Hohmann Shmohmann - who else uses high energy transfer courses?

[nadreck]

Ever since my second career mode iteration (.23) I have been playing with trying to complete the tree in a minimal amount of elapsed Kerbal calendar time and trying to get around the Kerbollar system to plant a flag everywhere plantable in a minimal amount of time. So given that I max the tech tree in less than 2 weeks on the Kallendar I can make any type of ship I want and that means fast multi LV-N propelled expedition fleets that can use >5 km/s dV as they leave LKO. How many of you eschew optimal launch windows and go for that nuke fueled high resource orbit or hyperbolic trajectory?

[No one]

You should probably add another option for those who are so dedicated to efficiency that they get gravity assists from Eve before going anywhere. I don't think anyone would do this, but then I didn't think anyone would use hyperbolic trajectories either.

[Franklin]

You should probably add another option for those who are so dedicated to not giving a damn about efficiency or accuracy that they think launch windows are what's on the side of the observation tower.

[Superfluous J]

I fall between the 2nd and 3rd options on that list. I go for very efficient single-burns in LKO during the proper windows when going to Eve, Duna, or Jool. I do very efficient single-burns in LKO at AN/DN for Moho, Dres, and Eeloo, and then do another single burn when out at their orbits to get a connection on the next pass. It's not quite as fuel efficient as hitting it on the first try, but it's close and I don't have to muck about with orbital alignment (though it's easier sometimes, because you get a bigger encounter opportunity)

When I start using life support I'll probably have to buckle down and do those Moho/Dres/Eeloo runs in the more traditional way, but until then it's just so much easier I can't not do it.

[Epthelyn]

I do so frequently, partly because I can make rockets capable of the delta-V required to ignore transfer windows by a fairly wide margin and partly because I like launching things whenever I want to, not to a schedule.

If I have to save fuel for whatever reason I will, but for standard trips to each of the planets, even in career mode, I'm never particularly bothered and will cut the journey time if I can afford to

[merendel]

I'll usualy alow for up to 20% additional dV expended per leg of the trip to expidite a transfer, particularly ones like jool. This is normaly because a window has passed and I want to go anyway. Other times its cause one is comeing up where I can get there in half the normal transfer if I spend a bit more dv. I still hohmann for most transfers however if a launch window is close when I want to go. Minmus however I almost always burn extra dV on. an extra 200dv leavign and agian slowing down at minmus can reduce the transit time by a day or more, well worth it when I'm striping the science off it.

Edited August 22, 2014 by merendel

[nadreck]

Rather than change my poll, I will leave it as it stands and encourage people to explain their variations on my theme as a few of you have already.

[No one]

Personally I sometimes launch when things aren't opportune and don't use gravity assists when doing anything with precision, but I do generally try to make my orbits efficient. And they're always elliptical.

I have rockets with the delta-v for hyperbolic though, or at least I did in .235. I finally decided that I needed to stop doing right before .24 came out when I launched my standard rocket to Duna. Said rocket had a transfer stage which was very heavy and had lots and lots of delta-v (Capable of getting to Moho without the oberth effect. And probably more, but that was the most delta-v intensive thing I did with it). It didn't end up needing said transfer stage, it got to Duna with the launch stages alone. I then decided to stop using such overkill.

[cantab]

I do what suits the mission at hand.

My cheap little probes: lots and lots of gravity assists planned. The initial departures were tricky because I wanted to arrive at Eve at the Moho/Eve node for the assist onto Moho. Even worked in a Munar assist on the way out for one of them, that took AGES to set up.

My one-way Eve rover: Straightforward Hohmann. Good thing too because it left me some delta-V for an impromptu stop at Gilly.

My Duna asteroid ship: First rendezvoused with an asteroid in solar orbit, then set up the gravity assist at Kerbin to go onto Duna. The transfer looped out somewhat beyond Duna's orbit and the encounter was on the inward crossing.

My Eve asteroid impactor: Along similar lines, but it'll be making several solar orbits before it hits.

My Laythe mission: Took an express transfer to get there in about half the usual time. The transfer orbit was closed, but with apoapsis out beyond Eeloo.

[EdFred]

It depends. Going to Eve, I found that the launch window doesn't have to be that close. Another 500dV on the transfer stage is no big deal, since aerobraking erases having a non-optimal intercept angle. Moho on the other hand is all about efficiency, because if that intercept angle is off, the dV required to get into a Moho orbit gets insane.

[panfish5]

I only use transfer winfows on duna and eve. Everything else is pedal to the metal.

[General Rarity]

I use transfer windows on everything except moons... I used to burn in interplanetary space but I found out about the Oberth effect, my ships are now less laggy and look much better than before.

[Overfloater]

I use transfer windows on everything except moons... I used to burn in interplanetary space but I found out about the Oberth effect, my ships are now less laggy and look much better than before.

Same case with me.

I do the Hohmanning straight from the planet's orbit, because interplanetary single stage missions don't work otherwise.

[Kasuha]

In my recent career run, I sent probes to all planets and moons within 50 days. They were optimized trajectories but were using all kinds of side lobes on the porkchop plot, definitely not minimum dv transfers by any means. The fleet I was using for that had enough dv so it was fun to do. But normally I run only one mission at a time and wait for optimal transfer window at least on the way there.

Note though that what comes from Alexmoon's planner are not Hohmann transfers in general, particularly if braking at target is included. It has to optimize for inclination change, too, so it deviates from Hohmann slightly to decrease dv on braking burn.

Edited August 23, 2014 by Kasuha

[FacialJack]

Hi all

Im relatively new in my KSP comprhension, (i mean, i install it several time this last five years(or close) but thats the first time i (buy it...) play so long, and under stand how to get everywhere. Wiz the 0.24 game, i start use KerbalAlarmClock, and so, i have now date for optimal transfer windows. They dont come in the order i plan to explore Kerbol sys, but im going to follow that order, as i think its more "realistic" For now, im sending unnmanned mission everywehere i can.

Eve and Moho are done, next transfer windows in 143 days: Jool (and 5 days after, Duna)

Just Duna will be my first Manned mission, wiz landing on other planet

[Madrias]

I launch when I bloody well feel like it. However, while I'm up there, I'll try for something kinda-maybe-sorta efficient. Then again, I plan a lot of missions around a 150% delta-V budget (sure, it means I carry a crapload of fuel around that I might never burn, but that's just how it goes sometimes. Better to have way too much than to have 25 units of fuel too little... especially when it comes to avoiding the old 'get out and push' that many of us do).

There have been a few times in the past where my strategy was to burn hard for the target, because I knew I had the fuel budget to do it (Seriously, the ship had enough dV to make it to Eeloo and back twice over. I was going to Minmus), then spend lots of fuel slowing down for my landing. Sure, it's wasteful, but when you're bored and it wasn't Career mode, it was worth doing.

[DocMoriarty]

OMGOMG and i always thought THIS is a launch window!

[magnemoe]

Mostly fuel effective burns however with some exceptions like the current probes to Eve and Duna in carrier, as I wanted the probes too target fast to do follow up manned missions, and to use the 48-7S I was asked to test

Return missions is often not optimal as I know how dV I have and how much I need.

[JDCollie]

OMGOMG and i always thought THIS is a launch window!

http://www.docmoriarty.com/ksp/gfx/launch_window_jpg.jpg

I'll admit, that got a giggle out of me.

[Fireheart318]

On August 24, 2014 at 7:40 PM, JDCollie said:

I'll admit, that got a giggle out of me.

Me too. I guess you could keep an eye out for a launch window through the launch window. That is, if you've got totally overpowered glasses or a big freakin teleskope

[QuesoExplosivo]

My ships that use the Kraken drive routinely take extremely high-energy trajectories in order to have low transit times (10,000 m/s delta-v to Jool, for example). My other, more sane ships use normal transfers.

[Kuansenhama]

I usually aim for transfer windows but always seem to get it a little bit wrong...

[James Kerman]

I have used transfer windows but who wants to wait 3 years?  I mostly brute force where I want to go and then I get out and push when I inevitably run out of fuel.

[magnemoe]

Back before 1.0 I often did a faster transfer to Eve, Duna and Jool as aerobrake could easy kill the extra 1 km/s. 
In 1.05 I have only used this sort of transfers to other planets.

[Musil]

I do worry about my kerbals spending too much time in space, I try to get them there and back before they get a high radiation dose in interplanetary space. 

And I did once ger a 280 days transfer to Eeloo... 

Edited March 21, 2016 by Musil