Not enough fuel to reach Duna/Jool

[Eumaeus]

I am having a lot of trouble being able to reach the outer planets. I was almost able to reach Duna but I couldn't get into orbit (ran out of fuel). Jool is completely out of the question, I need a major rocket re-design to get that far out. Has anyone had any luck? I have been using the Atomic Rocket Motor for interplanetary travel.

[trbinsc]

A little tip for you; Keep it simple, and don't bring anything you don't absolutely need. Extra weight is wasted ∆v.

[The Destroyer]

Uhm, How do you even GET there in the first place?

[mrxak]

The new nuclear thermal engine can get there with a single tank (the biggest one) of fuel, with a reasonable lander. It'll take a very long time, but you can intercept its orbit.

Here's the lander I used (click for bigger):

Just stick that (or something of a similar mass) on top of the biggest fuel tank, a nuclear thermal engine, and get the whole thing up into orbit. It'll take forever, but you'll have plenty of fuel leftover to land. No promises about getting back.

Here's another picture from a lower angle. That's Jeb, making his first steps on another planet.

Remember, the specific impulse of the nuclear engine is pretty horrible in an atmosphere, so keep it conventional for the first 100km.

Here, took another shot in the VAB of the interplanetary stage.

It's really that simple (though I'm thinking I might beef it up a bit since it's so slow). The liftoff stage is rather huge, but that part is relatively easy to figure out on your own.

Edited September 20, 2012 by mrxak
Added a couple more pictures.

[Shadownailshot]

If you don't plan on coming back, or you just want to make an orbiter at first, your launch and transfer stages can be a lot smaller. I have a craft (still running .16) that can reach either duna or eve's orbit with fuel left over for an orbit capture, and it's running only on chemical rockets. Fuel efficiency is key on interplanetary stuff. A lot less room for mistakes than moon landings. And as for how you get there, Check this out

[Eumaeus]

Awesome thanks!! I was able to reach Eve and Gilly Sadly I..err Jeb...had trouble landing. That moon has a ton of rotation and almost no gravity, it is very hard to land!! And it only took me 1600 days to get there!!

[Shadownailshot]

Awesome thanks!! I was able to reach Eve and Gilly Sadly I..err Jeb...had trouble landing. That moon has a ton of rotation and almost no gravity, it is very hard to land!! And it only took me 1600 days to get there!!

Only 4.4 Earth years! My friend did it in 75 days lol.

[samstarman5]

Only 4.4 Earth years! My friend did it in 75 days lol.

It definitely helps illustrate what space windows really mean. Give 0.17 a couple weeks, then watch 2010, and that might help illuminate the risks they were taking in what they did to get back to Earth ahead of time.

[Shadownailshot]

Yes it certainly does. I've now learned how to burn straight from my parking orbit above Kerbin to capture both Duna and Jool. I'm just testing orbital craft first to see what the atomic engine can really handle. The TWR is extremely low and frustrating, and I don't know how to physical time warp outside an atmosphere, so I have to live with it.

[RoboRay]

You can get a lot of free Delta V if your target planet has an atmosphere. Take Duna, for example... If you set your periapsis (peridun?) at 10km, air drag alone will slow you down enough from interplanetary speeds to aerocapture into an elliptical orbit. From there, make a small burn at apodun to raise your peridun up out of the atmosphere, or just adjust your orbit to bring you to your intended landing point.

As it allows you more control over picking your precise landing site, aerocapturing into orbit then landing is a little better than simply aerobraking into a direct landing descent, unless you are critically low on fuel.

You can also aerocapture at Jool into an orbit that encounters one of it's moons, but I haven't been to Jool yet.

Edited September 24, 2012 by RoboRay

[Markus Reese]

I had the same problem for the past couple days as you with getting to planets. If you are like me, you also want to return, so lander is a bit heavier. I found try to avoid complex rockets. You want to brute force out of kerbin as fast as you can get it. I had these big multistaged things, but I accelerated slowly off planet, so most of my fuel was spent in the time offsetting gravity. remember, that holding stable altitude is just accelerating up the same rate gravity is pulling you down. So by burning more fuel, you burn less fuel. Once you get powered out into orbit or escape, you can keep it light, but maintain a patience game with very slow acceleration rates.

For example, I had a minimalist lander design. It could just get off kerbin, and get enough to capture another planet's orbit minimized as much as I could. It theoretically works fine, I can return from any place, but couldn't get there to begin with trying to keep smaller stagings with nuc fuel etc. I finally got fed up, stripped everything I added to the lander and just added an equal amount of components (less actually) but had alot firing all at once. The result was the increase in thrust got me to space fast, and still had big engines to get the major acceleration done. Allowing smaller efficent engines for my maneuvering and capture as apposed to the dead weight of a larger fuel supplied efficent transfer stage. Doing that got me to Eve orbit quicker and easier with more fuel left over.

[Person012345]

I used this:

It sits on a 370 ton rocket made exclusively out of the "small" stock parts (although as you see I built it around a mechjeb module). It gives me 0.5 FPS on the launch though, because I have a sucky computer. When I get a better one I intend to strap a load more rockets to it and make it even bigger. Because more rockets is the kerbal way.

[dustyjo]

I don't know how to physical time warp outside an atmosphere, so I have to live with it.

It's ALT + >

[that1guy]

Try building in intent stages. For example, the pod has to come back to Kerbin, the lander has to be able to lift off the planet, and the bottom of the rocket has to get the whole thing into orbit. I know this sounds basic and dumb, but it helped me out.

[bradley101]

Just use the DSM 151 its ion engines and solar panels are great for crusie drives and renuable fuel!

[draeath]

Check out this bad boy. The nuclear reactor and battery are quite heavy, but it basically means I'll never run out of gas.

I could have saved about 8 tons at least if I went with solar panels, but I wanted it to be 'self contained.'

Of course, I have a crapload of mods installed...