spacecraft structures
DESCRIPTION
Spacecraft Structures. Heather Reed Mechanical Engineering Manager Laboratory for Atmospheric and Space Structures [email protected]. What is a structure?. Why does a spacecraft need a structure? PRIMARY or Secondary?. Lifecycle of a Structure. REQUIREMENTS (NEEDS). DESIGN. - PowerPoint PPT PresentationTRANSCRIPT
Spacecraft Structures
Heather ReedMechanical Engineering Manager
Laboratory for Atmospheric and Space Structures
What is a structure?
Why does a spacecraft need a structure?
PRIMARY or Secondary?
3 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
Lifecycle of a Structure
REQUIREMENTS(NEEDS)
DESIGN
ANALYSIS
BUILD
TEST
INTEGRATION
STUDENT NITRIC OXIDE EXPLORER (SNOE)
4 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
REQUIREMENTS
• What does this spacecraft structure need to do?
• Accessibility• Lift points
– Vibe– Acoustic– Shock
» Thermal» Radiation
ROCKET LAUNCH
GROUNDTESTING
ON-ORBITCONDITIO
NS
5 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
DESIGN – What shape will it be?
• SNOE was a “spinner”
6 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
DESIGN – What will it be made out of?
• Materials selection– Stiffness vs. Strength
• Car suspension – STRONG CAR, weak connection to the road– WEIGHT CHEAPEST RIDE TO SPACE = $35,000 per lb– Cleanliness
• Specific plastics only• Materials that can be scrubbed
• Aluminum is a great material
7 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
DESIGN – How will it be built?
• Manufacturability– Strongest structure is all one piece– How easy is it to assemble?
– Primary structure $$ < 1% of SNOE mission budget ($8M)
8 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
SPACECRAFT
ROCKETNOSECONE
ROCKET SECONDARYSTAGE
DESIGN – Will it fit?
• Solid Modeling– Static or Dynamic
9 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
Solid Modeling - SolidWorks
10 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
ANALYSIS - Modal Simulation Results
Mode 2 – 821 Hz – Mode shape plotRocking in the Y-direction
Mode 6 – 1270 Hz – Mode shape plotRocking in the X-direction
• 821 Hz: First predicted high mass participation mode.
• 741 Hz: Lowest frequency mode is a local connector bracket mode.
• Z-axis has very little mass participation below 2000 Hz.
• Two principal mode shapes shown below:
11 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
BUILDING IT – Your best laid plans
• Fabrication – Do 2 planes meet perfectly?
• Assembly – How clean is clean?
12 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
Why TEST?
• Vibration Testing• Thermal Vacuum Testing• Acoustic Testing• Shock Testing• Strength Testing• Spin Balance• Mass properties
NASA Goddard Gold Rules: • TEST AS YOU FLY, FLY AS YOU TEST
13 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
TESTING – Vibration Testing
• Mass model testing – Good practice• Test sensors - Accelerometers
LARGE SPEAKER “VIBE TABLE”
AT BALL AEROSPACE
SNOE SPACECRAFT
14 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
Vibration Test Specification
15 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
TESTING – Thermal Vacuum
• Less cooling without air – Electronics• Thermal expansion – Causing binding• More friction without air – Moving parts• HOT/COLD Operational and Survival limits
SNOE SPACECRAFT
LARGE TANK “RAMBO” AT BALL
AEROSPACE
16 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
INTEGRATION to the Pegasus
17 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
Secondary Structure – Solar Arrays
18 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
Heather Reed, CU Mechanical Eng 97’
• Work during Undergrad studies, BS ME in 1995– Space Grant College– NIST, NDE lab– CU football & basketball security– Hart Ranch snack shop
• Work during Grad studies on SNOE, MS ME in 1997– FEA, Solar panel substrate, Nutation damper, Torque rods,
Thermal blankets
• Employed at LASP after graduation• ME Manager in 2001, 8 ME’s then, 23 ME’s now• Current program is MAVEN, mission to MARS• Starting Program Management this week
EUV on MAVEN going to Mars
Langmuir Probe and Waves (LPW) – LASP / SSLLPW/Extreme Ultra-Violet (LPW-EUV) – LASP
LPW-EUV
20 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
Testing
• Engineering Unit testing – Mechanism Life Testing – Vibe, Life Test cycling– Luxel filter qualification – Vibe, thermal cycles– Light leak testing– Torque margins– Spring force – Magnetic field
• Flight Unit testing– Vibe test
• Random Vibe, response limit• Strength verification = ?
– Mechanism Run-in• Torque margins• Spring force
– Light leak testing
21 Nov 8th, 2011 Spacecraft Structures Heather Reed, ME Manager
Aperture Mechanism Life Test Plan
-40
-20
0
20
40
60
Tem
p (d
egC)
30V
22V30V36V
22V30V36V
22V30V36V
30V
200 Cycles
4280 Cycles
-5°C
-35°C
35°C
50°C