Mission to Duna

[capi3101]

To be honest, I think a fair amount of whether multiple NERVAs are necessary is a matter of which mods you're using. If you've got a lot of mods that improve the accuracy of your burns (Mechjeb still around? It's been a few months for me, guys; it's the one I'm thinking about here), you probably could get away with fewer. If you're less confident of your piloting or playing stock, I'd suggest multiple engines despite the increased cost and decreased efficiency; thrust definitely matters when you're sitting there having to eyeball it.

[Laie]

Telling mechjeb to summarily execute all nodes while you walk the dog certainly makes long burns more bearable; but the inefficiency comes not from steering errors or sumsuch, but from the fact that the burn takes so long. You're not applying your thrust at the right time, and probably not in the right direction as well. Setting up a series of smaller nodes helps with the latter, but not with the former.

[tg626]

Interesting thing I'm discovering is that I have to leave LKO in steps. One single burn has so much Dv that the burn time is longer then a single orbit, which causes the craft to crash into Kerbin O_O...

[Laie]

Interesting thing I'm discovering is that I have to leave LKO in steps. One single burn has so much Dv that the burn time is longer then a single orbit, which causes the craft to crash into Kerbin O_O...

Then either a) your TWR is way too low and you should consider adding more engines or you should wait for a launch window rather than force it at the wrong time.

To save the situation without rebuilding your vessel, you have to split up the maneuver into smaller ones (as you did). Actually, what would be even better: start at just the right time and keep burning prograde all the way; "prograde" will slowly move outward and eventually leave Kerbin. Unfortunately, I'm not aware of any mods that could help you to find the right moment.

[tg626]

This is the beast, and yes it has a VERY low TWR. But, hey, what the Kerbal! Right? I am presently raising it's Appo so I can do a short escape burn when the launch window opens in about 2 kerbal weeks.

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MechJeb, "Prograde" on Smart A.S.S., and hit the throttle will track the prograde marker. http://alexmoon.github.io/ksp/ can cal the window, as can Kerbal Alarm Clock. Biggest issue is knowing X m/s= Y mins, which at the moment works out to *about* 200m/s Dv= 10 Minutes burn time.

Edited August 12, 2014 by tg626

[Iforgotthis]

Wow tg626, that's really impressive! My Duna ship is small in comparison, cosy almost .

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It carries six; the 1st Officer, the 2nd Officer, 1st Engineer, 2nd Engineer, 1st Scientist, and the 2nd Scientist. The 1st Officer and the 1st Scientist will be the two to go down in the lander, becoming the first kerbals on Duna

It took three launches to get everything set up (one for the main ship, one for the lander, and one for the crew).

I'm unsure whether there will be enough fuel to get home with, but we'll have to see. I've got 2000+ units of fuel left for establishing an orbit and returning to Kerbin, so hopefully it will be enough.

If not, at least I'll have a Duna station...

Edited August 12, 2014 by Iforgotthis

[NecroBones]

This is the beast, and yes it has a VERY low TWR. But, hey, what the Kerbal! Right? I am presently raising it's Appo so I can do a short escape burn when the launch window opens in about 2 kerbal weeks.

http://imgur.com/a/6rDea

Wow, the burn times will probably be a little painful. But that's a beautiful ship!

My last trip to Duna kept the transfer and landing stages quite small:

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Edited August 14, 2014 by NecroBones

[Taki117]

Here's my Desgin, I went with an Apollo Style approach. The CSM engine runs on Monoprop, so it's incredibly efficient. The Orbital insertion/Duna Transfer Stage is the Novapunch single nozzle engine, Amazing efficiency out of it too.

[tg626]

Thanks for the compliments. Yes, the burn times can be incredible with a TWR of 0.04 to start off O_O

But the original design was built to *resemble* the proposal by Von Braun without consideration of the performance of the LV-N vs the hypothetical NERVA engine he based his design on, so I have no doubt it's just about the WORST way to get to Duna and Back

Burn times so far have been in the 30-60min range, and the #^&$* docking bug reared it's ugly head so I had to do some hand editing of the save file (thank god they are TEXT and I have Notepad++)

Right now, Jeb, Bob, Bill, and KrakenFodder #1 and#2 are headed to Duna while the "Kerbin Escape Stages" are coupled together and doing a Circulization burn to get back into HKO (projected orbit will be around 64,113,100m, well beyond Minmus for now)

Edited August 13, 2014 by tg626
Added link to Docking Port Bug Fix Tutorial