Although it's obviously fictional, I commissioned this design from a real scientist who put a lot of thought into it (see below). Any engineering mistakes are my fault and not his.
A note on textures: When publishing this model, I checked the box marked 'No Textures' because I thought it was the most honest answer. But technically, there is one UV mapped image for the solar cells (simple honeycomb pattern for materials assignment). Other apparent textures (such as rough/dirty metal, displacement map for the foil, etc) are simple procedural textures (cloud/noise style). These are included in the default (Blender) file, but may require adjustment in the exported formats.
The idea basically is that this platform can be maneuvered into place on an asteroid or a comet. It's expected primarily to be used on objects with substantial volatile ices, since a large part of the most valuable chemicals (like water, methane, ammonia, etc) can be found that way. It also processes some rocky/metallic elements, though.
The platform is basically a drilling rig.
A long drilling shaft runs the vertical length of the platform, containing a telescoping drilling shaft and a bit which can be changed for sharpening, just like a terrestrial oil drilling rig.
The bottom of the rig needs to form a gas-tight seal with the surface in order to extract the vaporizing volatiles as they are released from the rock. This is achieved through a soft-seal (probably silicone or something like that) which conforms to the surface.
There's not enough gravity to hold the rig down and make a good seal, so it's necessary to use the arms at the bottom to grab the asteroid. This is achieved through the twelve spikes, which use electromagnetic solenoids to drive them rapidly into the rock. The actuators then pull the rig tight against the surface.
As the drill engages the rock and ice, vapor and debris is released and sucked up the shaft under the resulting pressure.
The 'rock breaker' filters out large mineral particulates, pounds them down to a manageable gravel, and sends these up the mineral lines to the mineral refining system which is up at the top of the stack.
Meanwhile, the volatiles are piped up into a series of fractionating centrifuges. These divide the chemicals mainly according to density (although chemical stages could be added). These are then extracted and piped up to the holding tanks on the upper truss.
The mineral debris goes to several purposes. Some of it is extracted to use in the radiation mass shield around the crew torus habitat. Some is carried up for chemical refining in the upper rig. Some of this requires substantial heat, which is provided by a large solar heating furnace -- this is the large dish on the upper rig.
Naturally, the processing requires lots of power, which is provided by the large solar arrays. A lot of heat can be dumped into the upper rig for heating minerals, but unavoidably some will need to be dumped into the large thermal radiators shadowed behind the solar arrays.
There are ion propulsion arrays on the upper surface which are primarily useful when the rig is empty. When the rig has been operating, it can use electrolysis to separate water volatiles into hydrogen and oxygen, which is stored in the upper middle tanks