Req. 5.3.16.2.1: "Load Shedding Notification from SC"

The SIU FSW shall receive and process a load shedding notification message from the SC, then execute the necessary configuration commands within 15 seconds to power off all SIU-controlled LAT components and prepare for shutdown.

Basis (help)

[2] (3.2.8.3.2), [3] (5.3.5)

2: "LAT Instrument - Spacecraft Interface Requirements Doc." (NASA 433-IRD-0001)

3.2.8.3.2: "Load Shedding Notification"

The SC shall send a message to the LAT across the CTDB no less than 15 seconds prior to issuing a command to disconnect LAT power.

3: "LAT Performance Spec. - Level II(b) Spec." (LAT-SS-00010)

5.3.5: "Operating Modes"

The SI shall accommodate the observatory modes of operation identified in the GLAST Mission System Specification (MSS), Section 3.1.15, Modes of Operation. These modes are Sky Survey Mode, Pointed Observation Mode and Safe Mode. Additionally, the instrument must accommodate the spacecraft load shedding function identified in the SI/SC IRD, Section 3.2.7, Fault Protection.

Context (help)

Test(s)

013a: Operational Modes - Safe Modes

This test shall verify that the SIU FSW can perform the correct transition of the LAT into Safe Mode upon command, can properly execute the Safe Mode algorithms, and can perform the subsequent recovery via Engineering Mode. It shall also verify the correct response to SAA entry commands and subsequent recovery.