Tips on how to go interplanetary!

[Disco]

Ive been wondering how nooby I am that I havent even gone to other planets yet... The thing is, I cant come up with a rocket for interplanetary space travel.

Could you sent me some good designs (that can lift a decent load I want to make a base on Duna) KWrocketry rockets would be even better!

Thanks for reading!

[Taki117]

This will help you plan your missions. This will help if your destination has an atmosphere. And here's a convenient dV map. for help with how much to get there. Now, for interplanetary, it's best to build in orbit so that you are not really limited by size, but if you build bigger I suggest getting KAS so that you can add Struts on EVA.

[capi3101]

I'm gonna get ninja'd on this post anyway...so be it. Interplanetary is pretty much a function of "what do you want to do first".

What you might try is a combination craft - do two or three launches and dock them in orbit. Have one for the transfer stage, one as the lander/excursion module, and possibly a supply stage for extra fuel if you think you need it. Here's a good method for building a transfer stage -

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You can also do it in one big thwack, though by necessity that means building bigger rockets. I sent these off to Duna after doing a number of tests on Mün for a challenge:

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So what exactly would you like to do first?

EDIT: Yep. Ninja'd. Taki117 has given you the tools you need to do planning for interplanetary missions; hopefully my first imgur album will be of some use as well.

Edited February 16, 2014 by capi3101

[TheDarkStar]

For your first trip, anything that large is overengineered. Use only one LV-N and make a much smaller lander for one Kerbal.

[technion]

If it's your first trip...

An FL800 with an LV-N is capable of doing a Duna flyby if you can get it into LKO first.

[Disco]

All I want to do is get a lander to duna, then I want to make a base there.

[Starwhip]

I suggest unmanned probes/rovers first, to get the hang of it. Then go and do it with Kerbals. If you are up to it. For some reason, I am attached to the darn things and I would never send them interplanetary without a real ship, multipart, quite large.

[Geschosskopf]

All I want to do is get a lander to duna, then I want to make a base there.

OK, build a lander with about 2500-3000m/s in the tank. You need about 1500m/s to get back up off Duna and, if you have "enough" parachutes (see below), 500-1000m/s to land because the engines have to burn a lot until all the chutes open, and then some at the end, too. You also need enough thrust so TWR >1 on Duna (use Kerbal Engineer Redux for that), and "enough" parachutes (use the Parachute Calculator website for that). Almost all of Duna's surface is about 2500m so "enough" parachutes is when they'll have you hitting the ground at about 10-20m/s, which is enough for your engines to stop you at the last moment. If you land at lower elevation, you're even better off.

Oh, and build the lander low and wide. There's hardly any flat ground on Duna so expect to land on a steep hillside.

Now you need a transfer stage to get the lander to and from Duna. Assuming you aerocapture at both ends of the trip, allow about 1500m/s to get to Duna and about 1200m/s to get back home. Call it an even 3000m/s in the transfer stage (while pushing the lander) to be totally safe.

Then you need to get the lander and the transfer stage into LKO, either in 1 piece or launched separately and docked in orbit. Basically a function of how big a lifter you want to deal with.

That's pretty much it in terms of ship design. As for navigation, if you can get to Mun you can get to Duna. There's only the added complication of having to wait for a launch window and putting the ejection node in the right place on your orbit around Kerbin. As for aerocapturing, get just inside the orbit of Ike or Mun (depending on where), quicksave, and put your Pe at your best guess of what you need. Then see what happens and if it doesn't work out, F9, change the Pe up or down a bit, and try again. 11-12km usually works for Duna, 35-40km usually work for Kerbin.

The above aerocapture altitudes assume you're trying to get into low orbit and will land later. This isn't necessary at Kerbin; the air is thick enough you can set your Pe at 20km and come straight in for a landing. But this usually isn't a good idea at Duna. For your 1st Duna landing, aerocapture into an orbit below 100km and burn it down to about 50km circularized. Then do your de-orbit burn to hit somewhere no less than 1/4 of the way around Duna from where you do the burn. You'll land about 1 finger's width west of that point if you have the map view zoomed in all the way when you do this. Pop drogues early, pop mains early, and you'll also have to burn at fairly high throttle most of the way until the mains fully deploy. It's a bit disconcerting because you're screaming along at very high speed and fairly low altitude but it works.

Good luck.

[robopilot99]

You will want to look at this site'http://flyonbudget.onegiantleap.info/chapter8.html#aerobraking

Helped me in my missions big time. You also really need kerbal engineer. The delta-V readouts are super important

[Guapo]

"Long live the Confederation"

Hah. Why am I not surprised an old EV hand would be doing impossible things around the KSP forums?

[capi3101]

Hah. Why am I not surprised an old EV hand would be doing impossible things around the KSP forums?

Not sure I follow...that quote's intended as a reference to the Wing Commander novel "Action Stations" by William R. Forstchen. I have done a thing or two related to Wing Commander before, though unofficially.

I wouldn't necessarily say I do impossible things, either. Improbable perhaps.

(Bill's standby quote in my save game is, of course, a reference to the Enya song "Orinoco Flow", which was arguably one of the most annoying pieces of music ever written IMHO. I don't think it shows up in the Constipation XI mission report I posted previously though.)

I digress from the topic, of course. Apologies to all.

Geschosskopf's advice is sound; a lander with 2500-3000 m/s of delta-V and at least three kN of thrust per tonne is what you need (preferably you'd want closer to five kN per tonne but you can still take off with three). With that basic transfer stage I posted previously (the BZ-52 "tutorial"), you could easily make a Duna round-trip with a lander weighing up to 58 tonnes and with a comfortable margin for error. Put RCS on your lander, launch the transfer stage and lander seperately, dock them in Kerbin orbit and off you go. Of cours, that's just one way of doing it; you could just as easily incorporate all the elements into a single launch.

Edited February 24, 2014 by capi3101