Docking Nodes and HubMax's

[robogungt8]

I'm a noob at KSP, and I am attempting docking. I'm just setting up for some practice, where I will hopefully join a fuel tank to a spacecraft with a HubMax on the end of it. I ran into a problem, though: HubMax's are extremely heavy! I have a small lifter that is capable to taking a small probe to Duna, but it can't even put my hub in LKO. Should I just attach a docking port to the top of the lifter and dock with that, or try to build a stronger lifter to get the HubMax into LKO? Assistance is greatly appreciated.

Edited October 12, 2013 by robogungt8

[lammatt]

what is a hubmax?

[robogungt8]

what is a hubmax?

I think some people call them docking nodes...

[Dispatcher]

Either will work. The 6 way connector is intended for orbiting stations and (inter)planetary and munar bases. I have also seen them (rarely) used as a plane and spacecraft component. So either use a single docking port or else yes, put the 6 way on a larger tank & sporting an engine with serious thrust.

Good luck in your docking!

[The Destroyer]

Indeed, I find this extremeley heavy, which is weird.

[Commander Zoom]

IMO, it's not so much that HubMaxes are too heavy as that most probe parts are really, really light compared to anything that carries kerbals. You can build an entire functioning probe out of hardware that weighs less than a one-kerb lander can, by itself.

[capi3101]

Just to forestall the obvious next post (the one where you're having problems docking with the hubmax), I'll point out that the Hubmax is a structural part - it's is NOT a docking port in and of itself. To use it for docking, you have to add the clamp-o-trons one by one.

Here - took a screenshot of the Hubmax in action just this evening:

This is my Kerbin-orbiting Mir replica; it actually has two Hubmaxes in action (the one off of the station core, the other off the Kristall module). Note the one for Kristall actually has two batteries attached to the Hubmax...

So, really, you're just wanting to use the Hubmax as a target vehicle? Then here's what you need:

PAYLOAD

1xRockomax Hubmax Multi-Point Connector

1xProbodobodyne OKTO2 (mount forward)

1xZ-200 Rechargable Battery Pack (mount aft of the probe core)

2xOX-4W 2x3 Photovoltaic Panels (mount on the port and starboard side of the Hubmax)

1xClamp-o-tron Docking Port (mount forward)

BOOSTER

1xTR-18A Stack Decoupler (mount to aft part of the Hubmax)

1xRC-L01 Remote Guidance Unit (mount just below the decoupler)

2xZ-100 Rechargable Battery Pack (mount zenith and nadir on the top fuel tank about midway down)

2xStratus-V Rad. Mono Tank (mount port and starboard on the top fuel tank, about the same level as the batteries)

8xRV-105 RCS (mount 4 port, starboard, zenith and nadir as far forward on the booster as you can get them, the other four as far aft as you can get them)

1xRockomax "Mainsail" Liquid Engine (aft, of course)

2xFL-T200 Tank (attach to the BZ-52s...)

2xBZ-52 Radial Attachment Point (attach these port and starboard along the middle fuel tank)

2xFTX-2 External Fuel Duct (run these from the FL-T200s to the central fuel tank)

1xRockomax X200-32 Fuel Tank (mount this one below the bottom of the two Jumbo 64s, and attach the Mainsail to the bottom of this tank)

2xRockomax Jumbo 64 Fuel Tank (mount one on top just below the RGU, the other in the center, just below the first one)

You'll want strut-stitch the fuel tanks, of course; four struts oughta do the trick. If you're not familiar with strut-stitching, just attach four cubic octangonal struts (the piddly little ones) to the top of one tank and to the bottom of the tank immediately above it, and run EAS-4 Strut Connectors between the two (this is not strut-stitching, but a usable technique nonetheless). Firms up that connection - otherwise the Jumbo 64s are wonky as hell and dangerous to stack on top of each other. A few struts between the top of the booster and the payload wouldn't hurt much either.

Start at full throttle but watch your gee meter during the ascent. If it climbs out of the green, throttle back a bit; you'll be making your orbital insertion at about 1/3 throttle. Straight up to 10,000, 090 at 45 degrees to 30,000, 090 at 15 degrees to 50,000, then burn along the horizon on course 090 until your apoapsis is at the desired altitude. When you're in orbit, deploy the solar panels and let the target vehicle go. Your booster should have enough juice to de-orbit itself, which is why the probe core and batteries are on that piece of hardware (naturally, you'll need to deorbit the booster before the batteries run out of juice).

[MatzahMan]

I would redesign your rocket. I don't know if you know about different kinds of staging (asparagus, onion, etc.) its extremely helpful and lifting larger objects into LKO and beyond. Also, building a designated rocket for lifting heavy items is good because you can make a lot of different types of payloads using the same rocket design.

[capi3101]

MatzahMan's got a good point. That booster I designed in my last post? Seriously inefficient (though it does the job). I only suggested it because of the design's simplicity.

[robogungt8]

Thanks for all the help. I'll work on designing a new heavy-lift rocket. Thanks again!