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THEMIS Instrument CDR 1 UCB, March 24-25, 2004 EFI AXIAL BOOMS (“AXB”) Critical Design Review Rob Duck Mechanical Engineering Department Space Sciences.

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Presentation on theme: "THEMIS Instrument CDR 1 UCB, March 24-25, 2004 EFI AXIAL BOOMS (“AXB”) Critical Design Review Rob Duck Mechanical Engineering Department Space Sciences."— Presentation transcript:

1 THEMIS Instrument CDR 1 UCB, March 24-25, 2004 EFI AXIAL BOOMS (“AXB”) Critical Design Review Rob Duck Mechanical Engineering Department Space Sciences Laboratory University of California - Berkeley

2 THEMIS Instrument CDR 2 UCB, March 24-25, 2004 AXB – Overview THEMIS Axial Boom AXB – Design AXB – Double Deploy Assist Device AXB – Door Release Mechanism AXB – Frangibolt Actuator AXB – Sensor AXB – Open Design Issues AXB – Electrical Wiring Diagram AXB – Deployment Testing AXB – Thermal Vacuum Testing AXB – Mechanical Vibration Testing AXB – Fabrication AXB – Test

3 THEMIS Instrument CDR 3 UCB, March 24-25, 2004 AXB Design Review AXB located along center of THEMIS probe Two individual booms housed in a single tube Electrical Connection pin connectors (1 per boom) pin flight enable pin on top deck Mass Properties 4 Kg mass limit for the full boom AXB – Design Lower Deck Mount Composite Tube Safety Cover Axial Boom Upper AXB Lower AXB Housing1.32 lbs0.597 kg Upper Boom3.69 lbs1.674 kg Lower Boom3.69 lbs1.674 kg Total8.70 lbs3.945 kg THEMIS ProbeBoom Connectors Flight Enable Connector Stowed Axial Boom Upper Deck Mount

4 THEMIS Instrument CDR 4 UCB, March 24-25, 2004 Individual Boom Components Bobbin Actuator Cable Double Deploy Assist Device (“DDAD”) Door Release Mechanism Main Stacer Preamp Sensor Stacer Axial Boom Deployed Properties Tip to tip distance – 302” (7.67m) Upper main stacer stroke – 91.5” (2.32m) Lower main stacer stroke – 99” (2.51m) Sensor stroke – 40” (1.02m) AXB – Design Sensor Double Deploy Assist Device Bobbin (Cable & Actuator Inside) Preamp Main Stacer (Inside Can) Door Release Mechanism Items in blue italics are ETU focus areas

5 THEMIS Instrument CDR 5 UCB, March 24-25, 2004 Purpose Initiate stacer deployment Provide double cantilever support once deployed Occupy minimal volume while stowed Design Spring actuation extends supports Rocker guides provide stacer support Theory of Operation DDAD spring actuation –Stacer tip piece is released –Spring within rods pull stacer from can –Stacer supports extend and lock into place Rocker guides –Stacer pushes roller, rotates arm, & separates plates –Spring pulls plates together, maintains rocker force AXB – Double Deploy Assist Device Spring Roller Rocker Arm StacerTop Plate Bottom Plate Rocker Guide DDAD (Deployed) Rocker Guide (Section View)

6 THEMIS Instrument CDR 6 UCB, March 24-25, 2004 AXB – Door Release Mechanism Purpose Hold sensor and DDAD in stowed configuration Provide simultaneous stacer deployment from one actuation event Design Lower doors keep DDAD stowed Stacer tip piece holds lower doors closed Upper doors keep sensor stowed DDAD posts hold upper doors closed Stowed DDAD keeps posts on upper doors Theory of Operation Stacer tip piece is released DDAD deployment starts & pulls stacer DDAD separation occurs Upper doors separate from posts Upper doors open and sensor deploys Stacer tip piece separates from DDAD Lower doors open and stacer deploys Doors remain open, no tube interference Door Release Mechanism (Stowed) Door Release Mechanism (Deployed)

7 THEMIS Instrument CDR 7 UCB, March 24-25, 2004 Frangibolt Actuator Developed by Naval Research Labs and NASA Shape Memory Alloy cylinder elongates to fracture a bolt element Reusable Primary and secondary (redundant) heaters Flight Qualified in 1994 aboard Clementine Maximum Load: 500 lbs Operating Voltage: Vdc Frangibolt Actuation Fastener Material: Titanium Notched groove localizes break location Size #8 Fastener Required Break Force > 1050 lbs Design Margins At 100G, Actuator sees 250 lbs Actuator FOS: 2.0 Fastener FOS: 4.2 AXB – Frangibolt Actuator Frangibolt Actuator Actuation Fastener

8 THEMIS Instrument CDR 8 UCB, March 24-25, 2004 Testing Actuator Fastener –10% of lot is tested, tensile pull test –Min. Fracture = 1050 lbs, 100% pass Method of Operation SMA cylinder is compressed Fastener is assembled Current is applied & heats actuator SMA cylinder elongates Fastener breaks AXB – Frangibolt Actuator

9 THEMIS Instrument CDR 9 UCB, March 24-25, 2004 AXB – Sensor Sensor Stacer Smallest stacer ever designed Thickness ”, width – 1.00” Forms with less taper than traditional stacers DAG 213 coating Difficulties Bending or arching once deployed (see picture) Clips didn’t close well Handling – easy to tear Solutions Bending –Chord length matches free length of stacer –Chord termination close to stacer edge Clip closure –Use eyelets instead of rivets –Spacer between can wall and clip allows closure –Clip shape modified to avoid rivet contact Handling –Stowing only by qualified person, myself Straight DeployArched Deploy

10 THEMIS Instrument CDR 10 UCB, March 24-25, 2004 Sensor Test Circuit Once deployed circuit is floating Solution – add 50 Mohm resistor to chassis ground Exposed Insulators Too much exposed area on the sensor test circuit Solution – Design to contain insulators in cavities Boom Isolation from Tube Reduce boom temperatures Requires specific chassis ground line Sensor Can Height Smaller can height reduces can tilting effect AXB – Open Design Issues

11 THEMIS Instrument CDR 11 UCB, March 24-25, 2004 AXB – Electrical Wiring Diagram

12 THEMIS Instrument CDR 12 UCB, March 24-25, 2004 Sensor Deployment Total deploys: 7 Repeatability Test –Chord length: 40 1/8 inches AXB – Deployment Testing Boom Deployment Total deploys: 4 Stiffness: 1.65 Hz Repeatability –Requires horizontal deploy track –Week of May 17 DeployLength 140 1/4” 241 1/4” 341 1/4” Sensor is fully deployed before main stacer reaches full deploy length

13 THEMIS Instrument CDR 13 UCB, March 24-25, 2004 AXB – Thermal Vacuum Testing ETU Testing Designed to test actuator and mechanical integrity of boom Mass dummy used for preamp, no electronics Ramp and soak profile Vertical deployment in HiBay Vertical Chamber FLT Testing Horizontal deployment “THEMIS Snout” chamber –Delivery – June 29th –Horizontal Track – May 17 TestSetSoakActual TemperatureDeployDeploy Height PointTimeStacer CanActuatorTime(110” design) Room23 C 24 hrs23 C 23 sec107” Hot60 C10 hrs59 C 10 sec107” Cold-45 C2 hrs-48 C-60 C45 sec103” HiBay Thermal Vacuum Chamber Deployed Boom in Vacuum Chamber

14 THEMIS Instrument CDR 14 UCB, March 24-25, 2004 AXB – Mech. Vibration Test Mechanical Vibration ETU Test Date – 9:00 AM, Friday, April 23th Quanta Labs, Santa Clara, CA Single Boom Sine & Random Vibration – 3 axis, Limits TBD by Swales

15 THEMIS Instrument CDR 15 UCB, March 24-25, 2004 AXB – Fabrication Flight Deliverables Stacers – In house, require preparation Sensors – Week of May 3 Frangibolt Actuators – In house Mechanical Parts – Week of June 14 Fasteners – In house Composite Tube/Flange – Week of May 31 Stacer Preparation Trim, paint, & rivet Procedure complete Part Cleaning Written procedure complete Assembly & Fabrication Fabrication procedures - Week of June 7 Flight assembly begins week of June 14 Stowing the Boom Written procedure – Week of June 7

16 THEMIS Instrument CDR 16 UCB, March 24-25, 2004 AXB – Testing ETU Testing Complete week of May 17 Tests remaining –Mechanical Vibration –Boom Length Repeatability –Boom Run Out Measurement Flight Testing Total boom deployments: 4 Test Sequence –Actuator Deployment –Boom Deployment - Vertical –Run out measurement –Natural frequency measurement –Mechanical Vibration –Boom Deployment - Horizontal –Length measurement –Thermal Vacuum Hot Cycle (2 Cycles, soak & deploy Hot) –Boom Deployment in Chamber –Thermal Vacuum Cold Cycle (2 Cycles, soak & deploy cold) –Boom Deployment in Chamber

17 THEMIS Instrument CDR 17 UCB, March 24-25, 2004 AXB – Testing


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