Eve, 12,000 Delta-V... Really?

[Talonsin]

Does it really take 12,000 delta-V to land or launch from Eve? Obviously you can use parachutes on the way down and reduce the needed Delta-V but does it really take 12,000 to launch into a low orbit from Eve? Anyone land and take off from Eve? If you have, how about a pic of your ship?

Thanks

[Tiron]

Does it really take 12,000 delta-V to land or launch from Eve? Obviously you can use parachutes on the way down and reduce the needed Delta-V but does it really take 12,000 to launch into a low orbit from Eve? Anyone land and take off from Eve? If you have, how about a pic of your ship?

Thanks

Eve has 1.7 times as much gravity as Kerbin and an atmosphere 5 times thicker than Kerbin's at their respective sea levels. The atmosphere also extends about 27km higher than Kerbin's. All this adds up to substantially increased drag and gravity losses, plus needing to go higher (because of the greater extent of the atmosphere) and faster (because of the higher gravity) before reaching a stable orbit.

Eve is the hardest place to land and return from...although strictly by virtue of the fact that you can't land on Kerbol or Jool.

I can't say for sure that the number's accurate, but given the atmospheric and gravity characteristics I wouldn't be at ALL surprised if it were HIGHER than that.

[Syhrus]

I'd suggest following Scott Manley's current series. He's trying to do just this.

[Blue]

Every kilometre of altitude you can gain from sea level is more than 800m/s you save in Delta-v in the ascent. Launching from the highest point on Eve is roughly 7000m and that's enough to make the required launcher not much more demanding than a Kerbin sea-level launch.

[arq]

Even from the highest mountains, the usual number people throw around is 7km/s to get into Eve orbit.

[Specialist290]

On the plus side, if you can somehow get high enough that gravity stops being a problem for the LV-N's thrust-to-weight issues, they reach 99% of their Isp efficiency just after 43km up, at least if the same principles apply as in Kerbin's atmosphere.

Granted, I have yet to actually test this to see if it's practical.

Edited September 28, 2013 by Specialist290

[Captain Sierra]

The LV-Ns are so bloody heavy though. I think you'd waste more dV than you'd save dragging them to an altitude where they would work.

[Sirine]

With mod or mechjeb, yes. Without = No.

Pinpoint landing on Eve is hard, driving up hill to 7000m is even harder. Why the hack take the risk? Check my sign, my craft takeoff from Eve sea. and Yes, it can land on the Eve sea. Tested and proven, Just one thing, you can't plant a flag on water.

[Moar Boosters]

I built a lander with 10.5k delta-v and after about half a dozen failed attempts to land it on a mountain, I landed it on some plains about 2km high.

It failed to get up to orbit and jebediah fell back down into the ocean and died.

[csanders]

This is what it took to get me off of Eve. And yes, it's Dv is around 12000m/s. If you look at all the parachute packs, that's so I could land without burning hardly any fuel - and they all decouple on launch, along with the landing legs.

after launch:

Mamma I'm coming home

Edited September 28, 2013 by csanders

[Frederf]

FAR tends to reduce aerodynamic effects for most launches on Kerbin. How does it alter the Eve situation?

[csanders]

FYI, that ship has 6 outer asparagus stages, with 1 onion stage (the engines without the doubled up fuel tanks). The onion stage gave higher TWR, the asparagus gave efficiency.

The two red dots on the "after launch" picture are SAS modules - I used to have ONE on the second to last stage, didn't work. The thing is almost all aerospike engines, thus unstable, so it does need them to take off from a non-level service. Moving the SAS to the first aspargus stage that decoupled was key. Looking at that design, I could probably get more by making the last decoupler smaller as well.