Spricigo

well, maybe that is way I don't noticed the difference. I rely on KAC's prediction of closest approach to know If I need to burn prograde or retrograde to fine tune my intercept (several orbits ahead), doing that burn where the orbits are already tangent is what I found to be most reliable and convenient.

? I dont see it to make much difference, since you ultimately want both orbits to be equal. If the interceptor's orbit not reaching the target's orbit you want to burn prograde somewhere, if its crossing you want to burn retrograde somewhere. Ok, you may just use one of the points where the orbit crosses as your intercept point, but that just mean you burn retrograde, to match orbit, will also be the final approach maneuver.

https://m.imgur.com/a/DmGTv If you are behind/ahead your target you just need to stay in a orbit of different heigh. Lower orbits will be faster.

Now I'm curious. If let alone it will not just disapear like an uncontrolled vessel in similar trajectory? Anyway, as @The Aziz said the chances to hit anything are pretty low. Centainly it will not hit KSC if there is any noticeable inclination and in the slim chance it actualy crosses orbit with anything a brief manuever eliminate any risk.

Pretty much it.Gily landing/lifting off requires 30m/s deltaV, so small you have trouble to notice. Also, you know how when landing on Minmus thing seems to happens in slow motion? On Gily is more like a picture book.

Ok, I indeed overestimated the deltaV and the power of the thumper a bit. What I did that worked: 5° tilted east. If Im not mistaken that is yaw rigth once to you. Pre-launch:SAS OFF, throtle 100% Don't actively steer, let it fly itself. Just after the SRB burnout activate SAS and point it just below prograde,(2-3° is enough). Once SRB burned out activate next stage and raise the apoapsis to 85-90km. Cut the engine and coast to apoapsis, my rocket actualy fliped at this point but the apoapsis stayed well outside the atmosphere. Just wait until you reach 50km and you can reorient the rocket without effort. Around 65km start to burn to circularize, point 5° below horizont and watch the apoapsis in the map mod (I hope you can control the craft on map mode also in PS4) If it start to move away from your rocket reduce the throttle (or even cut the engine) you dont want to raise it too much at this time. you should archive orbit around 80-100km and have enough deltaV to complete the mission (~2km/s). I raised my orbit to 12kmx12km than changed inclination by 15° and still had 500m/s left. If the upper stage flipping bother you ad 2 basic fins neard the terrier engine and use 4 at the bottom of the SRB. You may also try a pair or hammer radialy attached to give just a little extra boost however (1) it will increase the rocket cost by 15-20%; (2)it may skew the ballance off weigh, thrust and initial angle. well, that is like to make a 90° turn, we want instead to cut the corner . Starting to turn rigth from the launchpad and progressively point to the horizont, that way we reduce drag loss (since we expose a lower area to the airflow) and our trajectory will be shorter.

Wait a minute... Did you just said you somehow managed to get into orbit (any orbit) launching vertically and not steering?!?!! What I suggested is to have a rocket, in the VAB, looking like that: Then press space and it will steer by itself. Not touching WASD or using SAS. With the correct combination of thrust and initial inclination, the first stage would be enough to put your apoapsis outside the atmosphere (somewhere between 70km and 150km) with fairly high horizontal velocity. At this point either a) wait for apoapsis and circularize or b) keep burning until your trajectory reach the desired orbit height. Any way from that point is basic orbital maneuvers * until you reach the orbit the contract asks. I will run some tests to confirm I didn't botched the calculations when suggesting the design. But seems very similar to others design I had used, and shared, without any problem. *burn prograde to raise the opposite side of the orbit, burn retrograde to lower the opposite side of the orbit, burn normal/antinormal at the ascending/descending node to change inclination.

I suppose the OP asked for help after getting enough fun not figuring out alone how to accomplish his goals. Either way, he is the one to decide what is fun in his game. @SiriusRocketry The manoeuvring part is pretty standard: launch to space, burn prograde at moonrise until you AP reach Moon Orbit (should get a encounter at this point) refine it for a low Mun Pe, .... The problem its the limitations in parts available in demo, launchpad restrictions and VAB restrictions. so you need to try to take any opportunity to make it more efficient. Everything is a luxury you should try to avoid. Winglets? Luxury! Decouplers? Luxury! Getting into LKO before burning to the mun? Luxury! Multiple tries? Luxury , mandatory.

I suppose that marginally better at AP where change in direction will be cheaper...if the relative inclination is high enough to matter at all.

Ok, that bring new possibilities: ->Are you flying with SAS on and your craft wobbling ? This may cause some disagreement between your probecore and control surfaces/engines to where your rocket should be pointed, since they are effectively pointing in slight different directions. That end in constant 'correction' input away from where you want the rocket to go. If that is the case flying with SAS off would be enough to solve the issue, specially if, as Ohm is Futile test suggest, the craft tend to follow prograde without input. ->If the parts inside the Service Bays are clipping outside drag will grab then. It may or may not be enough to make the craft flip. In PC you can see if that is the case with the aerodynamic overlay, but I don't know if that is a thing in PS4 version , so just try to keep the parts well inside the service bay, attach something at the nodes and the rest radially to that central part with enough room to not touch the sides. As other already pointed, you can reach orbit with much less than what you are using, and even a 'heavy' satellite should have plenty of fuel to reach anywhere within Kerbin SoI from LKO. While I didn't rule out an issue with that particular rocket, I suspect that some of the problem may be lack of experience in piloting/design. Don't worry, who don't know can learn and who know can teach. I suggest you to try a satellite like that: service bay with probecore, 2x z-100 bateries, [whatever scientific instrument the contract asks for] (nothing bigger then a mystery goo canister in this satellite, yet], nose cone for aerodynamic purposes, FL-t400 fuel tank, 4x solar panel around the tank and a terrier engine. That would be ~3km/s deltaV with good TWR. Below that a stack decoupler, a Thumper Solid Rocket booster and 4 AV-T1 winglets. Limite the thurst of the Thumper to 70%(no need to be very precise) Use the rotate tool to tilt the entire rocket in the VAB (lets say 10°) and add Launch Stability Enhancers. Launch it and see how it goes, don't try to steer it, just let if fly and stage as needed. If you go to orbit good, if not revert to VAB, adjust and try again. If too shallow decrease initial inclination or increase the thrust, If too steep the other way around. That will result in a functional satellite/launcher but its not highly optimized, you may stop there or keep reducing mass until you have 'just enough' to get the job done.

Start with a simple one, Basic DeltaV just make the calculations for deltaV, TWR, burn time, Isp, mass and thrust and display it next to the staging sequence in the VAB/SPH. It really only automatize calculation you may do it yourself or with an online tool, it barely change anything. OTOH you may be more comfortable with using out off game aids, like a transfer planner . Back to the topic at hand, that is how I do Duna: -Setup the CommNet, 2 satellite with RA-2 around Duna, 3 with HG-5 around Duna and 4 with HG-5 around Ike -Send the vessels to collect the science, usually a lander* for Duna and a lander for Ike. The one for Ike usually is good enough for the science in orbit. -Send tanker to refuel -Send interplanetary crew vehicle transfer vehicle, mostly to bring back the rescuees. Reusable -Send crew landers, rover and orbital vehicles for the rescue mission that appear. -Send the mining/refining/refuelling base. At this point my infrastructure is setup, I refine it as new technology is available and add some redundancy. Notice that, since you are playing in science mode, most of what I bring to Duna (or any other place) will have little or no use for you. I suggest to bring a good lander, capable of exploring 2-3 biomes at time and refuel in orbit (when you are done with Duna It will be good enough to explore Ike also) some fuel in orbit and a return vehicle (that can be the lander itself after drooping the, now unnecessary, science equipment). Also notice that if you manage to explore Duna, you will also be able to explore Gily (its even easier IMHO), and the lander design used in Duna don't need much adaptation to also work in Eeloo, Dres, Moho, Vall, Bop and Pol, granted reaching those destination is a bit more of a issue. *I have no shame.

@Ohm is Futile well, semmed the type that would flip when of prograde to me but I'll accept your analyses since you actually tested the vessel*. Still possible that the OP's vessel have a slight difference that make it want to flip but unlike with the replica actually resisting deviation from prograde. Maybe the SAS overcorrection? I'm out of ideas now.

To be fair, I didn't even aimed at his point. But yes, a mere matter of opinion. No big deal if we disagree

Yes, the side boosters also matter, that is why I counted 5 in front and 4 behind. I'm guessing the CoM is roughly between the middle tank and the bottom tank, turn on the CoM indicator in the VAB and confirm it. In any case that is the point you need to consider when looking if there is more drag in front or behind. and is not too crazy, It even fly straigth while pointed to progade. But with X AoA it become incontrolable. I would not be surprised if the adjustment needed turn out to be very small, like moving the booster a bit up/down or setting fuel flow priority.

@Ohm is Futile yes, there is amore drag in the top than in the botton, you need to consider it relative to the CoM (which in this rocket is way to the bottom): ahead of the CoM: 2 service bays, , 1 terrier, 5 fuel tanks behind CoM: 4 swinvel/reliant, 4 fuel tanks also the service bays and one of the fuel tank is more distant from the CoM so drag in those parts result in more torque .

Yep, lack of probecore prevent contracts completion. However I wondering why the contract didn't completed before decoupling from whatever was used to delivery it. If the OP just didn't waited 10s is somewhat easy to solve. But if he used a old vessel then redoing(or cheating) the mission will be required.

How much your payload weights? And what is the target orbit? (apoapsis, periapsis and inclination) The rocket seems overengineered to me. Making it smaller may allow for a more stable layout. (if nothing else, make it cheaper) Well, your rocket spin out of control because it is aerodynamic unstable. It means that there is more drag in front of CoM then behind, the rocket want to fly tail first. Notice this unstability only appear when you deviate from prograde, because that is the moment you expose a larger area (of the rocket's nose) to the airflow. So if you managed to stay aligned to prograde maybe you could maintain control. However for this you would need to have the rocket inclined East at the launchpad, and even then there is no guarantee.

Which don't mean : A) much more is necessary to cause lag. B) lag will not be frustrating if/when occur. C) such idea would improve realism a sensible amount. If you get a way to archive it, without lag, more power to you. But that was not my point.

The orbital parameters parameters are just a way to describe the orbit. Fortunately the game also draw it for us. Because, IMHO, is hard to explain without a picture.

Most of my SSTO are not spaceplanes, just saying...

No, it wouldn't. Nothing better to break the immersion than being unable to play the game because of lag.

The contract didn't broke. The option you are looking for is "activate engine" for the flea and "deploy" for the parachute. Worth notice that is the action done when staging. "run test" is only available for testing parts that don't have a staging action (like heatshields, landing gears).

So I'd say you want to run before learning to walk. Chances are that whatever you may be doing wrong with LKO only spaceplanes will also be issues with your interplanetary spaceplanes. Also in that sense, a iterative approach is usually a good way to go. Whatever you learned with LKO only spaceplanes will be useful for interplanetary vessels also, no need to reinvent the jet. Finally, decide what your objectives are (e. g. Scientific exploration of duna) and start designing. If you find a problem you can't solve yourself (e. g. difficult to land on Duna, crash every time) post a picture and ask for help.

I strongly recommend to give satellite contracts a try (and if you have difficulty ask for help) . It's a good way to practice orbital maneuvers and ship/mission design. As long the required orbits ate within communication coverage, no extra technology is necessary (but Propulsion Systems is certainly a good one for satellite contracts) For rescue missions you can just put a probecore and remove the crew of you regular crewed vessels. Don't forget to maintain a hatch accessible for your rescuees. Also, remember to remove the unnecessary crew before launch.

Personally I unlock Electricity, Precision Propulsion, Miniaturisation, Advanced Flight Control and Heavy Rocketry in that order.