Constraint Fingerprints

Twelve fingerprints

Constraint fingerprints on eight shared axes.

A constraint is fixed, computable and designed around - the velocity budget, the light time, the sunlight, the radiator, the queue for spares. Each figure scores the same eight constraints at one site from 0 to 5, where 5 binds hardest. The polygon takes the color of the destination's overall confidence; every underlying value carries its own tag in the table below.

Observed Building Projected Modeled Confidence scale

Reading the shapes

Small and lopsided inside, large and round outside.

Earth orbit and cislunar space barely register: sub-second or one-second light time, days to resupply, continuous sunlight. What spikes in Earth orbit is the thermal cycle - roughly 16 sunrises a day on the International Space Station and Tiangong - and the radiator, which carries Earth's own infrared and reflected sunlight as a load.

Mercury is the inner-system exception, spiking on heat rejection and communications. A radiator's output depends on its own temperature (σT⁴), not on how bright the Sun is, so Mercury's 6.7× sunlight passes straight through to collectors and light-based products and not at all to anything limited by waste heat. Earth stays within 28° of the Sun as seen from Mercury, which makes optical communications a requirement for every lander and orbiter after BepiColombo.

From Ceres outward the figures fill toward the outer ring on reach, latency, power and resupply, and collapse to zero on heat rejection. Callisto, Titan, Triton and Pluto are among the best places in the solar system to throw away waste heat and among the worst to make it - the constraint that binds is watts per kilogram of power plant, then transit time against design life. Titan alone rejects heat convectively into a 1.45-bar nitrogen atmosphere, roughly 4,000 W/m² against 459 W/m² for a vacuum radiator, a derived figure still awaiting independent review.

Gravity scores the opposite way from intuition: free-fall and very low surface gravity score high because anything that needs a gravity vector - holding dust down, holding a melt in a crucible, crew physiology - has to be built in. Ceres at 0.029 g, Triton at 0.079 g and Pluto at 0.063 g all fall below any plausible physiological threshold, so a crewed station at any of them spins.

The eight axes

What each axis measures and how it is scored.

• Reach - Δv from LEO. 0 under 1 km/s; 1 to 4 km/s; 2 to 7; 3 to 10; 4 to 14; 5 above 14 or no reaction-mass basis.
• Latency - one-way light time. 0 under 1 s; 1 to 2 s; 2 under 30 min; 3 under 1 h; 4 under 2 h; 5 hours or more.
• Power - scarcity of firm power at the site: sunlight fraction of 1 AU, length of dark spells, storm outages. 5 means fission or beamed power is the only option.
• Heat rejection - radiator burden from the local thermal sink: background temperature, incoming flux, and whether convection is available.
• Resupply - worst-case wait for a spare: launch window plus transit. 0 is days; 5 is years or never.
• Thermal cycle - amplitude and rate of the temperature swing at the transition, not the average. Rate breaks seals and solder joints faster than amplitude.
• Gravity - how far surface gravity sits from useful: 0 near 1 g, 5 for free-fall or cruise.
• Comms - the communications floor: RF noise, conjunction blackouts, Sun-angle limits and link budget.

Directional flux asymmetry - which side the Sun, the planet, the plasma or the dust comes from - is recorded in the table and not scored; it shapes layout more than feasibility.

Values

The site values behind the scores.

Record

Provenance.