QLF08_LaBel.pdf - 第22页
IC and Component Selection for Space Sy stems – Presented by Kenneth A . LaBel 22 Understanding Risk • Risk for a mission falls in to the same topic areas as parts selection – T echnical, programmatic, and reliability • …
IC and Component Selection for Space Systems – Presented by Kenneth A. LaBel
21
Is Testing Always Required?
• Exceptions for testing may include
– Operational
• Ex., The device is only powered on once per orbit and the
sensitive time window for a single event effect is minimal
– Acceptable data loss
• Ex., System level error rate may be set such that data is
gathered 95% of the time. This is data availability. Given
physical device volume and assuming every ion causes
an upset, this worst-case rate may be tractable.
– Negligible effect
• Ex., A 2 week mission on a shuttle may have a very low
TID requirement. TID testing could be waived.
A FLASH memory may be acceptable
without testing if a low TID
requirement exists or not powered on
for the large majority of time.
IC and Component Selection for Space Systems – Presented by Kenneth A. LaBel
22
Understanding Risk
• Risk for a mission falls in to the same topic areas as parts
selection
– Technical, programmatic, and reliability
• Technical risks
– Relate to the circuit designs not being able to meet mission
criteria such as jitter related to a long dwell time of a telescope
on an object
• Programmatic risks
– Relate to a mission missing a launch window or exceeding a
budgetary cost cap which can lead to mission cancellation
• Reliability risks
– Relate to mission meeting its lifetime and performance goals
without premature failures or unexpected anomalies
• Each mission must determine its priorities among the three
risk types
IC and Component Selection for Space Systems – Presented by Kenneth A. LaBel
23
The Risk Trade Space –
Considerations for Device Selection (Incomplete)
• Cost and Schedule
– Procurement
– NRE
– Maintenance
– Qualification and test
• Performance
– Bandwidth/density
– SWaP
– System function and
criticality
– Other mission constraints
(ex., reconfigurability)
• System Complexity
– Secondary ICs (and all
their associated
challenges)
– Software, etc…
• Design Environment and
Tools
– Existing infrastructure and
heritage
– Simulation tools
• System operating factors
– Operate-through for single
events
– Survival-through for portions
of the natural environment
– Data operation (example,
95% data coverage)
• Radiation and Reliability
– SEE rates
– Lifetime (TID, thermal,
reliability,…)
– “Upscreening”
• System Validation and
Verification