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[not a bug please move me][2.0.28] Space platform loses speed when passing planet

Posted: Sat Dec 21, 2024 11:21 pm
by jaylawl
This is not a bug, please move me. :arrow:

Environment:

Vanilla space age 2.0.28 + ingame calculator mod (https://mods.factorio.com/mod/calculator-ui?from=search)

Problem:

Space platforms lose a significant amount of speed when passing a planet.

Reproduction:

-> Have any space platform that is capable of traveling at a constant speed.
-> Have it travel on a space route that requires passing another planet. Example: from Vulcanus -> Fulgora, which requires passing over Nauvis or Gleba.
-> Observe the space platform speed in the exact moment it passes over a planet.

Problem details:

This happens with all my space platforms. My logistic platforms travel at a constant speed of 202 km/s (with only decimal variance). When passing over a planet, the speed rapidly dips down by 20 km/s to ~ 182 km/s, where it will linger for a while, before coming back up to its top speed.

The same happens with my flagship, which is an entirely different build. That one has a top speed of 302 km/s and also has a dip of 20 km/s when passing over a planet.

That dip is quite significant. For my logistic platforms its a 10 % speed loss for nearly half the trip (between all planets have a distance of 15.000 km).

I have ensured that its not the fault of my circuit network logic. The same thing happens regardless of whether im controlling the thruster or whether im just pumping fuel into the thruster 100 % of the time (which are ensured to be saturated with fuels)

One of my space platforms for reproduction purposes:

Re: [2.0.28] Space platform loses speed when passing planet

Posted: Sat Dec 21, 2024 11:48 pm
by Jap2.0
My understanding (which may be wrong, I haven't had a ton of time for SA yet) is that space platforms always "fall" toward the nearest planet at a speed of 10km/s—so half of the time it is being pulled forward, adding 10km/s, and half the time it is being pulled backward, losing 10km/s.

Re: [2.0.28] Space platform loses speed when passing planet

Posted: Sun Dec 22, 2024 12:00 am
by jaylawl
Jap2.0 wrote: Sat Dec 21, 2024 11:48 pm My understanding (which may be wrong, I haven't had a ton of time for SA yet) is that space platforms always "fall" toward the nearest planet at a speed of 10km/s—so half of the time it is being pulled forward, adding 10km/s, and half the time it is being pulled backward, losing 10km/s.
Aight now i feel stupid. I knew about this, but i believed this "pull" towards the planets would only happen when your thrusters are inactive. But i just checked and can confirm that the speed always changes exactly at the halfway point between planets.

So i guess that its not a bug then but its certainly unintuitive. :lol:

This flat -10 or +10 km/s feels like a primitive implementation compared to the polish in the rest of the game. It would make a lot more sense for these values to be applied in relation to the distance between planets.

Re: [2.0.28] Space platform loses speed when passing planet

Posted: Sun Dec 22, 2024 1:35 am
by Muche
The purpose of 10 km/s gravity is to not let (new, inexperienced) players get stranded in space on insufficiently designed platform.

Imagine a platform with plenty of ammo in the hub, but insufficient number of turrets. Asteroids eventually overwhelm them, destroy chemplant(s), the player quickly builds more turrets and prevents more damage. Platform is now safe but without thrust. It now sits in the middle of two planets.

The shape of gravity function determines recovery time. The current flat 10 km/s means a maximum of 12.5 minutes.
Would you be comfortable waiting 2h to recover, were the gravity in that spot be 1 km/s?
What about 20 hours with 0.1 km/s gravity?

Re: [2.0.28] Space platform loses speed when passing planet

Posted: Sun Dec 22, 2024 10:06 am
by mmmPI
jaylawl wrote: Sun Dec 22, 2024 12:00 am So i guess that its not a bug then but its certainly unintuitive. :lol:

This flat -10 or +10 km/s feels like a primitive implementation compared to the polish in the rest of the game. It would make a lot more sense for these values to be applied in relation to the distance between planets.
I don't think it would make more sense from gameplay point of view to have these values applied in relation to the distance between planets. Because that would mean having this effect ( helping stranded platform) be almost 0 in the middle between the 2 planets, which is where it's the most useful, and the same effect would be the stronger near to planet, where it's the least useful.

The lower the value the "easier" it is for everyone to make a regular platform that doesn't go "too fast" in the 2nd part of the trip. ( and risk crashing on asteroid or require circuit to controll speed).
The higher the value the "more helpful" it is to un-jam platform but the more difficult it is to handle the speed differential.
10km.s seem to be a sweet spot to me , it create a 20km.s differential, which is in proportion with the platforms speeds.

Re: [2.0.28] Space platform loses speed when passing planet

Posted: Sun Dec 22, 2024 10:18 am
by jaylawl
Yeah, the more i think about it i guess this is fine as is. Maybe just a little lack of communication ingame leading me to create an erroneous bug report is a bit of an issue.