Duna-Veterans advice / estimation needed

[AcidSludge]

I am currently planning a manned Duna-Mission with one Kerbal, and of course the brave Kerbalnaut should come back to Kerbin.

The CSM-Module with over 12.000 dV (just to be safe) is already in Kerbins orbit, waiting for the Lander to dock

But regarding my LM I'm unsure if my current mission planning work out, because this is my first land/start off again on a planet with an atmosphere except Kerbin. I try to briefly explain what I intend to to:

The Lander, as seen in the picture below, has the following stats:

Overall Weight: 19.205 kg

Engines: 2x LV-909 with 3751 dV / 100kN for 7:39,1 (TWR on Duna according to Engineer 1.77)

The LM is planned to land assisted by parachutes, 2x Mk16 and 2x Mk2-R (I could add more chutes to the landing on Duna-Stage, the return to Kerbin COULD involve a EVA to the space taxi docked on my Space Station, although a direct landing on Kerbin is planned), I'm (almost) certain this could work, but I'm unsafe about starting the LM and dock it again in the orbit of Duna with the CSM.

Long story short - Is that LM capable to start off Duna and reach a safe orbit with that weight and the availabe dV?

[Soda Popinski]

Looks good to me. Be wary landing on Duna if you plan to aerobrake while you enter. The atmosphere is thin and the mountains are tall. Very easy to smack into a peak before loosing much horizontal velocity.

[celem]

Yeah looks good. Soda makes an important point; Aerobraking requires really flat entry over Duna. Your 4 chutes ought to be enough for a 20t rig, if you make them ladder accessible then you can repack them on the EVA and re-use for the Kerbin return. Even if you dont want to aerobrake away a lot of speed, you still want to come in as shallow as you can manage, you wont even get first deployment until 10-11km, thats not a lot of time to slow to a speed that wont shred your chutes and/or ship.

You may need to pulse the engines once or twice to protect the chute deployment, when they actually open you ought not be going more than 100ms.

Despite this assisted landing you ought to have plenty to lift-off and make the rendezvous with CM

EDIT: wait, 4 chutes total? i see the 2 radial whites both on the same side of the ship, remember that this will cause a lopsided descent (unless you are light enough for the sas to hold attitude). those 2 on the plus side are repackable from the ladder. Not sure you can reach the 2 little white chutes mounted above the engines to repack.

Edited December 26, 2013 by celem

[AcidSludge]

EDIT: wait, 4 chutes total? i see the 2 radial whites both on the same side of the ship, remember that this will cause a non-vertical descent (unless you are light enough for the sas to hold attitude). those 2 on the plus side are repackable from the ladder. Not sure you can reach the 2 little white chutes mounted above the engines to repack.

Yep, there are waaayy more chutes at the LM, ten chutes (all properly aligned and with symmetry) at the moment, to be precise. I just planned to use four of them on Duna, the rest is planned for Kerbin, I tend to overengineer my crafts a bit regarding to parachutes. I'm, so to speak, parachutenoid.

[edit]Okay, it seems we have a GO for Duna tomorrow, thanks for your advices

Edited December 26, 2013 by AcidSludge

[celem]

Ahh that makes sense then. Good luck with your mission!

From the CM stats you mentioned and the lander shot you posted, ought to be a walk in the parkdesert

[Sirine]

For me... I will replace those 2x LV-909 with 2x LV-T30 (215 kN).

Below are my reason:-

Generally, LV-909 for anything below 6 tons.

Generally, LV-N for anything above 6 tons.

LV-T30 for anything above 6 tons, and landing on atmosphere, with precision landing requirement.

Just my personal choice.

19.xx tons...not kg.

Edited December 26, 2013 by Sirine

[FenrirWolf]

Tweak your parachutes to deploy higher up for your Duna landing.

Also, as previously mentioned you can use all your parachutes for descent to Duna then repack them for use back to Kerbin if you like. If there are some you can't reach when you're landed, you can always EVA and repack them in orbit too.

[AcidSludge]

I finished the Duna-Mission a few minutes ago, all went exceptionally smooth. I decided to use ALL of the chutes during the Duna-Landing and was able to repack all of them already while on Dunas surface with a a little jetpacking

The LM returned to Kerbin after 460 ingame days, the CSM stayed in Orbit and has to be refueled on my Space Station for further missions.

The landing on Duna happened on mission day 186 and touched down with smooth 2-3 m/s, assisted a little by the engines. I left Dunas SOI again on mission day 192.

Thanks again for your help

[MrPopcup]

Hey There Kerbalnaut! Congrats on the landing thing!

I've been playing KSP since .17 !

what I mean is I'm an experienced player, I love duna so much! in .19 I built a really big base there.. just because.. it's beautiful *__*!

ok, back to topic,( Just for your info, when your planning on Further missions ) when I landed on duna, for the first time in .18.. I landed there using only parachutes.. which is.. yeah.. not enough.. at all!

and now, What I do is, send a Transfer module ( CM ) like you did, that is capable of reaching duna ( yours is capable of reaching beyond.. to Eeloo! ) and then dock the lander with it, generally my lander weights 9 - 12tons max! I think yours is a bit 'heavy' for those engines, Also I'd really like to have 2+ TWR, you can left off from the atmosphere quickly so you won't be ' inefficient ' in taking off. follow these steps:

-1: Dock with your CM.

-2: Transfer to Duna.

-3: Aerobrake ( BUT BE CAREFUL! Aerobrake at 13.5 - 16 Km, this Used to put me in orbit, )

-4: Make a Stable Orbit ( I recommend to put it at 60 km, the lander can pretty much reach it easily.. )

-5: Un-dock, begin burning Retro-grade ( tip: use the Map first, mark your landing site *always make your trajectory go a bit further than your landing site*, then use maneuver node and begin burning ).

-6: Burn until you reach 12-9km, deploy Rogue Chutes ONLY.

-7: When you decelerate ( reach 350-400m/s, or less. ) deploy your normal chutes, that way you won't increase your G-force so much, that will rip your ship apart!.

-8: After all of the chutes get's FULLY deployed, start burning and keep your velocity between 14 - 20m/s, when you see your shadow ( or lights, at night.. ) closing to the ground, increase your throttle until you reach 4-2 m/s, and BOOM! you landed on Duna without causing trouble! ( DON'T FORGET TO REPACK YOUR CHUTES! do this by EVA'ing your Kerbal, Get close to the Chutes and press the right click button on the mouse, click repack. do this to all chutes, and set them to be the 1st stage ( on the left, you can see staging, drag all the chutes and put them at the top ).

-9: Gather science,science and science! EVA reports! Surface Samples! Plant a Flag! Jump around! Crew reports!..

-10: wait for the perfect time to return to kerbin, use Ksp-olex ( google it ). now, like docking near kerbin, launch and start your gravity Turn WHEN the brightest part of the atmosphere is done! ( it's located under the Altimeter ).

-11: dock with your Transfer ship, Transfer to kerbin and set your Periapses to be 20-30 km. Aerobrake and deploy your chutes!

[AcidSludge]

Hey There Kerbalnaut! Congrats on the landing thing!

I've been playing KSP since .17 !

what I mean is I'm an experienced player, I love duna so much! in .19 I built a really big base there.. just because.. it's beautiful *__*!

ok, back to topic,( Just for your info, when your planning on Further missions ) when I landed on duna, for the first time in .18.. I landed there using only parachutes.. which is.. yeah.. not enough.. at all!

and now, What I do is, send a Transfer module ( CM ) like you did, that is capable of reaching duna ( yours is capable of reaching beyond.. to Eeloo! ) and then dock the lander with it, generally my lander weights 9 - 12tons max! I think yours is a bit 'heavy' for those engines, Also I'd really like to have 2+ TWR, you can left off from the atmosphere quickly so you won't be ' inefficient ' in taking off. follow these steps:

-1: Dock with your CM.

-2: Transfer to Duna.

-3: Aerobrake ( BUT BE CAREFUL! Aerobrake at 13.5 - 16 Km, this Used to put me in orbit, )

-4: Make a Stable Orbit ( I recommend to put it at 60 km, the lander can pretty much reach it easily.. )

-5: Un-dock, begin burning Retro-grade ( tip: use the Map first, mark your landing site *always make your trajectory go a bit further than your landing site*, then use maneuver node and begin burning ).

-6: Burn until you reach 12-9km, deploy Rogue Chutes ONLY.

-7: When you decelerate ( reach 350-400m/s, or less. ) deploy your normal chutes, that way you won't increase your G-force so much, that will rip your ship apart!.

-8: After all of the chutes get's FULLY deployed, start burning and keep your velocity between 14 - 20m/s, when you see your shadow ( or lights, at night.. ) closing to the ground, increase your throttle until you reach 4-2 m/s, and BOOM! you landed on Duna without causing trouble! ( DON'T FORGET TO REPACK YOUR CHUTES! do this by EVA'ing your Kerbal, Get close to the Chutes and press the right click button on the mouse, click repack. do this to all chutes, and set them to be the 1st stage ( on the left, you can see staging, drag all the chutes and put them at the top ).

-9: Gather science,science and science! EVA reports! Surface Samples! Plant a Flag! Jump around! Crew reports!..

-10: wait for the perfect time to return to kerbin, use Ksp-olex ( google it ). now, like docking near kerbin, launch and start your gravity Turn WHEN the brightest part of the atmosphere is done! ( it's located under the Altimeter ).

-11: dock with your Transfer ship, Transfer to kerbin and set your Periapses to be 20-30 km. Aerobrake and deploy your chutes!

This is, more or less, basically what I've done on my mission Of course I'm coming back to Duna, I just tweak the LM-Design a bit before I start another mission. Actually I have planned 5 to 6 missions, including bringing more Kerbals along, dropping a rover, maybe a small plane, and of course a trip to Ike.