I was looking for a small magnetic containment field generator in RAW, but don't believe there is one? What I mean is a device that can be set up to produce a a containment field to keep atmosphere in like we see in the movies covering a hangar bay, BUT on a much smaller scale. A small generator that could cover a man-sized portal to work as a walk-through airlock and perhaps a medium generator that would allow up to Silhouette 2 or 3 vehicles to go through.

I've looked through supplements and couldn't find anything. Any ideas on rarity, encumbrance, price, etc. would be appreciated. If not hooked up to an external power source it would only run on an emergency backup battery for a couple hours or so, in my opinion.

I don't recall ever reading about something like you are looking for. But before just randomly giving you numbers I would like to know why you are looking for them.

PC mining "clan". Nomadic miners that move around and unpack at various places setting up a mining site. Often this would end up someplace with no atmosphere, very hot, very cold, etc. They have the means to produce life support, but as a matter of convenience it would be nice to seal off exits with a containment field instead of a full double airlock. Thus they can easily drive a small mining vehicle in and out of the "base" and don't have to construct an airlock somehow. So I imagined small semi-portable containment field generator that could be more easily produced then setting up two large vac-sealed doors.

Map not finished, but here's a low-quality image of a site map I was working on for their "home" while mining down a crack on an ice planet. Note the two blue walls set up at the vehicle entrance to the camp and an exit to the mine tunnels.

I would make the field generators just part of the startup cost of the base, not anything special you would need to buy. Charge them what they paid for the full airlock if you need a number, since it is basically the same thing. It does look like they are a very common piece of machinery.

Yes I could do that. But I'm making a list of gear they may have including detailing what is packed where on their ship. I'm not using the homestead rules thus far. There's an actual growing list of gear, vehicles, etc.

p47 of Far Horizons has some atmospheric generators - one for 9K & another for 4.5M - as a starting point.

p48 of Enter the Unkown has Portable Electric Perimeter Fence for 800. It's a stun fence, but you could rule it just as a low powered force field that holds in the atmo instead.

Aren't you basically describing the Retrofitted Hanger bay? I mean that's essentially a magnetic field generator, vehicle service gear, and the means to attache it to a section of a ship. Just replace ship with asteroid...

That sounds like a rather specialized piece of equipment, but built on some basic and standardized tech. The challenge would be with the power supply.

The Electric Perimeter Fence has a power supply that should be able to do what you're suggesting, so lets start with that. It's encumbrance 6, rarity 5 and 800 credits.

This is going to be slightly less bulky (encumbrance 5), slightly more rare (rarity 6) and moderately more expensive (1,200 credits).

I'd suggest it is capable of handling a Sil 1 sized hole (roughly 2m x 3m).

For the Sil 2 sized hole, it's going to need to be more than twice the size, due to the square cubed law, so lets say something like encumbrance 12. This is even more unusual a piece of equipment as openings of this size rarely occur anywhere other than a ship, so rarity 7. It being more powerful, larger, and rarer, lets put the price around 3,600 credits, shall we?

Sil 3 is basically a hangar bay sized passthrough. On a Sil 5 ship, the entire mod is 25k credits. However, that includes all the durasteel, etc. needed to enclose it. So lets say about a quarter of that is the cost of the airlock. That would put it around 6-7k credits... Say 7,500 to make it more interesting. Rarity, would be lower, since this is actually a pretty common size, so rarity 5. Encumbrance would be based upon integration into a ship. So, for a value, probably something on the order of 20-30. Why not make it 25 to split the difference?

So, in summary:

Hyperstatic Atmosphere Retention Field Generator (Sil 1), Encumbrance 5, Rarity 6, Cost 1,200

Hyperstatic Atmosphere Retention Field Generator (Sil 2), Encumbrance 12, Rarity 7, Cost 3,600

Hyperstatic Atmosphere Retention Field Generator (Sil 3), Encumbrance 25, Rarity 5, Cost 7,500

Hopefully that makes sense and helps a bit. I may just steal this for something I run at some point. Looks to be a neat little device.

I would not want to walk through that field without a ship or VERY heavily protected spacesuit around me (disregarding the vacuum on the other side for a moment)...

I can't help you with this, Sturn. Or rather I wouldn't do as good a job than Braendig has so there's little point. However, I will say that I really like the idea and I fully intend to have a climactic battle to one of my adventures take place in the loading bay of a big ship against a backdrop of open Space. Perfect for people to be thrown out of mid-battle and float away helplessly. I can think of one character in particular who would enjoy grabbing someone they didn't like in a lock and sticking their head through the shield into the vacuum. (They're not a nice character).

Lots of room for atmospheric drama with this.

The Electric Perimeter Fence has a power supply that should be able to do what you're suggesting, so lets start with that. It's encumbrance 6, rarity 5 and 800 credits.

This is going to be slightly less bulky (encumbrance 5), slightly more rare (rarity 6) and moderately more expensive (1,200 credits).

<my snip>

So, in summary:

Hyperstatic Atmosphere Retention Field Generator (Sil 1), Encumbrance 5, Rarity 6, Cost 1,200

Hyperstatic Atmosphere Retention Field Generator (Sil 2), Encumbrance 12, Rarity 7, Cost 3,600

Hyperstatic Atmosphere Retention Field Generator (Sil 3), Encumbrance 25, Rarity 5, Cost 7,500

Hopefully that makes sense and helps a bit. I may just steal this for something I run at some point. Looks to be a neat little device.

Thanks! This is what I was looking for. I think two of the medium ones will work for the mining clan.

They are going to be hard-wired into the PC ship or an on-site generator. Due to the obvious problems of one failing, I would think they would also include some sort of battery backup (enough for 1 hour of power?) with an audible alarm. On second thought, 10 minute battery backup could be more fun from a game point of view.