1. The jaunte and the heat sink

Alfred Bester’s The Stars My Destination is full of people who teleport by will alone, but the universe around them still obeys thermodynamics. You can arrive anywhere instantly, yet you still need a place to dump the waste. The desktop cannot jaunte, but it has the same afterthought problem: every clever thing it does leaves heat behind, and that heat needs a sink.

Entries 242 through 245 defined the thermal control attachment. This entry closes that arc and decides what to define next.

2. What the thermal arc settled

The desktop’s thermal control is now a coherent subsystem rather than a hand-waved margin.

The decisions are:

  • Thermal control keeps every other attachment within its operating temperature band.
  • The desktop rejects roughly 180 W average and 300–500 W peak.
  • Radiator area is roughly 0.7–1.0 m² at 280 K.
  • Radiators are body-mounted, not deployable, on two opposite faces of the body.
  • Heat pipes move heat from electronics and batteries to the radiator panels.
  • Radiator finish is optical solar reflector or silvered Teflon for low absorptivity and high emissivity.
  • Non-radiator surfaces use 15–20 layer MLI blankets.
  • Patch heaters protect batteries and mechanisms during eclipse.
  • Thermal control attachment mass is roughly 8–13 kg including radiators, heat pipes, coatings, MLI, and heaters.

These numbers give the structural attachment a known load: mass, area, thermal expansion, and deployment forces. They also give the operations attachment a known constraint: which faces must stay cold, which must stay warm, and which can tolerate being shadowed.

3. What remains outside the arc

Several integration questions were deliberately deferred:

  • How are radiators and solar arrays arranged so they do not stare at each other?
  • What is the exact thermal interface contract for customer payloads?
  • How is a radiator panel replaced or repaired over the desktop’s lifetime?
  • How do louvers or variable emittance devices fit into later versions?

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

4. Why structure is next

The next attachment to define is the structural attachment: the frame, panels, mounts, and interfaces that hold everything else. There are three reasons for this order.

First, the power and thermal attachments have now defined the major external surfaces. Solar arrays need area and pointing. Radiators need cold sky and clearance from hot equipment. Batteries and electronics need mounting and thermal paths. The structure is what resolves these competing claims on the same physical envelope.

Second, the desktop’s defining feature is modularity: attachments arrive, attach, and are replaced. That modularity lives in the structural interface. Rails, latches, blind-mate connectors, and guided insertion features are structural decisions before they are robotics or operations decisions.

Third, structural mass is a first-order driver of launch cost. The desktop’s structure must be light enough to launch, stiff enough to survive deployment and operations, and accessible enough to service. These three requirements pull in different directions, and the trade needs its own arc.

5. The structural questions to answer

The next few entries should answer:

  • What is the overall form factor and layout of the desktop body?
  • How are attachments mechanically attached, electrically connected, and thermally coupled?
  • What is the primary structure made of, and how is it manufactured?
  • How does the structure survive launch loads, deployment shocks, and thermal cycling?
  • How does the structure enable robotic access for replacement and inspection?

These are ordinary engineering questions, but they deserve their own arc because the answers determine whether the desktop is a sealed box or a serviceable workshop.

What this changes

  • The thermal control attachment arc is closed with consistent specifications for heat rejection, coatings, insulation, and heaters.
  • The next arc will define the structural attachment: frame, panels, mounts, and interfaces.
  • Integration questions about thermal control are held until structural, robotics, and operations attachments are defined.
  • The desktop’s attachment grid now has a third proven pattern, following the sensor and power arcs.