Spaceplane vs. Rocket - Eve Rescue Party

[Sovnheim]

Dear all,

For one of my first manned missions on an other planet, I decided that Jeb and two of his friends would go for a stroll on the surface of Eve.

That... seemed like a good idea at the time.

Unfortunately, I may have slightly underestimated the amount of Delta-V I would require for such a mission. Subsequently, my team is now stranded with little chances of ever getting back on their own. I am now working on rescuing them, and I have trouble figuring out which is the best option to do so :

Should I use a spaceplane or a rocket to rescue them ?

Bonus question :

Should I choose the spaceplane option, how much Delta-V should I pack?

It seems that despite the lack of oxygen, the thickness of the air on Eve would make a spaceplane a reasonable solution. What do you think ?

Thanks !

[Oafman]

Planes work with jet engines, which require oxygen, which Eve doesn't have.

Unless you have a mod which gives you other types of jet engine (eg Interstellar mod has great thermal turbojets which work in other atmospheres), you're better off with a vertical lander.

Making anything which gets into orbit around Eve is tough. Use the search option to find threads about it, there are hundreds.

Look for the highest ground close to where your kerbals are stranded, and try to put your lander there. If it's a long way, you could even parachute a rover much closer to them, which they can use to drive up the mountain to get to the lander. Launching from altitude makes such a huge difference on Eve, as you avoid the thickest part of the atmosphere. You need something like 8500m/s deltav from the highest point on the planet, while it's more like 12000m/s from sea level.

Whatever altitude you launch from, you need to have a TWR of somewhere around 1.8 at launch. Combining the high TWR with the high dv requirements is the big challenge. The easiest way to approach this is to build small. Really small. Consider command seats instead of a pod. Lots of the threads where this has been discussed give much more detail on these points.

Good luck

Edited October 28, 2014 by Oafman

[Wanderfound]

Despite my being a spaceplane partisan most of the time, I have to admit that Oafman is right.

Eve is all about the crazy dense atmosphere; you want to get up above it as quickly as you can, to a place where your ÃŽâ€V expenditure isn't instantly nullified by drag. Spaceplanes are all about ascending slowly while accelerating laterally; if you're making a fast vertical ascent, wings are just dead weight.

Worth a try, though. I don't know if anyone has ever managed a successful Eve ascent relying upon aerodynamic lift rather than pure rocket grunt. Make sure to post screenshots if you do.

[iFlyAllTheTime]

This thread got me wondering.

Do aero mods FAR and NEAR affect atmos on planets other than Kerbin?

[Geschosskopf]

Should I use a spaceplane or a rocket to rescue them ?

Bonus question :

Should I choose the spaceplane option, how much Delta-V should I pack?

It seems that despite the lack of oxygen, the thickness of the air on Eve would make a spaceplane a reasonable solution. What do you think ?

If you're stock, then spaceplanes won't work at all because there's no oxygen for the stock jet engines. There are various mods, however, that provide atmospheric engines that will work without oxygen. AFAIK, these are as follows:

Firespitter: has electric props

Kethane: has a jet engine that burns Kethane in any atmosphere

Karbonite: has jets and props that burn Karbonite in any atmosphere

KSP Interstellar: has thermal jets that work in any atmosphere at all without needing fuel

Of these, it used to be possible to make Eve SSTOs using both Firespitter and Karbonite. However, these engines have been nerfed recently--it's no longer possible with Firespitter AFAIK and while it might still work with Karbonite, it's at least a very significant challenge (I haven't been able to do it lately). It has never worked with Kethane, intentionally so. So that pretty much leaves KSPI, although you have to be pretty far up its tech tree to have the necessary efficiency.

So, all in all, unless you're well-advanced in a KSPI game, there is really no choice but to use a rocket. And this rocket will be a huge mountain of dozens of asparagus stages made of 1.25m parts. It will work but it will be hugely expensive and difficult to get to Eve to begin with. So unless you've got a lot of money in the bank already, this option has to wait a while in a career game. But this is no big deal unless you're using a life support mod so have a limited timeframe. Still, in that case, it's pretty cheap and easy to just drop supplies to the stranded Kerbals periodically while you're building up the bank account to build the rescue lander.

[Taki117]

This thread got me wondering.

Do aero mods FAR and NEAR affect atmos on planets other than Kerbin?

Yes! It changes the atmospheric curve for the other planets to be closer to real life.

[Geschosskopf]

Yes! It changes the atmospheric curve for the other planets to be closer to real life.

No, it changes atmospheric conditions to match preconceptions based on Earth's atmosphere. If real life laws were applied to the atmospheres in KSP, then Kerbin's atmosphere would be much less like Earth's than it is even in stock.

[Yakky]

This thread got me wondering.

Do aero mods FAR and NEAR affect atmos on planets other than Kerbin?

Yes they do.

[GoSlash27]

Are you averse to glitch exploiting to rescue them? If not, you can have them home in a week using a kraken drive infiniglider.

Otherwise, you're looking at a multi-stage launch vehicle with rovers and all the headaches that go with that.

Best,

-Slashy

Edited October 28, 2014 by GoSlash27

[The_Rocketeer]

I once landed a fellow called Derbart on Eve in a Nuclear Space Plane.

I think he's living there still.

[Frank_G]

This will get expensive, but it is doable. The only way i have ever managed to return from Eve was in an asparagus staged rocket. You need around 10.000 m/s to ascend from Eve´s surface.

So, i recommend 3 rocket ships, one for each kerbal, or instead of capsules you use one ship with external mounted seats, but personally i would never leave my Kerbals to this discomfortable way of ascend...

If you like, take a look in my signature. There is a link to the detailed report of my Eve return mission.

Godspeed and good luck, sir. You´ll need it!

[cantab]

An Eve ascent is one of the biggest challenges in KSP. I suggest redesignating your mission as a colonisation and coming back to them later

[Jeff Bird]

An Eve ascent is one of the biggest challenges in KSP. I suggest redesignating your mission as a colonisation and coming back to them later

I agree with Cantab. Getting them back up would be hard for a new player. Just drop them a habitat module and some cookies for now. They'll be fine. Then, who knows, maybe Heisenberg compensators will pop up in the tech tree.

[Jovus]

It has been 'proven' impossible to make an Eve SSTO. This doesn't directly answer your question, but it's a lot easier to make a multi-stage rocket than a multi-stage plane.

[GoSlash27]

It has been 'proven' impossible to make an Eve SSTO. This doesn't directly answer your question, but it's a lot easier to make a multi-stage rocket than a multi-stage plane.

Clarification: Without glitch exploiting. There are several successful Eve SSTOs out there that exploit kraken drives, ladder lift, infiniglide, or some combination thereof. But SSTO without cheating is beyond the capability of stock parts in a stock installation.

Best,

-Slashy

[DrMonte]

For awhile that is all you need:

Though some day you might come up with something like this:

[Sovnheim]

Are you averse to glitch exploiting to rescue them? If not, you can have them home in a week using a kraken drive infiniglider.

Otherwise, you're looking at a multi-stage launch vehicle with rovers and all the headaches that go with that.

Best,

-Slashy

I try to limit my missions to stuff that exists in real life, so I'll go for the multi-stage launch headache conundrum.

This should be fun - thanks a lot everyone for the help !

Edited October 30, 2014 by Sovnheim

[MarvinKitFox]

It has never worked with Kethane, intentionally so.

I've had great success is launching from EVE surface using Kethane SSTO.

That is , SSTO as in "does not drop any parts on the way up"

The Kethane turbine doesn't support good speed, but you can get *very* high up in EVE's atmo using them. Something like 45km up, and ~450m/s

Then a changeover/augment to normal vacuum rocketry is practical.

This is in stock atmo model, of course.

FAR has a much more severe taper off of pressure.