[1.7.3] Community Delta-V Map 2.7

[Kerbas_ad_astra]

Oh hey, updated version of the DeltaV map that I like.

Wonder when the Wiki page one will be updated.

Unfortunately, the wiki is experiencing migration issues, so updating its image will have to wait.

[Alshain]

I consider myself a pretty good pilot for efficient ascents but I can just barely get up into orbit on 3400. I think this map is a little off, 3600 would be a better value for Kerbin considering I'm above average.

[Kowgan]

Alshain, have you read the "Atmospheric ascents" disclaimer, and the two previous pages? We've had a discussion about it.

I'm sorry, I can't please everyone. Many people can reach LKO with 3000m/s, and many other need 4000m/s to do it.

I had to pick a value. Hence the disclaimer.

[Alshain]

Well, all I'm saying is it shouldn't be the map for the top 0.5% of players. But, if that is what you want, that is fine too I was just making a suggestion. My launches are incredibly efficient and I don't see how 3300 is even possible.

Edited May 31, 2015 by Alshain

[Kowgan]

I wouldn't go with 0.5%. Actually, I wouldn't choose statistics out of the blind. What I've decided to do is to pick something next to the most efficient ways. Just like all the previous, most notorious delta-V Maps we had prior to this one.

And by doing that, I'm not trying to exclude a portion of the players who currently can't be that efficient. Rather, I'm trying to show them it's possible to be more efficient. And if I can do it with 3300m/s, I bet you can do it too.

In any case. There is a link in the OP containing the master file, in case someone isn't satisfied with my version. It's pretty easy to download a trial version of the software I used to remake this and put your own values there. I'm open to questions regarding the software usage.

[NikkyD]

Can someone explain to me how to make the 130 m/s from just leaving kerbin SOI to Duna intercept ??? The rest should be aerobrakeable. MJs hohmann says 850 m/s to reach Dunas orbit

[Superfluous J]

Can someone explain to me how to make the 130 m/s from just leaving kerbin SOI to Duna intercept ??? The rest should be aerobrakeable. MJs hohmann says 850 m/s to reach Dunas orbit

Short answer: Do it in one burn.

Long answer:

If you're in LKO and burn to escape Kerbin's SOI, it takes (about) 950m/s. If you CONTINUE to burn, it takes an ADDITIONAL 130m/s for a total of 1080m/s to burn to Duna.

Of course, you have to do the burn at the right time and in the right direction, and without some tricks or mods or charts finding that right time can be difficult (but not impossible) in the stock game.

The 720m/s you saved is due to the Oberth Effect, one of my favorite things in all of space flight.

[NikkyD]

So for the 130 m/s to apply i need the right constellation of ALL involved planets/moons ?

[Superfluous J]

So for the 130 m/s to apply i need the right constellation of ALL involved planets/moons ?

Yes. The chart assumes you are minimizing dV expenditure by launching at ideal times and doing ideal burns.

And note: In this case, "all" is Kerbin and Duna.

[NikkyD]

I was already planing on a mun slingshot again, thats why "all" and in theory mun or minmus COULD be in the way when Duna is in the right spot

[Superfluous J]

I was already planing on a mun slingshot again, thats why "all" and in theory mun or minmus COULD be in the way when Duna is in the right spot

True, but interplanetary windows are large enough to just jump forward or backward an orbit (of your ship around Kerbin) or two so Mun is out of the way. Or burn 3 seconds earlier or later so Minmus is out of the way

Edited May 31, 2015 by 5thHorseman

[NikkyD]

Where can i find data on where duna needs to be for that maneuver to work ?

[Kowgan]

NikkyD: Here and here. And for in-game consultation, you have this and this.

[NikkyD]

i knew "there is a mod for this"

[Superfluous J]

If you want to do it all stock, I have a quick vid on how to, once you're in LKO, figure out how to time and aim your eventual burn using placeholder maneuver nodes that you eventually delete.

But as neat as it is to be able to do it all stock, I much prefer the transfer window calculator mod. It's amazing.

[rofltehcat]

If I want to do a Kerbin -> Minmus landing -> Mun landing -> Kerbin landing tour, how much dV do I realistically need?

My thoughts: 3300 + 930 + 160 + 180 (Minmus landing), 180 + 160 + ~70 (probably more, transfer to Mun SOI) + 310 + 580 (Mun landing) + 580 + 310 + 860 = 7620. If I pack a buffer of an additional ~30% I'd be at around 10k.

Sounds like a lot so I should probably do a refuelling stop in Munar orbit but I hate docking...

anyways, did I read the map correctly? Or did I go wrong somewhere? And should I pack more/less fuel?

[Kowgan]

For the Minmus transfer, don't forget to add the plane change maximum-required delta-V, which can go up to 340m/s.

For a direct Minmus-Mun transfer, I'd use Alexmoon's window planner. It can give you a proper direct transfer (about 241 m/s in ideal conditions).

Lastly, you don't need all that 860m/s in the very end, to return to Kerbin. Return + aerobrake costs about 280m/s from the Mun.

Everything else is correct.

[Superfluous J]

If I want to do a Kerbin -> Minmus landing -> Mun landing -> Kerbin landing tour, how much dV do I realistically need?

Let's break this down a bit:

3300 + 930 + 160 + 180 (Minmus landing) Correct.

180 + 160 + ~70 (probably more, transfer to Mun SOI) Actually 70 feels about right for a Minmus-Mun transfer. Maybe even less. This chart doesn't well represent transfers that don't include Kerbin as an endpoint, though.

310 + 580 (Mun landing) Yup.

580 + 310 + 860 You do not need that 860 to return. The aerobraking will do it for you.

If I pack a buffer of an additional ~30% I'd be at around 10k. 30% is a big buffer. I usually do 10%. Feel free to start at 30% but note how much fuel you have and next time adjust your margins.

So I've saved you 860 already so your 10k is probably closer to 9k. If you cut your buffer to maybe 20% (or 10% like I do) we're getting close to 8k.

And ship design can cut this even further. You will always need that much dV, but you can do more with less fuel with efficient design. Leaving things in orbit (which of course means knowing how to rendezvous and dock) and designing a lander that can efficiently land on both Mun and Minmus (hint: Go to Mun first and leave an empty fuel tank on the surface, so your lander is smaller for the rest of the trip including the Minmus landing) can cut your payload in half, which means your lifter will be half as big.

Which means it'll be cheaper. And easier to fly. And you'll feel like a baws.

[Streetwind]

Quick little note: on the OPM map, shouldn't Tal Intercept be connected to Low Wal Orbit, instead of Wal Surface?

[Misucat]

Quick little note: on the OPM map, shouldn't Tal Intercept be connected to Low Wal Orbit, instead of Wal Surface?

Fixed, thanks you for the report

[scavenger]

THANK you for the maps

it adds loads of fun and HELP so much for rocket design

warm thanks

[Kowgan]

Map updated to KSP 1.0.4.

[TicTacToe!]

Remarkable work, thanks to all those involved!

[Yakuzi]

Map updated to KSP 1.0.4.

Great stuff! Thank you so much Kowgan!!! (and WAC for the original)

[Mat2ch]

Hello Kowgan,

thank you very much for the chart! It was very useful in my latest missions and will be even more, when I try to get three Kerbals back from Eve

Could someone with an account update the Cheat Sheet site in the wiki?