Astroid build-up at low speed on trip to shattered planet

[ambbma]

I'm having an issue with a megabase type save that I haven't seen before and I'm not sure if it's a bug or a gameplay issue.

On 2.0.60, I have a ship that goes to shattered planet at low speeds - about 37kph - for a long time, 5+ hours. When it returns to solar system edge, a huge batch of asteroids is accumulated in a row above the top of the ship. When the ship then accelerates to top speed, about 100kph or more, the entire apron of asteroids is hurled into the ship and obliterates it. The only way to not lose my ship is to gradually increase my speed (by hand) so that the accumulated crust of asteroids doesn't overwhelm the ship.

Is this supposed to be a thing? If it's a bug, how can I better describe it, and if it's the way it's supposed to be, how can I avoid it.....

[jdrexler75]

It happens because when you frag an asteroid, the resulting smaller ones fly off at random velocities. Occasionally that random velocity exactly matches your ship's velocity, and so it stays in place with no relative motion. The ones with higher speeds will get picked off by your defenses, the ones with lower speeds fly off. But the ones with the same speed just keep piling up for hours, even when the chance is low for this to happen it will happen often enough during that time.

One solution would be to modulate your speed during the hour long trip, go a little slower or faster for a few minutes to let them fly off or get fragged. If you set a different speed for the return trip it will already be half as many piling up.

Another solution would be to rethink whether the five hour trip can be made shorter. I have my promethium ships fly fast up to about 50.000 km, then slow down until they're about half full and return, slowly until full and then fast. It avoid catastrophic events far away from the solar system. I can't think of a reason why you would need to go for five hours...

If you don't go as deep you can perhaps also go faster without overwhelming your defences. Since asteroids spawn faster at higher speeds you might even fill up promethium faster that way.

[Tertius]

May be not so long farming and instead balance farming and biter egg spoiling. Would keep asteroids from accumulating this way.
I built one promethium ship for a ~1 hour round trip. 30 minutes there, 30 minutes back. The 30 minutes are because of biter egg spoiling time.

• The ship arrives at Nauvis, loading a huge batch of eggs and dropping any promethium science packs. And it refills platform supply items (turrets, belts...) in case some were destroyed. Then it immediately takes off to the solar system edge at maximum speed (270 km/s, what you can get without quality).
• Promethium science pack production starts immediately after takeoff, because there are buffered promethium chunks.
• Speed is reduced to ~200 between the edge and the start of the main promethium farming area ~40.000 km distance from the edge.
• Buffered promethium runs out at about 20.000-40.000 km distance (don't remember exactly)
• Speed is reduced to ~120 between 40.000 and 120.000 km distance.
• Speed is reduced to ~60 beyond 120.000 km distance.
• Eggs run out at 28-30 minutes after Nauvis start at about 130.0000 km distance. In case eggs there are still there 28 minutes after Nauvis, they're obliterated into space to avoid hatching. Starting here, the promethium buffer is filled again.
• Ship turns round at 142.000 km distance.
• Speed is increased in reversed order, but with slightly reduced thrust to not overwhelm the turrets, because speed is higher with the same fuel supply.
• Promethium buffer is full at about 10.000-20.000 km distance from the edge.
• Stop at Aquilo to load quantum processors, fusion power cells and to refill railgun turret supply in case one was destroyed.
• Next stop Nauvis and the cycle starts again.

With quality, I could vastly increase flying speed, so I'm faster in the farming area and faster back, so I can load more biter eggs and deliver science packs faster, so the whole thing is more efficient. That's what I'm working on currently. But efficiency is not that important, because I could just build more farming ships.

[ambbma]

Thanks for the replies! That definitely explains things. I've changed my speed so once I get back to the solar system I bump the speed up a bit and after a bit of testing that seems to take care of it so far.

To explain a bit for the record, I've got 4 prometheus harvesters that can store 500k or so prometheus. It takes a long time, I'm not sure how long but well over 5 hours. Then when they return to nauvis they process the science with eggs delivered from nauvis while in orbit. The ships are big and slow at 11.3 tons and with defenses adequate for about 37km/s to the shattered planet. Inside the solar system they can max at about 170km/s. I don't use quality at all.

Perhaps I'll move to smaller faster ships in the future but at the moment I'm quite fond my giant ships!

[waterBear]

Perhaps I'll move to smaller faster ships in the future but at the moment I'm quite fond my giant ships!

This is a minor point, but smaller is not faster. The fastest ships I've seen (and built) are huge and wide. See the post on "ships that can reach shattered planet." The first several are small and slow, then they become massive and fast.

[Tertius]

This is a minor point, but smaller is not faster.

Size isn't the only factor for speed.
Maximum platform speed can be determined by some formula. Somebody posted it, unfortunately I didn't kept a link. Speed is decreased by weight and platform width (the wider the slower). Speed is increased by thrust.

The bigger you build, the more thrust you need to keep the same speed.
The wider you build, the more thrust you need to keep the same speed.
The wider you build, the more thrusters you can add, so you have more thrust.
The more thrust you have, the higher the speed.

Slowdown by width is less significant than speedup by amount of thrusters.

Some people with very fast platforms cheat by adding 2 rows of thrusters. They double the amount of thrusters while not increasing the width. May be it's these platforms you're referring to.

If you build one row of normal quality thrusters over the whole width of a platform, you will get about 300 km/s or slightly less. This seems some empirical limit due to some required minimum platform size to support asteroid defense and thruster fuel supply.
If you build the same but with quality thrusters, the increased thrust will significantly increase the speed with the same platform size. If you build with quality thrusters, you can also make your platform narrower without scarifying thrust.
A legendary thruster has 2.5 times the thrust of a normal thruster. Instead of 5 thrusters, you need only 2 for the same speed.

[Shirasik]

Maximum platform speed can be determined by some formula. Somebody posted it, unfortunately I didn't kept a link.

\data\core\prototypes\utility-constants.lua
as of 2.0.55, lines from 519 to 523

Code: Select all

    -- drag_coefficient = width * 0.5
    -- drag = ((1500 * speed * speed + 1500 * abs(speed)) * drag_coefficient + 10000) * sign(speed)
    -- final_thrust = thrust / (1 + weight / 10000000)
    -- acceleration = (final_thrust - drag) / weight / 60
    space_platform_acceleration_expression = "(thrust / (1 + weight / 10000000) - ((1500 * speed * speed + 1500 * abs(speed)) * (width * 0.5) + 10000) * sign(speed)) / weight / 60",

Units are: grams for weight, meters per second for speed, Newtons for thrust.
Long story short:
- thrust counts toward acceleration and top speed;
- weight and width counts against acceleration and top speed;
- width defines thrust required to make platform capable to move and limits top speed directly;
- weight mostly defines how fast platform can reach top speed;
- even in virtual edgecase of zero-width platform there still is a permanent 10N drag present (aka Earth's surface's free fall acceleration rounded up to 10);
- "1" in "thrust / (1 + weight / 10000000)" needed to avoid division by zero and can be omitted if you agreed what zero-weight platform can't exist.

[waterBear]

This is a minor point, but smaller is not faster.

Size isn't the only factor for speed.
Maximum platform speed can be determined by some formula. Somebody posted it, unfortunately I didn't kept a link. Speed is decreased by weight and platform width (the wider the slower). Speed is increased by thrust.

The bigger you build, the more thrust you need to keep the same speed.
The wider you build, the more thrust you need to keep the same speed.
The wider you build, the more thrusters you can add, so you have more thrust.
The more thrust you have, the higher the speed.

Slowdown by width is less significant than speedup by amount of thrusters.

Some people with very fast platforms cheat by adding 2 rows of thrusters. They double the amount of thrusters while not increasing the width. May be it's these platforms you're referring to.

If you build one row of normal quality thrusters over the whole width of a platform, you will get about 300 km/s or slightly less. This seems some empirical limit due to some required minimum platform size to support asteroid defense and thruster fuel supply.
If you build the same but with quality thrusters, the increased thrust will significantly increase the speed with the same platform size. If you build with quality thrusters, you can also make your platform narrower without scarifying thrust.
A legendary thruster has 2.5 times the thrust of a normal thruster. Instead of 5 thrusters, you need only 2 for the same speed.

All I was saying is that small isn't the same as fast. Especially with quality. Your comment bears this out.

Also you should note that it's possible to have multiple rows of thrusters without increasing width, by just putting the rows far enough apart. That can lead to huge ships hitting crazy speeds.