Abstract

A new mirror mounting technique applicable to the primary mirror in a space telescope is presented. This mounting technique replaces conventional bipod flexures with flexures having mechanical shims so that adjustments can be made to counter the effects of gravitational distortion of the mirror surface while being tested in the horizontal position. Astigmatic aberration due to the gravitational changes is effectively reduced by adjusting the shim thickness, and the relation between the astigmatism and the shim thickness is investigated. We tested the mirror interferometrically at the center of curvature using a null lens. Then we repeated the test after rotating the mirror about its optical axis by 180° in the horizontal setup, and searched for the minimum system error. With the proposed flexure mount, the gravitational stress at the adhesive coupling between the mirror and the mount is reduced by half that of a conventional bipod flexure for better mechanical safety under launch loads. Analytical results using finite element methods are compared with experimental results from the optical interferometer. Vibration tests verified the mechanical safety and optical stability, and qualified their use in space applications.

© 2012 Optical Society of America

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References

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    [CrossRef]
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    [CrossRef]
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2011

2010

2009

2008

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

2004

E. T. Kvamme and M. T. Sullivan, “A small low-stress stable 3-DOF mirror mount with one arc-second tip/tilt resolution,” Proc. SPIE 5528, 264–271 (2004).
[CrossRef]

2002

G. J. Michels, V. L. Genberg, and K. B. Doyle, “Finite element modeling of nearly incompressible bonds,” Proc. SPIE 4771, 287–295 (2002).
[CrossRef]

1993

A. E. Hatheway, “Analysis of adhesive bonds in optics,” Proc. SPIE 1998, 2–8 (1993).
[CrossRef]

1964

Bloemhof, E. E.

Boit, J-L.

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

Castinel, L.

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

Chang, Z.

Chin, O.

Choi, S.-C.

Doyle, K. B.

G. J. Michels, V. L. Genberg, and K. B. Doyle, “Finite element modeling of nearly incompressible bonds,” Proc. SPIE 4771, 287–295 (2002).
[CrossRef]

K. B. Doyle, V. L. Genberg, and G. J. Michels, “Displacement models of adhesive bonds,” in Integrated Optomechanical Analysis (SPIE, 2002), pp. 86–98.

Feria, V. A.

Garcia, J.

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

Genberg, V. L.

G. J. Michels, V. L. Genberg, and K. B. Doyle, “Finite element modeling of nearly incompressible bonds,” Proc. SPIE 4771, 287–295 (2002).
[CrossRef]

K. B. Doyle, V. L. Genberg, and G. J. Michels, “Displacement models of adhesive bonds,” in Integrated Optomechanical Analysis (SPIE, 2002), pp. 86–98.

Grassi, E.

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

Hartmann, P.

Hatheway, A. E.

A. E. Hatheway, “Analysis of adhesive bonds in optics,” Proc. SPIE 1998, 2–8 (1993).
[CrossRef]

Hwang, H.-Y.

Jedamzik, R.

Jung, G.-J.

Kihm, H.

Kim, S.-W.

Kvamme, E. T.

E. T. Kvamme and M. T. Sullivan, “A small low-stress stable 3-DOF mirror mount with one arc-second tip/tilt resolution,” Proc. SPIE 5528, 264–271 (2004).
[CrossRef]

Lam, J. C.

Laurent, P.

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

Lee, K.-J.

Lee, Y.-W.

Malacara, D.

D. Malacara, “Zernike polynomials and wavefront fitting,” in Optical Shop Testing (Wiley, 2007), pp. 298–545.

Martin, L.

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

Michels, G. J.

G. J. Michels, V. L. Genberg, and K. B. Doyle, “Finite element modeling of nearly incompressible bonds,” Proc. SPIE 4771, 287–295 (2002).
[CrossRef]

K. B. Doyle, V. L. Genberg, and G. J. Michels, “Displacement models of adhesive bonds,” in Integrated Optomechanical Analysis (SPIE, 2002), pp. 86–98.

Milliard, B.

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

Moon, I. K.

Moon, I.-K.

Moreaux, G.

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

Pamplona, T.

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

Prieto, E.

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

Reichel, S.

Rossin, Ch.

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

Schreder, B.

Sullivan, M. T.

E. T. Kvamme and M. T. Sullivan, “A small low-stress stable 3-DOF mirror mount with one arc-second tip/tilt resolution,” Proc. SPIE 5528, 264–271 (2004).
[CrossRef]

Yang, H.-S.

Yoder, P. R.

P. R. Yoder, “Mounting large, horizontal-axis mirrors,”in Opto-Mechanical Systems Design (SPIE, 2006), pp. 481–502.

Appl. Opt.

J. Opt. Soc. Korea

Proc. SPIE

T. Pamplona, Ch. Rossin, L. Martin, G. Moreaux, E. Prieto, P. Laurent, E. Grassi, J-L. Boit, L. Castinel, J. Garcia, and B. Milliard, “Three bipods slicer prototype: Tests and finite element calculations,” Proc. SPIE 7018, 701828 (2008).
[CrossRef]

E. T. Kvamme and M. T. Sullivan, “A small low-stress stable 3-DOF mirror mount with one arc-second tip/tilt resolution,” Proc. SPIE 5528, 264–271 (2004).
[CrossRef]

A. E. Hatheway, “Analysis of adhesive bonds in optics,” Proc. SPIE 1998, 2–8 (1993).
[CrossRef]

G. J. Michels, V. L. Genberg, and K. B. Doyle, “Finite element modeling of nearly incompressible bonds,” Proc. SPIE 4771, 287–295 (2002).
[CrossRef]

Other

K. B. Doyle, V. L. Genberg, and G. J. Michels, “Displacement models of adhesive bonds,” in Integrated Optomechanical Analysis (SPIE, 2002), pp. 86–98.

D. Malacara, “Zernike polynomials and wavefront fitting,” in Optical Shop Testing (Wiley, 2007), pp. 298–545.

P. R. Yoder, “Mounting large, horizontal-axis mirrors,”in Opto-Mechanical Systems Design (SPIE, 2006), pp. 481–502.

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Figures (13)

Fig. 1.
Fig. 1.

(a) ϕ800mm zerodur mirror mounted on bipod flexures. The mirror has three square bosses at the rim and they are coupled with flexures by using an epoxy adhesive. The back surface has pockets as shown in the sectional view. (b) Horizontal setup for measuring with an optical interferometer. A null lens or a computer-generated hologram is used for the aspheric mirror.

Fig. 2.
Fig. 2.

(a) Sensitivity of Zernike coefficient Z5 (astigmatism in x direction) with respect to the unit change of dimensional parameters of a mirror and flexures. Highly sensitive parameters are indicated by arrows with their names and they are represented in the lower figures. (b) Sectional drawing of the mirror. (c) Front view of the flexure.

Fig. 3.
Fig. 3.

(a) ϕ800mm zerodur mirror mounted on bipod flexures. (b) Bipod flexure is composed of Flexure A, Flexure B, and a shim. The shim can be changed easily to adjust mirror’s surface distortions.

Fig. 4.
Fig. 4.

Interferometric testing of ϕ800mm zerodur mirror in a horizontal position.

Fig. 5.
Fig. 5.

ϕ800mm mirror assembly is under 1 g gravity load in the y direction. The mirror is displaced in the y direction by 0.2 μm and is exaggerated in the figure.

Fig. 6.
Fig. 6.

Variations of the mirror surface error map with respect to the shim thickness. Shim thickness can be changed from zero, which means no shim, to 4 mm, which is the maximum thickness. PV and RMS values are listed.

Fig. 7.
Fig. 7.

Z5 (astigmatism) terms from interferometric measurements and finite element analysis are plotted with respect to the shim thickness.

Fig. 8.
Fig. 8.

System errors due to gravity in RMS are plotted with respect to the shim thickness. The minimum RMS value obtained from experiments is 10 nm, which is higher than the theoretical value of 7.5 nm.

Fig. 9.
Fig. 9.

Systematic error Ps due to the gravity effect is shown, where the RMS value is 10 nm and Z5 is 0.7 nm.

Fig. 10.
Fig. 10.

Stress at the adhesive under 1 g gravity load (a) previous monolithic bipod flexure and (b) proposed adjustable bipod flexure.

Fig. 11.
Fig. 11.

ϕ800mm mirror system with accelerometers.

Fig. 12.
Fig. 12.

ϕ800mm mirror system on a shaker for vibration tests.

Fig. 13.
Fig. 13.

Fundamental mode shape of the ϕ800mm mirror system.

Tables (2)

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Table 1. Random Vibration Profile and Specification Lists of the Acceleration Spectral Densities (ASD) in Each Frequency Band

Tables Icon

Table 2. Comparison of Modal Frequencies Obtained from Each Axis

Equations (1)

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Ps=12[P0R180(P180)].

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