together a little probe with a few hundred m/s of delta-V, put it on an Eve or Duna intercept with the previous stage, and see where you can get from there using just little course corrections and the energy of the planets around you.

Like Fenrir said, in map view hit tab until it says you're focussed on the planet you want to encounter, then zoom in with the scroll wheel. There should be your flyby. And if you need to make small adjustments with a big engine, right click the engine and drag the thrust Limiter down to 5%. It acts as a multiplier so 10% throttle on a 5% limiter gives you 0.5% of the usual full throttle.