How do I catch the aliens?

[private1028]

Their slowest ship has a delta-V of 552.7 kps and I have nothing that fast. They just run away.

[lemurs2]

I am far from an expert, but I find that if I have enough ships, split your fleet more or less in two. Then have the first fleet attack the alien ship. About two or three hours later send the second fleet to the same target.
It seems that after an action it takes a few hours for a fleet to act again.

[Premu]

Early on you can catch aliens by splitting your fleet, and sending both smaller fleets to intercept the ship at the same time. The aliens will evade the first one, but can't evade the second.

Of course half a fleet needs to be strong enough to deal with the alien ships.

Later on you can get some drives which can compete with the aliens - the earliest model is the zeta fusion drive with which you can realistically reach delta-Vs in the 800s even for very well armored battle ships.

[ulzgoroth]

The other answers covered the how to.

I'll note that delta-V isn't 'how fast'.

[gimmethegepgun]

Also, from what I know, the upcoming patch has the ability to auto-split a fleet in half for a pincer so you can do that without tedious micromanagement, and they're making it so that if your combat acceleration exceeds the enemy's then they won't be able to use their dV to run away since you'll just overtake them.

[private1028]

Originally posted by ulzgoroth:

The other answers covered the how to.

I'll note that delta-V isn't 'how fast'.

Okay. It's in kps - kilometers per second - so I thought it was a speed. Is it supposed to be acceleration? Like kps^2 (i.e. kilometers per second squared)? Also if the upcoming patch will split the fleet that's kwel!

Is this game buggy with STEAM CLOUD saves? I did a STEAM VERIFY and it corrupted my game. Went CTD and couldn't run anymore. So I did a reinstall and my game save went from 2040 to 2029 !! Nasty business and it cost me many mouse clicks in direct investment but better than scratch I guess.

[gimmethegepgun]

Originally posted by private1028:

Okay. It's in kps - kilometers per second - so I thought it was a speed. Is it supposed to be acceleration? Like kps^2 (i.e. kilometers per second squared)?

No. Delta-V is how much the spaceship can change its velocity. Or, in similar terms, its fuel.
A ship with high dV can catch a ship with low dV, even with a lower acceleration, by simply continuously chasing it until it can't flee any more. Basically the same way that humans way back when could hunt much faster creatures by chasing them until they collapsed of exhaustion.

[private1028]

Originally posted by gimmethegepgun:

Originally posted by private1028:

Okay. It's in kps - kilometers per second - so I thought it was a speed. Is it supposed to be acceleration? Like kps^2 (i.e. kilometers per second squared)?

No. Delta-V is how much the spaceship can change its velocity. Or, in similar terms, its fuel.
A ship with high dV can catch a ship with low dV, even with a lower acceleration, by simply continuously chasing it until it can't flee any more. Basically the same way that humans way back when could hunt much faster creatures by chasing them until they collapsed of exhaustion.

It's supposed to be a spatial vector or a scalar equal to the acceleration integrated over time. Not sure what the game means tho. I find the game's terminology confusing. Or maybe it's just me ...

[ulzgoroth]

Originally posted by private1028:

Originally posted by gimmethegepgun:

No. Delta-V is how much the spaceship can change its velocity. Or, in similar terms, its fuel.
A ship with high dV can catch a ship with low dV, even with a lower acceleration, by simply continuously chasing it until it can't flee any more. Basically the same way that humans way back when could hunt much faster creatures by chasing them until they collapsed of exhaustion.

It's supposed to be a spatial vector or a scalar equal to the acceleration integrated over time. Not sure what the game means tho. I find the game's terminology confusing. Or maybe it's just me ...

The delta-V of a ship is (obviously) the scalar. That's general usage, not TI-specific. The spatial vector would be the delta-V of a burn/maneuver, and isn't terribly relevant to Terra Invicta since individual burns aren't under player control (except in combat).

Of course, calling it 'acceleration integrated over time' phrasing is...totally true, but likely to be unhelpful unless you are unusually inclined to think in terms of vector calculus. gimmethegepgun's description is the exact same thing without the not really necessary mathematical digression.

[private1028]

Originally posted by ulzgoroth:

Originally posted by private1028:

It's supposed to be a spatial vector or a scalar equal to the acceleration integrated over time. Not sure what the game means tho. I find the game's terminology confusing. Or maybe it's just me ...

The delta-V of a ship is (obviously) the scalar. That's general usage, not TI-specific. The spatial vector would be the delta-V of a burn/maneuver, and isn't terribly relevant to Terra Invicta since individual burns aren't under player control (except in combat).

Of course, calling it 'acceleration integrated over time' phrasing is...totally true, but likely to be unhelpful unless you are unusually inclined to think in terms of vector calculus. gimmethegepgun's description is the exact same thing without the not really necessary mathematical digression.

Sorry my high school physics professor was a stickler for units. Pounded it in to all his students until we were blue in the face. Had a thing about dimensional analysis and wouldn't accept calculus solutions without the dimensions ... but I digress. How does the game manage the difference in gravity between objects? Delta V changes depending on the mass so the same engine should perform better on the moon than say LOE because of the difference in gravity. Or maybe I'm just going too far? Doing a transfer example I expected different values for the same engine pushing the same mass. I must have confused myself.

I haven't been this lost since George Gatewood at University of Pittsburgh, Allegheny Observatory asked me to help out on his PC simulation of the lunar lander mission to the moon. He was doing it on an Apple. I still remember all the poke and peek commands. It was horribly complicated.

[kalonjelen]

DV is literally a change in velocity for the ship - AKA acceleration. It is how much the ship can accelerate over a period of time. This is not the same as escape velocity requirements; ships with high DV and low kps mean that they can never escape a planetary body's gravitational pull from the surface but can travel between bodies without any real issue.

DV is in the game's terms how much overall acceleration you can do - basically how much fuel you have. mg or gs is how fast you can accelerate.

[ulzgoroth]

Originally posted by kalonjelen:

DV is literally a change in velocity for the ship - AKA acceleration. It is how much the ship can accelerate over a period of time. This is not the same as escape velocity requirements; ships with high DV and low kps mean that they can never escape a planetary body's gravitational pull from the surface but can travel between bodies without any real issue.

DV is in the game's terms how much overall acceleration you can do - basically how much fuel you have. mg or gs is how fast you can accelerate.

There's a lot of problems in here. You should maybe read over it again. (High DV and low kps???)

Also, while what you meant when you said delta-V is "literally acceleration" is probably true, what you said is obviously false and contradicts your own statements later.

Acceleration is literally the rate at which you change velocity with respect to time. Delta-V is not that.

[kalonjelen]

Originally posted by ulzgoroth:

Originally posted by kalonjelen:

DV is literally a change in velocity for the ship - AKA acceleration. It is how much the ship can accelerate over a period of time. This is not the same as escape velocity requirements; ships with high DV and low kps mean that they can never escape a planetary body's gravitational pull from the surface but can travel between bodies without any real issue.

DV is in the game's terms how much overall acceleration you can do - basically how much fuel you have. mg or gs is how fast you can accelerate.

There's a lot of problems in here. You should maybe read over it again. (High DV and low kps???)

Also, while what you meant when you said delta-V is "literally acceleration" is probably true, what you said is obviously false and contradicts your own statements later.

Acceleration is literally the rate at which you change velocity with respect to time. Delta-V is not that.

Sorry, I'll try and be clearer. In the game a ship has three values that it uses for various things, one of which is based on the other. The values are:
DV
mg (or g)
KPS (based on mg/g)

Yes, high DV and low KPS is correct. Your KPS in the game is your maximum escape velocity. It is used only when talking about whether or not you can leave the pull of a planetary body from the body.

You're absolutely right that DV is not acceleration, and I misspoke. DV is the overall amount of velocity changes that a ship can make before refueling. mg or g is the acceleration that a ship can do in terms of earth gravity. That said DV is absolutely the amount of change in velocity that the ship can do. It is how much accelerations a ship can take over time based on fuel. The magnitude of how much acceleration a ship can do is in mg/g.

[ulzgoroth]

Originally posted by private1028:

Originally posted by ulzgoroth:

The delta-V of a ship is (obviously) the scalar. That's general usage, not TI-specific. The spatial vector would be the delta-V of a burn/maneuver, and isn't terribly relevant to Terra Invicta since individual burns aren't under player control (except in combat).

Of course, calling it 'acceleration integrated over time' phrasing is...totally true, but likely to be unhelpful unless you are unusually inclined to think in terms of vector calculus. gimmethegepgun's description is the exact same thing without the not really necessary mathematical digression.

Sorry my high school physics professor was a stickler for units. Pounded it in to all his students until we were blue in the face. Had a thing about dimensional analysis and wouldn't accept calculus solutions without the dimensions ... but I digress.

Good for your teacher, who I agree with entirely on this, but I don't see how that connects. The units are the same!

Originally posted by private1028:

How does the game manage the difference in gravity between objects? Delta V changes depending on the mass so the same engine should perform better on the moon than say LOE because of the difference in gravity. Or maybe I'm just going too far? Doing a transfer example I expected different values for the same engine pushing the same mass. I must have confused myself.

You must have, since gravity has literally nothing to do with engine performance. I'm not sure exactly where you went wrong on this thinking. Remember mass is not the same as weight. An object weighs less on the moon but it has the same mass. And there's nothing about being on the moon instead of LEO that would make an engine perform better.

It might be easier for a low-thrust engine to perform an efficient escape burn, due to that escape burn needing less velocity change to escape the weaker gravity. That's the closest I can think of to what you're saying here.

[ulzgoroth]

Originally posted by kalonjelen:

Originally posted by ulzgoroth:

There's a lot of problems in here. You should maybe read over it again. (High DV and low kps???)

Also, while what you meant when you said delta-V is "literally acceleration" is probably true, what you said is obviously false and contradicts your own statements later.

Acceleration is literally the rate at which you change velocity with respect to time. Delta-V is not that.

Sorry, I'll try and be clearer. In the game a ship has three values that it uses for various things, one of which is based on the other. The values are:
DV
mg (or g)
KPS (based on mg/g)

Yes, high DV and low KPS is correct. Your KPS in the game is your maximum escape velocity. It is used only when talking about whether or not you can leave the pull of a planetary body from the body.

You're absolutely right that DV is not acceleration, and I misspoke. DV is the overall amount of velocity changes that a ship can make before refueling. mg or g is the acceleration that a ship can do in terms of earth gravity. That said DV is absolutely the amount of change in velocity that the ship can do. It is how much accelerations a ship can take over time based on fuel. The magnitude of how much acceleration a ship can do is in mg/g.

No. Very, very no.

First of all, your 'three values' are identified by a name in one case and units in the other two. Correctly, there are two values that fully describe ship mobility in TI (shouldn't quite, but do): delta-V (which is accounted in KPS) and acceleration (which is usually accounted in milligravities). The reason they shouldn't is that acceleration ought to change as the ship's mass dereases, but I believe in game that doesn't happen.

I'm not completely sure, but I suspect your third value is exhaust velocity (sometimes EV). That's an important design parameter - it determines how much reaction mass you need to achieve a given amount of delta-V. It is absolutely nothing like 'maximum escape velocity', but that isn't a thing at all. (And I can't even guess what 'based on mg/g' is supposed to mean.)

The ability to blast off from a body's surface is simply a matter of your thrust vs. the surface gravity. (Plus having enough delta-V to be able to achieve low orbit.)

[kalonjelen]

No. Very, very no.

First of all, your 'three values' are identified by a name in one case and units in the other two. Correctly, there are two values that fully describe ship mobility in TI (shouldn't quite, but do): delta-V (which is accounted in KPS) and acceleration (which is usually accounted in milligravities). The reason they shouldn't is that acceleration ought to change as the ship's mass dereases, but I believe in game that doesn't happen.

I'm not completely sure, but I suspect your third value is exhaust velocity (sometimes EV). That's an important design parameter - it determines how much reaction mass you need to achieve a given amount of delta-V. It is absolutely nothing like 'maximum escape velocity', but that isn't a thing at all. (And I can't even guess what 'based on mg/g' is supposed to mean.)

The ability to blast off from a body's surface is simply a matter of your thrust vs. the surface gravity. (Plus having enough delta-V to be able to achieve low orbit.)

That's fair, and I should apparently slow down a bit.

DV is the title and does represent the overall change in velocity a ship can do before refueling. I don't know what is in dispute about this, but that's what it is. It's also the typical title used in most old scifi - Heinlein and Niven used it quite often.

KPS is the unit for DV. I had thought that it was what is needed for escape velocity but that appears to be incorrect, and I apologize. Or maybe it's been changed since I first played. The escape velocity value appears to not be there, and the only thing that is shown (at least on habs) is the mgs required to leave the planet. As you can't launch directly from earth this is almost always mgs.

Your escape velocity is based on your acceleration - which is defined in game as milligravities/gravities. That is what I meant by 'based on mgs/gs'. And to be even more pedantic it's based on your 'cruise acceleration', as you can also have combat acceleration which is a different value.