Can I get this into orbit around Minmus?

[KPV922]

I need help.  I'm sort of a noob, and I just completed my first landing on Minmus.  So naturally instead of doing something just a step up, I want to put a very large space station in orbit around Minmus.  Namely, this space station: http://s1376.photobucket.com/user/KPV922/media/screenshot1_zpsgzqlkcfj.png.html  

Is that even possible?  If so, how would I do it?

 

Thanks  

[Snark]

That's going to be a bear to launch-- the aero's nasty, it's long and wobble-prone, and in any case you'll need to take that M700 off the bottom because you've left yourself with nowhere to attach the booster stage underneath to lift it.

Not impossible, but you've certainly made yourself a tough row to hoe. 

If you want to launch it close to as-is:  yes, you can do it.  It'll just take a honkin' huge booster stage, and you'll need to move that M700 off the bottom so you'll have a place to attach the bottom part with fuel & engines.  You'll likely want to use strut connectors to stabilize it during launch.  If you go this route, I'd suggest not trying to give it enough fuel to go all the way to Minmus, just to keep things manageable.  Get it so that it can reach LKO with empty fuel tanks, then refuel it in orbit via docking ports before sending it off to Minmus.

An alternate approach is is to do it the way NASA does:  in pieces.  Design your station as a set of modules, launch them individually, dock them in orbit.  Once you've got them all docked together, you can use a "tug" vessel to transfer from Kerbin orbit to Minmus orbit.  Some attention to design will be needed for the tug:  docking-port connections are a lot more "floppy" than connetions between pieces that are "welded" together, so trying to push the thing is likely to end up in a noodly mess.  However, if you can design the tug to pull the ship rather than pushing it (e.g. with engines stuck out to the sides on outriggers), that shouldn't be a problem.

 

[Foxster]

I'd start by getting rid of any of the stuff you don't really need. For instance: Why all the crew? Why all the batteries? Why all the solar power? Why all the RCS thrusters?

Also, if you really must have that central thin and bendy section then I'd put it at the top where it won't be the joint between two heavy sections. 

[Plusck]

Exactly as it is, pretty much impossible unless you turn the whole thing upside down. That means having to start by turning a probe core upside down to give you somewhere you can "control from here".

If you remove the 3x scanners, or make them 2x symmetry and put them between the solar panels, then it becomes certainly possible, if you radially mount a squat 2.5m vacuum stage (2x symmetry) to your ore tank and then radially attach a taller lifter stage to that (together with plenty of struts to keep the top bit steady) but it'll be very unwieldy and hard to control (I doubt you'll manage to eliminate bendiness, so you really should control from a probe core in one of the service bays).

However, there are a few things you really should change. Those docking ports are really interfering with the solar panels - you'll need to collapse panels before docking to two out of the three ports, and they're so close to the panels you'll probably want to collapse all panels on one side before docking to make sure you don't break them off. The batteries are really overkill, there's no need for 3x scanners, etc. Given that the M700 only works in polar orbit and is only ever needed once, its attachment to a permanent station is questionable too (though I do understand it from the looking cool perspective).

[RizzoTheRat]

The thin section in the middle will make for wobbles, but if you put struts from just below the 3 docking ports to the main body top and bottom you'll cure that.

There's a lot to be said for building/launching stations in modules.  If you stuck a pair of docking ports in the middle you could launch that in 2 parts and dock in orbit, however it would be a bit wobbly unless you have the clampotron seniors so I'd boost each half to Minimus first and then join them, making sure both halves have a probe core (or crew), power and RCS.

[HebaruSan]

Can you post the craft file somewhere (kerbalx.com is one option)? My gut says it's do-able as-is with 3 big radial stages, but I'd like to try it before committing to that.

BTW, if you paste in the complete URL to the image itself, the forum will display it inline:

 

[Warzouz]

Yes you can, but it'll be very wobbly. As other said, add struts in the middle. You can also reorganize your space station to have big parts at the bottom and lighter parts at the top. It's not rocket-wise but will reduce wobble.

You can also us KJR mod (Kerbal Joints Reinforcement).

In any case I suggest you put your survey scanner on a separate satellite (you can attach it at the top).

I agree that your space station is awkard. You have too much batteries, and you should favor the hitchhiker pod rather than the various lander cans. And why do you have a ore tank when you don't have any ISRU onboard ? RCS i useless, add reactions 2 reactions wheels instead. Why don't you have any fuel tank ? It's nice to be able to refuel when docking on a space station. I suggest you add a large docking ring at the bottom so you can expand the station.

Finally, I recommend you DON'T put docking rings new solar panels, you risk to destroy them it you mess a docking.

Here is my generic space station : Salamander Exploration Space Stations

 

 

[steuben]

If you're set on the design you may have to consider a puller style launcher and attaching it to the top in that picture, or building the launcher around the station. and the put up with a horribly in efficient launch profile.

[Reactordrone]

10 hours ago, steuben said:

If you're set on the design you may have to consider a puller style launcher and attaching it to the top in that picture, or building the launcher around the station. and the put up with a horribly in efficient launch profile.

If you build the transfer stage around the station you could swap out the shielded docking ports for regular ones and use those (with a few struts) as attachment points. The main lifter could then attach under the transfer stage tanks.

[KPV922]

I tried redesigning to make it more stable and easier to transport.  http://i1376.photobucket.com/albums/ah17/KPV922/screenshot1_zpspdmazii0.png

I made 3 modules.  I wasn't sure how often to add reaction wheels, so I added one per module.

I uploaded the craft file, so if anyone wants to test something here that is: http://kerbalx.com/crafts/9627/edit

Thanks for the help everyone  

Edited February 1, 2016 by KPV922

[AlphaMensae]

14 hours ago, HebaruSan said:

Can you post the craft file somewhere (kerbalx.com is one option)? My gut says it's do-able as-is with 3 big radial stages, but I'd like to try it before committing to that.

 

Yup, radial boosters are the way to go, with an upper/kicker/transfer stage underneath. That's how I launch my really BIG--1000-3000+ ton--and long ships into orbit.

Also second installing Kerbal Joint Reinforcement if you don't have it.  Just say no to excessive struts!

 

Edited February 2, 2016 by Laguna

[Sampa]

If I were you, I would launch it in two sections...launching the thin part with the lower part first and then the top piece second and put them together on orbit.  Just my two pieces!

[Snark]

9 minutes ago, Laguna said:

Also second installing Kerbal Joint Reinforcement if you don't have it.  Just say no to excessive struts!

Not arguing with you, since obviously everyone can make their own choices of what they like in the game.  And clearly KJR is a massively popular mod.  But just as an alternate viewpoint:  I suggest not using it, at least not until you've learned out how to play KSP without it.  Just as I'd advise players to get comfortable launching ships to orbit manually before they try MechJeb.

I agree to "saying no to excessive struts" ... but the way to do that is to design ships that don't need 'em.  Quite aside from the fact that making a stable, non-wobbly ship is part of the challenge of KSP, and KJR is nerfing that challenge:  it can also mask problems.  One of the functions that wobble serves is as an indicator that "this contraption has... issues."  Adding KJR will eliminate the wobble, but then you could find yourself running into other problems (e.g. aero stability).

I've been playing KSP for a couple of years, have launched many, many, many ships, including ones over 1000 tons, and they get along fine without excessive struts.

If you're in the habit of "extreme engineering" and like launching ships that are many thousands of tons, then I could see KJR maybe having a role... but other than that, it's worth considering avoiding it, at least for a novice player who's still learning to build ships.

[HebaruSan]

2 hours ago, KPV922 said:

I tried redesigning to make it more stable and easier to transport.  http://i1376.photobucket.com/albums/ah17/KPV922/screenshot1_zpspdmazii0.png

I made 3 modules.  I wasn't sure how often to add reaction wheels, so I added one per module.

I uploaded the craft file, so if anyone wants to test something here that is: http://kerbalx.com/crafts/9627/edit

Thanks for the help everyone  

Yeah, this version makes it to Minmus orbit, no problem. (I kind of still want to try the original though. ) The version with the delta wings is the final one---I forgot to re-take the initial launch screenshots after adding those for stability.

I got a little silly with the final boosters at the end, figuring I could deorbit them by leaving them active and staging after circularizing at Minmus them since they'd already be facing retrograde, but they had way more delta V than needed for that and ended up on crisscrossing escape trajectories instead. Oh well.

 

[KPV922]

Great.  I'll start trying to get there 

 

Quote

 I suggest not using it, at least not until you've learned out how to play KSP without it.

This is what I was thinking.  I have nothing against mods, but while I'm learning the game I want to stay stock.

13 minutes ago, HebaruSan said:

I kind of still want to try the original though

Here you go   http://kerbalx.com/crafts/9632/edit    Good luck  

 

Btw, does anyone have any tips for space station orbits?  I was just going to get it into a "close enough" orbit and call it good, but is there any easy way to get an equal, equatorial orbit?

 

Thanks

Edited February 2, 2016 by KPV922

[Plusck]

38 minutes ago, KPV922 said:

Great.  I'll start trying to get there 

 

This is what I was thinking.  I have nothing against mods, but while I'm learning the game I want to stay stock.

Here you go   http://kerbalx.com/crafts/9632/edit    Good luck  

 

Btw, does anyone have any tips for space station orbits?  I was just going to get it into a "close enough" orbit and call it good, but is there any easy way to get an equal, equatorial orbit?

 

Thanks

Absolutely agree for mods - even something as innocuous as KER will stop you making mistakes that you'll learn from. It becomes very hard to "do without" once you start. Don't do "gateway mods" !

 

For space station orbits, the main factor is "how much can I warp?" v. "how far up and down must landers go?"

For Minmus, I generally try to put the space station orbit at just over 24km. That gives 1000x warp and greatly reduces waiting (for rendezvous, or to return to sunlight). My Mun orbits tend to be more eliptical, between 40 and 60 km (a bit of more of an annoyance for warping purposes); I should probably fix that...

 

There isn't really any easy way of getting an equatorial orbit, other than fine-tuning your approach. If you're a brilliant planner, you'll get into Kerbin orbit at exactly the right inclination to match Minmus. If you're like everybody else, you'll correct inclination halfway out to Minmus.

Once you've got a decent Minmus encounter, drop another maneuvre node halfway there, set Minmus to focus and play with the node so that it gets you passing Minmus with Pe at the equator. Decide in advance which way round the moon you want to go (because once you've got one thing in orbit, you'll probably continue the same way with all future missions). Anti-clockwise is better, certainly, but less of an issue at Minmus than around the Mun.

When you capture to Minmus, leave Ap high, wait to Ap then adjust inclination as you wish. Keep in mind that a perfect equatorial orbit is not really what you want if you have a narrow-band scanner on board, since you'll never see any part of the moon other than what is directly under the ship.

Edited February 2, 2016 by Plusck

[Plusck]

(double post)

Edited February 2, 2016 by Plusck

[HebaruSan]

1 hour ago, KPV922 said:

Here you go   http://kerbalx.com/crafts/9632/edit    Good luck  

Thanks! My final answer is: Yes, you can get this into orbit around Minmus.

 

[Plusck]

20 hours ago, Plusck said:

Exactly as it is, pretty much impossible unless you turn the whole thing upside down. That means having to start by turning a probe core upside down to give you somewhere you can "control from here".

OK, I have to admit that my first phrase there was far too pessimistic.

And hats off to HebaruSan for demonstrating that : D

[Zhetaan]

I noticed that on your edited version, you attached the solar panels to a group of what appear to be structural fuselages attached to the larger station by quad-couplers on the top and bottom.  Unless the issue has been fixed, that will make a craft less stable because KSP doesn't support multiple connections except for struts (and fuel lines, which are strut-like).  Only one of those fuselage stacks joins the top of the station to the bottom; the others just sort of jut into space without connecting.  This is more of a problem because trying to launch the station strains the joint asymmetrically; with all respect to @HebaruSan's skillful piloting, it's still easier to pull it apart than to get it in the sky.

There is a workaround, however:  if you just have to have multinode connections, you can put docking ports on one of the quads and the four fuselages.  When the craft loads, three of the joints will start free, but they will immediately dock and then you'll have your quad-connection.  Keep that in mind if you ever want a ring station, too; otherwise, the only way to bypass KSP's connection rules is with a mod that lets you add struts in flight.

[Warzouz]

@Zhetaan is right. The double quadcoupler looks nice but isn't game friendly. This kind of node plug is not possible in KSP except with advanced skills I don't have and docking nodes only.

That's sad, but you should avoid those contraptions

[Superfluous J]

Note one easy way to nail a nice equatorial orbit around Minmus is to accept a "put a satellite in an equatorial orbit around Minmus" contract, and then set up your station to be perfectly aligned with that orbit (you don't have to match the orbit itself, just the inclination).

Then of course complete that contract because hey, money.

[Warzouz]

Or stick the satellite on your contraption and launch a 2 in 1 mission

[HebaruSan]

56 minutes ago, Zhetaan said:

I noticed that on your edited version, you attached the solar panels to a group of what appear to be structural fuselages attached to the larger station by quad-couplers on the top and bottom.  Unless the issue has been fixed, that will make a craft less stable because KSP doesn't support multiple connections except for struts (and fuel lines, which are strut-like).  Only one of those fuselage stacks joins the top of the station to the bottom; the others just sort of jut into space without connecting.  This is more of a problem because trying to launch the station strains the joint asymmetrically; with all respect to @HebaruSan's skillful piloting, it's still easier to pull it apart than to get it in the sky.

Yeah, it's a structural weak point (I did check it in the VAB, and indeed only one of those four tubes is attached on both sides), but not that much worse than the original's tapering down to a single narrow segment in the middle.

In both cases, putting the tanks and engines on the sides helps to compensate. I made sure to put the decoupler above the weak point, and a set of struts on the other side. In effect the side tanks form a reinforcing frame that holds the payload together, and the weak part doesn't have to bear much weight since the heavier bits get "pulled" along first. These payloads definitely would need more comprehensive strutting for a bottom-attached launcher.