Dinky Duna - a "Duna Permanent Outpost Mission Architecture Challenge" Mission Report

[DBowman]

Kudos to sturmstiger for a most excellent challenge: http://forum.kerbalspaceprogram.com/threads/31510-Duna-Permanent-Outpost-Mission-Architecture-Challenge

Recenty vosechu put in some hard work of collecting all the attempts not yet noted in the Original Post.

That got me to thinking that my current Deeply Duna is going to take a while but maybe I could throw something quick and dirty together with 'parts I have lying around'? The idea being to keep it small, simple, achievements oriented, and executable.

I have a reusable SSTO Duna Ascent Vehicle (DAV) I am going to use in Deeply Duna. It's intended only to transport Dunauts between Duna surface and Low Duna Orbit.

Very aerodynamic and futuristic, sort of stock linear aerospike engine...

To test it's Duna aero capture I had flown it there. I thought 'strap some drop tanks so it has the fuel to return from Duna & life support for the duration on it and it can be an outpost' - hence 'Dinky Duna'. 'Dinky' in both the British (attractively small and neat) and North American ( disappointingly/comically small, insignificant) sense.

The basic plan is an extended stay mission, that could be a permanent presence by doing a relay overlap of identical missions. For me it's really about hacking together a quick completion with some good constraints and technology / technique trailing.

For mission robustness / I want to hit that first transfer window with the second launch - I need that if the first launch fails then the second can complete the mission => close to 30t total payload. Also small means simple, simple means fly-able. A few extra ton I can cope with by spending more dV for a slightly off Hohmann transfer.

I can fly and complete just the 'Mission Robustness' second launch flight as a 'one off standalone' to get "Mission Execution 1" and use it's Mission Report to get "Mission Execution 3" on a plan for as many copies of identical flights as the eventual craft weight allows.

Here are some sanity numbers:

Earth Day 951 is the last D-K transfer in the 1000 days, returns by 1015, first window day 55 => 960 day mission < 1000 day "One-way Ticket Penalty" of 50% off the score.

My DAV is 6.5 ton, +960 LS weighs ???? so 2 at 15 ton each could be do-able. But lugging return fuel all that way will blow out the mass budget with the 48s.

I found the 'Duna Direct' mod that has two parts; a hydrogen tank and a reactor that does the Sabatier process to generate liquid fuel and oxidiser - http://kerbal.curseforge.com/ksp-mods/224286-dunadirect. One tank of H2 will make 360 fuel + oxidiser. How much does it cost to push 360 f&o to Duna ? => how much does Sabatier save: 1*48 engine => 360f&o is a 8.5 ton craft, H2+13f is a 364 kg craft! => 8400 vs 264 kg (excluding the engine) - a factor of 32 times or 3.14%. (16kg is H2 of 78.5 kg wet weight tank) Too good not to use to generate the return ascent and transfer fuel, and as a bonus it's exactly what Dr Robert Zubrin proposes for the real life (planned) Mars Direct missions.

Duna Ascent and Kerbin transfer requires: 100(just in case) + (1380 + 700 + 100(man)) *1.25 = 2725 + 100(just in case) m/s and I can stage the drop tanks. (got 2824 vac / 2742 atmospheric)

The times 1.25 is to hit "Crew Safety #2" of the challenge, succeed in the face of loosing 20% deltaV.

Transferring to Duna requires 100(jic) + ( 1200 + 100(man) ) * 1.25 = 1625 + 100(jic) m/s but I cannot stage anything I will need on Duna. I have to arrive with fuel such that adding 360 will get me home. So take the Duna asc+xfer config, jimmy the staging like it wont stage => 2232 m/s -1725 = 507 should be left, remove 360 f => 483 m/s left - so there should be slightly more fuel than I need left - 24m/s worth! we have a 100 m/s 'buffer'. Adding 2x45 will add 200 m/s @ 17250 kg = 34500 => 51.75 days => 61.75 = 247 EDay - a Duna transfer then will be well under the nominal 1200 m/s. So I go with extra Kerbin-Duna drop tanks.

After messing about the resulting 2 man transfer+outpost+rover+fuel-refinery+ascent vehicle ( DAV++ ) was a little too heavy on landing to hit Crew Safety #2, so I had to add one more engine. I wanted to keep the engines under the centre of mass so a single failure would not generate too much torque.

Not so areodynamic and futuristic, but all the extra junk will be left on Duna. The DAV++ can land okay with one failed engine & one failed chute, it can ascend with one failed engine.

Flight plan sketch for DAV++ from LKO is:

• be full of fuel.
  
• transfer to Duna
  
• aerocapture
  
• land somewhere low and flat
  
• use Sabatier and H2 to make the ascent and return fuel
  
• sit for XXX days, maybe take the rovers for a drive, selfies, Settlers of Catan, etc - try not to get on each others nerves.
  
• ascent to LDO
  
• transfer to Kerbin
  
• aerocapture
  
• take the shuttle down. The DAV++ can re-enter if it needed to.
  

Things I thought about but decided against:

• nukes - much more efficient! putting a nuke on a craft this small just does not pay off in fuel savings. Also makes the flight plan more complex by adding a rendezvous and as far as I know I'd have to have a 'buffer tank' with the nukes, if the buffer was too small I'd have to use the manual fuel transfer to keep it fed. Does anyone know a neat way to transfer fuel to 'an engine mounted straight to a docking port'? I had an idea how to make it flyable even under a single nuke out of two failure. In the end I thought to just keep it simple and 'Dinky'.
  
• life support recycling - I've only got 4 Kerbal, split across two craft, if it wasn't dinky I could send re-cyclers with a second wave.
  

I have a 30 ton re-usable launcher ( henceforth named Kerbin Lift Vehicle - 30 (KLV-30), like it's larger sister KLV-75 ), see 'Dash 4 Duna' (http://forum.kerbalspaceprogram.com/threads/112640-Dash-4-Duna-Duna-Permanent-Outpost-Mission-Architecture-Challenge) for details. It has TWR headroom so I added 720f to the 3rd stage, this left the recoveable first stage at 66% of launcher weight ( KLV-34.5 ). That will lift two DAV++ to meet the Basic Requirement of 4 Kerbals on Duna. Also as a bonus, travelling as a pair, in the case of 'total engine failure' of a DAV++ they can dock and one can get them both home on two engines, if they were 'great pilots' they could probably even do that in the middle of a transfer burn.

Now I jus have to fly it.

Edited April 9, 2015 by DBowman

[DBowman]

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imgur embed seems messed up - I cannot 'zoom' in to a pic, here is the album http://imgur.com/a/hT5uQ#0

• Don't forget to load the crew!
  
• Don't forget to set control from here on something pointing up!
  
• Launch on D247. Pretending the first launcher failed for some reason and I'm flying the backup "Mission Robustness" flight.
  
• Wait for dawn for the publicity snaps / paparazzi.
  
• 1.55 G launch max, to 80x80 LKO and de-orbit the 3rd stage, tidy.
  
• Separate DAV++s and name each craft; Dinky 1 and Dinky 2 ( cf B1 & B2 in https://www.facebook.com/bananasinpyjamas ).
  
• Jeb is in Dinky 1 and will fly with one engine and one chute disabled to simulate "Crew Safety #2".
  
• Dinky 1 Trans Duna Injection burn 1054+1 m/s tweak => t+271 KDay to Duna Pe @ 18.4Mm. Remaining 147 of 470f = 323 used.
  
• Dinky 2 Trans Duna Injection burn 1055 m/s => t+272 KDay to Duna Pe @ 35.6Mm. Remaining 149 of 470f = 321 used.
  
• Shutdown most LS to make it consume top hex can first. 3868 days unlocked, 99 days in the hex can.
  
• 99 days later, dump the life support hex can, turn on the outboard regular cans.
  
• Duna descending node inclination correction t+131 tweaks D2 @ 12.4 m/s got 18km Duna Pe, D1 @ 8.1 m/s got 37km DPe
  
• D1 crossed SOI, aerocapture wants 12km Pe for sub 200km Ap (thanks alterbaron: http://alterbaron.github.io/ksp_aerocalc/)
  
• D1 Duna aerocapture had max 570C on the wheels, 0.68G. 144 fuel left,
  
  • +5.51 m/s @Ap to18km Pe => 50km Ap,
    
  • 24m/s to circularise now since D2 is coming in.
    

  [*]D2 same AC,

  • +5 m/s @Ap for 18km Pe => 51km Ap.
    
  • 142 fuel left. +24 m/s to circularise=> 135 fuel left (luck was not with me on D2 'direct landing' had to circularise first)
    

• Oops the orbits are pretty inclined (5 degrees-ish), luckily at the next pass they happen to cross the equator near 84East where I want to land on low altitude rolling hills.
  
• D1 can get pretty close to target, so I decided to go for it . -21.72 m/s for impact 128f 7f=22m/s => 44 to spend - I think 4 secs to burn - went at 4sec burned much longer 102f left.
  
• D2 down with 123f left, 24km from D1.
  
• Crew Safety check:
  
  • VAB 'non staged version' of the craft with 102 fuel left has 433 m/s left => 333 + JustInCase, 333 * 5 = 1665 m/s so we landed with "Crew Safety #2" DeltaV intact.
    
  • VAB ascent config with 8 less fuel than full => 2791/2711 need 2725 so looks ok. I can get home with 330 fuel (legs cost 100 m/s)
    
  • I will transfer fuel from D2 which has excess. Next time add a little more fuel or H2.
    

  [*]Drove both craft to a meetup near the equator, about 30km for the longest drive. Joined up and D1 processing Sabatier - 104f t+272:3

  [*]All processed - but lets try pipe fuel between them and if so fill D1 since D2 could make to 483 => 13 excess

  • I used KAS to pipe join, pump fuel, and separate.
    
  • On quick save and restore it - lost one vehicle!!! There was just the attach source fuel tank floating there.
    
  • Am I doing it wrong? cause it seems like a problem!
    
  • Backed out to the previous quick save.
    

  [*]Deploy all the rovers & Dunauts for a group photo.

  [*]I made KerbalAlarmClock alarms for each crew & vehicle for ease of switching.

• Return planning:
  
  • launched KD 247
    
  • + 3868 LS => 4115 deadline for return = Kerbal Y10D281,
    
  • this is less than the "One-way Ticket Penalty" 1000 EDays away.
    
  • take ED 951 return window
    
  • 309 days LS on the craft and I want to leave as late as possible for score!
    
  • alexmoon says: Y9:398:4:00:00 @ 657+9 m/s (http://alexmoon.github.io/ksp/)
    

• Note TAC did NOT use furthest storage first - be sure to check all your containers before launch.
  
• It looks like maybe if you leave the brakes on it thinks you are moving over terrain and not let you warp save etc.
  
• D1: 2767 m/s on the surface, 1423 m/s left at 50x50 LDO.
  
• D2: 1427m/s left at 50x50 LDO
  
• Clean up the inclinations, D1 with the off centre thrust from an out board engine off is a little messy.
  
• Trans Kerbin Injection burns:
  
  • D1 arrive Kerbin Pe at +298:2, add .6 m/s to get +297 and get there before D1. 1417 m/s, pulls about 1G, 759 m/s left post burn.
    
  • D2 arrive Kerbin Pe at +298:0, pulls 1.5 G, 769 m/s left post burn.
    

  [*]Kerbin Descending Node & Pe tune manoeuvres: D2 9 m/s, D1 10.3 m/s

• TAC helpfully scares the snacks out of you with 'Food & water running out' warp stop warnings - I'm in Duna-Kerbin transit what am I going to do about it? - but it's a 32 day warning and I expect to AC with 10 days to spare.
  
• Kerbin SOI, I know Kerbin aerocapture will burn so I'm fine with any kind of Ap:
  
  • D1: 83546 km @ 928 => 38182 = 5000km capture - high == cool == good
    
  • D2: 83299 km @ 925 => 38197
    

  [*]Kerbin Aerocapture:

  • D1: 870 C peak temp 0.9 G.
    
    • 2nd pass 740 C, cabin at 61 C.
      
    • 3rd 600 C,
      
    • ++ m/s to raise AP out of atmosphere to get clear for D2 which is coming in.
      

    [*]D2: 865 C peak temp 0.86 G.

    • 2nd pass 750 C,
      
    • 3rd 690 C,
      
    • finally +52 m/s to circularise to 99x99. 742 m/s sec left.
      

    [*]D1 -11 m/s to catch more air after D2 circularised,

    • finally +31 m/s to circularise,
      
    • 712 m/s left - well under "Crew Safety 2" margins.
      

  [*]Dinky1 & Dinky2 both home safe in 100x100 LKO @

  • Y10 D271 02:39,
    
  • 965 Earth days away,
    
  • 822 days on Duna
    

Edited April 10, 2015 by DBowman

[DBowman]

3 Mission Execution:

1 - Actually flown every unique mission in the first 500 days: Evey mission is identical, I flew 1

2 - Actually flown every unique mission in the first 1000 days: as above.

3 - Actually flown every mission, or got at least #1 and posted a mission report: tick.

2 Crew Mobility

1 - More than 50% of the crew have a rover seat.

2 - Every one has a rover seat. Even if two rovers are lost everyone would have a seat.

3 Base Mobility: All my bases are self powered mobile.

2 Crew Safety

1 - The crew will survive the loss of a single unmanned spacecraft or base: Everything is crewed

2 - Also the crew will survive the loss of a single engine (or rover mobility) and the loss of 20% of DeltaV: I planed for it and think I hit the numbers.

2 Mission Robustness

1 - The loss of any single launch will not prevent getting 4 Kerbols to Duna before day 500: with a KLV-34.5 I can hit the first window even if the day 10 launch 'fails'.

2 - Also the loss of any single spacecraft or Duna module will not prevent 4 Kerbols to Duna: see the flights plan below there are plenty of windows.

I think I hit all twelve achievement points.

Primary score and efficiency from the 1000 day plan

[DBowman]

I hope it's clear whats going on:

• Red flights are to Duna, dark red when on Duna itself.
  
• Green flights are to Kerbin.
  
• To the left side is the nominal flight window.
  
• To the right the flown flight, e.g. a little late on the first one due to 4.5 extra tons to LKO.
  
• The LKOs are launches from Kerbin.
  
• The light red Duna flight at the bottom is one that I'd skip flying in order to max the challenge score, if the program was 'in perpetuity' I'd fly it. It would launch 172.5 ton that will not hit Duna before the 1000 days runs out, i.e. drag down efficiency for no score gain.
  
• The scorings I worked out are in gold.
  
  

There are three main plans that make sense:

1. One Shot: here I just send one launch here I worked it out as the first window. This makes some sense if the challenge was measuring a single, or finite set of flights - like an Apollo or something. You can see it has great efficiency, 104! But the challenge calls to keep Duna continuously occupied. 3588 @ 104 efficiency.
   
2. Two Shot: make one launch for the second window to get 'continuous occupation.', the second flight's crew will be on Duna when the challenge timer ends. This plan still has great efficiency. 6200 @ 90 efficiency.
   
3. Rack em Up: Launch everything you can: 28363 @ 50 efficiency.
   
4. The one I just thought of: I can just use the first six launches to hit 'continuous occupation' 10448 + 7175 = 17623 @ 85 efficiency (5412@26 Early).
   

If I had to pick a flight plan as an 'official entry' I'd go for #4, but I like the purity of the One Shot.

[DBowman]

BBowman: Dinky Duna

Until Day 0500: Launches 6, 207 ton LKO, Early Mission Value:5314, Efficiency: 26

Until Day 1000: Launches 6, 207 ton LKO, Sustained Mission Value: 17623, Efficiency: 85

Mission Execution 3, Crew Mobility 2, Base Mobility 3, Crew Safety 2, Mission Robustness 2

Mods: Deadly Reentry, TACLS, Duna Direct (in-situ fuel refining), KAS (for resource xfer), Mechjeb, Kerbal Engineer, Kerbal Alarm Clock, EVE, Enhanced NavBall (re-size and position)

Now back to Deeply Duna, and thinking about vosechu's "Realism Overhaul" version of the challenge (23 km/s to transfer - ouch).