Transfer Windows

[Lysergic]

I see a lot of people care about these, but I never bother. I just launch my probes into LKO, and burn at the right time so that I leave the Kerbin SOI having raised or lowered my orbit based on where I'm going. Then I just fiddle around with maneuver nodes, sometimes waiting a few months, until I get something that intersects with where I want to go. Am I doing this completely wrong?

[Mipi]

Doing it the same way. I find this more kerbal like.

[SpaceSphereOfDeath]

Yes, your way is EXTREMELY DeltaV heavy, yes it doesn't matter if you're off by a few days, but if you're off by a few months, then to go to, say Duna, may take more deltaV then a 2 way Jool mission

[Kasuha]

Am I doing this completely wrong?

That depends on what you consider wrong. If you want to spend as little fuel as possible, then yes, you're doing it wrong because you should use launch window calculator to get optimum launch window and use a mod which will perform the launch for you at appropriate time and angle.

If you don't care about delta-v that much and you're having fun doing that, then you're doing it right.

Yes, your way is EXTREMELY DeltaV heavy, yes it doesn't matter if you're off by a few days, but if you're off by a few months, then to go to, say Duna, may take more deltaV then a 2 way Jool mission

That's a misconception spread among people too dependent on launch windows and delta-v calculators. Yes, it's not as good as perfectly optimized trajectory. You might use maybe 10% more delta-v if you don't screw up (and waaaay more if you do but that's not the matter). I don't consider that extreme in any way.

Edited November 14, 2013 by Kasuha

[jduchock]

I used to all-out dV myself, but found that it was HIGHLY inefficient. To leave LKO, i set the Mun up for a Hohmann transfer then move the node around a bit in order to get a "spin-off" form the Mun to break Kerbal orbit. This typically uses half the dV required to do a straight break (approx 400± less dV).

With that in mind, every time you leave the surface of a planet, head for it's moon and use it as a flinger

[jwenting]

That's how I do it, and it works. Maybe not the most efficient, but much easier on the brain

[Matt56]

@Jduchock: I always use a gravity assist as well, but you have to do it at the right time. You don't want the Mun to fling you down toward Eve when you're trying to get to Duna.

Other than that, I wait for launch windows, but I don't use any mods for that. There tends to be some error, but practice makes perfect!

[Torham234]

I use the Launch Window Planner. It gives you a nice map of the deltaV costs, so you can plan an calculate required deltaV even if you are not leaving at the most optimal transfer window. From the map you can also see that the deltaV requirement is gradual, so launching few weeks later or sooner can still be pretty efficient.

[User Unrelated]

I use the Launch Window Planner. It gives you a nice map of the deltaV costs, so you can plan an calculate required deltaV even if you are not leaving at the most optimal transfer window. From the map you can also see that the deltaV requirement is gradual, so launching few weeks later or sooner can still be pretty efficient.

I am going to use this from now on...

I still don't really know what I'm doing when it comes to launching to anywhere but the mun, or minimus, but my method before was always to just launch into space randomly, and then hope and pray I can make it somewhere with the fuel I've got. Knowing when an optimal time period to launch would be, I feel like that'd help me save fuel, even if I don't really know exactly what I'm doing beyond that.

I've made it to both Eve, AND Duna back a few versions (not landed, though) with my random-launching-hoping-and-praying method...

I got to Duna completely by accident! I wanted to just launch some probe as far out as I could, and while I was thrusting towards the outer solar system, I saw my orbit flutter into the "new trajectory" purple color... thrusting the other direction for a sec, I caught Duna without even trying

Needless to say I was VERY excited. I still hadn't even made it to Minimus at that point haha

[Col_Jessep]

I use the Launch Window Planner. It gives you a nice map of the deltaV costs, so you can plan an calculate required deltaV even if you are not leaving at the most optimal transfer window. From the map you can also see that the deltaV requirement is gradual, so launching few weeks later or sooner can still be pretty efficient.

9 of 10 Kerbal Space Program Directors would recommend this tool to their friends!

I like it best because it gives you d-V maps for EVERY time. Let's say you want to go to Jool. You can get there 100 days early if you are willing to burn 200m/s more. I'd take that in a heartbeat.

[jduchock]

@Jduchock: I always use a gravity assist as well, but you have to do it at the right time. You don't want the Mun to fling you down toward Eve when you're trying to get to Duna.

Other than that, I wait for launch windows, but I don't use any mods for that. There tends to be some error, but practice makes perfect!

GRAVITY ASSIST...that was the term that i was looking for and just couldn't remember it...

[numerobis]

A gravity assist off the Mun is going to be hard to pull off in any useful way: it's too small to really matter.

[KSK]

Another vote for the launch window planner here. Between that and setting my conic drawing mode to zero, interplanetary flight just got a lot easier. At least it has to anywhere with an atmosphere and an SOI bigger than a small grapefruit. Moho is still.... challenging. Yeah that's a good word for it. Challenging.

[harold1363]

If you want a more efficient transfer burn I recommend either mechjeb or kerbal alarm clock. I use mechjeb to set up the node the save it with the alarm clock and time warp to the burn point from a probe I spawned on the ground.

[User Unrelated]

I just used the little transfer window thing, and it actually sort of works (for someone who doesn't know what they are doing)

From kerbin escape, I got to eve, circularize my orbit, and *attempted* a one-way science probe landing using only the fuel in 1 tall 1.25m tank and a standard gimballed liquid engine (forget the name)

and 1 medium 1.25m tank with a nuclear engine.

The ground LOOKED flat!... I hadn't even intended on landing, or going to eve with this craft, for that matter. I had put the parachutes on to return the materials lab to Kerbin after a tour of it's 2 moons. I had planned on dumping the fuel tank/booster... but I uh... forgot the decoupler

I figured, might as well go for another planet since no kerbals were in danger.

I still got lots of science! I just had to wait a while, because the larger solar panels further down the craft a-sploded.

SOMEHOW the thermometer, which got crushed underneath the probe body, survived, too!

Edited November 15, 2013 by User Unrelated

[User Unrelated]

A gravity assist off the Mun is going to be hard to pull off in any useful way: it's too small to really matter.

Hm? (actually the launch from the above lander!)

this WAS a bit dangerously close to the surface, though... didn't crash, but I ended up backing off a bit and didn't get ejected. I'm not experienced enough to pull it that close. I think the lowest point was 500m or something haha