Delta-V map for SFS 1.4

[Altaïr]

Hi there,

Here is a delta-V map that takes into account all official planets and moons. I'd like to thank @8bitCosmonaut that gave constructive feedback on my first attempts, which allowed me to make this one in the end:

For those who don't know that term, "delta-V" means literally "speed difference". When talking about a ship, its delta-V budget is by how much it can make vary its speed in total. Thus, spending 100 m/s simply means increasing (or decreasing) your speed by 100 m/s.

Here are a few tips when using that map:

• All maneuvers are supposed to be performed at the periapse of the concerned body
• The closest to the planet/moon your ship is, the more efficient your maneuver will be: this is the Oberth effect.
• Those are theoretical values, so depending on how precise is your trajectory, it's possible you have to spend a bit more delta-V in practice
• All values are calculated for an altitude of 10 km (except Phobos and Deimos: 5 km) above the atmosphere limit (ground level if there's no atmosphere). This is not the best possible trajectory, so the map already integrates a small margin.

For those who are not familiar with delta-V maps, here is an example:


Enjoy

 

[TtTOtW]

Thank you @Altaïr it is a very handy piece of work!

 

[Lt. Snakestrike]

god, it took me fucking forever to find this... need it for the 1 of everything challenge, its coming down to the wire.

 

[Lt. Snakestrike]

It be nice if this one was pinned. Just saying...

 

[Altaïr]

It be nice if this one was pinned. Just saying...

Good idea. I've just used my new moderator's privilege to do it

 

[Lt. Snakestrike]

I just wish it had the Saturn info in it... It's okay though, I found the info in the Mod thread.
Working on making a chemical booster for the Tsar to make trips to Titan Easier. I just realized it'll take one way too big to allow a direct transfer, so I guess I'm sticking with Veega.

 

[Pink]

We need a way to get to the outer planets via a direct trajectory.... Veega means that the astronauts are dead before they get there!

 

[Josh H.]

“Chewie, hit the hyperdrive!”

We need a way to get to the outer planets via a direct trajectory.... Veega means that the astronauts are dead before they get there!

 

[SPQRALAN]

This is amazing information. I made one for Earth and moon then I got lazy, but this, it's insane amounts of effort. I assumed that you calculated the values assuming a low eccentricity(0.001).

FOR ANYONE THAT SEES THIS:
This chart can predict fuel consumption using the ideal rocket(Tsiolkovsky Rocket Equation):

Delta_V= Isp × ln(mo/mf)

Solving for final mass:
\frac{m_{0}}{e^{\frac{\delta V}{Isp}}}

Mo
Mf=-----------------
e^(dV/Isp)

Subtract mf and mo to get fuel usage.

 

[Altaïr]

This is amazing information. I made one for Earth and moon then I got lazy, but this, it's insane amounts of effort. I assumed that you calculated the values assuming a low eccentricity(0.001).

FOR ANYONE THAT SEES THIS:
This chart can predict fuel consumption using the ideal rocket(Tsiolkovsky Rocket Equation):

Delta_V= Isp × ln(mo/mf)

Solving for final mass:
\frac{m_{0}}{e^{\frac{\delta V}{Isp}}}

Mo
Mf=-----------------
e^(dV/Isp)

Subtract mf and mo to get fuel usage.

Thanks

Actually I made a chart to calculate all transfers easily, so that part was not that long. The hardest part to me was about the graphics, how to make look it good.

For the orbital speeds I considered a perfectly circular orbit (e=0).

 

[SPQRALAN]

This is amazing information. I made one for Earth and moon then I got lazy, but this, it's insane amounts of effort. I assumed that you calculated the values assuming a low eccentricity(0.001).

FOR ANYONE THAT SEES THIS:
This chart can predict fuel consumption using the ideal rocket(Tsiolkovsky Rocket Equation):

Delta_V= Isp × ln(mo/mf)

Solving for final mass:
\frac{m_{0}}{e^{\frac{\delta V}{Isp}}}

Mo
Mf=-----------------
e^(dV/Isp)

Subtract mf and mo to get fuel usage.

Mo is numerator and the e^(dV/Isp) is denominator.

 

[s.victor.q]

Nice project. It will help in building vehicles.

 

[Blazer Ayanami]

So what's the Sun's escape velocity? I don't see it on the map.

 

[Lt. Snakestrike]

So what's the Sun's escape velocity? I don't see it on the map.

Well, you can be the one to find it via testing.

 

[Horus Lupercal]

So what's the Sun's escape velocity? I don't see it on the map.

Well, you can be the one to find it via testing.

There isn't one in vanilla SFS as you can't leave the Solar SOI.
You can push your orbit apo out of the system but you'll always eventually come back unless you enter another SOI and burn to stay inside it

That and the speed required is genuinely ludicrous.

 

[Altaïr]

So what's the Sun's escape velocity? I don't see it on the map.

It depends, the escape velocity isn't a constant, it depends on the distance to the Sun.
I calculated, If you are at Sun level, the escape velocity will be 78985 m/s. This is 23134 m/s more than Low Sun Orbit.

But you know how difficult it is to achieve LSO don't you? In practice, you would rather lower your perihelion at Sun level, and then burn prograde from there. Because of the Oberth effect, you would only need 416 m/s of delta-V.

If you want to escape the solar system directly from LEO, you'll have to provide 1701 m/s, which is "only" 485 m/s more than for Jupiter.

There isn't one in vanilla SFS as you can't leave the Solar SOI.
You can push your orbit apo out of the system but you'll always eventually come back unless you enter another SOI and burn to stay inside it

That and the speed required is genuinely ludicrous.

Even if the Sun has no SOI (or an infinite one), it's actually possible to escape it.

The escape velocity is equal to sqrt(2) × orbital velocity. When you are below that speed, your trajectory is elliptic, and your ship will always come back indeed. But when you are above, the trajectory is hyperbolic. In this case, the ship will never come back. That's the case in real life for the 2 Voyager probes or for New Horizons.

There's also a third possibility, which is a parabolic trajectory. But this one occurs if your velocity is EXACTLY the escape velocity. If it differs by 1 micrometer per second, it's either elliptical or hyperbolic. That's why this possibility is not considered in practice, it's mainly a theoretical one.

The eccentricity (as it was displayed in 1.35) is also a good indicator: you've reached escape velocity when the eccentricity reaches 1.

In practice, for any body with a SOI, the velocity you need to exit it is slightly below its escape velocity. It's because your orbit is still elliptical, but the apoapsis is beyond the SOI limit, which still allows you to leave. But even without a SOI, it is actually possible to leave a body influence once for all.

 

[Horus Lupercal]

the escape velocity will be 78985 m/s

Yeah, that's roughly the number my sheet is spitting out as well for solar EV.

Even if the Sun has no SOI (or an infinite one), it's actually possible to escape it.

Aaah, I was in the opinion that in SFS you have to be in orbit of something as a reference point for your location?

 

[Altaïr]

Aaah, I was in the opinion that in SFS you have to be in orbit of something as a reference point for your location?

Your location is still referenced from the Sun, but you don't need to be "in orbit" around the Sun. If your trajectory is hyperbolic you're not in orbit anymore and the ship will get further and further without ever coming back, but the game still can handle it. Mathematically it's just an hyperbola, and one of its foci is placed at the Sun's location.
Does it answer your question? I'm not sure I understood your point well...

 

[Horus Lupercal]

Yeah, that makes sense that there is a speed where you technically escape, but can you actually leave the SOI though? It doesn't have a multiplier, so does it stretch into infinity and you have this Solar-Brexit scenario where you're leaving, but you can't actually go?

 

[Altaïr]

Yeah, that makes sense that there is a speed where you technically escape, but can you actually leave the SOI though? It doesn't have a multiplier, so does it stretch into infinity and you have this Solar-Brexit scenario where you're leaving, but you can't actually go?

Ah no, I didn't say that in that sense. Of course, the Sun has no finite SOI, so no, you can't escape the Sun influence. At most at some point it will become negligible.

 

[The Dark in the Light]

I just wish it had the Saturn info in it... It's okay though, I found the info in the Mod thread.
Working on making a chemical booster for the Tsar to make trips to Titan Easier. I just realized it'll take one way too big to allow a direct transfer, so I guess I'm sticking with Veega.

Where can I find this? Gonna restart my trips to Enceladus soon.

 

[TtTOtW]

Where can I find this? Gonna restart my trips to Enceladus soon.

Nice

 

[Altaïr]

Where can I find this? Gonna restart my trips to Enceladus soon.

It's in GuHP20's planet pack thread:
https://jmnet.one/sfs/forum/index.php?threads/the-complete-solar-system.1345/page-6#post-48277
I didn't make it official because there wasn't much demand for it, and it also depends on the planet pack, so yeah sorry, it's not easy to find.

 

[Blazer Ayanami]

Where can I find this? Gonna restart my trips to Enceladus soon.

It's in GuHP20's planet pack thread:
https://jmnet.one/sfs/forum/index.php?threads/the-complete-solar-system.1345/page-6#post-48277
I didn't make it official because there wasn't much demand for it, and it also depends on the planet pack, so yeah sorry, it's not easy to find.

Etherian, notice that this deltaV map is for GuHP20's Complete Solar System, not Gurren Lagann's ACSS, which is the one you are using.

 

[Space pilot]

What to do with Delta v here