Part upgrades in tech tree

[Frozen_Heart]

After seeing Elon Musks tweet about upgrading the Falcon 9 rocket with more fuel and better engines, I started thinking about whether part upgrades could suit KSP. I my opinion I think that they could be integrated into the tech tree seamlessly and rather than simply giving a new part, they would improve all parts of a certain type. This would allow a solid rocket design to be improved and stay competitive throughout career if the player wished.

E.g.

Common bulkheads: Would allow fuel tanks to carry slightly more fuel and have slightly less dry mass.

Improved chamber pressures: Improves the ISP of all liquid fuel engines slightly.

Composite Materials: Reduces the mass of most parts slightly.

These would be placed in the tech tree just as part currently are and could be unlocked when the player has enough science.

[Hcube]

Wouldn't it be super-complicated ? Squad is trying to balance all the parts out now, and it seems rather complicated enough. Also the game is about green men, but also about physics, and physics tell you that there is no way you can put more fuel in a tank without increasing its size

But the real thing is that once you would have unlocked all the parts to max upgrade, all the others would become useless ! Why use an obsolete engine when you have its upgraded version ?

Unless you are talking about a system that transforms the part into a new better one when tou upgrade it thus you having only 1 at the time

Still once you would have upgraded everything the game would feel like easy mode

[sumghai]

One problem I forsee with tying part upgrades to tech tree progression is that this could cause problems with craft sharing.

Let's say user A has maxed out their tech tree with all the upgrades, and decides to share his craft to user B, reassuring the latter that it has enough dV to reach the Mun. However, as it turns out, user B has only unlocked the parts, and the lack of the required upgrades means significant performance differences that lead to the same craft falling short of entering the Mun's SOI.

Of course, one could post with their shared craft a list of all the specific tech nodes and upgrades that need to be unlocked, but this makes it unintuitive for newcomers to the game.

[Frozen_Heart]

physics tell you that there is no way you can put more fuel in a tank without increasing its size

Surprisingly not true. I know of 3 ways that can potentially allow more fuel to fit in the same tank.

Common bulkheads: Rather than a separate wall for both the oxidiser and fuel tanks, they share a single wall. Save mass and allows more fuel. This was used on some of the Saturn stages.

Stronger materials: Allows less to be used and so the tank itself can be lighter and with thinner walls. The lithium-aluminium alloy in the Falcon rockets is a good example.

Chilled fuels: Are denser and allow more to be put in the same space. Proposed by Elon Musk for the Falcon rockets as of yesterday.

Unless you are talking about a system that transforms the part into a new better one when tou upgrade it thus you having only 1 at the time

This is what I mean. An engine upgrade would effect all engines. For example the LV-909 could start having: mass 0.75, thrust 40kN, and max ISP 380s. It could then end up mass 0.40, thrust 60kN, and ISP 400s by the end of the tech tree after several upgrades. These would apply to all engines at once to stop a player using a single one to the exclusion of all else.

The only issue with this is craft sharing as sumghai points out. A player at the end of the tech tree would have the same craft perform better than a player at the start.

[NoMrBond]

What is required is the ability for research to retire parts from the VAB/SPH catalogue

You've just researched engine mk2! engine mk1 is set "category = -1" (the part.cfg for engine mk2 contains researchHides = engineMK1 or similar argument)

This would leave superseded parts still in the game but no longer appearing in the VAB/SPH (no mk1, mk2, mk3 clutter), similarly flights in progress are not lost/affected and craft using them can still be loaded

[Renegrade]

I'd definitely be for upgradable parts.

The only issue with this is craft sharing as sumghai points out. A player at the end of the tech tree would have the same craft perform better than a player at the start.

RealFuels handles this by letting you specify the tech level for a part during construction. If you want a universally-usable craft file, all you have to do is build it with the minimum tech that you have once you've unlocked all the parts necessary for the craft.

[Frozen_Heart]

You've just researched engine mk2! engine mk1 is set "category = -1" (the part.cfg for engine mk2 contains researchHides = engineMK1 or similar argument)

When I say upgradable parts I still mean it would be the same part, just with upgraded stats. It wouldn't cause dupplicated engines to appear in the tech tree.

[Crzyrndm]

With the way that KSP handles parts, the upgrade/tech level would have to be specified in the persistence and/or handled through seperate part definitions. Otherwise you can upgrade engines while they're on a solar escape trajectory/landed on Tylo which is just stupid (note that this doesn't mean multiple parts have to be visible to the player)

[NoMrBond]

When I say upgradable parts I still mean it would be the same part, just with upgraded stats. It wouldn't cause dupplicated engines to appear in the tech tree.

That is exactly what I am suggesting, even detailing the config argument which would allow it

That's what having the ability to change the category to -1 would do

[Hcube]

Surprisingly not true. I know of 3 ways that can potentially allow more fuel to fit in the same tank.

Common bulkheads: Rather than a separate wall for both the oxidiser and fuel tanks, they share a single wall. Save mass and allows more fuel. This was used on some of the Saturn stages.

Stronger materials: Allows less to be used and so the tank itself can be lighter and with thinner walls. The lithium-aluminium alloy in the Falcon rockets is a good example.

Chilled fuels: Are denser and allow more to be put in the same space. Proposed by Elon Musk for the Falcon rockets as of yesterday.

This is what I mean. An engine upgrade would effect all engines.

Oh yeah i was talking about pure math and volume, but you are completely right about the walls and the temperatures, i'm just thinking that it would feel weird to see the same tank getting more fuel what would be cool is getting a description in the science tree like the ones we have now, saying like "new pressure performances and fuel conditionments allow our engineers to put more fuel in smaller tanks" Because bigger is always better !

If all the parts get upgraded then i totally approve this idea maybe another tech tree dedicated to the upgrades, parallel to the original ?

[Jouni]

I see two options. Either we have the current Lego-style parts with no upgrades, or we get procedural everything and part upgrades.

Right now, we know exactly what a part does when we see it. Procedural parts and upgradeable parts both take that away. If we get one, there's no real downside to having the other one as well. And if we get procedural parts, we definitely need procedural engines, because they're much more useful than procedural fuel tanks, wings, or fairings.

[Frozen_Heart]

I see two options. Either we have the current Lego-style parts with no upgrades, or we get procedural everything and part upgrades.

Right now, we know exactly what a part does when we see it. Procedural parts and upgradeable parts both take that away. If we get one, there's no real downside to having the other one as well. And if we get procedural parts, we definitely need procedural engines, because they're much more useful than procedural fuel tanks, wings, or fairings.

I dislike procedural parts due to it removing the Lego like nature of KSP. If the ship is only made up of a couple of made to fit parts, it takes away things like part of a wing coming off or a fuel tank being destroyed. Half the vehicle would simply go poof instead.

I've played with the various procedural mods quite a bit and just didn't enjoy them at all.