Schott extreme lightweight ZERODUR mirror (ELZM) test results · JWST PMSA test configuration at...
Transcript of Schott extreme lightweight ZERODUR mirror (ELZM) test results · JWST PMSA test configuration at...
Schott extreme lightweight ZERODUR® mirror
(ELZM) test results
Ron Eng, NASA Marshall Space Flight Center
Mirror Tech/SBIR/STTR Workshop Greenbelt, MD November 2, 2016
1
Agenda
• Goals and motivations
• Schott ELZM
• Test facility
• Test setup
• Test results
2
Goals and motivation
• R&D - develop/improve test methods to characterize
lightweight mirror architecture for current and future
telescopes
• Competition - using same test setup and facility to
characterize competing mirror architecture
• Facility – utilize and add capabilities to existing
environmental test facilities
• Model validation - test data used for model validation
• Personnel – testing is labor intensive
• Learning – working with vendors
3
Lightweight ZERODUR Mirror Substrates by SCHOTTZERODUR (5ppb/K) is
on a favorable contourSpecific-
Stiffness/Transient-Response Plane
>30 years in space, > 30 missionsLightweight ZERODUR is derived
from advanced machining at SCHOTT (0.4m to 4.0m) +
deterministic OpFab
SCHOTT 88% Lightweighted ZERODUR Mirror
CostRisk
Lapse
%LW
For 1.2m substrateRoughly < $600K
in < 3 months
Schott ELZM
5
Diameter: 1.2m
ROC: 3.1m
Mass: 45kg; 88% lightweighted
Schott ELZM
6
Schott ELZM and test setup
7
8
JWST PMSA test configuration at XRCF
16 m ROC; ~4 m dia.
6 x 18.3 m test volume
4.25 m dia. Helium cooled shroud
Existing structure prevents testing mirrors with ROC < 3.5 meters
A pressure tight enclosure (PTE) configuration to test mirror with short ROC < 3.5 meter
9
Test configuration for short ROC mirrors
Interferometer and test
support equipment in
pressure tight enclosure
(PTE)
Mirror on test
stand
Thermal shroud
Alignment
stage
AMTD-2 test configuration with PTE
Mirror temp avg 292º K
10
Mirror temp avg 230º K
11
Mirror temp avg 250º K
12
Mirror temp avg 275º K
13
14
test article temperature and pressure data
rms Δ figures
Cycle 1
Cycle 2
ΔT = 2º C 5.9nm rms ΔT = 17 6.5nm ΔT = 42 9.5nm ΔT = 62 11.3nm
ΔT = 1 6nm ΔT = 15 6.9nm ΔT = 39 10.3nm ΔT = 61 10.7nm
Delta surface rms vs temperature
16
36 Zernike terms residual
Cycle 1
Cycle 2
ΔT = 2º C ΔT = 17 ΔT = 42 ΔT = 62
ΔT = 1 ΔT = 15 ΔT = 39 ΔT = 61
mirror rotations at 0, 120, 240 deg.
18
Gravity backout
19
0 deg 120 deg rotation 240 deg rotation
Gravity backout
20
Predicted modal frequencies and shapes
21
Preliminary modal test results
22
196.07 Hz
Acknowledgments
NASA MSFC
Mark Baker, Thomas Brooks, Michael Effinger, Darrell Gaddy, William
Hogue, Jeffrey Kegley, Brent Knight, Rusty Parks, Richard Siler, Phil
Stahl, John Tucker, Ernest Wright
Schott
Tony Hull
Arizona Optical Systems
Marty Valente, David Tiss
23
Backup slides
24
Cycle 1, 230º - 292º Kelvin
25
Cycle 1, 250º - 292º Kelvin
26
Cycle 1, 275º - 292º Kelvin
27
Cycle 1, 290º - 292º Kelvin
28
Cycle 2, 230º - 290º Kelvin
29
Cycle 2, 251º - 290º Kelvin
30
Cycle 2, 275º - 290º Kelvin
31
Cycle 2, 291º - 290º Kelvin
32