Final (spherical) curvature of (reflective or refractive) optics is effected by fixed contact angle of (a shallow, liquid optical) "pool" at the circumferential boundary (Figures 16 and 18), and by "elevation" of "liquid-level" inside boundary-ring. Of course liquids cannot "leak" out of such "pools", as shown in Figure 17. Toroidal, circumferential boundary rings are "poured" in advance of the latter step (Figure 18), and generally solidified prior to introducing the liquid mirror (for example) material. Self-Fabrication of liquid mirrors in orbit One option is the introduction of (i.e., "pumping" shown in Figures 16 and 19) a settable liquid into a circular boundary "trough" (Figure 17, 18, 20, 21 and 22). The liquid is then solidified. A liquid mirror plastic is then applied (Figure 23) which may or may not remain liquid depending on the application. It is then plated with a liquid metal which also may or may not remain liquid depending on the application. "A precision circular boundary (toroidal) trough" is needed to avoid "long-period" boundary errors (definitely impairing mirror surface sphericity, identified in Figures 9 and 24), while "short-period" boundary errors (identified in Figure 25) are precluded from affecting mirror sphericity by Young-LaPlace considerations (Figure 25). Probably best liquid plastic is Dow Coming silicone #200 [8, 9, 10], and presumably best liquid-metal is ultra-pure gallium [11, 12, 13], although many experiments are needed. Precise satellite overall temperature control will of course be needed at all times, implemented by a system like that illustrated in Figures 26 and 27. Variable-focus liquid orbital primary mirror via self-gravitation Next the important case of energy-handling variable-focus primary mirrors (Figures 28 and 29) is treated. The gravitational attraction of a ballast-mass "figuring" liquid (probably mercury) held in a (static) rotationally-symmetric, variable geometry, concentric enclosure fixed behind the mirror, is used for "fine tuning" the mirror focal length. Also note that such a system may for example be used as well for continuously varying focal length (in transmitting energy) to follow interplanetary/interstellar spaceships. That is, the primary mirror surface may gravitationally be altered (fine tuned) continuously from spherical to parabolic to plane to hyperbolic, via adjusting the size and shape (while maintaining rotational symmetry) of a gravitationally attracting bladder containing a massive liquid—probably mercury—stored behind the mirror. A variable focus primary mirror precision surface control is illustrated in Figure 28, where a "bellows" is carried on (bonded to) a complete set of radial splines encircling the mirror back structure. These splines are pivoted respectively at their centers, on a concentric raised ring encircling the mirror halfway from center to limb. A massive "figuring" liquid (like mercury - Figures 15 and 16) is carried in the (flattened) bladder between the bellows and the mirror.
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