C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design CRaTER and the Electronics Assembly Matthew Smith Mechanical Engineer (617) June 27,2005

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design CRaTER Telescope Assembly Electronics Assembly SIM Table NADIR +Z (Moon) ZENITH -Z (Space) Crater integrates two sub-assemblies: the Telescope Assembly and the Electronics Assembly. –The Telescope Assembly is being designed and built by The Aerospace Corporation –The Electronics Assembly is being designed and built by MIT. –MIT will integrate the two sub-assemblies and perform all functional, environmental and acceptance testing.

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design CRaTER Mechanical Interface Drawing

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design CRaTER Electrical/Mechanical Interface Interface Connectors J1 9 Pin D-Sub Male P-B-12 J2 9 Pin D-sub Female S-B-12 J3 1553, BJ3150 J4 1553, BJ3150 PART OF MID DRAWING NUMBER Mounting Hardware - Six #10-32 SHCS Surface roughness of 63 micro inches or better for interface surfaces. Mounting surfaces have Electrically Conductive finish (MIL-C-5541 Cl 3)

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design CRaTER Design Requirements for Protoflight Hardware from the NASA Mechanical Environments and Verification Requirements Document # 431-RQMT –Must demonstrate that we meet the performance requirements after being subjected to the net C.G. limit load of 12 g’s in any direction –Must demonstrate that we meet the performance requirements after being subjected to sine vibration of 8 g’s, Protoflight level, from Hz., (Level=1.25 X Limit Level, sweep rate= 4 Octaves/Minute/Axis.) –Must demonstrate that we meet the performance requirements after being subjected Random Vibration environment of 14.1 grms for Protoflight Hardware (Level=Limit Level +3dB, Duration= 1 Minute/Axis) –Demonstrate the ability to meet performance requirements after subjected to Protoflight acoustic environment. (OAPL=143, Level= Limit Level +3dB, Duration = 1 minute) –Natural frequency Stowed- >35Hz required. >50Hz is recommended. Deployed- >3Hz in the deployed configuration when hard mounted at the spacecraft interface. –Factors of Safety (FS) Demonstrate positive Margins of Safety (MS) for all Yield and Ultimate Failures (MS= Allowable Stress(or Load)/(applied Limit Stress(Load)x FS-1) FS for metallic Flight structures is: 1.25 for Yield and 1.4 for Ultimate Keep mass below 5.6kg. –Excludes mounting hardware and Thermal Protection System

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design CRaTER Mechanical Testing –Sinusoidal Vibration 5-100Hz at 8g’s (Protoflight) 4 Octaves/minute/axis. –Random Vibration 14.1 grms (Protoflight) 60 sec/ axis. –Will perform low level sine sweep, up to 2000 Hz. Frequencies shall be verified and reported up to 200 Hz. –Acoustics testing will not be done at the instrument level. –Shock testing to be done at the Observatory Level. CRaTER has no self induced shock.

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design CRaTER Mass Properties Estimate Summary ORIGINAL PROPOSAL TIM (April 2005) PDR (June 2005) grams CBE: CRaTER (Electronics and Telescope Assembly) Reserve 1300 (30%) 1288 (30%)640 (12%) Proposal Allocation5600 Extra requested allocation 400 MLI/TPS and Hardwaren/a % Reserven/a 87 MLI and TPS Total 377 Requested Allocation6377

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design CRaTER Mechanical Analysis, CRaTER –The fundamental frequency is estimated to be 564 Hz. –Not required to produce an FEM since our predicted first frequency is >75 Hz. –No fracture critical Items. –Will meet all Factors of Safety requirements. More analysis to be performed.

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design of Electronics Assembly Top Cover Analog Board Electronics Enclosure Digital Board (Bottom Cover Not Shown)

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design Electronics Assembly Electronics Assembly Requirements (Internal) –Have proper contact area to support Thermal and Mechanical needs –Provide safe structure to support Telescope Assembly. –Provide for mounting 2 Circuit Card Assemblies. The Analog Board must be shielded from the Digital Board. The Analog Board to provide direct linear path for electronics from the telescope interface to the Digital Board interface to reduce noise. Provide adequate surface area for electrical components. –Interface to the Spacecraft to be on one side of the Electronics Enclosure. The interface connectors to be on the Digital side of the Electronics Enclosure (separate from the Analog side) –Provide GN2 purge interface inlet and outlet ports. The Electronics Assembly will meet all these requirements.

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design Electronics Assembly Preliminary Natural Frequency Estimates –Based from Steinberg Vibration Analysis for Electronic Equipment- (Simply supported on 4 sides.) Top Cover~ 160Hz Analog Board~ 99 Hz Digital Board~ 114 Hz Bottom Cover ~ 138 Hz –Further frequency, stress, and loads analysis will be performed

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design CRaTER NEAR TERM TASKS –Further develop analysis on natural frequencies and stresses using SOLID WORKS and COSMOS –Continue to work the weight issue to maintain margin. –Finalize interface between Telescope Assembly and Electronics Assembly.

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design Backup slides

C osmic R Ay T elescope for the E ffects of R adiation MECHANCIAL DESIGN ORIGINAL PROPOSED WEIGHTS Component/subsystemweight kg,(lbs) mechanical structure Electronics Sensors Fasteners Crater sub-total mass reserve 30% Crater grand total mass max

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design Mass Properties MASS PROPERTIES (FROM TIM in APRIL) gramslbs Electronics Assembly Analog board Digital board interconnect cables A/D Mechanical enclosure interconnect cables Sub-Total Detector Assembly Detector Board (3 total) TEP Package (2 total) Detector Mechanical enclosure Sub-Total Crater Total Reserve 30% Total Max

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design CRaTER Mass Properties CURRENT MASS PROPERTY ESTIMATES Electronics Assembly gramslbs Analog CCA Digital CCA Interconnect Cable, A/D Internal E-box Cables Mechanical Enclosure Top Cover Bottom Cover Hardware Purge system Electronics Assembly Sub-Total Detector Assembly Detector Board (3 total) TEP Package (2 total) Detector Mechanical Enclosure Detector Assembly Sub- Total Crater Total

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design Mass Properties Miscellaneous Estimates GSFC Supplied Material grams lbs MLI and TPS Mounting Hardware Misc. total % reserve Misc. Grand Total

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design Drawing List Drawing NumberDrawing TitleRevqtylayout completedrawing createdcheckedReleased Electronics Assembly-n/a0% Digital Electronics, PWA02125% Analog Electronics PWA Electronics Enclosure 01175% Cover, Top Electronics Enclosure 01175% Cover, Bottom Electronics Enclosure -175%

C osmic R Ay T elescope for the E ffects of R adiation Mechanical Design Electronics Box Assembly PolyimideTop coverBottom Cover ModulusE(lb/in^2)8.7E+51.00E+07 heighth(inches) Poison ratiou lengtha (in) widthb (in) weightW (lb) gin/sec^2386 pi3.14 D=E*h^3/(12(1-u^2)D= density pmass/area=W/gab2.73E E E-05 for a a simply supported board on 4 sides f=pi/2((D/p)^.5)(1/a^ 2+1/b^2))^.5frequency= This is from an example by Steinberg, vibration analysis for electronic equipment page 149