Concepts

Cross-cutting material: a subject that is not one machine, one component, one facility or one destination, and that would otherwise be restated on every page it bears on.

Environment references collects the documents hardware is designed against rather than measured by. The Cross-Program Design Specification for Natural Environments converts environment models into the design values a US deep space program’s requirements inherit [1], and the page lists the Lunar Sourcebook, the Global Reference Atmospheric Model series for Mars, Venus, Titan and the giant planets, and the galactic cosmic ray and orbital debris models behind shielding mass alongside it. The destinations as measured are under Environments.

Tethers is here because a tether belongs to no single vehicle class: it carries the vehicle’s weight during a rappel, its power and its data at once, and what governs it is breaking force at the bend and temperature it is actually pulled over rather than a single rating. One lunar surface power tether broke at 7219 N over a gentle bend at -190 C and at 990 N over a 78 degree knife edge at +200 C [2].

A page belongs here when its subject spans destinations and vehicle classes. A part with a published flight or qualification result belongs on Avionics, something that runs on a processor on Software, a laboratory on test facilities, and a destination’s own properties on Environments.