SCIAMACHY Life Limited Item (LLI) Tracking

LLI tracking is required because the

have an in-flight switches/cycles budget which must not be exceeded.

LLI In-flight budget
switches/cycles burning time (hr)
NDFM 49000a / 98000b n/a
APSM 49000a / 98000b n/a
NCWM 2400 n/a
SLS 24317 477
WLS 7500 25
Cryo Heatpipe 22c / 40d n/a

a) with safety factor (margin) 2 (no longer applicable)
b) without safety factor
c) with high safety factor 3 (no longer applicable)
d) with safety factor 2

In support of the operational LLI tracking, SOST-IMF performs a LLI 'prediction' by estimating the LLI activations based on the planned timelines. As long as the actual operations do not differ from the planned operations, LLI estimate and operationally tracked LLI usage shall be identical. The LLI prediction can be found on the LLI status page. Note that the prediction includes the non-LLI entries 'ASM diffuser exposure' and 'ESM diffuser exposure'. It was found useful to accumulate a record of the diffuser exposure times during the mission lifetime.

For the Cryo Heatpipe item, LLI tracking is performed via recording execution of decontamination.

Page generated 20 February 2002; last update: 19 November 2007