Grav Modules

[gchuck]

IMTU, I always handled grav modules as self contained units, sans power source. They can be made small enough for a 'grav belt', or large enough for a star ship.

Weight of the modules is subjective, anywhere from a kilo or two, up to several hundred k for a starship.

Whats the general consensus on how small a 'module' can be fabricated?

A player wants to build a 'grav drone', with hi-def camera, smaller than a 'matchbox' car.

I realize all this takes is a 'hand-wave', but for some reason this is eating at me.

Comments?

 

[Timerover51]

IMTU, I always handled grav modules as self contained units, sans power source. They can be made small enough for a 'grav belt', or large enough for a star ship.

Weight of the modules is subjective, anywhere from a kilo or two, up to several hundred k for a starship.

Whats the general consensus on how small a 'module' can be fabricated?

A player wants to build a 'grav drone', with hi-def camera, smaller than a 'matchbox' car.

I realize all this takes is a 'hand-wave', but for some reason this is eating at me.

Comments?

I have always figured that the grav plate was a flat plate set parallel to the gravitational field, was at least a foot square, and with equipment weighed several pounds or kilograms. That would eliminate a Matchbox-car sized drone. I also have always thought that all a grav plate did was supply lift, it did not propel you anywhere, so you have to have a drive unit as well.

Then again, if he wants to make it, let him but charge him a million credits or so for such drastic miniaturization.

 

[kilemall]

Ya, I go with raw low efficiency null-grav/anti-grav initially, then as it gets more powerful you get more range with onboard plates, vehicle/ship modules, actual inertial nullification, and at higher levels intrinsic to fusion reactor improvements, material science, capacitor building (metallic hydrogen stabilized until overloaded then boom), and G-bombs.


The grav belt is higher tech because it requires miniaturization. Arguably you could have a vaccsuit a TL earlier with more of a torso suit and a full backpack powercell.

 

[Condottiere]

Comes down to cost in the end.

If a propeller driven drone can perform the same task for one hundredth of the retail price, you'd need to show a specific need for a grav variant.

 

[SanDragon]

No atmosphere to push against!

 

[Grav_Moped]

No atmosphere to push against!

Yep. Or trace/thin atmosphere. Or you don't want to clip bystanders with the rotors.

On the other hand, do they work in artificial gravity?
Would they have reaction jets for use outside a gravity well?

I'd figure you could get the grav equivalent of a COTS camera drone (same range, endurance, and maneuverability/autonomy) for about the same cost as a TL 7.5 (that is, one you can buy right now) prop version, starting at TL9. The cost of professional-grade grav drones scale proportionately.

At TL8, it's going to cost significantly more and be a lot larger.

Upgrade features at higher cost:
- First-person-view glasses (but FPV video can be displayed on a pressure-suit or combat-armor HUD).
- Visual-spectrum stealth
- IR stealth (uses a chill-can from a combat environment suit)
- Limited autonomy
- Payload (unless small, this will require a larger drone as well), including weapons.

 

[kilemall]

I always figured the grav vehicle cost value was not in better performance per credit, but in being a sort of universal vehicle rather then having to have a vehicle designed for a specific gravity and atmosphere.


In other words it costs more then a more conventional aircraft, but costs less then maintaining a stable of specific vehicles tailored to different planets.


IMTU the jets continue improvement at least through TL10 and outperforms the grav vehicles- but are largely bound to their planet.

 

[wellis]

I always figured the grav vehicle cost value was not in better performance per credit, but in being a sort of universal vehicle rather then having to have a vehicle designed for a specific gravity and atmosphere.


In other words it costs more then a more conventional aircraft, but costs less then maintaining a stable of specific vehicles tailored to different planets.


IMTU the jets continue improvement at least through TL10 and outperforms the grav vehicles- but are largely bound to their planet.

How about reaction engines for space travel? Do unmanned vehicles in space use that instead in your TU?

 

[Epee]

"High Def Camera" is a relative term and slippery slope also. Optical resolution depends on optical aperture and so there is going to be a limit as to what can be resolved with a cellphone-sized lens, no matter the CCD behind it. That is the physics of light, not a matter of tech.

 

[Vargas]

There was a grav using drone back in JTAS . . . but I can't recall which issue at this point. (Understandable as it was around 35 years ago . . . ).

 

[gchuck]

There was a grav using drone back in JTAS . . . but I can't recall which issue at this point. (Understandable as it was around 35 years ago . . . ).

I think I remember the one you're talking about. IIRC it was packed with sensors, and the size of a basketball.

I'm fretting over a tiny camera drone. For use in a breathable atmosphere, or indoors, for scouting purposes.

 

[willtron3030]

Optical resolution depends on optical aperture and so there is going to be a limit as to what can be resolved with a cellphone-sized lens, no matter the CCD behind it. That is the physics of light, not a matter of tech.

And suddenly, I'm pondering: Does the gravitational lens effect incur chromatic aberration the way refractive systems do?

 

[Grav_Moped]

IMTU, I always handled grav modules as self contained units, sans power source. They can be made small enough for a 'grav belt', or large enough for a star ship.

Weight of the modules is subjective, anywhere from a kilo or two, up to several hundred k for a starship.

Whats the general consensus on how small a 'module' can be fabricated?

A player wants to build a 'grav drone', with hi-def camera, smaller than a 'matchbox' car.

I realize all this takes is a 'hand-wave', but for some reason this is eating at me.

Comments?

Just for game balance purposes, it shouldn't be pocketable, but needs to be something obviously carried -- maybe tennis-ball sized if the flight duration is limited, softball-sized with (essentially) unlimited flight time.

What he's looking for (miniaturized) would be available at TL 15 as restricted Imperial technology.

Wait, he's building this? Ok, he needs access to TL 15 components (and experience with TL 15 components, too). Then use a variant of the LBB2 computer programming rules (LBB2 '82, p. 40-41).

1. Mechanical design/assembly of device: Prerequisites: Mechanical-1 and Electronics-1. 10+ per week to succeed, DM: +1 per level of Mechanical >1, +1 per level of Electronics >1.

2.Grav unit/power system assembly: Prerequisites: Mechanical-1 and Engineering-1. 9+ per week to assemble, +DM +1 per level of Engineering >1.

3. Control and telemetry system: 9+ per week to succeed. Prerequisites: Computer-1, Communications-1 and Electronics-1. DMs: DM +1 per level of Computer >1.

For each step, a critical failure may cause a fatal flaw in that system while apparently succeeding.

Size is going to be a function of TL.
Additional features may be a function of TL.

 

[kilemall]

How about reaction engines for space travel? Do unmanned vehicles in space use that instead in your TU?

I do have some souped up reaction-like thrusters IMTU, mostly it's for rough frontier situations out in the Oort cloud since everything is Jump-1 and so all that 1000D jazz would block out a major portion of my play biome.



I like the differentiation, between that and the different generations of tailsitters vs. belly landers for different inertial dampening ability, you can tell a lot about how old and what role a ship has by such factors.

 

[Commander Truestar]

I always looked at grav-plates/modules as advances on monopole research.

So, IMTU, a grav device is something that has:
- internal Control systems
- grav-plates(or modules)
- Either an Internal power plant/battery or access to a power feed
- the needed sensors to complete instructions given it (where am I? how to I get where I need to go)
- the needed devices to complete it's job (arms, cameras, etc...)

As theoretically known monopoles are essentially microscopic, the question becomes how large can an artificail monopole be made and what is the size/lift ratio?

Since these are still significantly open scientific questions, but still are based in hard science theory, my grav devices have a relatively open formula

the monopole(s) create lift or thrust(IE: a change of the direction of some /most /all of the monopole's directional axis) based on a ratio of the power fed to the monpole(s) from their power source. To a maximum limit, the amount of power creates a maximum "charge" in the monopole, which createsthe desired lift or thrust.

To get a larger effect, you need both a larger module/plate and larger power source

Hence, a grav Belt allows significant manuvering of one sentient being with small modules and rechargable batteries

But an air raft requires both larger modules and a fusion power plant along with fuel for that plant.

 

[Condottiere]

I had a recent epiphany.

Gravity based and related technologies and drives are very much plot driven in Traveller.

 

[kilemall]

I had a recent epiphany.

Gravity based and related technologies and drives are very much plot driven in Traveller.

Uh huh. Just like Star Trek or anything else.


I still think it's worth going through hard thought so your world is at least internally consistent and is describable at least in effects and choices, but never forget what effect that has on play.

 

[AnotherDilbert]

MT mentions a minimum size of grav drives:

MT RM, p66.

This would indicate a minimum size of 20 litres (40 kg), unless you use the very expensive TL-12 low power version with a minimum of 3 litres (2 kg) giving 0.1 tons of thrust for Cr30,000 requiring 0.001 MW power.

 

[gchuck]

Wait, he's building this?

I think I missed something here.

Yes. He is building this drone. From off the shelf parts. He is not 'cobbling' together a tiny grav module. The grav modules are coming from a civilian 'security' system.

It's on a C class starport, with a Scout base. The starport is shared with a large Solomani contingent, and a sizable Wise Council presence.

Resources are plentiful. They have a unified objective.

 

[Grav_Moped]

If you're assuming the grav modules are commercial off the shelf items, then the mini-drone is also commercially available (or available through appropriate channels). What else would such small grav units be used for?

A drone's camera, controls, and uplink/downlink are already solved problems as of TL 7.5 (i.e. right now).

What's left is play balance. Do you want these things available in your universe? If they are, your players' adversaries may know of them, expect them, and perhaps even have countermeasures (RF jamming, hacking, spoofing, EMP guns to disable them). They might even have them and use them, or something equivalent at a lower TL.