Systems and methods for providing mirrors with high stiffness and low inertia involving chemical etching

1. A method of fabricating a mirror for use in limited rotation motor systems, comprising:

providing a mirror structure including a beryllium mirror structure comprising a plurality of wall sections arranged in one or more shaped patterns;

exposing the beryllium mirror structure to a bath that includes a fluid etching agent;

mechanically agitating the bath during exposure of the beryllium mirror structure to the fluid etching agent and drawing the beryllium mirror structure from the bath including the fluid etching agent at a controlled rate such that the plurality of wall sections are chemically milled to have a triangular cross sectional thickness that tapers towards an open end of the wall sections.

2. The method as claimed in claim 1 , wherein said fluid etching agent includes hydrofluoric acid (HF).

3. The method as claimed in claim 1 , wherein said fluid etching agent includes nitric acid (HNO 3 ).

4. The method as claimed in claim 1 , wherein said mirror structure further includes a front reflective mirror surface.

5. The method as claimed in claim 1 , wherein said mirror structure is removed from the fluid etching agent when the mirror reaches a target reduced weight.

6. The method as claimed in claim 1 , wherein said method provides uniform milling of exposed surfaces of the beryllium structure.

7. A mirror for use in a limited rotation motor systems formed from the method of claim 1 .

8. The method as claimed in claim 1 , wherein said mechanically agitating the bath of the fluid etching agent comprises moving the beryllium mirror structure with an up-and-down motion in the bath of the fluid etching agent.

9. The method as claimed in claim 8 , wherein the bath of the fluid etching agent is mechanically agitated while drawing the beryllium mirror structure from the bath.

10. A method of fabricating a mirror for use in limited rotation motor systems, comprising:

providing a mirror unit including a backing structure that is opposite a mirror surface, wherein the backing structure comprises a plurality of wall sections arranged in one or more shaped patterns, said wall sections each having a base and an open end;

exposing the backing structure to a bath that includes a fluid etching agent to thereby provide chemical milling of the backing structure, wherein the fluid etching agent comprises 60% concentration hydrofluoric acid (HF) one part and 69% concentration of nitric acid (HNO 3 ) nine parts;

wherein one or more of the plurality of wall sections of the backing structure is chemically milled to have a cross sectional thickness that tapers from the base to the open end of the one or more wall sections, a thickness of the base being reduced by close to 50% and a thickness of the open end being reduced to close to 100%.

11. The method as claimed in claim 10 , wherein said backing structure includes beryllium.

12. The method as claimed in claim 10 , wherein the plurality of wall sections are chemically milled by mechanically agitating the bath of the fluid etching agent and drawing the backing structure from the bath at a controlled rate.

13. The method as claimed in claim 12 , wherein said mechanically agitating the bath of the fluid etching agent comprises moving the backing structure with an up-and-down motion in the bath of the fluid etching agent.

14. The method as claimed in claim 13 , wherein the bath of the fluid etching agent is mechanically agitated while drawing the backing structure from the bath.

15. The method as claimed in claim 10 , wherein the plurality of wall sections are chemically milled to have a thickness of no greater than 0.25 mm.

16. A method of fabricating a mirror for use in limited rotation motor systems, comprising:

providing a mirror unit including a backing structure that is opposite a mirror surface and made of beryllium;

mechanically milling the backing structure to have a plurality of wall sections arranged in one or more shaped patterns, wherein each wall section is mechanically milled to a thickness of about 0.5 millimeters (mm);

exposing the backing structure to a bath of a fluid etching agent having a beryllium removal rate that is equal to about 18 microns per minute; and

mechanically agitating the bath during exposure of the backing structure to the fluid etching agent and drawing the backing structure from the bath of the fluid etching agent at a controlled rate such that the plurality of wall sections are chemically milled to have a triangular cross sectional shape that tapers from a base having a reduced thickness of about 0.25 mm towards an open end.

17. The method as claimed in claim 16 , wherein the backing structure is exposed to the fluid etching agent in the agitated bath for a time in a range of about five minutes to about six minutes.

18. The method as claimed in claim 16 , wherein the fluid etching agent comprises 60% concentration hydrofluoric acid (HF) one part and 69% concentration nitric acid (HNO 3 ) nine parts at a temperature in a range of about 15° C. to about 25° C.

19. The method as claimed in claim 16 , wherein said mechanically agitating the bath of the fluid etching agent comprises moving the backing structure with an up-and-down motion in the bath of the fluid etching agent.

20. The method as claimed in claim 19 , wherein the bath of the fluid etching agent is mechanically agitated while drawing the backing structure from the bath.