Duna Semi Direct (getting ready for the Martian)

[tadswana]

So, I've recently been reading Zubrin's "the case for Mars" in preparation for the upcoming The Martian (which I'm super excited about), and have been inspired to attemp the "Mars Semi Direct program" put forward with a minimal 4-vehicle program for KSP. The four vehicles required are:

• Launch Vehicle (LV): getting to Kerbin orbit (4500m/s) and lift for the three below.
  
• Duna Ascent Vehicle (DAV) - sent in advance with fuel production on Duna for the ascent (maybe also to refuel the KRV?).
  
• Habitat (HAB) - sleeps 3 with research capabilities, science lab, power, comms, and a dockable rover. This is the initial transport of the 3 Kerbals from Kerbin all the way to Duna.
  
• Kerbin Return Vehicle (KRV) - Kerbin to orbit of Duna and return to Kerbin. Transports the little guys.
  

Key delta-Vs:

• Kerbin to Orbit: 4500 m/s
  
• Orbit to Duna: 1430 m/s
  
• Duna Descent: (aerobrake)
  
• Duna Ascent: 1380 m/s
  
• Duna return to Kerbin: 1060 m/s
  

The mission concept is based on Zubrin's "Mars Semi-Direct" which you can see in his presentation here Basically it involves:

• DAV sent to Duna unmanned for production of fuel.
  
• DRV sent to Duna orbit unmanned.
  
• HAB sent to Duna with crew and descent to within IVA of the DAV.
  
• Crew science the hell out of Duna, then ascend to Duna orbit in the DAV and return to Kerbin in the DRV.
  

Originally it was proposed by Zubrin without the DAV, and two DRVs that produce fuel on the ground and transport the crew. This allowed the first DRV unmanned to be delivered and produce fuel, and then the next DRV with crew and return in the first DRV, allowing colonisation through leapfrogging. The Mars Semi Direct concept was developed to minimise cost, and only commit the crew once the ascent vehicle was fuelled and ready and the return vehicle was in orbit. I understand that Mars Semi Direct is the basis of Andy Weir's "the Martian" which got me thinking.

I'm doing concept design now and will post pictures as I go. Needless to say they will be stock, and going for lowest cost as possible due to fiscal constraints on Kerbin.

Embrace your inner Dunatian (thanks Davidy12)!

Edited September 24, 2015 by tadswana
clarification of HAB taking the kerbals.

[SpaceplaneAddict]

Elaborate. I like it anyway. Will do.

[Guest]

Maybe will attempt. (I'm not the greatest at this stuff. Hyper edit FTW. I won't actually use it thought.)

[davidy12]

I'd say "Dunatian", and I've done this a million times, really fun.

[tadswana]

Dunatian it is!

Would love to see screen shots of your vehicles!

[Stoney3K]

How are you gonna land your Kerbals on Duna? If the DAV is already on the ground, that leaves the HAB module which would dock with the KRV in Duna orbit, transfer crew (and possibly fuel), and de-orbit, remaining on Duna after the mission, right?

[Foxster]

Yup, we either need another vehicle to get the Kerbals back to orbit from the surface or return the DAV or HAB to orbit. How you want to do it OP?

[killakrust]

Presumably the intention is to take the Kerbals down in the HAB?

[tadswana]

Crew land in the HAB and go back up in the DAV (I've amended the post for clarity).

It's made me really think about the details of this, any comments really welcome!

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Presumably the intention is to take the Kerbals down in the HAB?

yep, that's the plan!

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So, I made my first attempt at the DAV last night with a delta-V of 1500m/s. I'm going to put a jettison-able heat shield on the top for Duna atmospheric entry and then pop the chutes for the ride down. I'll use the last bit of fuel for the final touchdown.

I'm starting to understand the beauty of Zubrin's idea now, as the delta-V to Duna is about the same as the ascent from Duna, so no fuel is wasted and mass is minimised. Running the ISRU and drill is probably a little heavier than the idea of direct methanation of the atmospheric CO to liquid methane for the fuel, however does the same thing.

[YNM]

I actually have KASA and Tantares installed on 1.0.2 KSP and I'm planning a mission to Duna using four LEM (only three is manned, so total crew of 6), a DOS, and an extended S-IVB (for propulsion). If I add a separate habitat module, then send it before the crew, that also mines fuel for some kind of extended LEM, would that count in ? With the previous design even I believe I can get to Laythe with a nuclear engine powered S-IVB than FASA's J2.

Edited September 24, 2015 by YNM

[tadswana]

I actually have KASA and Tantares installed on 1.0.2 KSP and I'm planning a mission to Duna using four LEM (only three is manned, so total crew of 6), a DOS, and an extended S-IVB (for propulsion). If I add a separate habitat module, then send it before the crew, that also mines fuel for some kind of extended LEM, would that count in ? With the previous design even I believe I can get to Laythe with a nuclear engine powered S-IVB than FASA's J2.

I would think so, send some pics.

I'm thinking that the nuclear engine would be very well suited for the KRV as it's working in vacuum for the entire mission profile.

[Foxster]

Here's my Duna adventure...

Javascript is disabled. View full album

[davidy12]

Thanks for your shout out.

I use Space Y, Tundra exploration, and Space Y expanded, the two rockets I build for cargo to Duna are the SNLS (Super Nova Launch System), and I built a replica of the Hermes to get crew there. The DAV is the Rodan capsule (Want to stay low on part counts so no ISRU). And Because I like to leave marks that I were here (besides Hab and Rover) I decouple the Solar panel trunk and some spare fuel and the whole re-rendezvous song and dance and head home. I'll try to post pics this weekend.

Edited September 24, 2015 by davidy12

[tadswana]

Foxster - thanks for the images, you gave me some great ideas, particularly for the DAV and the rover.

I'm hoping on running the mission and posting the photos soon with my concepts!

[Foxster]

Foxster - thanks for the images, you gave me some great ideas, particularly for the DAV and the rover.

I'm hoping on running the mission and posting the photos soon with my concepts!

It didn't end up exactly as per your specification because I built it just before you clarified how they were to return to orbit but I think it's close enough.

If I was doing it again I wouldn't dock the rover in that way. Was way too hard and it took a lot of F5+F9 to make the dock happen. It would have been much simpler just to use the claw. But I had the docking ports so wanted to use them at least once.

To make it sorta realistic it is important that at launch the rover's tank is empty and the two landers have just enough fuel to make the Duna landing. Then there is a point to making the fuel and moving it around.

[selfish_meme]

I'm actually putting together a 'The Dunatian' pack that includes a save file with all the assets in place to do a 'The Martian' run-through. I take submissions from the community and you can do whatever bits you want, just look at what is already done, test it improve it and submit it, get your name added to the contributors. I also need just testers and people to do documents and videos. Something for everyone. It's all being done in stock. I am looking to make a beta savefile release on the release of the film 1st October. The curse page for downloads is in my signature, the forum thread is here

[Stoney3K]

If I'm correct, the Mars (Duna) Semi-Direct mission would be two or three separate launches, right? So the mission profile would be something like this:

* DAV + refinery launches unmanned and transits ahead of manned mission. DAV + refinery lands on Duna and starts mining fuel to refuel DAV.

* Habitat module launches into LKO empty, possibly picking up fuel from an orbital depot.

* KRV launches with our three adventurers, and docks with Habitat module. Alternatively, HAB+KRV can launch as a pair.

* The HAB module provides housing for our three Kerbals during the long transit period (right?). On Duna capture, KRV remains in orbit, and HAB deorbits to land next to the DAV.

* Science is done. Kerbals stay in the HAB module on Duna.

* On a return window, the DAV launches into Duna orbit and docks with the KRV, and the DAV/KRV combo return to Kerbin.

The manned transit could also be done in the KRV like on the return trip, but that would mean the KRV is quite a hefty ship with enough facilities to sustain three Kerbals for up to a year.

[YNM]

My current main ship always try to wiggle out (some super silly Kraken, really !) two of the four DEMs (LEM for Duna) (their placement, think of Mir and replace everything except the DOS and Kvant-1 by the LEMs) so I'm not sure if I have to reconsider the lander design and position- even possibly closer to the book by sending the ISRU - capable lander first and everything else later. Won't do a kerbin slingshot though. Or I can send the ISRU- capable Hab first, which means no need for relaunch at all, just need to ensure the two LEM left have all the things they need, which is a fuel line mount. Would report again later, but yeah, it's quite shocking that they never wanted it !

Mods used: FASA, Tantares, MechJeb (imagine launching four rockets in a day ! That's boring), Persistent Rotation, fuel transfer mod (by dmagic I think), Snacks, and some other small things like RPM and whatnot. The wiggle events really leave huge debrises and is sort of dangerous to look at. Scenario is that a one-year old soviet operational station is reworked to be an interplanetary vessel to Duna, with help of four LEM (will be reconsidered) and an extremely extended SIV-B (Saturn IB - Saturn V upper stage). Carries six crews, three from each nation, to Duna and back home. Will aerobrake a lot, so it's going to be somewhat reusable ! The scheme can be extended to reach Laythe even, as long as ISRU and nuclear engine is installed.

[SpaceplaneAddict]

What about a DDV, Duna Descent Vehicle?

[mythic_fci]

I watched the film just yesterday - it's amazing! I highly recommend anyone and everyone here to see it ASAP, especially if you enjoyed the book. One thing about the movie - unlike the book, the MDV is never mentioned - it's implied that the crew took the combined MAV/MDV (MADV?) down instead of taking two vehicles, as (spoiler alert!) Mark invents his own contraption to extract the hydrogen from hydrazine, which is extracted with (presumably) the descent stage of the MADV. Just saying, if anyone wants to try that method.

[tadswana]

If I'm correct, the Mars (Duna) Semi-Direct mission would be two or three separate launches, right? So the mission profile would be something like this:

* DAV + refinery launches unmanned and transits ahead of manned mission. DAV + refinery lands on Duna and starts mining fuel to refuel DAV.

* Habitat module launches into LKO empty, possibly picking up fuel from an orbital depot.

* KRV launches with our three adventurers, and docks with Habitat module. Alternatively, HAB+KRV can launch as a pair.

* The HAB module provides housing for our three Kerbals during the long transit period (right?). On Duna capture, KRV remains in orbit, and HAB deorbits to land next to the DAV.

* Science is done. Kerbals stay in the HAB module on Duna.

* On a return window, the DAV launches into Duna orbit and docks with the KRV, and the DAV/KRV combo return to Kerbin.

The manned transit could also be done in the KRV like on the return trip, but that would mean the KRV is quite a hefty ship with enough facilities to sustain three Kerbals for up to a year.

Yep, that's the way I think it rolls...

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So,

Here's my first pass at the DAV, it's sitting on Duna right now mining away and replenishing. I'm sending the KRV now, and the manned HAB will go once the DAV is full up.

Mental note to self: don't put OX panels on the DAV again, as they can't retract and burn up in the aerobrake Drilling very slow with secondary panels only... lol.

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This is the aerobrake into Duna (with aforementioned OX panels... doh!). and the drogue chute for the descent <1000m/s. Small amount of propellant used for the final touchdown.