KSP scaling

[TheDestroyer111]

Why does scaling in KSP look like this:

- Spacecaraft engines have the same Isp as real ones, but the spacecraft themselves have a far lower deltaV

- Most vehicles have to be roughly 2 times smaller in KSP (a human won't fit in KSP's 1.25m Fl-T-based parts), but their mass is about the same despite of the size being smaller

Huh? I'm wondering more about the second one, because the first one is probably simply caused by the different mass fraction of spacecraft, am i right? (up to 8/9 pieces of mass is fuel mass in KSP assuming the spacecraft is a fuel tank with nothing else, while in reality an entire rocket, with all the engines and payload, has more, but it doesn't seem to explain things fully)

[Guest]

10 minutes ago, TheDestroyer111 said:

- Spacecaraft engines have the same Isp as real ones, but the spacecraft themselves have a far lower deltaV

You don't need as much delta-V to get around the system so the parts are artificially inflated in dry mass which, due to Tsiolkovsky's equation and its dependence on the mass ratio of the craft, results in lower overall delta-V for a given craft.  This creates "difficulty" because the stock system is so tiny.

10 minutes ago, TheDestroyer111 said:

- Most vehicles have to be roughly 2 times smaller in KSP (a human won't fit in KSP's 1.25m Fl-T-based parts), but their mass is about the same despite of the size being smaller

See above.  Everything in KSP is artificially dense to create the tiny solar system.

If you had realistic densities in KSP Kerbin would be a Ceres-class object without an atmosphere orbiting a low-end M-class star.  Jool would actually be a "super Earth" sized rocky planet (because you can't have a gas giant that small) with some Ceres objects floating around it.

 

[theJesuit]

4 hours ago, regex said:

You don't need as much delta-V to get around the system so the parts are artificially inflated in dry mass which, due to Tsiolkovsky's equation and its dependence on the mass ratio of the craft, results in lower overall delta-V for a given craft.  This creates "difficulty" because the stock system is so tiny.

See above.  Everything in KSP is artificially dense to create the tiny solar system.

If you had realistic densities in KSP Kerbin would be a Ceres-class object without an atmosphere orbiting a low-end M-class star.  Jool would actually be a "super Earth" sized rocky planet (because you can't have a gas giant that small) with some Ceres objects floating around it.

 

Is there a mod for this?

[The Optimist]

4 hours ago, regex said:

If you had realistic densities in KSP Kerbin would be a Ceres-class object without an atmosphere orbiting a low-end M-class star.  Jool would actually be a "super Earth" sized rocky planet (because you can't have a gas giant that small) with some Ceres objects floating around it.

-The KSP sun is too small to initiate nuclear fusion, afaik.

-Jool is slightly smaller than the earth

[Guest]

29 minutes ago, The Optimist said:

-The KSP sun is too small to initiate nuclear fusion, afaik.

No, the radius is within the lower end of M-class stars.

29 minutes ago, The Optimist said:

-Jool is slightly smaller than the earth

My bad, thanks for the correction.

40 minutes ago, theJesuit said:

Is there a mod for this?

I had an RSS config for it at one point, was considering moving it over to Kopernicus but I'm way to burnt out to care anymore.  It's fun, and if you correct the lighting to match what the actual star puts out it's very moody.

[Gaarst]

The KSP is not too small to have fusion. But it is way too light, even for a brown-dwarf: at 9 M_J it couldn't fuse anything and would be classified as a sub-brown dwarf.

44 minutes ago, theJesuit said:

Is there a mod for this?

You mean a mod with real sized planets ? 64K or 10x Kerbol System come to mind (or RSS but then you'll get real planets).
Or a mod which replaces what the planets are by what they should according to their masses or radii ? Not aware of any.

[theJesuit]

18 minutes ago, regex said:

No, the radius is within the lower end of M-class stars.

My bad, thanks for the correction.

I had an RSS config for it at one point, was considering moving it over to Kopernicus but I'm way to burnt out to care anymore.  It's fun, and if you correct the lighting to match what the actual star puts out it's very moody.

 

11 minutes ago, Gaarst said:

The KSP is not too small to have fusion. But it is way too light, even for a brown-dwarf: at 9 M_J it couldn't fuse anything and would be classified as a sub-brown dwarf.

You mean a mod with real sized planets ? 64K or 10x Kerbol System come to mind (or RSS but then you'll get real planets).
Or a mod which replaces what the planets are by what they should according to their masses or radii ? Not aware of any.

Mod that replaces the planets with accuracy on size and mass with adjustments for atmospheres.

Jool may become the new Kerbin.  

[Guest]

18 minutes ago, theJesuit said:

Jool may become the new Kerbin.  

Too far outside the habitable zone, IIRC.  Pretty sure that correcting the densities of the bodies will result in a stable system regardless.