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How to read Delta-V map?


CrazyGreenPilot_RUS
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Ideally, you add up all of the numbers between your starting point and your end point, remembering to add extra for any inclination change corrections you might need (typical inclination change amounts are listed next to the colored bar.) And also add the numbers again if you have to retrace your steps. For example:

3400dv to launch into Kerbin orbit + 950 to reach the edge of the Kerbin system + 980 to get a fly-by of the Jool system + 270 for a mid course inclination change + 160 to capture into high orbit of Jool + 620 to get a fly-by of Vall + 910 to get into orbit around Vall + 860 to land on Vall + another 860 to take off from Vall again + another 910 to escape Vall's orbit + another 620 to reach a high orbit around Jool again. Then work your way back down the Dv tree for each of your other destinations.

There is however a LOT of variation possible. You can use gravity assists from other moons to alter your course. You could do aerobraking in Jool's atmosphere or at Laythe to reduce your dv requirements considerably.

There's some bad news, however. It's basically impossible to do the mission you're attempting without bringing along mining equipment and ISRU converter to make fuel along the way. Tylo and Laythe each have extremely different landing and take-off requirements that a single ship is going to have difficulty handling efficiently for both. Tylo has no atmosphere and its gravity is about the same as Kerbin's. You basically need a fully fueled ship as big as what you use to launch from the surface of Kerbin for the landing AND fully fueled for the trip back up.

Laythe, on the other hand, has an atmosphere nearly as thick as Kerbin's. And while that means that you can descend quite easily with just parachutes, you won't be able to get much thrust out of vacuum optimized engines for the re-ascent.

I'm not saying it can't be done. But my choice would be to make a mothership that stays in orbit of these moons and have a couple of different landers optimized for their task.

Edited by HvP
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11 minutes ago, CrazyGreenPilot_RUS said:

For example, I want to fly to the Jool, land and take off from Laythe, Tylo, Vall, and Bop and back to the Kerbin. How much dV do I need?

Ok, check under Jool it says : 22300 dV, thats the complete cost of Kerbin Ground->Jool ''Ground''

The last icon before the planet is how much it costs to reach 210km orbit, so you go 22300-14000=8300Dv

Does that help a bit? Every DV number is the cost to transition btw orbits and btw orbit and ground,

so its just a matter of calculating each trip, uhh i hope i helped a bit.

 

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15 hours ago, HvP said:

There's some bad news, however. It's basically impossible to do the mission you're attempting without bringing along mining equipment and ISRU converter to make fuel along the way. Tylo and Laythe each have extremely different landing and take-off requirements that a single ship is going to have difficulty handling efficiently for both. Tylo has no atmosphere and its gravity is about the same as Kerbin's. You basically need a fully fueled ship as big as what you use to launch from the surface of Kerbin for the landing AND fully fueled for the trip back up.

Laythe, on the other hand, has an atmosphere nearly as thick as Kerbin's. And while that means that you can descend quite easily with just parachutes, you won't be able to get much thrust out of vacuum optimized engines for the re-ascent.

I'm not saying it can't be done. But my choice would be to make a mothership that stays in orbit of these moons and have a couple of different landers optimized for their task.

Thanks, I'm gonna use some legal cheats on Laythe. It is this valve that able to throw air with unbelievable speed. I can reach about 1200 m/s with only air on Kerbin. Also I have a mothership with about 35000 dV Liquid Hydrogen ion engine from KSPI already on 17000 km orbit of Kerbin( - about 4000 dV) and rescue capsule with 2500 dV to land on Kerbin. And two stage landing module specially for Tylo and I can refuel it about 12 times from saved fuel. I think this is enough but my 2 nuclear reactors don't want to work.:(

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9 hours ago, HvP said:

But my choice would be to make a mothership that stays in orbit of these moons and have a couple of different landers optimized for their task.


My Jool-5 parked a mothership between Val and Tylo...  I used a dedicated Laythe lander, and the core of the Tylo lander landed on the remaining moons.

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the deltaV map tells you how much you need to get there from kerbin, as others have explained. however, there is no exact way from the map to figure out how much to go from two other destinations. if you want to go from laythe to vall, you certainly need to spend the amount to get in orbit around laythe, and up to escape speed, and you certainly need to pay the cost to land on vall; but how much for a hohmann transfer between the two moons? and what will be your intercept speed afterwards? if that answer can be calculated (and not simply eyeballed), i don't know how.

i had a similar issue for going from gilly to moho.

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