Delta-V and Eve

[Tokay Gris]

So, I know that from sea level it takes around 12.000 or 12.500 m/s.

And I know that from the top of that mountain (25°0'57"S, 158°27'21"W, according to Kerbalmaps) it should take around 7.500 m/s.

But how much delta-V would it take from, say, 4000m?

Because the top of that mountain is hard to reach by rover or in my case: A vessel with wheels.

I tried to use hyper edit to find out, but apparently every time I use this, some of my engines just break of.

Is this knowledge out there somewhere?

EDIT:

Here is my current attempt.

Packs about 11.000 m/s with sufficient TWR I hope. Currently driving to a mountain nearby.

EDIT: Watching that vessel roam the surface of Eve and listening to Woodkid "Run, Boy, Run" is actually fun.... A wooping 5 m/s for safety....

Edited November 1, 2013 by Tokay Gris

[Kerbocracy]

Nice lander! I like the rover/lander combined concept. But question for you - does it really have 11km/s dV? It doesn't look like it to me. Reason I'm asking is that I'm currently building an eve-return system and I've been struggling to produce something that I have confidence in for getting off Eve. I don't have any mods for dV estimation, so I'm going off feel. I know that getting off Eve is like 2.5x Kerbin roughly in dV. So with my vehicle I'm testing on Kerbin - getting Kerbin orbit and then some. The one I have now is like Kerbin escape + 2000 dV. I think that's adds up to close to 7000 m/s. But right now my ship is quite a bit bigger than yours. It has 5 stages, and 2 booster stages on top of that. The last stage is an asparagus burn for high atmosphere. Finally, I have a single ion-electric engine attached to the lander can for final orbit correction and return to the mothership. I heard that the Eve atmosphere goes out to 100km, so I imagine there is a ton of dV lost in air resistance and the gravity turn must be much later than on Kerbin.

Anyway, how did you get the 11km/s dV estimate? Have you tried to take off from Eve in it? How does it do in taking off from Kerbin?

[maccollo]

Your rover should be able to reach that mountain top. The slope is actually quite gentle if you go around it.

Don't know how much you would need from 4000 meters, but from 7500 meters you need a little more than 8 km/s.

So from 4000 meters... maybe 9.5 km/s is a good estimate?

[Tokay Gris]

Nice lander! I like the rover/lander combined concept. But question for you - does it really have 11km/s dV?

Thanks, but not my idea.

And yes, it does have 11.000 m/s Delta-V. Actually, according to MechJeb, it has 11.900 Delta-V.

Keep in mind that it is just supposed to get a Kerbal into Eve orbit. Not a pod.

And also that the whole stuff with wheels, parachutes, nuclear batteries, science equipment and the rest are decoupled on launch. The actual payload is an octo brain and a seat.

Anyway, how did you get the 11km/s dV estimate? Have you tried to take off from Eve in it? How does it do in taking off from Kerbin?

The estimates are from MechJeb and Engineer Redux.

It did take of from Kerbin just fine with lots of delta-V to spare. It even landed at KCS again on its tail and still five small tanks almost full.

According to the numbers, it should get off Eve ok, even slightly above sea-level. But currently I am testing the concept. And driving to a mountaintop.

Will tell you how it went.....

[allmappedout]

Good luck! We're all counting on you.

[MrPopcup]

I took off from eve at 2xxx meters, i made a topic with a video too, i reached orbit, rendevouz with the LEOS ( Low eve orbiting station ) and in the way, I had to get off the seat and use his jet pack to get in, by this I mean: TAKE OFF above 2800 meters! It really profits you!

[Tokay Gris]

Ok, all very promising. Ascent looked fine, delta-V was enough (starting altitude was 4000m), BUT:

There seems to be a problem in the very last stage.

As far as I can make out, the last stage decouples the last radial tanks and engines just fine, but for some reason regards the octobrain and the seat (as well as the Kerbal on it as part of one of the lateral tanks.

Which results in the last tank with the engine running going thataway, while a sad looking Kerbal, still sitting in his seat somehow invisibly attached to an empty fuel tank is tumbling through space... Well. Not long, since it is still not orbit.

Hm.... I hope I can repair that problem in the VAB, otherwise I have to start from scratch.

[Col_Jessep]

Somebody was kind enough to put a table with required d-V from certain heights on the Wiki: http://wiki.kerbalspaceprogram.com/wiki/Eve#Orbital_statistics

A little late but maybe it helps somebody else.

[TABLE=class: wikitable]

[TR]

[TH=bgcolor: #F2F2F2, align: center]Altitude (m)[/TH]

[TH=bgcolor: #F2F2F2, align: center]Delta-V Required (m/s)[/TH]

[/TR]

[TR]

[TD]0[/TD]

[TD]11,282[/TD]

[/TR]

[TR]

[TD]1000[/TD]

[TD]10,731[/TD]

[/TR]

[TR]

[TD]2000[/TD]

[TD]10,219[/TD]

[/TR]

[TR]

[TD]3000[/TD]

[TD]9,743[/TD]

[/TR]

[TR]

[TD]4000[/TD]

[TD]9,300[/TD]

[/TR]

[TR]

[TD]5000[/TD]

[TD]8,888[/TD]

[/TR]

[TR]

[TD]6000[/TD]

[TD]8,507[/TD]

[/TR]

[TR]

[TD]7000[/TD]

[TD]8,150[/TD]

[/TR]

[TR]

[TD]7540[/TD]

[TD]7,968[/TD]

[/TR]

[/TABLE]

[Sirine]

http://forum.kerbalspaceprogram.com/threads/48503-Eve

Just ignore those big bold word. In that thread.

It can land on Eve chemical ocean, and takeoff to Lower Eve Orbit, no problem (even control manually).

[brienne]

And yes, it does have 11.000 m/s Delta-V. Actually, according to MechJeb, it has 11.900 Delta-V.

The rover seen in first post? 11900 dv?

What is your secret?

[Kerbocracy]

while a sad looking Kerbal, still sitting in his seat somehow invisibly attached to an empty fuel tank is tumbling through space... Well. Not long, since it is still not orbit.

Hm.... I hope I can repair that problem in the VAB, otherwise I have to start from scratch.

Sorry to hear about your Kerbal being attached to the wrong thing..that's rough. I installed MechJeb too look at my deltaV but found out that the mechjeb module has a weight of 6, which totally throws off my delta v estimate. I installed engineer redux, and their assembly module is virtually weightless, so I could get a read on my dV. The rocket I was about to send to Eve was about 9300 dV, which would be able to handle certain takeoffs - say 5000m and above. But seeing the incredible dV that yours has, I want to try for a smaller design now that I've got a read on dV as I build. So thanks for that. I do want to send a lander can though rather than a seat. I also like the idea of leaving the science gear there. But I can send an unmanned lander to do science; I just need the Kerbal there to get a soil sample.

One question I have, is that currently my 9300 dV lander is about 130 tons. One thing I'm wondering about is how to slow the thing down as it lands. I don't want to waste fuel on the landing, but can't really fit any more parachutes on it. I used an online parachute calculator and found out I was coming up short. My landing trials on earth were controlled crashes (landing at about 13 m/s) and hence didn't allow for a viable re-takeoff. I was kinda hoping that on Eve with the thicker atmo my parachutes might be more effective. But then again the gravity is bigger. The parachute calculator indicats that I will still have a controlled crash at about 9 m/s given my current config.

So. It's back to the drawing board for me. I want to build a lander (based on the light lander can) that has about 13k dV, so I can go wherever I want on Eve. I want to bring a rover. I want to bring some science gear but am prepared to leave it there. Perhaps it will go on the rover.. More work for me. My first three attempts at this have probably taken about 8 hours of building testing time:) But alas, it's fun.

Oh and P.S. - I think you have to go through re-entry in the atmo, right? For this reason I was strapping a giant heat-shield on my lander that gets ejected after entry. But for realism sake I think this is part of the requirement...

[Tokay Gris]

The rover seen in first post? 11900 dv?

What is your secret?

Hm... Secret?

I decouple everything that is not needed. Everything but the centerpiece is dropped. Wheels, science equipment, nuclear batteries, parachutes... everything decouples on launch.

The actual launcher looks like this, if unfolded:

[Tokay Gris]

Somebody was kind enough to put a table with required d-V from certain heights on the Wiki: http://wiki.kerbalspaceprogram.com/wiki/Eve#Orbital_statistics

A little late but maybe it helps somebody else.

[TABLE=class: wikitable]

[TR]

[TH=bgcolor: #F2F2F2, align: center]Altitude (m)[/TH]

[TH=bgcolor: #F2F2F2, align: center]Delta-V Required (m/s)[/TH]

[/TR]

[TR]

[TD]0[/TD]

[TD]11,282[/TD]

[/TR]

[TR]

[TD]1000[/TD]

[TD]10,731[/TD]

[/TR]

[TR]

[TD]2000[/TD]

[TD]10,219[/TD]

[/TR]

[TR]

[TD]3000[/TD]

[TD]9,743[/TD]

[/TR]

[TR]

[TD]4000[/TD]

[TD]9,300[/TD]

[/TR]

[TR]

[TD]5000[/TD]

[TD]8,888[/TD]

[/TR]

[TR]

[TD]6000[/TD]

[TD]8,507[/TD]

[/TR]

[TR]

[TD]7000[/TD]

[TD]8,150[/TD]

[/TR]

[TR]

[TD]7540[/TD]

[TD]7,968[/TD]

[/TR]

[/TABLE]

Perfect! Exactly what I was looking for.

Thanks a lot!

[Tokay Gris]

Oh and P.S. - I think you have to go through re-entry in the atmo, right? For this reason I was strapping a giant heat-shield on my lander that gets ejected after entry. But for realism sake I think this is part of the requirement...

Also and not to ignore: The plates you use as heats shield provide incredible stability and impact tolerance. One of my tests had one underneath and survived 10 m/s on impact unharmed.

Also, you can place a lot of parachutes directly on the plates. You need to stabilize it, though, otherwise it turns upside down when the parachutes deploy.

[Kulebron]

Here is my current attempt.

Packs about 11.000 m/s with sufficient TWR I hope. Currently driving to a mountain nearby.

Wow, I tried making a similar thing, with aerospikes and thin tanks, but it was much bigger and not near 11k m/s. Could you share the craft file?

[Kulebron]

Hm... Secret?

Now I see the reason: you put this bike seat instead of landing can (600kg) as I did.

Poor kerbals!

[Tokay Gris]

Now I see the reason: you put this bike seat instead of landing can (600kg) as I did.

Poor kerbals!

Well.... he does have a capsule on the surface. But it stays there.

;-)

[Tokay Gris]

Could you share the craft file?

Sure! As soon as I find a workable server for this...

[Kerbocracy]

Also and not to ignore: The plates you use as heats shield provide incredible stability and impact tolerance. One of my tests had one underneath and survived 10 m/s on impact unharmed.

Also, you can place a lot of parachutes directly on the plates. You need to stabilize it, though, otherwise it turns upside down when the parachutes deploy.

Interesting; I've never tried landing on my heat shield...problem is that the extra weight it has will make for a faster landing. Doesn't the shock go up the structure and knock stuff loose (decouplers and such)?

I really like the idea of putting the parachutes on a detachable lower half. Mass reduction is critical I'm finding. I had a system that had 11k dV last night, and I added struts for stability and it dropped to 9k:)

I'm also going for the powered descent, so the lander will have a bottom stage that will remain, with science, parachutes, and the descent engine, taking as much off the ascent stage as possible. I still insist on the lander can though because conceptually I think the Kerbal needs 'storage' for the soil sample...

[magnemoe]

Hm... Secret?

I decouple everything that is not needed. Everything but the centerpiece is dropped. Wheels, science equipment, nuclear batteries, parachutes... everything decouples on launch.

The actual launcher looks like this, if unfolded:

Nice, note that you could probably managed with more fuel on the upper stages, in 0.22 the 48-7S has 30Kn over 20Kn in 0.21

You want to keep an low TWR for the lower stages to avoid pushing against the terminal speed.

I just used an Eve lander from 0.21 and put the science stuff in an landing stage and had TWR of 2 or more all the way.

http://imgur.com/a/LplKh#3

[Tokay Gris]

Damn!

I miscalculated.

First: That vessel has 11.900 delta-V in vacuum. Which Eve doesn't have.

Second: I forgot that there is a Kerbal on top. Which reduces the delta-V in vacuum to slightly above 10.000. And 8.775 m/s in atmosphere.

Which means: I really have to get on top of a mountain. Just tried from 2000 m and I was just able to get to space, but not to orbit.