1. 1 EDAC Concerns for Flight Software and Hardware Design Craig Pires LADEE C&DH Lead NASA-Ames Research Center Moffett Field, CA Craig.Pires@nasa.gov Scott Christa Karen Gundy-Burlet Greg Limes Larry Shackelford (GSFC)

2. 2 Mission Overview 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 Specific objectives are: –Determine the global density, composition, and time variability of the lunar atmosphere; –Confirm the Apollo astronaut sightings of dust jumps and diffuse emission –Laser Communications Demonstration: 622 Mbs Record download rate from the Moon! Clementine spacecraft image of moon dust corona Gene Cernan’s drawings of the lunar sunrise

3. 3 3 Photo: Buddy Secor

4. 4 Photo: Bill Anderson

5. 5 Photo: Ben Cooper

6. 6 This photo was taken by a still camera which was on a sound trigger at Pad 0B at WFF. The photographer is Chris Perry of the WFF Optical Systems Group. Photo went viral as soon as released. Examples of coverage: http://www.cnn.com/2013/09/12/t ech/innovation/frog-and- rocket/index.html?hpt=hp_c4 “Meet the Press”, on September 15, 2013 Frog Photobombed Launch!

7. 7 Trajectory 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

8. 8 Avionics C&DH 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

9. 9 Software Requirements 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

10. 10 Software Structure 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

11. 11 Experiences - Phasing Loops Orbital Position Plot

12. 12 Experiences - Phasing Loops Periapsis #1 Detail

13. 13 Experiences - Phasing Loops Periapsis #2 Detail

14. 14 Experiences - Phasing Loops Periapsis #3 Detail

15. 15 Lunar Orbit Normal Activity –Average about 1 to 2 a Day –Some Groups of Events –Patterns or Locations “Uncorrectable” Errors –Where in Memory –Sensitive Spots

16. 16 Lessons Learned 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

17. 17 Lessons Learned - Improvements 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

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