Low cost, minimal complexity and rapidly prototyped "common bus" design

Lunar Atmosphere and Dust Environment Explorer (LADEE) is a NASA mission that will orbit the Moon and its main objective is to characterize the atmosphere and lunar dust environment.

• Lunar Atmosphere and Dust Environment Explorer (LADEE) is a NASA mission that will orbit the Moon and its main objective is to characterize the atmosphere and lunar dust environment.

• Low cost, minimal complexity and rapidly prototyped “common bus” design.
• Model-Based Software Development

Phasing Loops

• Phasing Loops

• 3 Perigee Manuevers
• Time, Opportunity for Adjustments
• Similar to past missions
• (Clemintine, Wind WMAP)

• Lunar Orbit Insertion

• First LOI for Capture
• 2 additional LOI lowering orbit

3U Compact PCI – Broad Reach

• 3U Compact PCI – Broad Reach

• Active Memory

• BAE Rad750 128Mb

• Nibble Correct (64 Bit)

• Broad Reach DMOAB SDRAM Storage

• 1GB SECDED (32 Bit)
• 4 FAT16 Partitions* (*Primary)

• Other C&DH Memory

• SRAM – Devices
• EEPROM & Flash – Program Storage

Requirement Summary:

• Requirement Summary:

• Provide ability to enable/disable scrubbing
• Provide corrected/uncorrected memory error counters and last error address
• Enable/Disable EDAC interrupts
• Provide corrected, uncorrected, and critical error events
• Overwrite uncorrected memory error locations to prevent continuous reporting

Flight Software built on CFE

• Flight Software built on CFE

• Separate Tasks
• Message Based

• Memory Scrub Task

• VxWorks Driver
• Handles Interrupts
• Silences Correctable and “Uncorrectable”
• MS Task
• Configures Drivers
• Records and Logs Events

Orbital Position Plot

• Orbital Position Plot

Periapsis #1 Detail

• Periapsis #1 Detail

Periapsis #2 Detail

• Periapsis #2 Detail

Periapsis #3 Detail

• Periapsis #3 Detail

Normal Activity

• Normal Activity

• Average about 1 to 2 a Day
• Some Groups of Events
• Patterns or Locations

• “Uncorrectable” Errors

• Where in Memory
• Sensitive Spots

Events can happen fast in Groups

• Events can happen fast in Groups

• (May loose events due to rapid frequency)

• Van Allen Belt effects higher than expected

• Events happen anywhere

• Groups of events at random times
• Multi-bit errors occurred far from Earth

• Unusual Events

Mapping Locations by usage

• Mapping Locations by usage

• FAT Tables mapped out
• Reverse mapping on Addresses
• Exact location of data files (LLCD has helped)

• Improved logging of Events

• Better ways of injecting events during testing