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awfulcraftdesigns

[1.0.5] [Delta-V Readouts] [Sandbox] Attempt at a Duna Mission, I don't believe even with KER (Kerbal Engineer Redux), KAC (Kerbal Alarm Clock), and KAX (Kerbal Aircraft Expansions) can give me enough of the readouts required to get to Duna!

Question

As the title says, I'm attempting a Duna Mission (hoping that there isn't any major inclination) but not sure of the DV requirements. I'd like either an SSTO or Rocket being capable of the transfer burn and the most efficent transfer window (I will figure this out using the Transfer Window Planner Mod). Of course, I will try to build a craft myself first but I'm clueless as exactly how much DV is required. A rocket that I can test which can get me to Duna (Either SSTO or a VAB Consturction) so I get a rough idea from the readouts on KER.

 

Mods I'm using (All Abbrevaitions in the Title):

KER

KAC

KAX

Transfer Window Planner

Texture Replacer (When I work out how to do Custom Spacesuits, regardless it is still installed)

SpaceY and SpaceY Expanded

RasterPropMonitor

Precise Node (See here, since I can't exactly get mine to show the Window...thats why there is a seperate thread here: 

 

Rocket Factory

 

Thank you for the help KSP Community, it is much appreicated and I wish the best of luck and I appreciate the people who are willing to help me!

-awfulcraftdesigns, wishing the help he is given...good luck and peace out! :wink: 

 

Mission Update:

(PIcs Coming Soon!)

Edited by awfulcraftdesigns

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So, a mission to Duna and back will depend on exactly what your objectives are.  For example, if you just want to do a crewed landing on Duna and then return to Kerbin, the mission will look like this:

  1. Get to low Kerbin orbit.
  2. Eject to interplanetary Duna intercept.
  3. Arrive at Duna.  Either slow to orbit and then land, or land directly.
  4. Having landed at Duna, take off and get to Duna orbit.
  5. Eject to interplanetary Kerbin intercept.
  6. Arrive at Kerbin, reenter, land.

So, there are various ways to do these things.  The way you design your mission is to start at the end of the mission and then work backwards.  On each step, evaluate how much dV it needs, and then design your rocket to have that much dV.

For example, start by designing a Kerbin reentry capsule (step 6).  With a lightweight capsule and a good heat shield, no dV required; just let aerobraking do your work for you.

Now add a stage below that that has enough dV to do an ejection from low Duna orbit to get to Kerbin (step 5).  The amount of dV needed depends on planet alignment.  There are tools out there for this-- my favorite is http://ksp.olex.biz, which will tell you what the launch window looks like and how much dV you need.

Then below that, something that has the dV to get to low Duna orbit from the surface (step 4).  This is typically around 1200 m/s, if I recall correctly.

Next, add design to your Duna lander so that it can arrive and land on Duna (step 3).  There are various ways to do this, but I'm a big fan of aerobraking for Duna; play your cards right and you need practically no dV for this.  Heat shield, drogue chutes, regular chutes.  Don't need many parachutes-- just enough to slow down to a few dozen meters per second, then use a last-minute burst of engine thrust to cushion the landing.

Then a stage below that with the dV to get from low Kerbin orbit to Duna (step 2).  You can use the launch planner linked above to get the dV for this.

Then, finally, put a booster on that package that will get it to LKO from the surface (step 1).

So... that's it for your mission planning.

The flip side of the coin is "Okay, so I have a payload like this and I need N meters per second of dV, how do I design that?", which is another issue.  However, I'm not sure where your uncertainties lie-- so let's pause here for a moment.  Does the above get you what you need, or do you still have questions?

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Just now, Kerbin vonKerbal said:

When in doubt, go overkill and get over 10k delta-v. Because why not.

Thanks, but not exactly giving me any craft ideas...you get me? No offence, just saying could've thrown in a few images of a ship capable of reaching Duna...

Will SpaceY give me the 10k Delta-V I require? Likely to make piloting errors but still...might be nice to know if its worth the install

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5 minutes ago, Kerbin vonKerbal said:

When in doubt, go overkill and get over 10k delta-v. Because why not.

Maybe he's not planning a one-way mission. I'd add another 10k for the return leg.

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Just now, Kerbart said:

Maybe he's not planning a one-way mission. I'd add another 10k for the return leg.

Again, no offence but not exactly answering  either of my questions? (The comment and the OP)

I'd like a return leg, but not gonna happen, I know I'm gonna screw up.

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I'd bring about 7700 m/s for a return trip.

  • 4000 m/s to get to orbit.
  • 1200 m/s for transfer burn and course corrections
  • 2000 m/s for landing and return to orbit
  • 500 to get a Kerbin intercept.

Note: This assumes you are going to be aerobraking at kerbin at the end, so you periapsis should lower than 35 km.

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YBq26Um.jpg

oxcMnVP.jpg

aNGxXgY.jpg

all of these crafts are duna capable,have about 6000dv at kerbin, but start dropping bits at duna (why bring back the landers)

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With a couple of airbrakes and a few parachutes added I flew the ship I made for your Mun rescue to Duna the other day. You should probably start with unmanned probes first though.

It did use aerocapture at Duna to save fuel. Once you know what you're doing it should take about the same Delta-v as a Mun mission.

 

LOR%20rescue_zpsyp7uctc0.jpg

duna%20lander_zps2slxbc6i.jpg

Edit- Just realised you've gone back to 1.0.5. The parachutes have a much lower opening speed in that version so that lander won't work as well since you'll have to burn the motor to slow down enough to open the drogue chutes leaving little safety margin for return to orbit.

Edited by Reactordrone

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 I send a lot of ships to Duna instead of just one. A station core with hab and lab. a service module that carries the crew, a lander, and a fuel tanker. Each requiring a separate launch.

screenshot299_zpscvcx9rem.png

This is the basic launcher that is tweaked for each payload

screenshot292_zpshrk6fnvj.png

To build the launcher I basically use Snark's method and this D/V map for reference.

 

 

 

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9 hours ago, Snark said:

So, a mission to Duna and back will depend on exactly what your objectives are.  For example, if you just want to do a crewed landing on Duna and then return to Kerbin, the mission will look like this:

  1. Get to low Kerbin orbit.
  2. Eject to interplanetary Duna intercept.
  3. Arrive at Duna.  Either slow to orbit and then land, or land directly.
  4. Having landed at Duna, take off and get to Duna orbit.
  5. Eject to interplanetary Kerbin intercept.
  6. Arrive at Kerbin, reenter, land.

So, there are various ways to do these things.  The way you design your mission is to start at the end of the mission and then work backwards.  On each step, evaluate how much dV it needs, and then design your rocket to have that much dV.

For example, start by designing a Kerbin reentry capsule (step 6).  With a lightweight capsule and a good heat shield, no dV required; just let aerobraking do your work for you.

Now add a stage below that that has enough dV to do an ejection from low Duna orbit to get to Kerbin (step 5).  The amount of dV needed depends on planet alignment.  There are tools out there for this-- my favorite is http://ksp.olex.biz, which will tell you what the launch window looks like and how much dV you need.

Then below that, something that has the dV to get to low Duna orbit from the surface (step 4).  This is typically around 1200 m/s, if I recall correctly.

Next, add design to your Duna lander so that it can arrive and land on Duna (step 3).  There are various ways to do this, but I'm a big fan of aerobraking for Duna; play your cards right and you need practically no dV for this.  Heat shield, drogue chutes, regular chutes.  Don't need many parachutes-- just enough to slow down to a few dozen meters per second, then use a last-minute burst of engine thrust to cushion the landing.

Then a stage below that with the dV to get from low Kerbin orbit to Duna (step 2).  You can use the launch planner linked above to get the dV for this.

Then, finally, put a booster on that package that will get it to LKO from the surface (step 1).

So... that's it for your mission planning.

The flip side of the coin is "Okay, so I have a payload like this and I need N meters per second of dV, how do I design that?", which is another issue.  However, I'm not sure where your uncertainties lie-- so let's pause here for a moment.  Does the above get you what you need, or do you still have questions?

I would like to carry a pre-assembled space station (from LKO) to Duna, with 2 Landers (One for Ike and One Duna), a Crew of 6 (Possibly a crew of 8 because of the Landers becoming manned, whilst the other 6 sustain the station) cause Wynaut, sorry couldn't help myself to the Pokemon Reference), Enough Power for it to stay indefinitly in its Final 25km Duna Orbit, Solar Panels (Duh), Fuel (For Re-Fueling on Interplanetry Missions) and a Return Stage that can get to Kerbin if I'm bored...But of course, it'd be good to start simple and space stations aern't exactly simple...regardless either that or what you've said above would be cool. So here is what I'm planning my mission to look like  (Also it'd be helpful to have some input on weither or not SpaceY is worth installing for a mission like this):

1. Get to Low Kerbin Orbit

2. Assemble the Modules stated above and wait for a Launch Window with Duna

3. Eject for Duna Encounter

4. Arrive at Duna. Do a circularisation burn, till I get a 25km Equatorial Orbit (Give or take 0.1 Degrees)

5. Send the Landers, with enough Dv to return to the station.

6. Wait until I'm bored and return some of the crew to Kerbin to bring up fresh recruits.

 

Of course, I know this will take alot of work and that is why I'm here before the community asking them for help!

Good Luck Guys and Thank you Snark for the delightful response :D

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Just now, Reactordrone said:

Duna atmosphere goes up to 50km so are you shooting for a 75km orbit i.e 25km above the atmosphere?

Yes, I suppose...I didn't know it went up so high...So yes a 75km Equatorial Orbit

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Your mission plans seem pretty grand for a very first mission to Duna ever, which I assume this is for you considering you don't know even the dV requirements.

3 hours ago, awfulcraftdesigns said:

it'd be good to start simple

This, 100% of the way. Your first Duna mission should look a lot like your first Mun mission, with a bigger transfer stage. And (unless you did it this way when you went to Mun) you should have an orbiter and a return stage.

Snark pretty much nailed it, though I don't see a link to said dV map (I could be missing it but I looked twice) so here's the one I use:

Spoiler

Q8JvCu8.png

Using this map, note you can land on Duna (with aerocapture and braking) for LESS dV than Mun. It's a bit more to get back, though:

From LKO, Mun takes 860+310+580 (or 1750) to land on, and 580+310 (or 890) to return from. This is 2640m/s from LKO. I'd like 3000 myself for margins.

From LKO, Duna takes 950+130+10* (or 1080-1090) to land on and 1450+360+250+130+10* (or 2190-2200) to return from. This is 3270-3290m/s depending on how much you spend to fix your angle. I'd bring at least 3500 myself for margins, and probably try for 4000.

So really, Duna SEEMS daunting (and is from a logistics standpoint. Which is why I think you should start with a one-shot, Apollo-style mission to start) but as far as dV is concerned, it's really just a step up from Mun.

Edited by 5thHorseman

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2 minutes ago, 5thHorseman said:

Your mission plans seem pretty grand for a very first mission to Duna ever, which I assume this is for you considering you don't know even the dV requirements.

This, 100% of the way. Your first Duna mission should look a lot like your first Mun mission, with a bigger transfer stage. And (unless you did it this way when you went to Mun) you should have an orbiter and a return stage.

Snark pretty much nailed it, though I don't see a link to said dV map (I could be missing it but I looked twice) so here's the one I use:

  Reveal hidden contents

Q8JvCu8.png

Using this map, note you can land on Duna (with aerocapture and braking) for LESS dV than Mun. It's a bit more to get back, though:

From LKO, Mun takes 860+310+580 (or 1750) to land on, and 580+310 (or 890) to return from. This is 2640m/s from LKO. I'd like 3000 myself for margins.

From LKO, Duna takes 950+130+10* (or 1080-1090) to land on and 1450+360+250+130+10* (or 2190-2200) to return from. This is 3270-3290m/s depending on how much you spend to fix your angle. Id bring at least 3500 myself for margins, and probably try for 4000.

So really, Duna SEEMS daunting (and is from a logistics standpoint. Which is why I think you should start with a one-shot, Apollo-style mission to start) but as far as dV is concerned, it's really just a step up from Mun.

The help is much appreicated @5thHorseman and I've done a Mun Landing before so yeah...personally I know that I'll probably need roughly 5500 myself in terms of Dv because I'm likely to slip up and make a few errors. I hate inclination burns and even though this one is so minor it is still frustrating 0.6...just jeez...No clue how to aerobrake no offence, and neither do I know how to aerobrake. Also I have no clue how I don't get outside the Sol's Orbit since whenever I plan a manoveur node...it just gets complicated. I can do Mun just fine...its things that require launch windows which make it difficult xD! So yeah, help much appreciated once I'm in a roughly a 1,000,000 Ap and Pe for doing the transfer burn would be nice.

Also don't exactly fully understand KER so that'd help as well xD. In the grand scheme of things, I might just build a station around Kerbin anyway and then piece by piece send the Duna station from said station. So start with the Lander etc.

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7 minutes ago, awfulcraftdesigns said:

No clue how to aerobrake

It's when you come in from orbit or interplanetary space and enter the planet's atmosphere, using it to brake your ship so you don't have to spend the fuel. It is quite daunting (and you can blow up if you get too hot from it) so I frequently skip it and just bring the extra fuel. However on Duna it's not very bad. If you try it, quicksave when you enter Duna's SOI and then burn radially to set your Pe around 15-20km off the surface. Then ride it down and see what happens. If you blow up, set your Pe higher but note the higher you go, the less braking you get. You can either burn to help the atmosphere out, or orbit once and come back down to brake again. Then, once your Ap is down low enough, burn at it to raise your Pe up over 50km so you won't brake anymore. Boom, orbit with VERY little fuel expenditure.

10 minutes ago, awfulcraftdesigns said:

whenever I plan a manoveur node...it just gets complicated

That's one of those "logistics" I mentioned that makes interplanetary much harder than getting to Mun. If I may suggest: Use the TIME listed in the transfer window planner and ignore everything else. When you're within a few days of that TIME, launch your ship into Kerbin orbit (I'd say around 100km, not 1,000km like you mentioned) and then place a maneuver node on the night side of the planet, somewhere midway between that and your orbital "sunset". Drag it out about 1150m/s or so and then scroll out so you can see your Sun orbit. Right-click the Sun Apoapsis so you can see the numbers, and scroll back in so you can see your Kerbin orbit AND that Ap number in the same screen, and then drag the maneuver node a little left and right and see which one makes the number go up. Find the spot on your orbit where dragging it left OR right makes it go down. That's the sweet spot. You've located where you want to burn.

Scroll back out, and then tweak the AMOUNT of the burn so you just touch Duna's orbit. If you're lucky, you may even get your encounter.

I should really make a video on this :D But that's the core of pretty much every Transfer-Window-Assisted interplanetary maneuver I've ever done.

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5 minutes ago, awfulcraftdesigns said:

might I suggest we start up a PM discussion about why SpaceY isn't working for me (since it is off-topic) and possible space craft designs that I build and you test etc.? Would also be nice if I had a mod like KW Rocektry or SpaceY that actually works xD and is updated to 1.0.5 atleast. Sorry if its such a short post I just thought I'd let you know. Thanks for the help again @5thHorseman and do you think it'd be simpler in the grand scheme of things when you take the station idea into account?

Actually I can't help you with SpaceY or KW Rocketry. I've literally never used them and may not have ever even visited their threads. I am personally pretty averse to using non-stock parts and physics (though I have no problem with others using them!).

Taking a station to Duna will be FAR harder than dropping boots on the ground and planting a flag and coming home. For the same reason that doing so on Mun is easier.

Maybe, MAYBE taking a station there and just getting it into orbit is easier than the landing part, but I still suggest the smaller mission. So much unexpected things can go wrong, and it's far easier to get discouraged when your 10-hour play session is ruined because you forgot a probe core or solar panel. If you instead lose the 30 minutes you spent beefing up your Mun rocket to make it to Duna, it's not nearly as bad.

I'm about to go offline for quite some time so won't be replying. Yay nice summer days :D

Edited by 5thHorseman

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Just now, 5thHorseman said:

Actually I can't help you with SpaceY or KW Rocketry. I've literally never used them and may not have ever even visited their threads. I am personally pretty averse to using non-stock parts and physics (though I have no problem with others using them!).

Taking a station to Duna will be FAR harder than dropping boots on the ground and planting a flag and coming home. For the same reason that doing so on Mun is easier.

Maybe, MAYBE taking a station there and just getting it into orbit is easier than the landing part, but I still suggest the smaller mission. So much unexpected things can go wrong, and it's far easier to get discouraged when your 10-hour play session is ruined because you forgot a probe core or solar panel. If you instead lose the 30 minutes you spent beefing up your Mun rocket to make it to Duna, it's not neary as bad.

I'm about to go offline for quite some time.

Oh, yeah...totally forgot, anyway got any mod suggestions before you go offline that are similar in concept to them? (Sorry I should've stated I was looking for suggestions not only those two mods)

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Precise node. I won't leave Kerbin's SOI without it. 

 

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+1 to Horseman's recommendation to start small.

KSP is very much a walk-before-you-run kind of game.  There are a lot of skills and techniques you need to develop to pull off an interplanetary mission, and those skills are not a random grab bag:  they're "ordered", in the sense that you need to develop skill A before you can work on skill B, i.e. B builds on A.  If you try to do everything at once, you're likely to end up frustrated.

So a good approach is generally to start with a simpler, less ambitious mission and work on that.  For example, as Horseman suggests, a simple mission of "send small ship with one kerbal, land, plant flag, take off, go home."  That will exercise a lot of the skills you'll need... and if you've never been interplanetary before, I think you'll find that even such a small, simple mission will be quite a challenge, even without all the extra difficulties of bringing along a big space station and such.

Once you have mastered that... then you'll be in a much better position to figure out how to take it to the next level with a bigger, fancier mission.

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27 minutes ago, Snark said:

+1 to Horseman's recommendation to start small.

KSP is very much a walk-before-you-run kind of game.  There are a lot of skills and techniques you need to develop to pull off an interplanetary mission, and those skills are not a random grab bag:  they're "ordered", in the sense that you need to develop skill A before you can work on skill B, i.e. B builds on A.  If you try to do everything at once, you're likely to end up frustrated.

So a good approach is generally to start with a simpler, less ambitious mission and work on that.  For example, as Horseman suggests, a simple mission of "send small ship with one kerbal, land, plant flag, take off, go home."  That will exercise a lot of the skills you'll need... and if you've never been interplanetary before, I think you'll find that even such a small, simple mission will be quite a challenge, even without all the extra difficulties of bringing along a big space station and such.

Once you have mastered that... then you'll be in a much better position to figure out how to take it to the next level with a bigger, fancier mission.

Thanks Snark, I just wish I knew where to start? (Also on the off-topic comment, know any 3.75M Capsules that aern't the Taurus or Stock One?)

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35 minutes ago, awfulcraftdesigns said:

I just wish I knew where to start?

Where we said to start :) Take the ship you sent to Mun, give it about 1000-1500 more m/s of dV, add parachutes to the lander portion, and go! Make mistakes. Figure out why they are mistakes and try again.

If you get it right on the first try you're doing it wrong. :)

EDIT: I know of no non-stock anythings when it comes to parts. I only use non-stock parts when they add a whole new function to the game (Like Extraplanetary Launchpads and the like).

Edited by 5thHorseman

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Just now, 5thHorseman said:

Where we said to start :) Take the ship you sent to Mun, give it about 1000-1500 more m/s of dV, add parachutes to the lander portion, and go! Make mistakes. Figure out why they are mistakes and try again.

If you get it right on the first try you're doing it wrong. :)

Thanks, I just need insperation, thats what I meant by I don't know where to start...as in designing my rocket xD

Again, anyone got any suggestions for 1.0.5 3.75m Capsules...much appreciated :D 

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3 hours ago, awfulcraftdesigns said:

Thanks, I just need insperation, thats what I meant by I don't know where to start...as in designing my rocket xD

When in doubt, follow the Kerbal Way:  slap one together and see how it does!  Then if it doesn't work, you'll have something specific to work on (e.g. posting a screenshot in the questions forum for advice).

3 hours ago, awfulcraftdesigns said:

Again, anyone got any suggestions for 1.0.5 3.75m Capsules...much appreciated :D

Personally, I'd suggest that "starting small" means "start with a 1-kerbal craft" so you only need one of the 1.25m capsules (e.g. Mk1 command pod or lander can).  Bigger ships (e.g. 3.75m) are a bigger challenge, and I'd suggest mastering the small craft before graduating to the bigger ones.

That said, if you've really got your heart set on a 3.75m capsule, Nertea's Near Future Spacecraft has a pretty sweet 6-kerbal command pod that's 3.75m on the bottom, tapering to 2.5m on the top.

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Some rough budget estimates off the top of my head:

Ground to Low Kerbin Orbit: 4000 m/s

Transfer burn to Duna: 900 m/s

Duna capture via aerobraking: 0 m/s (thin atmo, go as low as 10km; heat shield optional)   ---   Powered capture: 400 m/s

Low Duna Orbit to Surface: 1300 m/s [parachutes hardly matter, but may save a few m/s]

Surface to Low Duna Orbit: 1300 m/s

Transfer burn to Kerbin: 700 m/s

Kerbin capture via aerobraking: 0 m/s (warranty void if attempted without a heat shield)  ---- Powered capture: 400 m/s

Low Kerbin Orbit to Ground via parachutes: 100 m/s [deorbit burn only]  ---   Powered descent: 2000 m/s

Total minimum: 8300 m/s

Total maximum: 11000 m/s

I'd allot 10 km/s as a safe bet.

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