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NASNCP-2006-2 14290 3 sth Aerospace Mechanisms Symposium Compiled by Edward A. Boesiger Lockheed Martin Space Systems Company, Sunnyvale, California Proceedings of a symposium hosted by the NASA Langley Research Center and Lockheed Martin Space Systems Company and organized by the Mechanisms Education Associati... | Document | AMS_2006.pdf | 1 |
The NASA STI Program Office . . . in Profile Since its founding, NASA has been dedicated to the advancement of aeronautics and space science. The NASA Scientific and Technical Information (STI) Program Office plays a key part in helping NASA maintain this important role. The NASA STI Program Office is operated by... | Document | AMS_2006.pdf | 2 |
NASA/CP-2006-2 14290 3 8th Aerospace Mechanisms Symposium Compiled by Edward A. Boesiger Lockheed Martin Space Systems Company, Sunnyvale, California Proceedings of a symposium hosted by the NASA Langley Research Center and Lockheed Martin Space Systems Company and organized by the Mechanisms Education Associat... | Document | AMS_2006.pdf | 3 |
The use of trademarks or names of manufacturers in the report is for accurate reporting and does not constitute an official endorsement, either expressed or implied, of such products or manufacturers by the National Aeronautics and Space Administration. Available from: NASA Center for Aerospace Information (CASI) ... | Document | AMS_2006.pdf | 4 |
PREFACE The Aerospace Mechanisms Symposium (AMS) provides a unique forum for those active in the design, production and use of aerospace mechanisms. A major focus is the reporting of problems and solutions associated with the development and flight certification of new mechanisms. Organized by the Mechanisms Educat... | Document | AMS_2006.pdf | 5 |
CONTENTS ... Symposium Schedule ............................................................................................................................... vi11 Symposium Organizing and Advisory Committees ................................................................................... xii Precision Linear Ac... | Document | AMS_2006.pdf | 7 |
Faying Surface Lubrication Effects on Nut Factors ................................................................................ 157 Deneen Taylor & Raymond Morrison Torque Loss and Stress Relaxation in Constant Torque Springs .......................................................... 163 Robert Postma Mechanical... | Document | AMS_2006.pdf | 8 |
Come-Along Tool Development for Telerobotic In-Space Servicing of the Hubble Space Telescope ....................................................................................................................... 345 Jonathan Penn Planetary Airplane Extraction System Development and Subscale Testing ................... | Document | AMS_2006.pdf | 9 |
SYMPOSIUM SCHEDULE WEDNESDAY, 17 MAY 2006 8:OO 8:OO 9:oo 9:30 1 1 :45 1 :oo Wednesday Presenters' Breakfast - Terrace Room CHECK-IN AND REFRESHMENTS - Auditorium INTRODUCTORY REMARKS - Auditorium James Wells, Host Chairman NASA Langley Research Center, Hampton, VA Stuart Loewenthal, General Chairman Lockhe... | Document | AMS_2006.pdf | 10 |
2~45 SESSION 111 - “BIG PICTURE” John McManamen, Session Chair NASA Johnson Space Center, Houston, TX SoftRide Vibration and Shock Isolation Systems that Protect Spacecraft from Launch Dynamic Environments Conor Johnson, Paul Wilke & Scott Pendleton, CSA Engineering, Inc., Mountain View, CA Summary of the New AIA... | Document | AMS_2006.pdf | 11 |
10:15 10:30 12:oo 1 :oo 3:30 3:45 0 Lessons Learned From the Windsat BAPTA Design and On-Orbit Anomalies Steve Koss, Naval Research Laboratory, Washington, D.C.; Scott Woolaway, Ball Aerospace & Technologies Corp., Boulder, CO BREAK SESSION VI - JWST Casey DeKramer, Session Chair Swales Aerospace, Beltsville... | Document | AMS_2006.pdf | 12 |
FRIDAY, 19 MAY 2006 7:15 7:45 Light Refreshments - Auditorium Friday Presenters’ Breakfast - Terrace Room 8:15 SESSION Vlll - TOOLS & AIRCRAFT - Auditorium Gerard Migliorero, Session Chair ESNESTeC, Noordwijk, The Netherlands Mechanism Development, Testing, and Lessons Learned for the Advanced Resistive Exercise ... | Document | AMS_2006.pdf | 13 |
SYMPOSIUM ORGANIZING COMMITTEE James E. Wells, Host Chair, NASA LaRC Robin Tutterow, Host Co-Chair, NASA LaRC Stuart H. Loewenthal, General Chairman, Lockheed Martin Edward A. Boesiger, Operations Chairman, Lockheed Martin Carlton L. Foster, NASA MSFC Claef F. Hakun, NASA GSFC Christopher P. Hansen, NASA JSC Wa... | Document | AMS_2006.pdf | 14 |
Precision Linear Actuators for the Spherical Primary Optical Telescope Demonstration Mirror Jason Budinoff* and David Pfenning* Abstract The Spherical Primary Optical Telescope (SPOT) is an ongoing research effort at Goddard Space Flight Center developing wavefront sensing and control architectures for future spac... | Document | AMS_2006.pdf | 15 |
mirror, a direct measurement of its surface wavefront error is possible. Taking various defocused images at the center of curvature and using an iterative transform solver, the phase error of the reflected wavefront can be determined3. From the phase error tip, tilt, defocus, and other Zernike terms (currently trunc... | Document | AMS_2006.pdf | 16 |
Table 1. Pyrexm Mirror Segment Requirements Tipmilt Range Tipmilt Resolution Tipmilt update rate Position Hold Actuator Thermal Stability Static Load Mirror Requirement I Value I Units I Note Size I 0876 I mm (inch) 1 Point-to-point hex f 2.0 degree 0.05 arcsecond As allowed by focus resolution 1 HZ 0 Amp Po... | Document | AMS_2006.pdf | 17 |
Kinematics of the Seqment Assemblv & Grubler’s Mobilitv Criterion The mirror requires only tip tilt and piston adjustment, 3 degrees of freedom. A hexapod would provide 6 degrees of freedom; but we don’t need 6. Therefore, a tripod was selected to provide the rigid body motions required. The end joints of each strut... | Document | AMS_2006.pdf | 18 |
Figure 4. The SPOT linear actuator, shown with a six-inch ruler for scale. Figure 5. An exploded view of the SPOT linear actuator Stetmer Motor/Harmonic Drive Gearhead The HD14 1OO:l harmonic Drive gearhead Phytron 500 step per revolution or 0.72 degree step size 3-phase stepper motor, 2.5 Amp winding Agilent HED... | Document | AMS_2006.pdf | 19 |
Figure 6. The Phytron ZSS 52 / HD14 actuator Differential Satellite Roller Screw Several options exist for rotary-to-linear motion: lead screw, ball screw, or roller screw. Generally the most precise of these is the satellite roller screw. A differential roller screw was selected. After several months of vendor int... | Document | AMS_2006.pdf | 20 |
The minimum effective lead, Lff, was found to be 0.02 mm per revolution, or -21 microns per revolution. A bind condition determines the total stroke, which for this differential roller screw is -6 mm. Rollvis Swiss S.A., a Swiss manufacturer of precision roller screws, fabricated the roller screw as Model RV160/19,0... | Document | AMS_2006.pdf | 21 |
Figure 9. Helical Coupling Bearinas Barden 1 O6HCDUL back to back duDlex oair. ABEC-9. SAE52100 steel 30-mm bore diameter, 15-degree contaci angle, 14 7.1 4-mm (9/32") diameter 440C balls, 36-kg (80-lb) heavy preload Static load capacity 1005 kg (221 6 Ib) Machined p ca Winsorlube oil Figure 10. Barden 106HC Du... | Document | AMS_2006.pdf | 22 |
Where K = torsional spring rate r = radius of notch cut b =thickness of flexure section t = width of notch E = Modulus For the SPOT tripod, each leg consists of 2 links and 3 joints. Ground is considered a rigid link, and the mirror is the “end effector” or output link. Conclusion Further testing to fully chara... | Document | AMS_2006.pdf | 23 |
The CRlSM Motor/Encoder Assembly and Diaphragm Bearing Assembly Design Jeffrey Lees" and Ed Schaefe; Abstract This paper will describe the thin section angular contact bearings and WS2 dry film lubrication used on the compact Reconnaissance Imaging Spectrometer for Mars (CRISM) motor/encoder and diaphragm bearing ... | Document | AMS_2006.pdf | 25 |
CRISM Thermal Design The CRlSM thermal design provides both active cooling of the IR focal plane to cryogenic temperatures to reduce dark current and passive cooling of the spectrometer housing to -80°C for low background. Simultaneously it keeps the electronics section near -40°C (Fig. 2). Cryogenic cooling is prov... | Document | AMS_2006.pdf | 26 |
CRISM Bearing System The CRlSM instrument rotates the OSU do" from nadir. The OSU weighs 20.9 kg (45.9 Ibf) and is supported by the motor/encoder (Figure 3) and the diaphragm (Figure 4) bearing assemblies. The motor- encoder side used a thin-section angular-contact duplex pair mounted back to back and was designed t... | Document | AMS_2006.pdf | 27 |
Parallel Corrugated Diaphragms m I s 7 1 I k- Bearings Flex link L Interface r /- Titanium Housing Figure 4. CRISM Diaphragm Bearing Assembly Anti-Sunward Radiator The CRlSM duplex bearing pairs were separated by titanium spacers so that the preload offset would remain constant over temperature. However, th... | Document | AMS_2006.pdf | 28 |
Encoder Disk- Interface Bearing - Bearing 7 Spacer Bearin - 0.80 0.70 h C ~ 0.60 0 9 .- v $ 0.50 C (d 5 0.40 !!! - (d 2 0.30 E C - 0.20 0.10 Bearing - Retainer Figure 5. CRlSM motodencoder spindle - - L - Clearance at LMC I I l~l~l~l~l~l~l~l~l -200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0 20... | Document | AMS_2006.pdf | 29 |
CRlSM Bearing Lubrication The thermal analysis of the CRlSM motor/encoder and diaphragm bearing assemblies indicated that they would operate at -40°C and -90°C respectively. The analysis indicated that the diaphragm bearing assembly would be too cold for oil or grease lubrication. Our tests showed that -40°C was bey... | Document | AMS_2006.pdf | 30 |
CRISM Bearing Tests Identical sets of sputtered MoS2-coated and WS,-coated thin-section Teflon-toroid angular contact duplex-pair bearings were purchased simultaneously (Figure 7). Prior to running the tests, an initial set of pictures using a scanning electron microscope were taken of both types of bearings (Figure... | Document | AMS_2006.pdf | 31 |
rigure iua. w& boaring Figure IUD. ~os~~oaring Following the test of the WS2-coated bearings in which 57952 cycles were completed, we were concerned that the bearings seemed much rougher than they were prior to the test. After a visual inspection of the bearings, a significant amount of debris in the bearings was fo... | Document | AMS_2006.pdf | 32 |
bearings. Although this may be an advantage for continuously rotating higher speed mechanisms acting as an additional lubricant Figure 11. Post life test bearing Figure 12. Post life test bearing raceway Figure 13. Post life test b6amlllY mabcway CRISM Bearing Anomalies Bearina Ball Spacing The APL Space Departme... | Document | AMS_2006.pdf | 33 |
torque spikes. Grease and oil lubricated bearings may exhibit the same problems as the CRISM dry film lubricated bearings to a far less noticeable degree due to the grease or oil between the ball and toroid. The evidence for this conclusion with the CRlSM bearings is two fold: 1. The significant amount of Teflon con... | Document | AMS_2006.pdf | 34 |
L Figure 15. Toroids in “down” position Unfortunately, we never photodocumented this effect, thus, it was extremely difficult to find pictures of the flight hardware demonstrating this effect clearly. Figure 15 clearly shows all the toroids uniformly aligned in the “down” position. Figure 16 shows most of the toroid... | Document | AMS_2006.pdf | 35 |
A Figure 17. CRISM riignr uearings I I.: .. I .. ,C , . ' , -,. c I. ; riyure IO. Deuririya stuFncu uriu uiiy~icu s- a 22 | Document | AMS_2006.pdf | 36 |
Appendix 1 Date Operation 12/04/2003 Initial torque measurements Table 2 lists the operations and measurements made to the flight motor/encoder bearing assembly. Most measurements were an average running torque. Some measurements were a peak torque when there was a significant torque spike to the running torque. On... | Document | AMS_2006.pdf | 37 |
Acknowledgements This work was performed at Johns Hopkins University Applied Physics Laboratory under a contract with the National Aeronautics and Space Administration. The authors would like to thank all those who helped design, fabricate, integrate and test the CRISM instrument. Reference herein to any specific co... | Document | AMS_2006.pdf | 38 |
Gear Teeth Particles and Bearing Failures William H. Greenwood* and Jeffrey G. Dabling* Abstract Torque is transmitted from rotary solenoids to rotate drive arms that advance a ratchet wheel as part of a safety mechanism in missile warheads. The small volume constraint led to single gear teeth to transmit the torq... | Document | AMS_2006.pdf | 39 |
A new generation of safety mechanisms is nearing production. The safety mechanism of Figure 1 is among the new generation and transmits torque from the rotary solenoid to the drive arms by way of gears. Due to the limited stroke of the solenoid and the volume constraint, the gears are actually single gear teeth cut ... | Document | AMS_2006.pdf | 40 |
Table 1. Ratchet wheel rotations to failure, MoS2 on gears, no MoS2 on bearings Powder at gear teeth Initial investigation The energized stroke of the solenoid is on the order of five milliseconds and the spring (de-energized) return of the drive arms is also on the order of five milliseconds. The initial investiga... | Document | AMS_2006.pdf | 41 |
al Figure 3. Gear tooth wear zone has a powdered layer. The solenoids from failed units were rotated manually and some roughness in rotation was noted. However, a quasi-static torque test of the solenoid at 16 and 22 volts showed nearly the same torque as measured before the installation into the ratchet wheel asse... | Document | AMS_2006.pdf | 42 |
,A ri F- A PA Figure 4. Solenoid ball bearings before (left) and after (right) life cycle test. When ball bearings fail from high loads, the initial signs are many small pits as bearing material spalls, then the ejecta from the pits are rolled into the bearing surfaces that cause more localized high loads and acce... | Document | AMS_2006.pdf | 43 |
Table 2. Ratchet wheel rotations to failure, no MoS2 on gears, no MoS2 on bearings CP008 CP009 12 Feb 2003 180 Rough manual rotation 14 Feb 2003 260 Rough manual rotation Several units with the wear resistant outboard gear were tested with the same disappointing result: the units failed to operate after a few ratc... | Document | AMS_2006.pdf | 44 |
Table 3. Ratchet wheel rotations to failure, Nitronic 60 gear, no MoS2 on gear or bearings Date Wheel cycles p CP011 20 Feb 2003 72 Bearings 3 and 4 bad, bearings 1 and 2 fair CP037 20 Feb 2003 280 Bearings 3 and 4 bad, bearings 1 and 2 fair CP034 21 Feb2003 220 Bearing 3 very bad CP045 CP054 CP021 Outboard roto... | Document | AMS_2006.pdf | 45 |
A Temporary Solution - Bearing Shields As our early efforts to decrease particle generation at the gear teeth were unsuccessful (Tables 2-4), we looked for a quick solution; so that environmental and flight tests could continue. A shielded bearing was suggested as a way to prevent the gear teeth particles from enter... | Document | AMS_2006.pdf | 46 |
Table 5. Wheel rotations to failure, plastic shields over bearings, no MoS2 on gears or bearings -- -- unit # Date Wheel cycles -- CP046 03 Mar 2003 524 Failed, bearing 1,3,4 - bad, bearing 2 - good CPO14 03 Mar 2003 520+ No failure, bearing 1 - bad, 2 - fair, 3, 4 - good CP020 04 Mar 2003 820+ No failure, bearing ... | Document | AMS_2006.pdf | 47 |
Why so many gear teeth particles? The tribological investigation continued to evaluate material pairs or lubrication that would decrease the gear particles. Some standard pin on disk tests at a high contact stress showed long life of the MoS2 lubricant and little particle generation. This caused us to calculate the ... | Document | AMS_2006.pdf | 48 |
acceptance. Changing the solenoid design from a single shaft to two solenoids side by side was considered, but rejected as too drastic a change. The change selected was to use ball bearings as followers between the solenoid and drive arms. The space was limited but the small 1.0-mm by 3.2-mm ball bearing could be ma... | Document | AMS_2006.pdf | 49 |
References 1. D.W. Plummer and W.H. Greenwood (1993). A Primer on Unique Signal Stronglinks, SAND93-0951, Sandia National Laboratories, Albuquerque, NM. 2. J.E. Shigley and C.R. Mischke (1 989). Mechanical Engineering Design, 5'h edition, McGraw-Hill, New York City, NY. 36 | Document | AMS_2006.pdf | 50 |
Failure of Harmonic Gears During Verification of a Two-Axis Gimbal for the Mars Reconnaissance Orbiter Spacecraft Michael R. Johnson', Russ Gehling**and Ray Head** Abstract The Mars Reconnaissance Orbiter (MRO) spacecraft has three two-axis gimbal assemblies that support and move the High Gain Antenna and two sola... | Document | AMS_2006.pdf | 51 |
Radiometer MCS (Mars Climate Sounder) This atmospheric profiler will detect vertical variations of temperature, dust, and water vapor concentrations in the Martian atmosphere. Radar SHARAD (Shallow Radar) This sounding radar will probe beneath the Martian surface to see if water ice is present at depths greater ... | Document | AMS_2006.pdf | 52 |
continuously articulated so the wings remain sun pointed and the High Gain Antenna maintains a lock on Earth. This continuous motion must be performed while the spacecraft maintains precise pointing for high resolution imaging and high-speed data transmission to Earth (see Figure 1 for a mapping configuration). Beca... | Document | AMS_2006.pdf | 53 |
The need for the harmonic gear to take the external loads led to the selection of the size of the harmonic gear in concert with the required output stiffness. The available volume and mass allocation for the actuators was minimal on the MRO spacecraft, requiring use of the smallest gears possible to achieve the requ... | Document | AMS_2006.pdf | 54 |
of the actuator components, Penzane 2001-3PbNp Oil was utilized in the motor bearings and Rheolube 2004 grease was chosen for the lubricant throughout the harmonic gear. Other flight applications with the same material combinations for the harmonic gear components had also used Braycote@ because of a much lower oper... | Document | AMS_2006.pdf | 55 |
Figure 6. Engineering Development Unit Configuration in Vacuum Chamber Flexsp I i n e Table 2. Materials and Surface Finishes of Heritage Hardware from Previous Programs with Similar Stiffness and Life requirements as the MRO Applications Lubricant Program (Harmonic Drive Size) MRO (size 32) 15-5 PH H1150 Meloni... | Document | AMS_2006.pdf | 56 |
The EDU actuator operated up to 6.1 million input revolutions, when the output telemetry indicated the actuator was not following the input signals properly. Later analysis revealed there were indications of improper operation as early as 4 million input revolutions that were not diagnosed due to limitations in the ... | Document | AMS_2006.pdf | 57 |
Once the dramatic failure of the harmonic gear assembly was seen, a detailed review of the manufacturer’s documents uncovered that there were some problems with the Melonite coating on the group of flexsplines that included the life unit, labeled Lot B. Two additional Melonite processing groups of flexsplines had be... | Document | AMS_2006.pdf | 58 |
Since the lubricant type made absolutely no difference in the life capability of the harmonic drive gear teeth, it was clear the problem was related directly to the material combination of the components and their internal stress level. The appearance of the failure surfaces gave the impression of a possible galling ... | Document | AMS_2006.pdf | 59 |
The test units for LM Harmonic Assemblies #3, #4, and #5 were tested in the harmonic drive test fixture, in the environment, with the applied load and input speed listed in Table 4. The stiffness of the units was measured at the start of the testing as shown in column 2 of Table 4. The life tests already discussed ar... | Document | AMS_2006.pdf | 60 |
LM Harmonic Assemblies #1 and #2, with failure at a similar number of revolutions using very different lubricants, indicated the lubricant was not a significant player in the failure mechanism. This eliminated the lubricant as a variable in further failure investigation. The LM Harmonic Assembly #3, with nodular iro... | Document | AMS_2006.pdf | 61 |
Harmonic Gear Assemblv Internal Preload Settinq The cup type harmonic gear assembly has zero backlash due to the angle of approach, along the rotation axis, of the flexspline teeth relative to the circular spline teeth (Figure 14). This arrangement leads to a two-sloped stiffness curve of the output of a harmonic ge... | Document | AMS_2006.pdf | 62 |
Measured Initial Harmonic Drive Stiffness Rotation Angle Figure 15. Typical Harmonic Gear Assembly Stiffness Note two regions of stiffness: low near zero torque and larger at high torques. The following figures are from measured data on the fliaht harmonic aear assemblies: (Note: the following figures' axes are ro... | Document | AMS_2006.pdf | 63 |
ji Applied Torque Applied Torque Figure 18. Next Larger Plug Size Over Figure 17 Figure 19. Next Larger Plug Size Showing Showing a Small Change in Shape Showing Little Change Conclusions and Lessons Learned The most significant result of the failure investigation was determining that the internal stresses due to ... | Document | AMS_2006.pdf | 64 |
Stacer Driven Deployment: The Stereo Impact Boom Robert Ullrich’, Jeremy McCauley*, Paul Turin*, Ken McKee* and Bill Donokowski* Abstract The Impact’ Booms carry 3 scientific instruments each on the twin NASA Stereo2 satellites. When stowed for launch the boom is 1.54 m in length, when deployed the boom extends to ... | Document | AMS_2006.pdf | 65 |
The Science Flowdown Requirements The requirements for the Impact boom were based on the scientific needs of the three instruments mounted to it: the Mag (built at Goddard Space Flight Center); the SWEA, supplied by CESR, Toulouse, FR; and the STE-D, supplied by UCB - SSL. The magnetometer for this mission is very s... | Document | AMS_2006.pdf | 66 |
e Figure 4. Solid Model Section View of Stowed Impact Boom Impact Boom Mechanism The Impact Boom consists of five concentric Gr/E Tubes, ranging from 50 mm to 210 mm in diameter, with a pair of aluminum rings bonded to each end. Each ring pair contains three lock pins, pointing outward at the Sun-ward end, and inw... | Document | AMS_2006.pdf | 67 |
At both ends of each tube there are inner and outer interlocking aluminum rings that ‘sandwich’, and are bonded to, the Gr/E. After an extensive search, Loctite Hysol 9309NA was used to form the bond. The thermal environment for the boom is rather severe: it will be in the shadow of the spacecraft for all of the sci... | Document | AMS_2006.pdf | 68 |
Lock Din details Once the rings are bonded to the tubes, the locking pins / rollers are installed into precision radial bores in these inner and outer rings. When the segment locks, the pins are pushed into the sockets by custom wound torsion springs, two for each pin. The ‘arms’ of the springs also provide alignme... | Document | AMS_2006.pdf | 69 |
P % the Stacer via a woven Dacron (parachute shock) cord. Similar to the device found on (old) dial telephones that prevented the dial from being rotated faster than an old telephone exchange could count, the flyweight brake supplies braking force proportional to the rotational speed of its weight assembly. If the f... | Document | AMS_2006.pdf | 70 |
At deployment, the formation of the Stacer starts with the initial coil winding out of the storage canister onto a cylindrical tip piece, which is slightly larger than the free coil diameter of the Stacer. Thus the Stacer grabs the tip piece tightly, and the subsequent coils ‘stack’ up on the prior, producing the ch... | Document | AMS_2006.pdf | 71 |
For the purposes of torque (force) margin analysis, the initial push is 45 N, final thrust 18 N (the lowest value obtained). This lower value was used to bound the design force available for deployment. The Torque (force) Ratio (tR) requirement from GEVS SE (Sec. 2.4.5.3) is: t~ = tavaill trequird 2 3-0 and the Tor... | Document | AMS_2006.pdf | 72 |
relative to each other, and carrying the vibration loads. These also incorporate ‘kick’ springs to aid in their deployment, and to alleviate any possible “stiction” from the alignment blocks. The boom is not retractable once deployed. Re-stowing is achieved by removal from the spacecraft, and hand retraction of each... | Document | AMS_2006.pdf | 73 |
When testing deployables, the desire is to prove beyond question that the mechanism will deploy in space, however, it must be tested here on the ground first. How many times? GEVS provides a minimum, and each program defines how many additional operations. This brings up wear margin: the design must show that it is ... | Document | AMS_2006.pdf | 74 |
I Impact Magnetometer Alignment 0.090 0.085 0.040 0.045 0.050 0.055 0.060 0.065 0.070 0.075 -1 Average Deviation in the X-Y Plane (degrees) Circle Diameter = Std. Deviation Figure 17. Magnetometer Alignment Error For the final determination of pointing error, the root of the sum of the squares was calculated to ... | Document | AMS_2006.pdf | 75 |
point for spring loaded deployables: don’t rely on a single safety path. A lock down plate in front of the stacer assembly would have caught the stacer, preventing damage. These recommendations have been implemented in the procedures, and stowing fixture used now: the stowing procedure has a minimum requirement of t... | Document | AMS_2006.pdf | 76 |
I .- Figure 18. Stereo “B” Spacecraft: Impact Boom location References Space System Reliability and Safety Office, Code 302; “General Environmental Verification Specification for STS and ELV, Rev A; (June 1996), National Aeronautics and Space Administration, Goddard Space Flight Center, Greenbelt, MD 20771; June, ... | Document | AMS_2006.pdf | 77 |
4260 [I 67.72-1 (Deployment Travel) r SWEA Deployed Position m ‘i 2 r ” r SWEA Stowed Position +X ___) - 1267.4 [49.907 (from Boom 4299.5 Origin [I to 69.272 Magnetometer) ------I - 5803.1 1228.477 (Overoll incl Blankets at each end) -1 DETAIL B Boom Origin (Bottom of Insulator Pad) Figure 20. Impact Boom ICD... | Document | AMS_2006.pdf | 78 |
Heritage Adoption Lessons Learned: Cover Deployment and Latch Mechanism James W incentsen. Abstract Within JPL, there is a technology thrust need to develop a larger Cover Deployment and Latch Mechanism (CDLM) for future missions. The approach taken was to adopt and scale the CDLM design as used on the Galaxy Evol... | Document | AMS_2006.pdf | 79 |
cools, a Push Piston return spring resets the actuator for further ground testing. Resetting of the cover and Latch Arm is manually performed. Latch Mechanism Cover 7 Hinge Mechanism 7 Energy Absorber Mechanisms Energy Absorber Structure Figure 1. Cover Deployment L and Latch Cover Ring Magnets Instrument... | Document | AMS_2006.pdf | 80 |
Figure 3. Latch Arm assembly, rotated Push Piston and actuator return spring ot in Locking Piston Torsion Arms Figure 4. Latch mechanism cross section 6- Hinge Mechanism Figure 5. Hinge Mechanism 67 | Document | AMS_2006.pdf | 81 |
Hinge Mechanism The Hinge mechanism works by means of two sets of nested compression springs acting against a lead screw / carrier nut combination. A clever and complex design, the Hinge is fully single fault tolerant. For some failure modes, such as the loss of a spring, the Hinge is two-fault tolerant. A graphic o... | Document | AMS_2006.pdf | 82 |
Push Rod can be removed from the plunger subassembly without stressing or twisting the sensor leads. The mechanism is reset by first removing the striker and Front Cap and then the Plunger subassembly is removed from the housing and the core replaced. During prototype cover deployment tests, several types of honeyco... | Document | AMS_2006.pdf | 83 |
Figure 9. Three-cell core, 50.8-mm (2411) long I Figure 10. Three-cell core, 88.9-mm (3 70 | Document | AMS_2006.pdf | 84 |
Peak Lead crush load bsd eMnat.d by precnuhing Bottomed * I I I I I I I I 1 out 8 mn. Area under curve I energy absorbed Deflection Figure 11. Hexcel Honeycomb crush strength curve’ 318-5052-,0007, 3 Cell, 3.5in Samples Displacement vs Force Sample -1 -5 Displacement [in] Figure 12. Force / Displac... | Document | AMS_2006.pdf | 85 |
Heritage Adoption Lessons Learned Sufficient review of a heritage design is necessary before adoption as heritage designs may impose unnecessary limitations, constraints, or failure modes on interacting mechanisms or systems. Additionally, a flight readiness review of a heritage design is necessary, as it can not be... | Document | AMS_2006.pdf | 86 |
honeycomb design and reducing the torque output and energy absorption. The overall design would have been much simpler, reducing drawing, fabrication, and installation costs and schedule with the removal of the Energy Absorber structure and simplification of the Hinge mechanism. Additionally, the crushable honeycomb... | Document | AMS_2006.pdf | 87 |
Conclusion Heritage designs offer projects an attractive means of reducing cost and schedule. However, without a through review and investigation of the state of readiness, a heritage design may impose unnecessary limitations and restrictions, in addition to cost and schedule impacts. It is recommended that trade st... | Document | AMS_2006.pdf | 88 |
Problems and Product Improvements in a Qualified, Flight Heritage Product Chuck Lazansky’ and Scott Christiansen* Abstract This paper will discuss improvements to an existing, qualified, flight heritage launch restraint and release mechanism. The changes made to the design are the result of customer feedback, test ... | Document | AMS_2006.pdf | 89 |
The outer race is prevented from turning by two latch pawls (called “toggles”) that engage the OD of the race. The latch-release paH of the mechanism consists of a lever-arm which reacts the radial load from the toggles, and retains them in the outer race (Figure 2). Nominally, the lever arm is held against a stop f... | Document | AMS_2006.pdf | 90 |
History of Product The product was developed and fully qualified in 1999 with two test units. The initial production run of 4 units was delivered, and successfully flown, with the FalconSatl program. Following the initial run, roughly six production runs were completed for various programs, totaling roughly 50 units... | Document | AMS_2006.pdf | 91 |
showed relatively low inertial forces on the lever, which could not overcome the lever retention spring and drive the lever in the direction of release. Tests were developed to assess latch performance. The lever retention spring force was measured, and also the net force required to release the lever arm from the t... | Document | AMS_2006.pdf | 92 |
intermittent vibration behavior and the variability in release force measurements. If the toggle is on the “flat” area of the lever, a tangential driving force results and leads to release of the device. If a toggle is located on the curved surface of the lever, no driving force is present and no release occurs (Figu... | Document | AMS_2006.pdf | 93 |
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