Getting to Eve and Back

[Thobewill10]

So i got to thinking after seeing this post in a separate thread...

Ok, some back-of-the-envelope calculations:

Kerbin properties:

surface gravity: 9.807m/s^2

GM:

3530 km^3/s^2

radius: 600 km

Eve properties:

surface gravity: 9.807*1.7m/s^2 = 16.66m/s^2

radius: 700km.

assume a 200km orbit to be safely above the atmosphere

Law of Gravity:

g = GM/r^2

=> GM = g*r^2 = (16.66E-3km/s^2)*(700km)^2= 8164 km^3/s^2 for Eve

(as a side note, this means Eve has a mass = 1.223E23 kg, about 2.3x Kerbin)

Circular orbital velocity:

g = v^2/r

=> v = sqrt(g*r) = sqrt(GM/r)

=> At surface:

v_700 = sqrt[(8164 km^3/s^2) / (700km) ] =

3415 m/s

At 200km altitude

v_900 = sqrt[(8164 km^3/s^2) / (900km) ] =

3011 m/s

Gravity drag:

Find an altitude above Kerbin equivalent to 200km above Eve; reaching this altitude should incur the same gravity losses in either case.

specific energy change to go from Eve surface to 200km:

dE = GM/r2-GM/r1 = (8164 km^3/s^2)/(900km) - (8164 km^3/s^2)/(700km) = -2.592 km^2/s^2

equivalent altitude above Kerbin:

r2 = GM/(GM/r1+dE) = (

3530 km^3/s^2) / ((

3530 km^3/s^2)/600km -

2.592 km^2/s^2) =

1073 km

Air drag:

This is a bit trickier. Drag force scales linearly with density, but I'm not sure how that translates into drag losses. Maybe the best way to deal with this is to modify a small part (maybe a parachute) to add the appropriate extra drag for each design.

Oi, that was more complicated than I thought. I'm doing all of this off the top of my head, so feel free to check my numbers, but these seem about right.

So in total, a normal rocket that can launch from Kerbin and reach a speed of ~3000 m/s at an altitude of ~1000km (which would put it in an escape trajectory and then some) should be able to reach low Evonian orbit, not accounding for drag...

Is it even possible to create a one-rocket design that can leave kerbin, land on eve and return to kerbin again? I seek to answer these questions.

The logical first step would be to build the smallest possible rocket that can get into a low Eve orbit. With the thick atmo, landing it shouldn't be a problem.

So, my first goal is to reach a speed of at least 3 km/s at 1000 km up. This does not account for drag, but it should give me a starting point.

This almost certainly won't work, but i figured i'd give it a chance. Asparagus stalk-booster staging should give this the best bang for its buck.

EDIT: It didn't quite make it.

So that can't quite do it, but it's promising.

Added more fuel tanks and fins.

Gemstone II was a resounding success. It was able to reach a top speed of 6292.2 m/s at an altitude of 2593 km. I think this should definitely be capable of reaching Eve orbit, if not escaping.

Next: to get it there!

Carries 1200 m/s worth of delta-v, enough for orienting, aerobraking, etc. I don't plan on orbiting Eve at all.

Also carries some RCS fuel.

I'll post updates as it happens. Anyone else interested in going at this?

Craft files attached. They require the fuel bug fix.

Edited September 1, 2012 by Thobewill10

[Thobewill10]

Gemstone II was a resounding success. It was able to reach a top speed of 6292.2 m/s at an altitude of 2593 km. I think this should definitely be capable of reaching Eve orbit, if not escaping. Next, I need to build something to put all that jazz in Eve orbit in the first place.

[cocomoe1002]

Landing on the new planets should be easy... because they have a atmo. And a atmo slows your speed as a cause of friction and drag during reentry. But since KSP doesn't have heat reentry down yet... it is mostly drag that slows u down. but not enough to land of course! But the fact that KSP isn't always on the realistic side, getting off of Eve and returning to Kerbin is a challenge. Noting that Eve has a 10x thicker atmo then Kerbin. And also slightly bigger then Kerbin. This raises a few things. A 10x thicker atmo is harder to fly through but on the bright side you should have more control of the aircraft on Eve atmo too. On the bad side since Eve is slightly bigger then Kerbin you might need a little more power to get of Eve. To do this your going to need more power and fuel is a problem too. And something also that i dont get is that the rocket you take off on the launch pad on Kerbin, is probably designed to get out of Kerbin gravity. Correct? So isn't the lander probably smaller and has less fuel then the part u launched with. noting the fact that Eve is bigger and has more gravity and more atmo. I am testing and making modules and testing them on Kerbin then doing to math on Eve's statistics. By doing that i can predict how a mission might go. But the odds are to difficult. So how?

[TheDarkStar]

Since the atmosphere will be much (at least five times) thicker, you should revise that so you first have some air-breathing engines, then aerospikes or the smallest engines to get home.

[Thobewill10]

Check the top of my post. I addressed that and linked to a quotation by silent_prtoagonist in which he calculated the amount of delta-v required to get off Eve without accounting atmo. I got an additional 3 m/s of delta-v than is required, which should account for atmospheric drag.

Also:

Since the atmosphere will be much (at least five times) thicker, you should revise that so you first have some air-breathing engines, then aerospikes or the smallest engines to get home.

Air breathing engines won't work on Eve, or i'd have used the s**t out of them

[zapy97]

can you please attach the 2 craft files to your post

[Thobewill10]

Sure! I'll do that now.

Also, I finished constructing the transfer stage. Now i need a massive rocket.

Carries 1200 m/s worth of delta-v, enough for orienting, aerobraking, etc. I don't plan on orbiting Eve at all.

Also carries some RCS fuel.

[Thobewill10]

Did someone mention a massive rocket?

[Exovian]

Yes, you did. Nice work!

[Bluejayek]

I see your massive rocket, and raise you an even more massive rocket.

19 stages of raw power. I reached 24,000m/s on an escape trajectory from kerbol SOI with this thing, so it has upwards of 20,000m/s of delta V. More once the krakensbane kicks in... Controlled the second and third last stages at 10,000m/s is impossible.

Edited September 1, 2012 by Bluejayek

[Thobewill10]

Jesus bleeping bleepity bleep man. That would probably be able to do a bleeping powered landing on Eve and come back, and then maybe go out again for good measure.

[Bluejayek]

Jesus bleeping bleepity bleep man. That would probably be able to do a bleeping powered landing on Eve and come back, and then maybe go out again for good measure.

Well, we shall see

The thing lags like nothing else on the launchpad.... And second through 8th stage or so each last <10 seconds (That entire second panel of liquid fuel tanks is asparagused in groups of three). The only way I know to eject them is when I see the engine nozzle turn gray again, watching the fuel tank indicators is useless.

That aside, my intention for the planetary landings is to do a two ship profile. One ship will hold a lander (probably a 1 man capsule) that will have enough fuel just to get back into orbit. Then, the second craft will rendezvous, and the lander pilot will transfer over to an empty seat (Kicking a kerbal off on the launchpad, or using the crew tank, the only mode I have ever installed). This second craft will do the return back to kerbin, leaving the lander orbiting eve or whichever.

I highly suspect my first successful landing mission will end when I try to do a victory lap landing on the Mun on the return voyage.

[Tommy521]

That's going to be one long lonely flight.

[Thobewill10]

That's going to be one long lonely flight.

not to mention cramped.

[ferrin]

As Celestial bodies get further and further out, you will need to utilize the surround objects to get you where you want to go.

You will most likely need to use the Mun or Minmus to basically slingshot you out to whatever your aming for.

[Bluejayek]

True. It will be cool if they add like "Entertainment Modules" just for kicks in the next update A lead in to proper IVA's

[r_rolo1]

@ Thobewill10

Cool, another Eve project contributor I see that you got some good ideas out of there and of Scott Manley, but the 8 engines in the outside are a cool idea.

BTW I tried a home made version of your Gemstone II ( with the fuel bug fix , mind that ) and the ship alone would be enough to go to Eve with a half FL-T400 tank to burn.

And to be honest I don't think you need a much bigger rocket than my Eve I for this Your massive rocket could get some cuts

[Bluejayek]

Jesus bleeping bleepity bleep man. That would probably be able to do a bleeping powered landing on Eve and come back, and then maybe go out again for good measure.

Well, I tested my rocket on a simulated eve and return mission. For this I burned out to a 20Gm apoapsis, recircularized on kerbin and landed, took off again and repeated.

The album below isnt particularly complete, but you get the idea.

The astute observer will notice that the engine on my second last stage morphed. I realized hours into this mission that I had accidentally swapped that engine to the lander engine yesterday for a different mission profile, so I had to edit my persistence file to swap it back. The mass difference of 0.75 means I wouldn't have had quite as much fuel if it had been there the entire way, but I believe the krakens attacks on my craft make up for this gain.

Other comments. I didn't technically land on the first landing. I slowed to a stop and then burned out at about 500m from the surface as I was coming in on the water. I don't think this makes any significant difference in delta V requirements or anything. Also, my last landing was a lithobraked 20m/s+ landing with about 0.5kg of fuel left. Luckily my pod survived.

http://imgur.com/a/KJrr9#15

[Tommygun]

I like what you are doing with the fuel pumps, a lot of people seem to over look them and don't realize their value.

I also like how you put a large fuel tank at the bottom without an engine.

[Kerbal123_Furry]

Good I copied a Scott manley's craft. It can enter  stable orbit around eve.

However I can't make it to eve without save file edit.