FLIGHT HARDWARE
FAMILIARIZATION
University Nanosat
Outline for Satellite Fabrication
Familiarization Course
Day 1
ESD Familiarization
Contamination and Cleanliness Slides
Basic hardware handling practices
Mechanical fabrication and integration
Electrical fabrication and integration
Outline for Satellite Fabrication
Familiarization Course
Day 2
Soldering basics
Cable and Harnessing basics
Polymerics basics and materials
Spacecraft Integration and testing
Lessons learned / No No’s
Facility tour
ESD Familiarization
Dale Stottlemyer
• ESD Movie
• Slides
• Tour of Electronics room and work stations
• Demo/hands on use and checking of wrist straps
• Demo/hands on of proper packaging techniques
Contamination and Cleanliness
Dale Stottlemyer
• Slides
• Demo/hands on of gowning procedures
• Cleaning procedures
• Do’s and don’ts
Basic Hardware Handling Practices
Dale and/or Joe
• Documentation
• Personnel Safety
• Hardware Safety
• Lifting (By hand / by crane)
• Grounding of personnel and Hardware
• Storage
• Demo / Hands on
Documentation
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Certification Logs / Travelers
– Also known as a build book
– Document what you do and who does it
– Document Tests performed, and results of the Test
– Document changes made from the initial build, and any redlines to
drawings
– Inspect work that needs inspection
– Document inspection failures and what was done to resolve the issue
Failure Reporting
– Keep track of failures for the future (PFR’s)
– Document resolution, and concurrence of all responsible personnel
Certificate of Compliance
– Keep C of C’s for purchased parts and materials
Personnel Safety
• Personnel safety is top priority
- Two man rule
• General housekeeping
- Keep area clean and free of debris and clutter
• Hazardous materials
- Should all be marked, MSDS’s cataloged for inspection
• Heavy Equipment
- Above 25 pounds, absolutely have two people
Hardware Safety
• Cleanliness
- Space hardware should be kept in a clean environment
- Tools should be clean and free of all oils and other contamination
• Tool safety
- No broken, worn or damaged tools, use the right tool for the job
- Tethered tools should be used above hardware
- Inventory of all tools before and after each operation
• Grounding
- Space hardware and personnel should always be grounded
• Temperature and Humidity
- Temperature and Humidity should be monitored at all times
- Temperature from 70 F to 85 F, Humidity from 30 to 70%
Lifting
• Crane Safety
- Only qualified personnel should operate the crane
- Hard hats should be worn for overhead lifting operations
- Hard hats should be removed when hardware is below you
• Proper Lifting Fixtures
- Lifting fixtures should be tagged and load tested
• Proof Testing
- Performed by Quality Assurance group, twice capacity
• Tethers
- Use for safety of the hardware and personnel
• Don’t lift to much by hand
- Avoid to prevent damage to hardware and personnel
• Proper lift points
Grounding
• Personnel grounded at all times
- Wrist or foot straps worn at all times around hardware
• Hardware grounded at all times
- Hardware always attached to ground
• Make before break ground
- When changing positions with the hardware or personnel, make
another ground attachment before removing the first.
• Check workstations and ground straps regularly. Work stations
should be checked visually every day, and every 6 months for
certification. Wrist straps should be tested every day.
Storage
• Controlled storage area
- Controlled Access and Removal
- Safe, ESD, controlled and clean environment
• Store in ESD approved containers
- ESD bags, containers should be used at all times
• Grounded shelves
- Ensure that cabinets and racks are grounded
• Temperature and Humidity
- Temperature from 70 F to 85 F, Humidity from 30 to 70%
Mechanical fabrication and integration
Jerry Kienle
• Design to build – Can not cover every possible scenario
• Materials
• Raw materials
• Platings
• Fasteners and Inserts
• Special fastener requirements for NASA
• Torquing
• Inspections
• Demo/Hands on
Design to Build
• Dissimilar Metals
- Thermal properties and chemical reactions
• Ease of Fabrication
- Design around equipment available
- Materials selection
• Ease of assembly
- Do not position fasteners where you cannot get to them
• Proper fasteners
- Correct grade, size and material
- External fasteners should have a locking or capturing capability
• Clearance for components and connectors
- Initial build should not be of the flight hardware
- Fit check of all components and harnesses before build for flight
• Ability to withstand all environmental loads
- Address vibe, thermal, wear and tear during integration and test
Materials
• Types of Materials
- Materials compatible to space flight and process equipment
- Materials not to use
- Strength of materials
• Material Certifications for all flight hardware
Plating
• Anodize
- Highly protective with some wear resistance
- No conductivity, if needed remove from area needed
• Iradite/Alodine
- Used for environmental protection and prior to paint or silk
screening etc…
• Paint
- Correct emissivity, low out-gassing, high resistance to flaking,
chipping, pealing, chemical resistance etc…
• Metals Plating
- Gold good, zinc bad, nickel vs. chrome etc…
Fasteners and Inserts
• Helicoils
- Locking vs. Non-locking
- Correct materials
- Use only when inserts cannot be used
• Inserts
- Locking vs. Non-locking, lightweight vs. heavyweight
- Correct materials
• Type of fasteners and materials
- Socket head/cap screws, hex head, flat head, button head
- Do not use phillips or slot headed unless there is nothing else available
• Number of fasteners
- Keep to minimum, but ensure hardware will not come apart
• Locking mechanisms
- Locktite, Nilock, Polymerics, do not use deformed metal locking devices
Special NASA Requirements
• Material Certifications
- All parts and pieces should have a C of C (Certificate of
Compliance) stating all materials used have been manufactured in
accordance with the original specifications of that material or part
• Hardness testing
- Done in accordance with ASTM D 2240
• Special screening for #10 and above
- Done in accordance with S-313-100 (GSFC Fastener Integrity
Requirements)
Torquing
• Torque wrenches
- Should be calibrated and on a calibration schedule
• Torque values
- Reference Mechanical Engineers Handbook
• Torquing locking fasteners
- The torque required to overcome the locking features torque (running
torque) shall be added to the torque value indicated in the table.
• Torquing sequence
- Finger tighten all fasteners, snug up diagonally opposite fasteners until all
heads are seated, torque to within proper limits in a criss-cross pattern. Do
not successively tighten fasteners that are next to each other.
• What to do if over-torque
- Bolts, screws, inserts, and nuts which are tightened to torques which
exceed values specified shall be removed and replaced with new fasteners.
Inspections
• Dimensional checks
- Verify parts are built to the correct dimensions specified in the
drawings
• Verifying proper fit
- Assemble parts and verify no conflicts or parts or sub assemblies
• Verify mounting interface
- Ensure that the pieces that mate with each other do so properly
• Witness torquing
- Each nut and bolt must be witnessed during the torquing
operation.
Electrical fabrication and integration
Joe Perez
• Design to build
• Parts
• Materials
• Offgassing and Outgassing
• Inspections
• Demo/Hands on
Design to Build
• Parts placement
- Ensure that you have the proper parts for what you are trying to
accomplish, verify parts and boards match one another, cuts,
jumpers, and adding parts to a board are no, no’s.
• Pad sizes
- Ensure that the parts and pad sizes fit each other.
• Number of layers
- You could deal with anywhere from 2 to 16 layer boards while
doing board design and build, keep it simple if at all possible.
Parts
• Grade of parts
- Parts range from COTS to Space quality
• Plastic parts
- You should try to avoid flying plastic parts if at all possible
• Surface mount vs. through hole
- You can get more parts per board with surface mount, but you need to
ensure you have someone to lay them down. This will also increase the
number of layers of your board more than likely
• Glass body parts
- Special care should taken when these parts are used
• Screening
- The higher the reliability of the parts the more screening that they go
through, this will also be reflected in the price.
• Connectors
- Many types range from micro to circular
Materials
• PCB materials
- Mil-P-55110, try to use as much as possible
• Plastics
-Try not to use
• Wire types
- Teflon/Extruded Teflon, buy to mil specs
- Mindful of the derating requirements of the wire
- Temperature and chaffing considerations
Offgassing and Outgassing
• Materials dangerous to the crew
- Off gassing is dangerous to the crew, out gassing is dangerous to
the hardware
• Outgassing materials
- Materials should be selected for the lowest out gassing and total
mass loss available
• Outgassing handbook
- NASA Publication 1124
Workmanship basics
• Soldering basics
– Slides
– Examples
• Cable and Harnessing basics
– Slides
– Examples
• Polymerics basics and materials
– Slides
– Examples
Integration and Test
Guy Robinson
• Transportation
• Thermal Vacuum
• Vibration
• EMI/EMC
• Solar Array tests
• Mission Simulation Tests
• Operations Testing
• Lessons learned / No No’s (Everybody)
Transportation
• ESD issues
• Requires two ground braids attached to spacecraft
• Ensure grounds are in firm contact with hardware
• Make before break grounds
• Ensure personnel at same potential of spacecraft
• During short transports cover with ESD approved material
• Proper lifting and handling techniques
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Two man minimum during move of flight hardware
Use extra person for every 25lbs above 50lbs
Use GSE attachments to support lifting aids
During lift no jerking or swinging hardware
Ensure lifting and handling area is clear of obstacles
Transportation (cont.)
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Proper Packaging Process
– Pack using ESD approved materials in doubled bag
• Ensure ground braid protrudes from 1st ESD bag
• Attach bag materials to mounting GSE
– Ensure cleanliness is maintained throughout transportation process
• Need special covers for optics
• At and below 10K level use N2 purge (using K-bottles, regulator, and
distribution system)
• Select packing material with care (leeching, adhesives, etc.)
– Design of transportation container is critical
• Incorporate isolation dampeners between hardware and transportation
container
• Ensure container has proper lifting capabilities
• Use a that container has instrument capability
– Instrument hardware
• Include humidity and shock
• Transportation needs to be temperature and humidity controlled
Thermal/ Thermal Vacuum
• Chamber cleanliness
• Ensure chamber has been properly cleaned
• During hardware installation observe cleanliness procedures
• If chamber is big use full clean-room or at minimum 100K cleanroom garment with boots
• Bake-out
• If cleanliness is critical components need to be baked separately
• If cleanliness is less a concern bake-out the entire hardware
• Bake-out using either TQCM (preferred), Vacuum gauge, or if in
thermal oven use time as the control to determine when done
• Bake-out at highest temperature possible
Thermal/ Thermal Vacuum (cont.)
• Thermal Cycling
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Least costly normally used to qualify space components
Need to consider thermal conductance
Operate hardware like it will operate in space (as much as possible)
Have at minimum 8 cycles including a survival cycle
Operate also if applicable during transits
Incorporate at minimum two hot and cold starts
• Thermal Vacuum
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More expensive but better in determining acceptability of thermal design
Validates workmanship better than Thermal Cycling
Develop profile that accounts for hot and cold operation of space hardware
Be mindful of thermal red and yellow limits and placement of thermal couples
• Damage to flight hardware (i.e. batteries) may result
• Critical components double up on thermal couples
• Adjust environment if near red limits
• Ensure thermal couples are electrically isolated from structure
• Need same considerations as thermal cycle
Thermal/ Thermal Vacuum (cont.)
• Thermal Balance
• Most expensive or the thermal tests but can validated the thermal
design since proper thermal flux is applied to the space hardware
• Requires that coating and blanketing be installed
• Normally done in the middle of thermal vacuum cycles
• Thermal balance campaign need to identify how flux is distributed
throughout orbit
• Determine hottest and coldest operating states of hardware
• Use these operating states to develop operating tests used during thermal
balance
• Ensure that hardware is bias to either extreme prior to performing the
test
• Need to carefully consider placement of thermal couples
• Again be mindful of red and yellow limits of hardware
• Turn on/off hardware before breaking red limits
• You can add (or remove) simulated solar flux to help control temperature
Vibration Testing
• Sine sweeps
• Do a sine sweep prior to performing random or sine burst
• This is done not only to identify first mode but develop a baseline
condition of the structure
• Install accelerometers with care
• Out of plane accelerometers response is often below primary drive signal
• Need to identify best way to attach accelerometers
• Bees wax
• Super Glue on Kapton tape
• Use lowest drive signal that will excite modes
• Often ¼ G sine sweep can identify modes
• When analyzing modes above 400Hz are difficult to predict and very
small structural changes can effect performance
• Structure settling (sweet spot) change modes
• If first mode changes there is a problem in the structure
Vibration Testing (cont.)
• Modal Survey
• Modal survey is needed when structure modes will interface
with other hardware near your hardware
• Modal requires that you know the bending modes of the
structure (analysis)
• Accelerometer need to be placed so modes can be seen
• When doing the analysis consider how system is driven (i.e. how
attached to shaker table)
• Best to use displacement sensors
• Can use accelerometers but is more difficult
• Use long duration dwell sine sweep to ensure modes reach
steady-state
• This test often takes several attempts to get the data needed to
perform the analysis
Vibration Testing (cont.)
• Random Vibration levels
• Acceptance
– Meets the expected launch load with 3 certainty
– Use this level if qualification has been done or after change/small repair
of the structure (i.e. installation of flight battery)
– Consider flight duration when determine how long to apply 0db relative
level
• Proto-flight
– Normally PSD is 3-6db higher than acceptance level
– Use this when you have a one of a kind hardware and are flying what
you test
– Test duration period is same as acceptance level period
• Qualification
– This level is at minimum 6db above acceptance level
– Use this when you want to make several of the same hardware
– Test duration period is normally 2X longer than either acceptance of
Proto-flight
Vibration Testing (cont.)
• Sine Burst
• Used to verify structural strength of structure
• Drive levels are typically combined axis requirement
• Consider how best to excite all three axis simultaneously
• Can qualify flight structures using EM structures
• You can substitute static pull testing but this test is better
• Includes dynamic characteristics
• Normally done with profile shown below
Acceleration in G's
Sine Burst Profile
25
20
15
10
5
0
-5
-10
-15
-20
-25
Sine Burst levels
No qualification,proto-flight
levels
Ensure that your first mode is
not excited
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Freq normally between 18
to 22Hz
Vibration Testing (cont.)
• Pyroshock
• Used to validate that shock doesn’t effect components near separation area
• Used on all separation/deployment area (not limited to launch separation
system)
• For analysis use 3db loss for each mechanical attachment
• Prior to firing pyros dry-run procedure including accelerometers responses
• Ensure that you have enough head-room on accelerometer plots so saturation is not
seen
• Typically explosives are used so please leave the connection and firing to
qualified personnel
• Safety
• Don’t touch hardware during shake operations
• If unusual noises or first mode is changed stop test immediately and
investigate
• Ensure you have qualified people to support tests (i.e. explosives, etc.)
• If it looks risky or dangerous it probably is so review the test
• Don’t simply apply maximum drive levels use at minimum 3 intermediate
points (e.g. –12db, -6db, -3db, then 0db relative)
• Ensure that you run sine sweeps and aliveness test to verify hardware
condition hasn’t changed
EMI / EMC Tests
• Guideline use Mil-STD-461E to define what test need to take place
• These tests are hard to conduct and take proper planning to execute
effectively
• Use a self-compatibility test to verify hardware system
• Self compatibility doesn’t determine how much margin you have in the design
• Conducted Emissions
• Used to determine if components power operations are compatible on a
common bus
• Conducted Susceptibility
• This test is important if your payload is sensitive to power spikes
• Care needs to be taken when running this test since power systems can be
destroyed during this test
• Radiated Susceptibility
• Normally this test is done if your equipment has low threshold of RF
interference
• Radiated Emissions
• Normally this test is done if your equipment has multiple transponders and
there is a possibility of interference (e.g. have a transmitter and a GPS
receiver)
Solar Array Tests
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Illumination Tests (ensure you use the proper spectral content)
Ensure that all solar strings are wired correctly.
Verifies the output of each of your strings.
Verifies that you are able to charge your battery.
Power Output Tests
Verifies you have enough battery to turn on after launch.
Verifies that you have enough battery capacity for your eclipses
Verifies initial turn on draw of all experiments.
Verifies minimal safe mode operations, and turn on capacity.
Battery Charging Tests
Mission Simulation Tests
• Final Checkout of Space Hardware
• This test will provide the mission operators an opportunity to
operated the space vehicle using the operators command & telemetry
database.
• The test needs to use well understood functional procedures to verify that
commands & telemetry operate as expected.
• Allows the command and telemetry databases to be validated
• Simulates On-orbit Operations
• Includes payload operations, as well as all major operational modes of the
spacecraft
• Look at mission modes and power consumption to ensure you can
perform your mission while on orbit.
• Identify problem areas that needs to be corrected prior to operating on
orbit
• This include dangerous commands
Operations Testing
• RF Compatibility
• Ensure that you are able to communicate with your spacecraft before you
leave the confines of the ground.
• This test will verify that satellite can be operated and controlled in a manner
that is compliant with the communication system.
– Ensure that the communication process is understood
• Mission Rehearsal Testing
• Try to operate the satellite in a manner that simulates LEO (launch and early
operations), normal operation, and abnormal conditions
• This testing rehearses the operator in identifying, and correcting problem often
encountered during orbit.
• Look at mission modes and exercise how to enter into each mode of operation
• Need to have independent team that poses problems to operators and grade
how well recover takes place
Lessons Learned
• Take your time to do it right or suffer the consequences !!!
• Document all steps taken in the assembly and test phases, you never
know when you might need that data again.
• Make sure you do the paper work at minimum the end of the day or you
will not know you configuration and this will be a problem !!!
• Don’t hide mistakes or problems, sooner or later it will come back to
haunt you.
• Make sure you know the roles each of the team play or you will have
confusion
• Launch, wait, Drink heavily, and Be Happy