Delta-V maps?

[Mr.Rocket]

Anyone one have any good delta-v maps? I've found a few, but none of them seem to be accurate for interplanetary stuff. For example, they say it takes about 130 delta-v to get to Duna after exiting Kerbin SOI, but i find this false, and it is really more than 1000 delta-v. Either that or I'm just reading them wrong:sticktongue:. Also, if you want to share a delta-v map, you can show it here. Thanks in advance:D! (also if this is in the wrong forum please move it)

[jsfalconero]

The dV maps assume that you are using transfer windows -times when the planets are aligned such that the minimum amount of fuel is needed to reach the target. I sometimes ignore them but the result is that it can take stupid large amounts of dV to make the transfer. It takes patience to wait for the windows but you CAN make it to Duna for 130 dV. I don't know if it's equally efficient to burn out of Kerbin's SOI then time warp to the window, but that might be a way to cut down on the waiting.

[Superfluous J]

I use this one fairly exclusively, though I also use this tool as well.

You may be either reading the chart wrong or executing your transfer improperly. To get from Kerbin's SOI to Duna's SOI, assuming you did the burn to exit from Kerbin's SOI correctly, does only take about 130 dV. More accurately, to get from Kerbin's orbit to Duna's SOI in a single burn, it takes about:

680 (dV to Keostationary)

+180 (dV to Mun's orbit)

+70 (dV to Minmus' orbit)

+20 (dV to Kerbin Escape)

+130 (dV to Duna SOI)

which is about the 1000 dV you reported.

Note it takes even more to slow down to get into Duna oribt, but if you're clever you can aerobrake and capture for much less.

[Mr.Rocket]

I use Kerbal alarm clock before i launch, warp to the given window, then launch. The manuver takes about 1000 delta-v? You definatly need to speed up more than 130 m/s to get to Duna, right? I actually ecounter the 1000 delta-v after i am out of kerbin SOI, when i am in orbit around the sun? I use that same map as you showed.

Edited December 6, 2013 by Mr.Rocket

[maltesh]

The delta-V maps assume that you're doing the burn direct from LKO. If you are burning from LKO, aligning your departure trajectory to leave the SOI in the direction of Kerbin's travel, to put your apoapsis at about the distance of Duna from the sun, that is indeed a delta-V of about 1000m/s.

If you burn just to escape Kerbin, get into solar orbit, and /then/ burn to transfer to Duna, it costs about 50% more delta-V. Do similar for a high-requirement destination, such as Jool or Moho, and you increase the delta-V requirement by more than 100%.

[Mr.Rocket]

Ohhhhhhhhh, I didn't know that:). I always burned to escape kerbin SOI, then warp out of it, then do the burn for Duna. Thanks sooo much, i didn't think that was possible.:sticktongue: You can see my confusion.

[rpayne88]

I've had that problem a lot. I use the proper launch window and left over 1km/s dv extra (after the plane change) to get to Dres. When I got there, I didn't even have enough to make orbit. Fortunately, it was a probe.

[Guest]

I only use delta-V maps for suggestions on how much I need to land/take off from a particular location. Otherwise they're wildly optimistic. Alex Moon's launch window planner is a much better tool for mission planning.

[KerbMav]

Yes, the dV needed to brake into an orbit - with no moon to sling around, no atmosphere to aerobrake ... will be a short visit to Moho for my probe ...

[Grizzlol]

If you play around with the parameters provided by the Launch Window Planner tool by alexmoon, you will find that the resulting dV requirements can differ greatly depending on when and how you execute the entire process, so it is not surprising to find that dV maps can be wildly inaccurate as they provide limited information.

Once life support is added to the game, this particular tool (Launch Window Planner) will be even more useful still, as you can choose to prioritize travel time versus fuel consumption and vice versa.

[Pixel of Life]

http://alexmoon.github.io/ksp/

I have not used this but it seems like it could be quite accurate.

[jduchock]

Start factoring in the Krag system and you will find you need 30-50k + dV for a round trip. Fortunately, the mod adds two additional levels of time warp which makes it go faster, but the only way i have been able to make it to Krag and back is by Impossible Innovation, Interstellar Warp or Orion... I decided to wait till .23 to set up a kethane planet map for fuel outposts to Krag...which will take weeks