A Very Basic Space Program | RSS/RO/RP-1

[seyMonsters]

A Very Basic Space Program | Episode 97 | KSP RSS/RO/RP-1

 

[jimmymcgoochie]

When you decouple something that only has stage 0 and it isn’t the root part, you usually have to add an empty stage 1 before staging or it doesn’t work.

Just use the “fine tune closest approach” mode in MechJeb maneuver manoeuvre planner to fix an inaccurate transfer burn.

It’s often more efficient to launch to a different LAN than the Moon for an interplanetary transfer, use the Transfer Window Planner fork on CKAN and you could save a lot of delta-V.

[seyMonsters]

A Very Basic Space Program | Episode 98 | KSP RSS/RO/RP-1

 

[jimmymcgoochie]

The Jupiter probe needs to change its orbit at apoapsis where orbital velocity is low enough that ~100m/s can make a noticeable difference, not at periapsis where it’s barely a drop in the bucket.

500x500km!? If you’re going to launch to that altitude do 500x150 and then circularise at apoapsis, otherwise ascent guidance will try to do it all in one burn and run out of fuel by being inefficient.

Oh look, unreliable engine is unreliable, again… Use a proper engine like the AJ10-advanced or LMAE instead, those actually work.

[seyMonsters]

A Very Basic Space Program | Episode 99 | KSP RSS/RO/RP-1

 

[jimmymcgoochie]

I think RO/RP-1 has added the RD-254, the vacuum-optimised version of the RD-253. It’s about three times as powerful as the RD-0210 and a bit more efficient too plus very high reliability. If not it’s in CH4/ROEngines Extended.

TestFlight engine failures are permanent- if it fails, it’s dead (unless you cheat and reload a save afterwards ); TestLite allows you to restart engines if they fail in some circumstances, TestFlight does not.

I think the station problems might be due to some parts being designed for nitrogen pressurisation at 1atm (101kPa, the larger station modules) and others for oxygen pressurisation at 0.3atm (30.3kPa or so, the D-2 capsules and smaller station modules) and since it was only oxygen pressurisation that was running things got weird. Don’t EVA from a large part as it vents the whole thing, and don’t turn habitats off as it wastes a lot of O2 trying to depressurise it later. Probably best to destroy it and build something new without those ugly, heavy docking ports in the middle.

Edited November 24, 2022 by jimmymcgoochie

[seyMonsters]

A Very Basic Space Program | Episode 100 | KSP RSS/RO/RP-1

 

[jimmymcgoochie]

I think you need to check the burn time on both of those METAL probes- the smaller one is using an engine that might not last the full duration, while the larger one has a burn time of 40 minutes which just won’t work for Mercury, cosine losses will eat the delta-V. You should also check the power production down at Mercury and adjust your solar panels accordingly, you don’t need nearly as much panel area that close to the Sun and every gram counts when going to Mercury.

A well-insulated kerolox stage using something like the RD-58 might be a better choice for a Mercury capture stage as it’s significantly more efficient than any hypergolic stage and doesn’t need the heavier HP tanks so will be lighter too; it’s possible to use hydrolox for Mercury capture as I’ve done it a couple of times, but that requires much MLI and radiators.

Spoiler

This is how I did it in my current RP-1 save:

1500 ton rocket, 25km/s vacuum delta-V at launch.

Bonus fuel from stage 2 plus all of stage 3 and some of stage 4 (all hydrolox) needed for TMI burn.

At this point I was 300m/s short of orbit, but that was including the RCS propellant for stages 4 and 5 which I burnt as the engines fired.

And just crept into orbit on the last dregs of fuel, using only the RCS because there wasn’t enough left for the generic thrusters due to residuals. Also note the tiny solar panels which are more than enough to power everything.

 

[seyMonsters]

A Very Basic Space Program | Episode 101 | KSP RSS/RO/RP-1

 

[jimmymcgoochie]

That was EARTH space low data, not Titan. Contracts are glitchy though, enjoy the glitch in your favour for once.

When doing flybys of moons you should adjust your orbit at apoapsis where orbital velocity is lowest and the little delta-V you have makes more of a difference- NOT periapsis where it’s only a tiny fraction of orbital velocity around a gas giant. Put your node on the blue orbit (before the next flyby) and use the gravity assist to your advantage, not the purple one which is after the next encounter and even further out of alignment.

[seyMonsters]

A Very Basic Space Program | Episode 102 | KSP RSS/RO/RP-1

 

[jimmymcgoochie]

You were 0.6% away from that Astris not lighting at all! Get rid of it! An AJ10-Advanced or similar would be a much better choice, or just a cluster of 2kN generic thrusters and enough RCS to balance any asymmetric thrust.

Also PVG is better suited to atmospheric ascents, whereas where you landed would have worked as a direct ascent to a return trajectory; less efficient but faster, point up and keep going until the trajectory hits Earth’s atmosphere.

That Saturn probe is exactly the sort of mission you want to keep going as long as possible- as many flybys as you can get out of it for maximal science and then crash it into the atmosphere when the fuel runs out. While the velocity of Discovery 14 is probably too high to survive an encounter, Titan is a pretty benign place to aerobrake and land due to the relatively thick atmosphere and low gravity, though the very high upper edge of the atmosphere mean it takes a while to get down to the surface. Well worth sending a dedicated mission.

[seyMonsters]

A Very Basic Space Program | Episode 103 | KSP RSS/RO/RP-1

 

[jimmymcgoochie]

That first probe isn’t making orbit. Not even close. Stock SAS also wasted a ton of RCS fuel rocking side to side in the roll axis, use MechJeb instead as it doesn’t do that.

The reason the second stage is having to climb so much is probably because those solid boosters aren’t being decoupled after burning out. It would also be worth checking the PVG settings and reducing the pitch rate a bit so you get more altitude and so have more time to accelerate to orbital velocity.

As for those course corrections- let MechJeb take the strain, it’s usually more efficient. You may want to consider adding a small, cheap UHF antenna to your transfer stages so you can control them and plot a correction node right away.

[seyMonsters]

A Very Basic Space Program | Episode 104 | KSP RSS/RO/RP-1

 

[jimmymcgoochie]

You can change to a polar orbit from anywhere, but with a high apoapsis after capture it’ll be really cheap to do so at the apoapsis.

The weirdness with the capture burn is because the stock delta-V system doesn’t play nice with RO and has actually been disabled in more recent versions of RO.

The wobbly RCS is a new one, but you could have kept it pointing in the right direction with a bit of spin-stabilisation. The previous stage hit the residual limits of the SPS engine, if those smaller tanks hadn’t been there it would just cut out earlier. Moral of the story- don’t cram all the science into the middle of the craft in one big limp, spread it out and use the CoM offset tool in procedural avionics and RCS Build Aid to balance it out.

And as for the spinning: it’s nothing to do with engine issues and everything to do with not shutting down the engines until the node was over burnt, with MechJeb dutifully trying to point back towards the node that was now behind it.

Edited December 29, 2022 by jimmymcgoochie

[seyMonsters]

A Very Basic Space Program | Episode 105 | KSP RSS/RO/RP-1

 

 

[seyMonsters]

A Very Basic Space Program | Episode 106 | KSP RSS/RO/RP-1

 

[jimmymcgoochie]

No wonder MechJeb is getting confused by a rocket where the boosters don’t separate after burning out. The fact that it has to pitch up almost 45 degrees after that is a clear sign that it’s really not happy about it.

Phantom forces were strong with that probe, the RCS couldn’t counter it hence the constant spinning.

[seyMonsters]

A Very Basic Space Program | Episode 107 | KSP RSS/RO/RP-1

 

[jimmymcgoochie]

Those solar panels are overkill, smaller panels and a fuel cell would be a lot lighter and give you better fuel margins.

[seyMonsters]

A Very Basic Space Program | Episode 108 | KSP RSS/RO/RP-1

 

[jimmymcgoochie]

I’ve had similarly inept docking attempts from MechJeb, it often seems incapable of working with weak RCS

The mod you’re looking for is TAC fuel balancer, definitely worth getting.

[seyMonsters]

A Very Basic Space Program | Episode 109 | KSP RSS/RO/RP-1

 

[jimmymcgoochie]

I’d say there’s a phantom force in the transfer stage due to part clipping of some kind, try rebuilding the transfer stage from scratch and avoid clipping as much as possible- if that doesn’t help then try rebuilding the probe.

Ceres and Vesta have fairly similar orbits, the transfer windows line up by coincidence in the 60s and 70s.

You can set patched conics up to 6 patches in the main menu settings - I’ve had Kerbol > Jool > Tylo > Jool > Vall > Jool > Laythe all shown at once. I think there are ways to push it even higher with mods, though more patches = more computation required so it can make the game slower.