Weird gravity settings?

[Pink]

Hi. I'm a new guy experimenting with accidential crashing.
(he says, as if it was an original joke)

I'm on the latest version of SFS android.

And I was messing around in the text files for the planets, and I noticed that the gravity settings seemed wrong, especially for the moons of Jupiter.

(The gravity setting for Earth is 9.8 m/s^2, and I presume that all the others should be scaled according to that?)

Example: The surface gravity for Ganymede ought to be about 1.4 m/s^2 according to Wikipedia, but in the file settings it is about 4 m/s^2?

Maybe I'm missing something and that's intended, but can anyone shed light on this?

Many thanks!

 

[8BitCosmonaut]

Looks like he forgot the scale it down.

 

[Pink]

Thanks.
I was wondering why it was so difficult to land gently on those moons!

 

[8BitCosmonaut]

Thanks.
I was wondering why it was so difficult to land gently on those moons!

You could always brute force your way to the moon by using powerful engines like the Hawk. But if you are patient, you can design highly efficient landers with low thrust engines, plan ahead, and do some simple math to determine how long you have to burn in order to reach a gentle velocity before you reach a certain altitude. Say, 10 m/s at 300 meters.

 

[8BitCosmonaut]

You could always brute force your way to the moon by using powerful engines like the Hawk. But if you are patient, you can design highly efficient landers with low thrust engines, plan ahead, and do some simple math to determine how long you have to burn in order to reach a gentle velocity before you reach a certain altitude. Say, 10 m/s at 300 meters.

But this won't be necessary for this game, everything is scaled down so much you can bring powerful engines with you easily, added to the fact that engines can throttle down to 0.1%, its even easier.

I recommend you to just eyeball it.

 

[Altaïr]

Yeah, Stef made it quite a tough challenge by setting the jovian moons' gravity so high. Ganymede's gravity is even greater than Mars and Mercury!
The advantage is that it allows some powerful gravitational slingshots, but that's not really a consideration for unexperienced players.

You can lower their gravity in the configuration files indeed. That will probably reduce their sphere of influence radius though. If it's reduced too much, you can fix this by raising the "multiplierSOI" factor in the ORBIT_DATA section.

 

[8BitCosmonaut]

Yeah, Stef made it quite a tough challenge by setting the jovian moons' gravity so high. Ganymede's gravity is even greater than Mars and Mercury!
The advantage is that it allows some powerful gravitational slingshots, but that's not really a consideration for unexperienced players.

You can lower their gravity in the configuration files indeed. That will probably reduce their sphere of influence radius though. If it's reduced too much, you can fix this by raising the "multiplierSOI" factor in the ORBIT_DATA section.

Stef is high on C++, anymore and he'll start running his own version of SpaceX.

 

[Chara-cter]

Stef is high on C++, anymore and he'll start running his own version of SpaceX.

I thought it was C#
Nvm, they kinda similar

 

[Pink]

Thanks everyone!
Personally I wanted the gravity to be a little more realistically scaled, so I went and adjusted it.

Just for fun, This is what I did:

Spoiler: Planet gravities

All numbers in m/s^2

Planet: default / real life / my game

Mercury: 3.27 / 3.7 / 3.7

Venus: 8.87 / 8.87 / unchanged

Earth: 9.8 / 9.8 / unchanged
Luna: 1.42 / 1.62 / 1.62

Mars: 3.61 / 3.72 / 3.72
Deimos: 0.054 / 0.003 / 0.05 (nano-gravity is no fun, IMHO. )
Phobos: 0.087 / 0.0052 / 0.08

Jupiter: 25 / 25 / unchanged
Io: 4.32 / 1.8 / 1.8
Europa: 2.32 / 1.314 / 1.31
Ganymede: 5.84 / 1.428 / 1.43 (Wow. Over half of Earth's, and no aerobraking!)
Callisto: 4.24 / 1.235 / 1.24

 

[Altaïr]

Thanks everyone!
Personally I wanted the gravity to be a little more realistically scaled, so I went and adjusted it.

Just for fun, This is what I did:

Spoiler: Planet gravities

All numbers in m/s^2

Planet: default / real life / my game

Mercury: 3.27 / 3.7 / 3.7

Venus: 8.87 / 8.87 / unchanged

Earth: 9.8 / 9.8 / unchanged
Luna: 1.42 / 1.62 / 1.62

Mars: 3.61 / 3.72 / 3.72
Deimos: 0.054 / 0.003 / 0.05 (nano-gravity is no fun, IMHO. )
Phobos: 0.087 / 0.0052 / 0.08

Jupiter: 25 / 25 / unchanged
Io: 4.32 / 1.8 / 1.8
Europa: 2.32 / 1.314 / 1.31
Ganymede: 5.84 / 1.428 / 1.43 (Wow. Over half of Earth's, and no aerobraking!)
Callisto: 4.24 / 1.235 / 1.24

That's a realistic choice. By also making sure their dimensions and orbit radius are appropriate (except eventually Deimos and Phobos) this would make an interesting mod

 

[8BitCosmonaut]

Thanks everyone!
Personally I wanted the gravity to be a little more realistically scaled, so I went and adjusted it.

Just for fun, This is what I did:

Spoiler: Planet gravities

All numbers in m/s^2

Planet: default / real life / my game

Mercury: 3.27 / 3.7 / 3.7

Venus: 8.87 / 8.87 / unchanged

Earth: 9.8 / 9.8 / unchanged
Luna: 1.42 / 1.62 / 1.62

Mars: 3.61 / 3.72 / 3.72
Deimos: 0.054 / 0.003 / 0.05 (nano-gravity is no fun, IMHO. )
Phobos: 0.087 / 0.0052 / 0.08

Jupiter: 25 / 25 / unchanged
Io: 4.32 / 1.8 / 1.8
Europa: 2.32 / 1.314 / 1.31
Ganymede: 5.84 / 1.428 / 1.43 (Wow. Over half of Earth's, and no aerobraking!)
Callisto: 4.24 / 1.235 / 1.24

Try to do a 5g challenge.

 

[Pink]

Try to do a 5g challenge.

I think I saw that in a KSP video... Required a 100 stage rocket didn't it?

 

[8BitCosmonaut]

I think I saw that in a KSP video... Required a 100 stage rocket didn't it?

Nope, this Russian guy just use procedural engines and made a really big engine.

 

[Pink]

That's a realistic choice. By also making sure their dimensions and orbit radius are appropriate (except eventually Deimos and Phobos) this would make an interesting mod

Hmm.
I went and looked at the radiuses and orbits (I used the semi-major axis for the real life orbits) of the planets to check if they were scaled with Earth.
Mercury, Venus, Mars and Jupiter all had a radius that was within 1.2% of what it was supposed to be. Pretty much just a fault of rounding off huge numbers, and not important at all .

Of more interest was the orbits...
Mercury was 6.5% off, Venus was 5.8%, which MIGHT be noticeable... if you were actively looking for it.

Mars' orbit was 1.6% off from what my envelope maths says, which I also consider negligible.

There were some much more significant errors with the outer planets, but that's only the fault of the planet pack I installed.

Absolutely useless fact:
The radius of the Sun was 9% wrong, which is only important if you're trying to make a precision landing on it.

 

[Altaïr]

Oh, it seems quite accurate then, I thought there were more inaccuracies...
The Sun is not exact indeed, but raising its radius would actually increase its mass, which would make all planets rotate faster around it, and make interplanetary trips more expensive.
If it was adapted to SFS scale its characteristics would be:
- radius = 35000 km (instead of 31500)
- gravity = 274 m/s2 (instead of 100)
But I wouldn't recommend those changes (unless you really want a challenge) because it will make the game much much harder.

 

[Pink]

Oh yeah, I didn't think of that...
Increase the radius, and the gravitational force goes up to maintain the same surface gravity.

 

[Altaïr]

Oh yeah, I didn't think of that...
Increase the radius, and the gravitational force goes up to maintain the same surface gravity.

Exactly

 

[Pink]

(BTW, you can edit this topic as "solved", if you want. Just noticed that it still says "open".)

 

[Danny Batten]

(BTW, you can edit this topic as "solved", if you want. Just noticed that it still says "open".)

Done

 

[Blazer Ayanami]

Hmm.
I went and looked at the radiuses and orbits (I used the semi-major axis for the real life orbits) of the planets to check if they were scaled with Earth.
Mercury, Venus, Mars and Jupiter all had a radius that was within 1.2% of what it was supposed to be. Pretty much just a fault of rounding off huge numbers, and not important at all .

Of more interest was the orbits...
Mercury was 6.5% off, Venus was 5.8%, which MIGHT be noticeable... if you were actively looking for it.

Mars' orbit was 1.6% off from what my envelope maths says, which I also consider negligible.

There were some much more significant errors with the outer planets, but that's only the fault of the planet pack I installed.

Absolutely useless fact:
The radius of the Sun was 9% wrong, which is only important if you're trying to make a precision landing on it.

Yeah that's why I made my planet pack myself, using Earth as reference