Eve science return system

[DJRWolf]

It is only a small part of the system needed to get science from the surface of Eve but I feel it is the important part of getting off the surface of Eve and back into space in a way that you can also get back to Kerbin. The kind of mission profile I have for this is to put 8 (or extra's as backups) into orbit of Kerbin and they wait there for a departure window to Eve. Waiting for departure along with them is the "Return Bus" that will collect all of the "science package's" and get them back to Kerbin's surface safely.

First is the lander that have the Science Jr and Mystery Goo. With Eve being a lot like Kerbin I'm guessing that it having 4 Mk16-XL parachute's should be enough for a soft landing. Once it is on the ground you have the Science Jr and Mystery Goo to preform the experiment. After you are done with that you dump the parachute's (or anytime before that after your on the ground) and launch it back into orbit. I was able to launch it from KSC with the solids at 70% thrust to a 75 km orbit (using MechJeb).

After you get it into orbit you will then need to pick it up with the return bus. That part of the system can bring back up to 8 of the lander's science package's. You will need plenty of delta-v on this as you will have to rendezvous with all of them. The plan I have is once the bus gets to within 75-100m of the lander's return section you switch back to the science lander and have that dock with the bus. Then it will be the smaller of the two that has to use thrusters to come in and dock. Once docked the science return system has a decoupler just below the Science Jr so all you will have left is the minimal needed to keep weight and awkwardness down as the bus starts to more and more of them docked to it. To land on Kerbin it will just use a parachute.

Links to the craft:

Lander:

https://dl.dropboxusercontent.com/u/5052189/Science%20Return%20Alpha.craft

Return bus:

https://dl.dropboxusercontent.com/u/5052189/Probe%20Return%20Bus.craft

[Giggleplex777]

You'll need a lot more fuel than that! It takes almost 12 km/s f delta-v to get to orbit from surface level.

[DJRWolf]

You'll need a lot more fuel than that! It takes almost 12 km/s f delta-v to get to orbit from surface level.

Does Eve take more fuel then Kerbin to get into orbit? Because the lander/return-to-orbit part of the system I test launched from KSC and it made it to 75km orbit with some fuel to spare (but not all that much). I thought Eve was slightly smaller and would therefor require less delta-v to get into orbit.

[Sirine]

Does Eve take more fuel then Kerbin to get into orbit? Because the lander/return-to-orbit part of the system I test launched from KSC and it made it to 75km orbit with some fuel to spare (but not all that much). I thought Eve was slightly smaller and would therefor require less delta-v to get into orbit.

Check out my sign. and the ascending video. You will get an ideal how much fuel is needed.

[Jacob01]

Does Eve take more fuel then Kerbin to get into orbit? Because the lander/return-to-orbit part of the system I test launched from KSC and it made it to 75km orbit with some fuel to spare (but not all that much). I thought Eve was slightly smaller and would therefor require less delta-v to get into orbit.

Nope. In real life, Venus is slightly smaller than Earth. But in KSP, Eve is 700,000 KM in diameter, and Kerbin is 600,000 KM. Eve also has a thicker atmosphere, therefore requiring more delta-v to get into orbit.

According to the wiki, Kerbin takes 4500m/s of delta-v to gain orbit but Eve takes 11,500m/s of delta-v to gain orbit. By just looking at the ship, I very much doubt it has enough.

If you watch HOC gaming's latest career mode video, he is building something you tried to here. Maybe you could look there and try to build a new one?

[DJRWolf]

Just so I can get an idea to do KSC testing; what orbital altitude should I aim for to see if it should work on Eve without having to spend the time to go there?

(This is right were my Simulator idea could come in very handy to tweek a design)

[Sirine]

The below craft can lift a crew from Eve sea lvl. You are welcome to test it... and maybe you could tell us, how many orbital altitude should you notice.

http://www./view/5l5qrtgbn1kp6at/017%20-Eve%20Lander%2BLifter%20Mk2.craft

It can't lift 2 crew...not enough DV for that. Means, this craft is DV tight...on Eve 90x90km orbit.

[nhnifong]

The below craft can lift a crew from Eve sea lvl. You are welcome to test it... and maybe you could tell us, how many orbital altitude should you notice.

http://www./view/5l5qrtgbn1kp6at/017%20-Eve%20Lander%2BLifter%20Mk2.craft

It can't lift 2 crew...not enough DV for that. Means, this craft is DV tight...on Eve 90x90km orbit.

I can't load this, it has a generic error.

can you show a picture of it?

[Sirine]

I can't load this, it has a generic error.

can you show a picture of it?

Sure..here u go.

[Sirine]

And full craft file here.

http://forum.kerbalspaceprogram.com/threads/21975-The-New-Stock-Repository-Version-0-21?p=633793&viewfull=1#post633793

[I_Killed_Jeb]

yikes OP, you release an Eve return craft without even trying it out for yourself?

[DJRWolf]

yikes OP, you release an Eve return craft without even trying it out for yourself?

I did test it at KSC. If you have nothing constructive to add, please shut up.

Anyway, to continue the constructive discussion, I added another SRB and here is the Delta-v info as reported by MechJeb.

I conducted another test launch with the new configuration to a Kerbin orbit of 125km and I had fuel to spare.

Edited January 21, 2014 by DJRWolf

[I_Killed_Jeb]

I did test it at KSC. If you have nothing constructive to add, please shut up.

bit touchy are we? good thing you released a KSC return craft. oh wait...

you were told you need >10km/s dv for eve surface return and you add a booster to take it to 5k. strong work.

[Rune]

I did test it at KSC. If you have nothing constructive to add, please shut up.

Anyway, to continue the constructive discussion, I added another SRB and here is the Delta-v info as reported by MechJeb.

https://dl.dropboxusercontent.com/u/5052189/screenshot5.png

I conducted another test launch with the new configuration to a Kerbin orbit of 125km and I had fuel to spare.

https://dl.dropboxusercontent.com/u/5052189/screenshot6.png

Then again, as you have already been told, Eve is nothing like Kerbin. Kerbin needs around 4.5km/s in delta-v to reach stable orbit from sea level. Eve, about 11. So deorbit that thing, then take it back to orbit, and you will get closer to what you need for Eve. I say closer, because still the extra 2km/s above two kerbin orbital launches make the problem exponentially more difficult. You are reading ~5,900m/s on your design, and 3.5 come from the last stage, so your attempt isn't even an efficient three-stage design, I could get as much with two.

Rune. Bottom line? Not even close. But keep trying! And go for something easier before tackling the hellish-est planet on the Kerbol system.

[DerekL1963]

With Eve being a lot like Kerbin I'm guessing

Less guessing, more flight testing before releasing to the public.

[DJRWolf]

I scraped everything below the mono-propellent tank and started from scratch. Still had fuel left in the 2nd stage booster after getting to 325km Kerbin orbit. Can't deorbit and relaunch as the landing gear are dumped with the SRB's.

Edited January 21, 2014 by DJRWolf

[Neotician]

I did test it at KSC. If you have nothing constructive to add, please shut up.

Anyway, to continue the constructive discussion, I added another SRB and here is the Delta-v info as reported by MechJeb.

https://dl.dropboxusercontent.com/u/5052189/screenshot5.png

I conducted another test launch with the new configuration to a Kerbin orbit of 125km and I had fuel to spare.

https://dl.dropboxusercontent.com/u/5052189/screenshot6.png

See that Total deltaV figure in the mechjeb window? You need to get that to about 11,000 m/s^2 , and that is the amount you need to have left after you have landed, just to reach orbit.

At best you need about 7,000 deltaV to launch from Kerbin and get to eve.

Then you need about 2300-2500 to get back.

So we're looking at a total of 20,500 deltaV to Launch, get to eve, launch from eve and get back, assuming that you use zero fuel on landing on eve and landing on kerbin.

Oh, you also need TWR (thrust to weight ratio) of 1.7 (calculated in kerbin gravity) or more to be able to take off from Eve, since it has a gravity 70% stronger than Kerbins.

[DJRWolf]

So we're looking at a total of 20,500 deltaV to Launch, get to eve, launch from eve and get back, assuming that you use zero fuel on landing on eve and landing on kerbin.

Oh, you also need TWR (thrust to weight ratio) of 1.7 (calculated in kerbin gravity) or more to be able to take off from Eve, since it has a gravity 70% stronger than Kerbins.

Thanks for the TWR info. Don't need it to get back to Kerbin. Just into orbit so the Probe Bus can pick it up. Currently planning on using parachutes for landing on Eve and Kerbin.

[I_Killed_Jeb]

Have you actually landed on Eve yet? Might be a good place to start to get a sense of a return vehicle.

[The Destroyer]

A good thing to do is aim for the highest peaks- higher alt, less atmo, less delta-v needed.

[DJRWolf]

Have you actually landed on Eve yet? Might be a good place to start to get a sense of a return vehicle.

Not yet. Just the Mun so far. This is where my Simulator idea would come in handy as I could have just start it right from the surface of Eve to test it and posted screen caps of it in orbit without having to spend the time just getting there and making it past the landing just to test it.

A good thing to do is aim for the highest peaks- higher alt, less atmo, less delta-v needed.

I do plan on using parachutes as the only means to land. How would aiming for the higher elevations workout with that? Also, what about the TWR from there?

[Captain Sierra]

So . . .you haven't been outside Kerbin SoI and yet you have something which can supposedly take off on Eve, the single hardest planet in the game to get to orbit from. You can see where the disbelief comes from.

And to answer the question, the highest peaks are IIRC, 10km up, also getting you into slightly thinner air (the biggest advantage). TWR would be functionally the same.

[Rune]

Not yet. Just the Mun so far. This is where my Simulator idea would come in handy as I could have just start it right from the surface of Eve to test it and posted screen caps of it in orbit without having to spend the time just getting there and making it past the landing just to test it.

I do plan on using parachutes as the only means to land. How would aiming for the higher elevations workout with that? Also, what about the TWR from there?

Aiming means timing your deorbit burn so you end up on top of a mountain. Yah, as scary as that sounds. Thankfully this time EVE's atmosphere is a dense soup. T/W remains unchanged, though, you just launch out of a more reasonable density. Check out the terminal velocity tables at the wiki so you can remain under them and do an efficient ascent burn.

And yeah, total delta-v is the number you want to increase even further, you are getting there... And seeing for yourself just what a monstrosity it takes. I think you can get away with about 10.5 is you launch from high enough and are very efficient. But very efficient means very efficient, you would do better to pack 12km/s if you are not used to do perfect gravity turns and inserting to orbit in a single burn or close to it.

How about choosing as the first interplanetary target Duna instead? It's much, much easier, 2km/s to launch from.

Rune. You know, because you shouldn't try to go for the hardest mission possible right away... much frustration will ensue.

[DJRWolf]

I have some missions in a sandbox game aimed at Eve and Duna (still in Kerbin orbit awaiting departure window) but they are unmanned orbital ones only. I am looking at sending manned missions to Duna and Dres for my next step. Would that first attempt work at getting a sample return from Duna even with it's thinner atmosphere for the parachutes?

[Rune]

I have some missions in a sandbox game aimed at Eve and Duna (still in Kerbin orbit awaiting departure window) but they are unmanned orbital ones only. I am looking at sending manned missions to Duna and Dres for my next step. Would that first attempt work at getting a sample return from Duna even with it's thinner atmosphere for the parachutes?

Sure! Duna just requires that you help the parachutes a bit at the end, since the terminal velocity is higher and normally not survivable. Packing an extra 500m/s for the last 100 meters or so would do the trick, and then it's only 2km/s back to orbit and a pitiful T/W, and another or so to get on a kerbin intercept. Call it 4km/s to get from a Duna decaying orbit to the ground and then back to kerbin, and you will have enough to spare. You could pack 4,000m/s in a single stage, BTW, you just need a mass ratio=e^(4,000/9.81/isp), which works out to 2.84 for KSP's most efficient chemical engines (LV-909's, isp=390). That means 1.48 kg of fuel for each 1 kg of empty spacecraft.

Rune. Getting you acquainted with Mr Tsiolkovsky.

Edited January 21, 2014 by Rune