1. The anarchist’s power grid

Ursula K. Le Guin’s The Dispossessed is about a society that keeps its technology sparse and shared, where power is distributed rather than hoarded. The desktop’s power attachment is not anarchist in any political sense, but it is distributed: generation, storage, and switching are spread across the platform, and every attachment pays for what it draws.

Entries 237 through 240 defined the power attachment. This entry closes that arc and decides what to define next.

2. What the power arc settled

The desktop’s power system is now a coherent subsystem rather than a collection of assumptions.

The decisions are:

  • Power attachment covers generation, storage, and distribution as one logical unit.
  • Average demand is roughly 200 W, with peaks to 400–600 W.
  • Solar array area is about 3 m²: triple-junction GaAs on deployable wings, silicon on body-mounted backup panels.
  • Array mass is roughly 10–14 kg.
  • Battery capacity is 300–400 Wh of lithium-ion, sized for eclipse plus margin at 50% depth of discharge.
  • Main bus is regulated 28 V, with switched distribution and an essential bus for critical loads.
  • Derived voltages are 12 V, 5 V, and 3.3 V.

These numbers give the thermal attachment something concrete to reject. They also give the structural attachment a known load in terms of mass, deployment forces, and centre of gravity.

3. What remains outside the arc

Several integration questions were deliberately deferred:

  • How do the solar array drive mechanisms interface with the attitude control system?
  • What happens to the array during robotic operations or docking?
  • How is the battery replaced or augmented over the desktop’s lifetime?
  • What is the exact power interface contract for customer payloads?

These will be answered when the thermal, structural, robotics, and operations attachments are defined.

4. Why thermal control is next

The next attachment to define is the thermal control attachment: radiators, heat pipes, coatings, heaters, and louvers. There are three reasons for this order.

First, every watt of electrical power eventually becomes heat. The desktop now knows it generates roughly 200 W of continuous heat on average, with higher peaks. That heat must go somewhere.

Second, the thermal design is coupled to the power design. Solar arrays absorb solar energy and radiate from their back sides. Batteries have narrow temperature bands. Electronics prefer stable temperatures. The radiator area and location depend on these constraints.

Third, thermal control is one of the largest physical attachments. Radiator panels compete with solar arrays, antennas, sensors, and docking fixtures for surface area. It cannot be designed in isolation.

5. The thermal questions to answer

The next few entries should answer:

  • How much heat must the desktop reject continuously and at peak?
  • What temperature ranges must each attachment stay within?
  • Does the desktop use passive radiators, heat pipes, or active loops?
  • How are batteries and electronics thermally isolated or coupled?
  • What coatings and multi-layer insulation are needed?

These are ordinary engineering questions, but they deserve their own arc because the answers constrain the mechanical layout and operations.

What this changes

  • The power attachment arc is closed with consistent specifications for generation, storage, and distribution.
  • The next arc will define the thermal control attachment.
  • Integration questions about power are held until thermal, structural, and robotics attachments are defined.
  • The desktop’s attachment grid now has a second proven pattern, following the sensor arc.