Eve DSTO

[psyper]

I've seen a lot of discussions lately on working out if a craft can get off of Eve using only a single stage (SSTO) and I think the conclusion is pretty much no, not without exploits.

So I was wondering. Would a double-stage to orbit (is that even a thing?) would work. IE have drop tanks that you can stage half way up. I'm thinking of a space plane that could ditch some tanks and engines once they are used up?

Edited October 14, 2014 by psyper

[Red Iron Crown]

Two stage to Eve orbit is theoretically possible. I wouldn't bother with wings, though. They're just wasted mass.

[Jimbimbibble]

If you have something like Kethane that allows you to use air breathing engines, sure.

[Geschosskopf]

I've seen a lot of discussions lately on working out if a craft can get off of Eve using only a single stage (SSTO) and I think the conclusion is pretty much no, not without exploits.

You can, with a bit of effort, make an Eve SSTO using Karbonite, if you consider that an exploit. Kethane doesn't work so well as its jet engine only works well with a combination of high throttle and low speed.

[KerikBalm]

I seem to recall some challenge to make the lightest eve lander ended up with something like a 2 stage to orbit vehicle.

The first stage was an ion powered plane, and the 2nd stage was a landercan with I think a FL-T200 tank and a 48-7s.. maybe it was more stages than that... but I think if it was, it could probably be adapted to 2 stage.

Kethane doesn't work so well as its jet engine only works well with a combination of high throttle and low speed.

Well, with that thick atmosphere, you don't need to go very fast, so it should be able to get you up out of most of the soup, no?

On another note: NEAR/FAR - how hard is it to get off eve with that mod?

Ignoring gravity and atmospheric drag, you only need a dV of ~3.5km/s

With NEAR/FAR, as long as your lander isn't pancake shaped, and has a decent TWR, you should be able to get into orbit with a dV of much less than 12km/s, no?

6km/s? that should be feasible in a single stage...

[Geschosskopf]

Well, with that thick atmosphere, you don't need to go very fast, so it should be able to get you up out of most of the soup, no?

True, for the 1st 20km or so, you often can't go fast and even if you can, you don't want to exceed the relative low terminal velocity anyway. But that's only about 1/4 of the ascent and after that, you start needing to build up speed towards your ultimate orbital velocity. And this is where the Kethane jet dies on you. It simply doesn't work above a certain speed, even if there's still plenty of air available. I believe this was a deliberate design decision specifically to prevent using it for an Eve SSTO. It's mostly intended for low flying on Eve--air liners, scout planes, cargo planes, etc.

[Jouni]

A two-stage lander should be relatively easy (for an Eve lander), assuming that you aim for the highest mountain. For example, use a Mk1 lander can, an X200-32 fuel tank, and a Skipper as the upper stage, and a Rockomax decoupler, an S3-7200 fuel tank, an S3-14400 fuel tank, and a KS-25x4 engine cluster as the lower stage, and you're already at around 8000/9100 m/s of delta-v with high enough TWR. For a bit more delta-v, replace the inefficient 3.75 m fuel tanks with 2.5 m tanks, and maybe add some extra fuel to the upper stage. Add a few SRBs to the lower stage, and you get more delta-v and more TWR, even if you don't detach them.

[psyper]

You can, with a bit of effort, make an Eve SSTO using Karbonite, if you consider that an exploit. Kethane doesn't work so well as its jet engine only works well with a combination of high throttle and low speed.

I've used kethane quite a lot before as a means to supply my operations off-world so to speak and have recently switched to karbonite which I'm quite a fan of at the moment so an SSTO using karbonite would be awesome!! Something to think about when I start getting contracts there...

[Laie]

True, for the 1st 20km or so, you often can't go fast and even if you can, you don't want to exceed the relative low terminal velocity anyway. But that's only about 1/4 of the ascent and after that,

Looking at the screenshots from my eve rocket, I was going 160m/s at 15km. Terminal velocity all the way, getting to 15km took about half of the flight time and 80% of the fuel spent.

[GoSlash27]

I'm thinking 2 stages to orbit is going to be iffy, especially if you're lifting payload. I'm interested in finding out if it's possible. Maybe a challenge?

I concur with Red Iron Crown that wings will do you more harm than good... except where you're using ions. An ion Eve glider with drop tanks *might* be possible, especially if you drop the wings once you've reached the edge of the atmosphere.

Best,

-Slashy

[psyper]

I'm thinking 2 stages to orbit is going to be iffy, especially if you're lifting payload. I'm interested in finding out if it's possible. Maybe a challenge?

I concur with Red Iron Crown that wings will do you more harm than good... except where you're using ions. An ion Eve glider with drop tanks *might* be possible, especially if you drop the wings once you've reached the edge of the atmosphere.

Best,

-Slashy

Thats what I'm thinking - drop tanks with wings attached to them so when it reaches a certain height you can kick those off and reach for the stars. A challenge is a good idea...

[psyper]

I'm interested in finding out if it's possible. Maybe a challenge?

Bang!

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