Tom B wrote:

>Nice work so far.

Thank you.  I like the ‘so far’.  So it could be improved…. ;-)

>>    - is 'bus' the right word?  I'm sort of imagining the main ESS feeding 'big' subsystems (to the

>>right) more directly but the internal and external 'small' electrics through some sort of step

>>down if that's the right expression.

>Data bus: Moves bits of information around to other systems.

>Electrical distribution bus: Moves charge around to other systems.

>Depending on how you want to lay things out, you can have multiple of each in a vehicle.

Yes, I toyed with the idea of putting lots more in but didn’t think it was overly helpful.

I also toyed with including (or making a separate diagram for) more computer links/terminals etc but decided, again, it wasn’t particularly helpful (or at least, would make it too confusing). 

I might revisit the latter.  I can see a 2^nd and 3^rd schematic for water/waste water and computers.  Trying to get them all on one might produce the kind of diagram I was rather hoping to avoid!

>One reason is to keep different sorts of data separate (like on an airliner where you don't want to

>have the passenger entertainment bus being the same physical wiring as the flight control bus (and

>this stupidity has actually been designed into several modern airliners and hackers have actually

>shown they can go from entertainment bus to flight control).

Oh no!  I’d not heard that but I can imagine.  Even I know that that would be a Bad Idea!  Yes, it would be cheaper but not safe/wise.  For this reason I thought about putting the Auxiliary ESS as a complete separate system but it was too difficult to draw on without adding lines everywhere to represent it being able to feed two subsystems when I didn’t know which the second would be (I thought that would be fun for players: “OK, life support is a given but you have to choose between your interior lighting/fresher and comms, say”.  Of course, if it’s easily switchable, it’s not such a problem.

>Multiple power buses will exist for reasons of varying voltage/current loads (you aren't likely to

>deliver motor power and the power for your microelectronics via the same bus - motor start or

>high acceleration might well jump the power demand leading to spikes electronics don't love).

Yes, my knowledge isn’t great, but this I did kind of understand.  Hence the drive train being a distinct subsystem from the others (I’m assuming the +1 subsystem for the Aux ESS doesn’t include driving), and the ‘little’ things (interior and exterior electronics) have their own bus.  Glad to know I wasn’t too far off the mark there.

>Are  you using a petrol engine in zero G or in zero P/vacuum? Are you using a combustion engine

>on a planet that has incompatible atmo - heavy, thick, exotic or insidious, or just plain tainted or

>maybe just low or too high on O2 partial pressures.... or too much CO2?

Nope.  See above.  “Energy Storage System” (direct from JTAS 3) seems to me to be a battery rather than petrol engine.  Not sure what else ESS could be, but I’m definitely picturing an internal battery (perhaps under the floor rather than a small thing in the ‘engine’ compartment.

>Batteries might really make more sense.

Yes, I assume that Marc Miller I’m guessing it was, thought so too.

>>- is the Auxiliary ESS only powering Life Support and 1 other subsystem in an emergency a bit

>>mean?  Is 12 hours too generous?  (Though I think we're in speed of plot territory here).

>You'd want to cover:

>heater (for cold planets)

>cooler (for hot planets)

>Atmo systems (whatever you think appropriate)

I’m taking those three as all part of ‘life support’.  I was tempted to detail this more, but perhaps on another sheet.

>Comms - short range and long range radios, maybe laser or maser, plus a distress beacon (and it

>would have a battery backup)

>Cabin lights

>Door locks if they are electrical and don't have any manual opening options (which they should

>really)

See above – I thought it fun if PCs have to choose.  But yes, comms would be the obvious one and I did think of adding the interior lights as a ‘must’ but decided that made it a bit too easy.   I’m thinking the Aux ESS really is ‘emergency only’ (hence thinking 12 hours might be a bit generous).  (And how feasible is it to jimmy it so you can have three subsystems but less time!  oooh, Task rolls…)

>Any heaters or coolers that prevent the vehicle's fluids from boiling or freezing.

oooh, now I didn’t think of that.  Good thought.  (Though I suppose you could subsume it in life support.  Or indeed, in ‘water systems’ as they’re part of the electronics because they need pumping, filtering etc.)

>Transponders: Basic one, probably.

>Vehicle Data Recorder: Variable by jurisdiction

oooh, another good thought.  I’ll add it as an optional extra.  Perhaps in a text description that I’m feeling ought to accompany this.

>AG? What for exactly? Making it more comfortable in high G planets? If so, that better be

>supported by your Auxilliary ESS too.

Hmmm, good thought.  Though I think I’m going to say that’s not standard and is provided for on ATVs specifically designed for, let’s say, more than 2G.

>If to make you feel less queezy in low-G planets... then not so critical to have Aux ESS support.

That’s more what I had in mind.  A ‘luxury’ option if you like.

>To lift the vehicle over crevasses or whatever... not necessary for Aux ESS, but will need some sort

>of tie in to controls and vehicle sensors to manage largely automated jumps.

Definitely not thinking that.  Or we might as well just have a grav vehicle!    (But love the Moon Patrol link – thanks for the memory!)

Which reminds me, when it says it's 'all terrain' I assume that means water but further I assume that it only really means 'can wade through rivers' or perhaps cross the bottom of a (small?) lake.  I didn't imagine that it really operates on the surface of water as a boat.  Or is that wrong?  

The JTAS [Mongoose] 1 version of the ATV article makes a differentiation with a different vehicle version that operates as a waterbourne vehicle which tends to reinforce my opinion about the basic ATV.

><snip list of charging points>

Great list.  I have the ‘larger one’ for connecting the ESS to starport or starship charging (as per JTAS 3).  The ‘small ones’ are what I was thinking of, but I do have one line that goes to an external outlet and I’d not committed myself on whether that was a bit beefier (your ‘medium sized’ one) or just a standard ('small') one – but I like the idea of it being so.  Maybe the engineer has jury rigged something to step down from the exterior outlet to hand comps when out 'camping'.

>>[subsystem control panels?]

>Yes and no. Some things that one is not meant to watch or control (say motors themselves mostly

>outside) would likely not.

Well I do have a little auxiliary computer CPU helping looking after the drivetrain but I can imagine you could only control it ‘directly’ by plugging in a handcomp or something.

The ‘controls’ from the airlock is a good idea.  Again, perhaps something for descriptive text rather than another line on the diagram.  But good thought.

>Also: To what I said above:

>Depending on the purchase jurisdiction, more or less safety equipment would be required to be

>present at time of purchase. Similarly, more or less comms/tracking/autonav/transponder type

>stuff will be required at time of purchase again based on purchase jurisdiction (unless you get an

>export only model).

Oooh, that’s a good thought.  Although it does of course raise questions about where the March Harrier and/or the ATV were bought.  But…

>Further, any ATV that's 'been around' could have been up or down modded with various things that

>prior users felt were necessary or vestigial.

… yes, the March Harrier has been kicking around for (I think I said 40 years) so the ATV may be elderly too.  Which means all sorts of things could be missing/added.  I like that.  Perhaps a d66 table is called for along with some descriptive text. 

<sigh>  This is really turning into a Thing, isn’t it?!  (I’ve already thought I ought to do a similar thing but for the new Mongoose _Vehicle Handbook_ version at TL12.)

>The cost of a model may also dictate the interior fit and finish, the power plant options, any

>onboard entertainment and computers,

Well, the outlets were for PCs to 'bring their own'.  But yes, posh ones would add this kind of stuff.

>Also note that your schematics does not allow for any weapons integration or any external sensor

>integration (like from drones or other exterior sensor packages). Both of those may need antenna >systems that link to the data buses.

It sort of does in that that’s what the optional ‘dome’ is if you look at JTAS 3.  It says it can host just those types of things.  But yes, I can see an argument for an additional feed for maybe a fixed external mount or two.  Certainly on militarised versions.

>Also, redundancy beyond the Aux ESS may be more common with higher end/higher quality

>version of an ATV. That might include duplicate computers or other systems.

yes, I put in the auxiliary computer for just this reason.  I could change it to an optional extra but it seems like an obvious thing even the base model would have at least a limited back up version of.  I was wondering however if I should sever *any* connection with the main computer (shades of Virus?!?) but decided it would most likely have some kind of ‘last state’ feed and perhaps a diagnostic connection and/or a ‘reboot’ link.

Many thanks for the thoughts and help.

tc