I'd like guidance with setting up a future Duna base

[Commissioner Tadpole]

Recently, I've been interested in setting a base on Duna - mostly because I've been reading The Martian by Andy Weir - but... I'm not really sure how I could send everything. Unlike Mun/Minmus trips, interplanetary voyages can only occur once in a period, and I'd like to send everything up in one go instead of spending years sending one thing at a time.

However, not only I'm awful at rendezvousing(only recently I've been getting better), but I'm not sure how I'd haul the ending result. Especially since I'm even worse at sending rovers. I'd need a good manual of how such a vessel could look like - It includes just a base that can support 6-8 Kerbals and two rovers that can handle their own in Duna, so it probably wouldn't be too complicated.

And then there is the landing site. As my rover exploration around the Mun has shown, rovers take far too long to get anywhere important. And I have ADHD, so I won't survive long trips to see worthwhile things. And then there is the risk of rovers breaking down on the way(which can be rendered moot with a good rover), which means the roving crew will be royally screwed. Due to this, I'd like a landing site that is around 1.5km away from the polar ice caps, but isn't overly flat and that is possible to see Duna's sky with ease. But I might be asking for too much here, so the third requirement can be discarded.

I hope I'm not asking for too much. Despite being here since late 2013, I still don't have a solid grasp on things(I rarely send Kerbals outside the Kerbin system), especially involving orbital assembly. I've heard a lot about this tactic, but never got to do it before, so I'd like to try it out.

Edited March 22, 2015 by Commissioner Tadpole

[SmallFatFetus]

The Martian was such a great book! I too was inspired by that and began my Duna mission. (link in sig) What I am doing is getting all my modules in orbit with thier transfer stages attached, then transferring them all 1 day apart. this way I can aerobrake one after another, but not too close that I run the risk of things getting deleted and not too far that I miss transfer windows or something. My mission isn't so much a base as it is a landing and return, but it still applies here because there will be several ships moving together out of the kerbin system. Good luck!

SmallFatFetus

[stibbons]

When I started my Mun base I used fixed landing probes to scout around for a good base first. I dropped four or five in various craters and plains areas. Zooming out and panning around a probe can give you a reasonable idea of what the landscape is like around it. After I picked one, the next mission dropped a rover nearby, and it only took a short time driving that rover around to nail down my eventual base site.

[Wanderfound]

You can send ships to Duna at any time you like; it just costs a bit more ÃŽâ€V if you do it outside the transfer windows. But as Duna only takes about 1,000ÃŽâ€V to reach normally, adding a bit more range to your ships is no great hardship.

The most obvious way to manage precise landings on Duna is to fly there; stick some small wings on, glide to the target, then pop chutes and descend.

[Kryxal]

Also, a bit of prograde/retrograde and some radial in or out and you'll adjust arrival time without doing much to your periapsis. This is also useful for avoiding Ike.

[impyre]

I use a method I call the "wagon train". Instead of building one huge ship, build several smaller ships. I usually send up two mining modules, one comms module, one science module, and however many infrastructure modules/crew modules/return modules I'll need. I like to also include an emergency module that contains things which may help me mount a rescue or extend how long my kerbals can survive in the event of the unthinkable.

- - - Updated - - -

You can send these all off in the same launch window (they are usually pretty good for a few days), and with excellent placement in orbit, you can essentially just execute a transfer burn for one, switch to the next, execute its burn (rinse/repeat).

[celem]

People have mentioned that you can depart at any time, this is true of any destination but is especially useful for Duna and Eve since they are pretty affordable for big sections of the year. If you havent seen it then this is the tool you need to plot these sub-optimal intercepts. Its also available ingame via a lightweight mod. (works for any universe/solar system) The most important bits are phase angle (where in your orbit you burn from) and the dV (how long to burn). Using these tools you should realise you also become much more free in journey time as well as departure date. You can send 2 craft out the same day and have them arrive 100 days apart, or can shorten the flight by 100 days for a modest increase in dV.

This last bit is massively useful for Duna. You can aerobrake to scrub off the extra intercept dV created by a high-speed transfer and send ships there in very short order without overpaying to slow on arrival.

You can also as mentioned create congalines. Start ejecting ships a day before the 'optimal window as given by KAC or whatever' and keep going up to a day after. You can get a full flotilla even with some stuff making multiple periapsis burns due to low TWR. I often do this when working with RemoteTech so that only 1 craft needs a big dish to reach Kerbin, the flotilla then short-range to each other since they are all on the same trajectory and transfer as a pack.

As for Orbital Assembly, theres a thread right above/below this one about that very subject, some good hints in there. Biggest game-changer for me was learning how to use RCS Assembly Tugs so that an Orbital Assembly doesnt itself dictate probe/power/RCS port/torque ring placement, but only the overall ship design..

Landing Site/Rovers. Yes rovers suck, its sad, realistic and true. Unless you have months to make the drive like NASA its pretty much unviable since you cant usually reliably physics warp a moving rover. The only way to make this worth taking is to put down on the intersection of biomes, preferably 3 or more. You can either wiki the moons/planets and eyeball the biome maps against the game, or use something that pulls the biome data out for you while still in orbit. KER in surface mode, scansat...whatever. If you really dont want a mod i've used grav scanners as bootleg biome detectors since the experiment considers biome relevant all the way to high space. (KER in surface mode or scansat is king for true altimetry and slope detection)

Unfortunately, unless the body is high-grav and/or atmospheric its usually infinitely easier and often lighter in payload terms to send a lander capable of hopping. Rovers only really become a viable alternative on places like Tylo and Eve. (Laythe, but i'd take a minijet before a Rover, and Duna i'd lander-hop)

Edited March 22, 2015 by celem

[DoToH]

I like the "colony fleet" approach. Have your ships in LKO with their transfer stages ready, as SmallFatFetus and impyre said. KAC is highly recommended. You can do mid-course burns to time their intercept with Duna as you like. Don't forget to set KAC SOI change alarms for all of them.

In my 0.24 save, I built my Jool station and kethane reffinery this way. 11 ships parked in LKO waiting for launch window (5 for the station parts, 1 miner, 1 fuel hauler from miner to station, 1 with 5 scan sats, 1 tug and last 2 with fuel ressuply). Shame I lost the screenshots.

Edited March 22, 2015 by DoToH

[Scarecrow88]

If it was me, I would gather my fleet in Kerbin orbit, and transfer them all to Duna in the same transfer window. Using Kerbal alarm clock mod to alert you to significant events for each ship is really helpful. It's up to you whether you design your ships and base so that they need to rendezvous in space for specific tasks, or whether you can land them on Duna as individual ships and assemble the base on the ground.

As for landing site, sending a probe ahead to scout a suitable location makes sense.

[Commissioner Tadpole]

Thanks for all your help! I guess I'll just use the Vessel Samba method and send everything in a fleet. (I have KAC so it should be easy) Still, I'd like an example of a rover that can handle its own on Duna. I suck at building rovers.

People have mentioned that you can depart at any time, this is true of any destination but is especially useful for Duna and Eve since they are pretty affordable for big sections of the year. If you havent seen it then this is the tool you need to plot these sub-optimal intercepts. Its also available ingame via a lightweight mod. (works for any universe/solar system) The most important bits are phase angle (where in your orbit you burn from) and the dV (how long to burn). Using these tools you should realise you also become much more free in journey time as well as departure date. You can send 2 craft out the same day and have them arrive 100 days apart, or can shorten the flight by 100 days for a modest increase in dV.

I've tried using alexmoon's manuever calculator, but it's... very advanced. I don't really know how to use it.

This last bit is massively useful for Duna. You can aerobrake to scrub off the extra intercept dV created by a high-speed transfer and send ships there in very short order without overpaying to slow on arrival.

Yeah, I had this idea in mind as well. The Trajectories mod will be very handy here.

You can also as mentioned create congalines. Start ejecting ships a day before the 'optimal window as given by KAC or whatever' and keep going up to a day after. You can get a full flotilla even with some stuff making multiple periapsis burns due to low TWR. I often do this when working with RemoteTech so that only 1 craft needs a big dish to reach Kerbin, the flotilla then short-range to each other since they are all on the same trajectory and transfer as a pack.

But how many days does a Kerbin-Duna window last? I'm afraid of accidentally losing it.

As for Orbital Assembly, theres a thread right above/below this one about that very subject, some good hints in there. Biggest game-changer for me was learning how to use RCS Assembly Tugs so that an Orbital Assembly doesnt itself dictate probe/power/RCS port/torque ring placement, but only the overall ship design.

Oh. Will give it a check.

Landing Site/Rovers. Yes rovers suck, its sad, realistic and true. Unless you have months to make the drive like NASA its pretty much unviable since you cant usually reliably physics warp a moving rover. The only way to make this worth taking is to put down on the intersection of biomes, preferably 3 or more. You can either wiki the moons/planets and eyeball the biome maps against the game, or use something that pulls the biome data out for you while still in orbit. KER in surface mode, scansat...whatever. If you really dont want a mod i've used grav scanners as bootleg biome detectors since the experiment considers biome relevant all the way to high space. (KER in surface mode or scansat is king for true altimetry and slope detection)

Unfortunately, unless the body is high-grav and/or atmospheric its usually infinitely easier and often lighter in payload terms to send a lander capable of hopping. Rovers only really become a viable alternative on places like Tylo and Eve. (Laythe, but i'd take a minijet before a Rover, and Duna i'd lander-hop)

I've tried lander-hopping though. It was an awful experience and I don't want to repeat it.

[Landge]

Basically what these guys did, Wagon Train style. Before your transfer window to Duna arrives, launch your ships and assemble them in Kerbin orbit. Stagger their transfer to Duna where they will arrive at least 3 days apart. You can ease them into Duna orbit one at a time as they arrive in Duna's SOI.

Check out my Destination Duna missions in my sig...

Edited March 22, 2015 by Landge

[celem]

Specifically to follow-up on the size of the KAC windows. I go with +/- a day or a day and a half. Beyond this you start needing to fine-tune midcourse to get back onto the intercept. (Or tweak the ejection to compensate for going early/late, but I dont understand these things, I use the tools and punch in the numbers. If it comes out squint i'll correct downrange). Its long enough that you can realistically get 7-8 big unwieldy ships rolling in a jool window, with half of them making 2 burn passes on nuke clusters. Thats about as far as i've pushed it, its harder with life support as you cant pile them in orbit but is still wing-able.

Edited March 22, 2015 by celem