Delta-V map

[r_rolo1]

But I heard that the new ISP system meant that engines got a big fat zero thrust on Eve's surface. Maybe that's not true, but I haven't tested it yet.

Some do. Others have their efficiency heavily reduced and there is one that actually performs better at pressures higher than Kerbin ( the aerospike ).

[Endersmens]

Some do. Others have their efficiency heavily reduced and there is one that actually performs better at pressures higher than Kerbin ( the aerospike ).

Ah, so the aerospike is the Eve goto engine now.

Wait wasn't it already?

[r_rolo1]

Well, it is diferent. In 0.90 all the engines worked ( sort of ) in Eve and the aerospike was the one that suffered less from the pressure. Nowadays most engines nil themselves in low Eve atmo ( BTW that is unrealistic, but gameplay is gameplay :/ ) and the aerospike actually works better in Eve than in Kerbin

[Endersmens]

How is it unrealistic?

But anyways, my point still stands, transfers have not changed. (unless SQUAD changed orbits or something)

[r_rolo1]

Nixing the thrust of a rocket engine due to outside pressure should only happen if the exterior pressure is above the combustion chamber one while the engine is working ( think on it as the atmo pushing the exhaust into the combustion chamber again ) While that most likely would happen above certain pressures for some designs ( like in the 92-3 atm pressure of RL Venus ), there is no way that any rocket engine would be blocked by the 5 atm of pressure of low Eve atmo. Even the typical water rocket engine used in demos for small kids would most likely still have some thrust in Eve ...

BTW the reason why the aerospike is mostly insensible to atmospheric pressure changes is exactly because it does not have a combustion chamber

Edited April 30, 2015 by r_rolo1
Added the water rocket reference

[zekes]

Well, transfers haven't really changed....

The only things that need updating are ascents from kerbin, Duna, and Eve. (as far as I've heard eve is impossible now)

even with ladder glitch?

[Endersmens]

ladder glitch...?

- - - Updated - - -

Nixing the thrust of a rocket engine due to outside pressure should only happen if the exterior pressure is above the combustion chamber one while the engine is working ( think on it as the atmo pushing the exhaust into the combustion chamber again ) While that most likely would happen above certain pressures for some designs ( like in the 92-3 atm pressure of RL Venus ), there is no way that any rocket engine would be blocked by the 5 atm of pressure of low Eve atmo. Even the typical water rocket engine used in demos for small kids would most likely still have some thrust in Eve ...

BTW the reason why the aerospike is mostly insensible to atmospheric pressure changes is exactly because it does not have a combustion chamber

Interesting.

Also, yeah I knew that about the aerospike, that was why it's ISP would only change 2 seconds between 1 atm and vacuum.

[patrioticparadox]

Anyone know of a 1.0(2) updated map?

[cybersol]

Anyone know of a 1.0(2) updated map?

This thread has some: http://forum.kerbalspaceprogram.com/threads/96985-1-0-2-WAC-s-Delta-V-Map-%2824-05-2015%29

However, I would take the atmospheric numbers with a large grain of salt.

[SAI Peregrinus]

Nixing the thrust of a rocket engine due to outside pressure should only happen if the exterior pressure is above the combustion chamber one while the engine is working ( think on it as the atmo pushing the exhaust into the combustion chamber again ) While that most likely would happen above certain pressures for some designs ( like in the 92-3 atm pressure of RL Venus ), there is no way that any rocket engine would be blocked by the 5 atm of pressure of low Eve atmo. Even the typical water rocket engine used in demos for small kids would most likely still have some thrust in Eve ...

BTW the reason why the aerospike is mostly insensible to atmospheric pressure changes is exactly because it does not have a combustion chamber

It's not about the exhaust being forced back in, it's about the transition of the flow from laminar to turbulent due to separation from the engine bell. The supersonic exhaust generally has a very low pressure, and when the pressure is below about 25% of atmospheric pressure the exhaust separates. It can then move off-axis, causing the rocket to flip, vibrate and tear apart, or damage the engine. KSP doesn't model that, it just makes the thrust decrease. Aerospikes and other altitude-compensating engines are designed to mitigate this issue.

[patrioticparadox]

Thanks for the link cybersol!

[Alshain]

This thread has some: http://forum.kerbalspaceprogram.com/threads/96985-1-0-2-WAC-s-Delta-V-Map-%2824-05-2015%29

However, I would take the atmospheric numbers with a large grain of salt.

That is forgiving in my book. I would take those atmospheric numbers as wrong. 3300 delta V? That's about 300 too short. I wish I had the software, I'd make my own version.

Edited May 28, 2015 by Alshain

[carlorizzante]

Great tool, thanks.

But how does it work for the return route? Should I take in account the same DeltaV I spent for intercepting?

Quick example to get to Mun and back to Kerbin.

4.500 - Getting into Orbit around Kerbin
860 - Intercept Mun
210 - Orbit Mun
860 - Intercept Kerbin
6.430 - TOTAL

[Tatonf]

No.

First, this map is pre 1.0, and the atmospheric numbers are not correct. Please refer to this map for up to date numbers :

A journey to Mun would more be like :

3400 - Going to LKO

860 - Intercept Mun

And that would be it if you only intend to do a fly-by because of the free-return trajectory.

 

Now if you want to make a low orbit and then come back to Kerbin, it would be :

3400 - Going to LKO

860 - Intercept Mun

310 - Be captured in LMO

275 - Going back to a 30 km Kerbin periapsis

The last number is unfortunately not displayed on the map and is the result of testing. But if you haven't done any testing, 310 would be a good approximation.

[mrmcp1]

5 hours ago, carlorizzante said:

Great tool, thanks.

But how does it work for the return route? Should I take in account the same DeltaV I spent for intercepting?

Quick example to get to Mun and back to Kerbin.

4.500 - Getting into Orbit around Kerbin
860 - Intercept Mun
210 - Orbit Mun
860 - Intercept Kerbin
6.430 - TOTAL

Going from the numbers from the map you have the right idea but for the intercept Kerbin you can save a huge amount of Delta V by aerobraking around kerbin (i.e. using the atmosphere to slow down) @Tatonf has used the updated numbers and has accounted for aerobraking. If you want an updated map in a similar style I made one a couple of weeks ago. 

 

Edited April 21, 2016 by mrmcp1

[carlorizzante]

Thanks. So it's correct that to get back to Kerbin I'll need a minimum of ~800 DeltaV left, from the orbit of Mun. Just the same I needed to get to Mun in the first place.

I thought that I needed less DeltaV. My assumption was that from Mun I'm basically falling back to Kerbin. Oh well... I was wrong

I'll try aerobraking into Kerbin's atmosphere. Sounds fun. Thanks for the map.

[Tatonf]

No. Once you're in orbit around the Mun, you need a minimum of 275 m/s, not 800.

[Sarahleth]

On 21/04/2013 at 7:31 PM, Nuprin Feelgood said:

I apologize for not knowing or remembering the original author of the image.

The oldest place i can find this posted is on this site http://www.aplusphysics.com/projects/kerbal.html At the bottom it has a link saying "Kerbin System Delta-Vee Map" which takes you to the image. That was posted on Dec 01, 2013.