Mounting Probes

[ThreeMartiniLaunch]

I'm in the "thinking out loud" stage of planning a grand tour.

I will not be landing Kerbals on all bodies, and may not visit all bodies with the main ship, but I would like to at least land / orbit probes.

For example, I do no plan on the main ship visiting all of Jool's moons, but would like to land probes on them, or at least put something into orbit.

My question has to do with mounting the probes.

I've done a Jool expedition before and just mounted the probes around the outside of the ship and on the front of side mounted fuel tanks. The problem with this method is you have to launch two probes at a time.

I've mounted probes on the nose of my spaceship before. I suppose one could mount probes to the rear of a ship as well. But more than a couple probes and things get wobbly and aesthetically unappealing.

Is there some third alternative I'm missing? I'll probably be taking six or eight probes of three different designs.

Thanks in advance.

Edited September 6, 2013 by ThreeMartiniLaunch

[Hallofo]

Perhaps if you had a mounting "bay" close to the centerline of the ship (as opposed to on the sides) so that the mothership was not terribly off balance when you drop a probe? I can't post pics atm, but think of a strut/girder segment in between your fuel/engines and command pod with a bunch of doc-o-tron mounted probes.

If your probes are still too heavy and throw it off balance, maybe try manually shutting down a main engine or two to balance the thrust better?

Just a few ideas off the top.

[Free Trader Beowulf]

If they are small probes and the ship is large and has plenty of torque, then you don't need to worry about launching them in pairs. The new system of torque means you don't have to worry too much about balancing everything up. Last night I sent a tug down to LKO from GEO carrying a 3.7 ton tender on one side and it flew just fine. The tug is 160 tons and has 8 large ASAS, which I think is overly torquey.

Alternatively, mount them on the front of side mounted fuel tanks and when you launch one of a pair, shift some fuel or monopropellant to counterbalance the lost weight. So if you launch a single 1 ton probe from a pair, for example, shift 125l of monopropellant from the side with the probe to the side without to compensate.

The real problem I find with carrying lots of probes is that they increase the part count very quickly, I launched a ship to Jool a few nights ago with six probes as well as a large mothership and it lagged horrendously. That ship had a dedicated probe carrier on the nose - a central gantry with six small RCS tanks arranged around it on the ends of girders. Each RCS tank has a clamp-o-tron junior on the front and a probe docked to that. When the probes are gone I'll dump the carrier into Jool where it will perform important scientific monitoring on its way down.

[Free Trader Beowulf]

This is my carrier on the front of the mothership

Sorry it's not a great picture, the probes are built around the custom red tanks on the left. The carrier actually ended up docked backwards because I didn't think about how I was going to dock it in orbit. I've used this arrangement before and it should fly fine even with unbalanced probe launches.

[Tokay Gris]

How about this one?

Brought six probes to Jool... Ok, did not work as planned (See "Mission to Jool") but should give you the general idea I tried.

Edited September 5, 2013 by Tokay Gris

[CoriW]

What if you use fuel tanks as a counterbalance?

If you took perhaps 8 of the smaller fuel tanks and radially attach them around the central stack of your mothership, then attach the probes on top of them, you would be able to use fuel transfer as a counterbalance every time you launch a probe. If you use fuel tanks that are approximately the same weight as each one of your probes and then also keep an extra fuel tank in the central stack of your mothership, then every time you launch a probe you could fill up the corresponding "balance" fuel tank from the extra central fuel tank leaving the other "balance" fuel tanks empty, thus keeping the mothership balanced.

I hope that makes sense, because it was hard to explain.

EDIT: Actually it looks like "Free Trader Beowulf" has already mentioned this, I should of read the whole thread before responding. xD

[Jean Deaux]

Don't forget you don't have to use the space bar to stage the launch of probes you have in symmetry, you could just right click on the dock/decoupler and manually launch each probe one at a time.

[Temstar]

I've mounted probes on the nose of my spaceship before. I suppose one could mount probes to the rear of a ship as well. But more than a couple probes and things get wobbly and aesthetically unappealing.

Is there some third alternative I'm missing? I'll probably be taking six or eight probes of three different designs.

Oh depending on how radially different in design are your three types of probes (and thus their weight/CoM) there is a simple solution:

Have say 8 radial docking ports and one nose docking port. Mount your eight probes on the radial ports at departure and leave the nose port empty.

When you need to release a probe, undock an opposing pair, send one off on it's mission and then move the other one to the nose docking port so it's inline with the mothership's CoM

At next destination release the probe on the nose port

At next destination undock another opposing pair, release one and dock the other one on the nose port

And so on...

[Fizwalker]

I'm a noob, but I had a thought. Depending on the amount of fuel you are hauling out on your grand tour of the outer planets, if you bring out 3 of those Rockomax Jumbo 64 tanks in a rough equilateral triangle, with a truss running along a side with the appropriate number of docking ports for your probes. If it's built right, you ought to be able to place the truss close to being inline the center of thrust, so that even if you launch a probe, the center of thrust/mass won't become unbalanced. Of course, these tanks might be far enough apart, you could put the probes so that they could launch from between the tanks from each side... (I originally thought you could mount them on one side and just drop them out from there...) Depending on the spacing you have.

However, it might be easier to do what Temstar suggests.

[ThreeMartiniLaunch]

Excellent suggestions.

Thanks to everyone for replying.