Tips wanted regarding a trip to Eve

[Hacktech]

Hey there!

I've been trying for a while now to get a ship to another planet, but the same thing happens over and over. I keep running out of fuel half way there. Can someone please give me some pointers on how to build a ship to Eve, and ofcourse other useful tips regarding the trip..

- Hacktech

[ninjaADude]

By get to Eve I hope you mean orbit it; not land. Eve's atmosphere is thicker than Kerbin's, requiring upwards of 12,000 delta-v to escape. With parachutes a 1-way landing could be facilitated easily, but you cannot reasonably expect to return to orbit.

That said, let's go over the basics of interplanetary rocket building.

Your rocket will probably need to orbit Kerbin before leaving for another celestial body. Because of this, most experienced rocketeers use lifters to get their rockets in orbit before departing for Kerbol orbit and beyond. You can build a lifter to have one or several stages, depending on how heavy your craft is. When you have acquired a stable orbit, drop the lifter and let your actual rocket do the work from here.

Moving between planets requires a good amount of fuel, and since getting fuel in to space is not easy, the best way to do so is to use rockets with higher efficiency (ISP). The most efficient rockets in the game are jet engines, but since they don't work outside of Kerbin and Laythe, they'll do you no good getting to Eve. The best rocket engines you can use are actually the Ion engines, which are incredibly efficient. The downfall of ion engines is that they use quite a bit of electricity and have virtually no power. Unless you are using a very small probe or are incredibly patient, ion engines won't work either. The best engines for moving around in space are arguably the nuclear engines. While they don't have a lot of thrust, their ISP is very high in space, making them perfect for inter-planetary travel. Remember that they do not work so well in the atmosphere though, their ISP is less than half! If you have empty tanks on your ship, remember that you can bring up fuel from other ships, dock and refuel your main ship before departing, potentially increasing your range by vast amounts!

Assuming you've gotten this far, and you have an encounter with Eve, you will need to get as close to Eve as possible. To be captured in Eve's orbit you will need to slow down quite a bit. Unfortunately, slowing down uses quite a bit of fuel, so instead of using fuel, you need to get your periapsis over Eve as small as possible. When your periapsis is lower than ~96,700m, you will enter Eve's atmosphere. This sounds scary, but not to worry! You will use the gasses inside of the atmosphere and the drag of your ship to slow yourself down to orbit without expending any fuel at all! The recommended periapsis to be captured in Eve's orbit is 72,500m (KSP Wiki). Try not to go any lower; if you go too low, you will simply crash in to Eve! Once you are captured in Eve's orbit, use a little fuel at your apoapsis to increase your periapsis over Eve's atmosphere (96,700m) so you won't slow down any more.

Hopefully this gives you the basic idea of how to get to Eve efficiently. While it doesn't come close to covering everything, it should cut your fuel usage down by quite a bit. Have fun!

[tomf]

Planning

Look up the Delta-v required to get to Eve from the chart on the wiki

It says 4550ish to launch from Kerbin and then just over 1000 to get to Eve

Either work out with a pen/paper/calculator/spreadsheet a design for a rocket with the required deltaV

Or, install a mod like mechjeb or kerbal engineer redux

Building an asparagus staged rocket will help get the delta-v up

[tomf]

Mission

Get your rocket into a roughly 100km circular orbit

use either protractor, kerbal alarm clock, mechjeb, http://alexmoon.github.io/ksp/, http://ksp.olex.biz/ to work out the correct time to head off for eve.

Select Eve as the target

you will want to do a burn in kerbin orbit of about 1000m/s. Your resulting orbit should leave kerbin's SOI traveling parallel to Kerbin's orbit and backwards. Drag the maneuver node around until it is in the right direction. Fiddle with the node until it just brushes Eve's orbit. You should see that Eve will be very close to the point where you touch at the same time as you get there.

Do the burn to leave Kerbin

Place another maneuver node at the next ascending/descending node and use it to match inclinations. At the same time use the other adjustments to make sure you get an encounter

Some time before your encounter you can use another node to fine tune your arriving orbit for aerobraking.

Using a nuclear engine you should easily be able to pack a spare 500 delta-v.

[capi3101]

Do you happen to have any screenshots of the ship you're using?

General tips - add more fuel and engines with higher specific impulse. For most interplanetary jobs, you want the nuke engines. For Eve, you'll need to plan for roughly 9250 m/s of delta-V (that's got a fudge-up factor added in) assuming you're just doing a there and back again mission; you want to plan for 13,000 if you want to make a side trip and landing on Gilly. Assuming a twenty tonne payload, 5 X-32 tanks will do the trick (assuming five LV-Ns for your interplanetary stage). That's going to be a pretty hefty load to boost into Kerbin orbit; I'd suggest assembling such a craft in orbit with docking maneuvers.

Assuming you know how to pilot into Eve's SOI, try to get your periapsis down to at least 70,000 m on the approach. That should be low enough to affect an aerocapture without pulling your ship in for landing. Quicksave before you make the attempt. You definitely don't want to wait for periapsis like you would for the Mun; if you can't get the periap that low while transiting to Eve, do it as soon as you enter its SOI.

Got a guy orbiting Eve at the moment; had to send a resupply mission because I shot for Gilly and missed. Quick note about resupply missions: be sure that they enter orbit going roughly the same direction as the first mission...I sent enough fuel to make it out to some of the moons of Jool and have burned up half of it just trying to get the orbits aligned...

[Mr Shifty]

If you're landing: if you've got a lander with any weight on it, you'll need a decent amount of thrust to slow your descent enough that your parachute won't rip off when it deploys. (This killed me on my first 6-7 landing attempts.)