Help me choose my Munar lander design

[RainDreamer]

Not sure if this should go here or to spacecraft exchange. Please move if it is not fitting to be here.

Anyway, I just came up with 2 designs for a space tourism Munar lander for MissionController 2 civilian missions. Both designs have space for 5 kerbals, 3 astronauts and 2 tourists.

Here are the two:

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The Bulb has the pros of being more compact and simpler in operation comparing to the Sunflower. It can also be used for multiple landing as it can simply return to mothership and dock in with the top port and go somewhere else. It is, however, a little bit heavier due to having a built in heat shield that it has to haul along, thus cutting into its dV. It is also not very pretty, at least for me.

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The Sunflower is prettier (I think) than the bulb thanks to that observatory and generally slim shape. It is also lighter and free up some dV because its heat shield module is seperate. But it has a little less EC, and it is much more complicate to work with, having to do multiple docking and undocking maneuvers. It also can't be used for multiple landing unless there is a docking port on the mothership to keep the landing module.

So which one do you think is better in your opinion? It can be in any aspect, whether it is aesthetic, efficiency, or whatever.

I would also take recommendation to refine it and some example that I can draw inspiration on.

Edited March 25, 2015 by RainDreamer

[Tweety]

I no technical person.....the bulb proto because it looks nicer (my opinion) also looks easier to handle(?)

Tweety

Edit: Also what mods are they using? Looks very sleek and correct for the game.

[RainDreamer]

Edit: Also what mods are they using? Looks very sleek and correct for the game.

Uh...a lot of mods? My Game Data folder is 4.21 GB x-x You can ask me about the specific parts you are curious about and I can try to look at what mod it was from.

[EdFred]

Looks a bit too top heavy. There's a lot of "not-flat" ground on the Mun. It may tip over on landing. I prefer squattier landers. Mine can generally land on a 30-45 degree slope and not tip over. My KSP computer is at home, so I can't post an example now.

[RainDreamer]

Oh yeah, that is also one thing that the Bulb has over the Sunflower, due to its heatshield - it has lower COM. The landing legs frame is pretty nice though, allow these designs to be still stable due to its wide angle legs.

And I do wish for flatter lander too, but I am still trying to figure out a 5 kerbals design that doesn't comically bulge my fairings due to how wide it can be.

Maybe I can just send it in pieces..hmm...

[EdFred]

(1) 2.5m lander can with (3) 1.25m lander cans in 3x symmetry? And attach the legs to the outer lander cans? Shouldn't bulge too much.

[OhioBob]

I see pros and cons to both. I voted for Bulb only because it looks like it's less top-heavy and will be more stable on landing. The Bulb is also slightly less expensive. However, I think the Sunflower will have lower operational cost because it has less mass, hence lower launch cost, and greater ∆v. I believe that minimizing out-of-pocket expense is an important factor in space tourism because it will help to maximize profits.

[Sampa]

I believe that the safest lander design (for ALL landing types) should incorporate a relatively squat design and a low center of gravity for touchdown stability

[OhioBob]

I believe that the safest lander design (for ALL landing types) should incorporate a relatively squat design and a low center of gravity for touchdown stability

Agreed. I often put my landing gear on truss outriggers just to increase the width of the footprint.

[RainDreamer]

Hmm. I am thinking of just slapping on the biggest reaction wheel there is and let it balance.

Or you know. I just thought... Why didn't I make a horizontal lander.

Huh. Anyway, another reason that these things are like that is because I need to fit them behind a heatshield for reentry to kerbin, playing with DRE. Maybe I can design a wide lander module, but the core part with the kerbal will have to fit behind a heat shield.

[impyre]

I voted bulb for the same reason as the others... it's only really suited for low-g planets, and even then the design severely limits your landing options. I use a tri-engine lander, it's pretty low-profile and has the option of ditching the three engines and their tanks and using a tiny engine for emergencies when you really just need a bit more dV.

- - - Updated - - -

Hmm. I am thinking of just slapping on the biggest reaction wheel there is and let it balance.

Or you know. I just thought... Why didn't I make a horizontal lander.

Huh. Anyway, another reason that these things are like that is because I need to fit them behind a heatshield for reentry to kerbin, playing with DRE. Maybe I can design a wide lander module, but the core part with the kerbal will have to fit behind a heat shield.

You can get inflatable heat shields. The way I figure it, even if heatshields couldn't realistically *inflate*, there's no reason at all they couldn't unfold. I have large deployable heat shields for my oddly shaped vessels... but I don't even use them that often honestly. I find that it's easier and more reliable to simply create a ship designed to stay in orbit (with lander attached), and use separate pods for reentry. USI's Survival pack has some really nice escape pods that are KAS compatible, so you can attach them to a ship when you refuel it, do the mission, come back, and hop in the pods to get back on the surface. Other large equipment that must be returned is returned by itself.

[Sampa]

Hmm. I am thinking of just slapping on the biggest reaction wheel there is and let it balance.

Or you know. I just thought... Why didn't I make a horizontal lander.

Huh. Anyway, another reason that these things are like that is because I need to fit them behind a heatshield for reentry to kerbin, playing with DRE. Maybe I can design a wide lander module, but the core part with the kerbal will have to fit behind a heat shield.

Why not try using the inflatable heat shield?

[Tex]

In my opinion, both have their advantages and disadvantages.

Your "Bulb" concept lander would indeed be great for multiple landings, which would help you pull in a lot of science or see a lot of sights and cool features of the various surface terrains. The less Delta-v would indeed be offset by its ability to refuel, so that shouldn't be that much of a problem.

Your "Sunflower" concept, however, I think would be better for one-stop sightseeing trips where you could take photos and other observations. There's nothing stopping you from using both of them!

I like the designs, by the way, they look neat!

[smjjames]

The Imgur photos in the spoilers are broken for me for some reason. The imgur box shows up, but not the pics.

Edit: I went to the links themselves via quoting the post.

Edit2: How high is the CoM on the sunflower prototype? In my experience, tall landers have a tendency to tip over.

Edited March 26, 2015 by smjjames

[keeper]

I would go with the first one

[RainDreamer]

Why not try using the inflatable heat shield?

The expandable shield is glitchy at the moment =s

Also, the shield take a lot more vertical space than other shields too, making it even taller than the current design.

I also just added images showing the COM of both landers to the OP if people are interested.

Edited March 26, 2015 by RainDreamer

[OhioBob]

I also just added images showing the COM of both landers to the OP if people are interested.

There really isn't too much difference, is there? Is that with full fuel tanks? You might consider reducing the propellant down to what you'd expect on landing to see how much of a difference that makes in the placement of the COM.

[RainDreamer]

Nope, not that much differences. The bulk of the mass is still on the fuel tanks after all.

About the amount of propellent left after landing, you can see the red COM in the image, that is the dry COM of the craft without any fuel (thank you, RCS build aid!). The true COM of the craft after landing will varied depending on how bad my landing is, but it will vary somewhere in the middle of those 2. The gap for the Bulb is smaller due to its heavy built in heatshield. While the gap for the Sunflower is larger since it doesn't have one.

That said, I just did some field test. The Bulb's missing few hundred dV makes it quite harder to land and then take off again to mun orbit comparing to the Sunflower with its extra dV. I might have to add extra detachable fuel tanks on the sides of the Bulb's lander module... But that would increase the width of the fairing again. Hmm...

Edited March 26, 2015 by RainDreamer

[Sampa]

The expandable shield is glitchy at the moment =s

Also, the shield take a lot more vertical space than other shields too, making it even taller than the current design.

I also just added images showing the COM of both landers to the OP if people are interested.

That should be too much of a problem for the actual touchdown as you would just need to eject it anyway!

[Mr. Scruffy]

The bulb with its legs placed higher (and ladders adjusted), to lower its CoM.

[radonek]

I would not vote for either. As said above, short and squat designs are way to go. If you slap fuel tanks on crew module sides, not only you have much lower CoM, but you can also have CoM much closer to DCoM. As a bonus, you attach to them landing legs (and anything else not worth getting back up) for little more dV saved when you ditch them. And pushing heat shield all the way to the Mun, down and back is just a waste.

[smjjames]

The sunflower one should be okay as long as you don't land on a steep slope, though it could still tip over if you land wrong.

One of my early landers was a rather tall lander (stack of batteries plus command pod on top) which fell over on landing, but I managed to get it back up through use of the landing legs and SAS.

[merendel]

Both designs look nice but so do those sword replica's that people hang on the wall yet you wouldnt want to fight with one of those swords nor would I want to try to land either of those. I just dont like tall landers, too much chance of landing wrong and tiping over. I prefer ones I can land on a rather steep incline and not tip, particularly if the ship is going to be reused.

So anyway you get many bonus points for asthetics on both designs but from a practicality standpoint they are both kinda meh.

[RainDreamer]

Yeah, I am kind of an aesthetic person over practicality. More of an artist than an engineer. XP

Though I think I will try to consolidate what I learn from these prototypes and see if i can design a better lander. Probably will have to work in IR parts. Thanks for all of your help.