Mounting my rover to a rocket

[Starchaser]

So I'm having an issue I can't seem to figure out.

My first rover was less than successful, without being a total loss.

https://gyazo.com/baf09ac5c35f7138a72446c689be0b11

it only has 1 wheel left, and you can see the rocket that *ahem* landed it in the background. However it's completed 3 'beam science from the surface of the Mun contracts.

However, I was looking for something more robust, and after gaining several more nodes, I made another attempt.

https://gyazo.com/692b1621cd43d5a66632a68bf5e365bb

Testing it on KSC grounds, it works great. 

SO I saved it in the VAB as a subassembly, and began building a lander for it.

https://gyazo.com/e4a6b324b46726cac8d8a830c0b74d89

My problem, when I try to attach the rover to the rocket.....

https://gyazo.com/6b978f0fbe0afd725b02019d10deb47b

it won't attach at the top.  The ball at the top of the science jr seems like it's not there.

It will attach upside down though, and once I put it on like that, I can now attach stuff to the top of the sci jr.

https://gyazo.com/6115c9b8b6daceac090ede73c2febe33

What, if anything, am I doing wrong?

 

[Cpt Kerbalkrunch]

You just have to designate a new root part. It's one of the tools at the top of the VAB; along with the Move and Rotate tools. It's easiest to use docking ports, but you can choose to make the Science Jr your root part, and then make the part of the rover you want to connect it with the root part of the rover. You can do this while the rover is translucent and waiting for you to connect it to something. Should connect easily afterward.

[Starchaser]

Ok. I'll try that. As an aside, I have parts on the rover that I had hoped would turn it rightside up if it flipped, so I was trying to figure a delivery system that would allow me to place the rover even if it was upside down, so I constructed "landing struts' out of girders that would go around the rover. I went up from the launch pad and landed it, then dropped the rover and hit the throttle hard to lift off the rover without subjecting it to rocket exhaust, I landed hard after that. Hard enough that my constructed struts bounced me 100m in the air....

At the top of that arc, I started to power up the throttle again, and thought...wait. Let's see what happens, and just cut my engine. It bounced 3 more times before coming to rest, without breaking anything. 

[Geschosskopf]

7 minutes ago, Starchaser said:

At the top of that arc, I started to power up the throttle again, and thought...wait. Let's see what happens, and just cut my engine. It bounced 3 more times before coming to rest, without breaking anything. 

Just remember, that's in Kerbin's gravity.  At places with less gravity, such bounces might put you on an escape trajectory   If found this out the hard way with my 1st rover, in which I also included a self-righting mechanism.  It worked fine on Kerbin but was a disaster on Mun.

Since then, I've never used a self-righting mechanism.  I've instead focused on not flipping, which is much easier than making a self-righting mechanism anyway.

FWIW, though, the main problem with putting rovers on rockets is how to deal with what's called the "vertical to horizontal problem"  You can avoid this by doing like you're doing, putting the rover horizontally under the lander, but that's rather inelegant, making the lander legs long and ungainly.  Also, the rover sticks out in the slipstream on launch so causes lots of drag and can get too hot during launch.  But to avoid those problems, you need to mount the rover vertically and put it in a fairing, and then how do you get it down onto the ground?  Hence, the name of the problem.

The best solution I've found for this problem is to send the rover and the lander separately on their own engines.  The rover subassembly thus includes radial descent engines which, when it's on the rocket inside the fairing, will be pointing sideways.  Thus, it does the "vertical to horizontal" transition in space and lands flat on the ground.  Then it can drive the (hopefully) short distance to where the lander can down, pick up the Kerbals, and be on its merry way.

To do this, however, you must have 2 parts with ModuleCommand (probe cores and/or pods) mounted 90^ apart.  IOW, when building the rover in the SPH, one is in the default orientation facing the door, and will be used for driving on the surface.  The other is facing the ceiling and is used for the descent.  If you don't do this, the Navball will be all wonky for 1 phase of the flight or the other.  

[Starchaser]

I put it in a fairing horizontally. I should post a screenie, but I exited the game until evening. I'll come back and post a screenshot.

Balance was an issue as it's off center, but I cut it in half by putting a big antenna on the side of the craft. And since I am going to be able to drop it on it's tires, I ditched the self made landing legs. I'll make a very close approach, drop it from 5m or so, and lift back up a bit and land on stock gear nearby

I'm about 5 minutes from my target landing site. But I'll have to make that landing tonight.

Oh, and yes, I have 2 command points, as you mentioned. One on the rover and the command pod the pilot is on

Edited October 14, 2017 by Starchaser
missing info

[Geonovast]

You don't really even need to drop it.  You can touch down, and just decouple as soon as you touch down.  With the drop in mass, the thrust you're applying to slow down should suddenly be enough to start pushing the descent vehicle back up.  Then you can land nearby the rover.

[Starchaser]

23 hours ago, Geonovast said:

You don't really even need to drop it.  You can touch down, and just decouple as soon as you touch down.  With the drop in mass, the thrust you're applying to slow down should suddenly be enough to start pushing the descent vehicle back up.  Then you can land nearby the rover

Attempting this in my test in Kerbin resulted in rocket exhaust blowing up part of the rover. On Mun approach, understand my rover is about 1.5 tons, and the rest of my lander is about 7+ (4 parachutes, 2 inline batteries, command module 2 person cabin I believe is from one of the near future mods, (it's 2.5 meters,and incorprates a small generator) the smallest rockomax fuel tank (I like wide-based landers for more stability) and 2 radial engines.) so the drop in mass was not enough to result in lift. I dropped it at 15m from the surface, and the bottom of the lander bumped the rover on the surface, as I was too gentle with the throttle. However it wasn't enough of a bump to damage anything 

Edit; from my ship info window as I'm about to lift off. My lander is 13.5 tons

Edited October 15, 2017 by Starchaser
info correction