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CALIPSO Data User's Guide - Data Losses


CALIPSO HOME → CALIPSO’s User Guide → HOMEEssential Reading → Data Losses


The following figures show the percentage of data lost as a function of time for each day of the year for the entire CALIPSO mission (to date). Large data dropouts are annotated to indicate the cause of the data loss.

2006
2006 data loss.
2007
2007 data loss.
2008
2008 data loss.
2009
2009 data loss.
2010
2010 data loss.
 

List of some acronyms and terms used in the figures

Boresight
Boresight maneuver: A procedure to check and perhaps improve the optical alignment between the lidar transmitter and receiver telescope.

Breaking Maneuver
Braking Maneuvers are periodically required to maintain CALIPSO's position in the Afternoon Constellation (A-Train) of Earth Observing Satellites.

DMU
Drag Make-up Maneuver are periodically required to maintain CALIPSO's exact position in the Afternoon Constellation (A-Train) of Earth Observing Satellites.

GPS Anomaly
The CALIPSO Satellite relies on Global Positioning Satellites (GPS) for navigation and time reference.

Inclination Maneuver
Inclination Maneuvers are periodically required to maintain CALIPSO's exact position in the Afternoon Constellation (A-Train) of Earth Observing Satellites.

Operations Error
Commands that are sent to the payload are always reviewed, tested and verified prior to upload. Early in the mission, a single character error caused the loss of one day's worth of data.

Reaction Wheel
Reaction wheels are devices that aim the CALIPSO satellite in different directions and maintain attitude control.

Rep Rate
Repetition Rate - The laser transmit system fires at just over 20 times/second. The payload monitoring system will issue a violation and transition the laser system to a protected state to maintain the safe operation of the payload.

SAFE
This is a known state that the satellite may transition into during maneuvers or when the on-board monitoring system detects a situation (temperatures, voltages, etc) that may cause damage to the payload.

SCF
Science Computing Facility where the raw downlinked science data is processed into CALIPSO Level 1 and Level 2 science data products.

Solar Proton Event
High levels of solar proton events (i.e. solar flares) can damage electronics. During periods when solar proton events are earth-directed, the CALIPSO payload may need to shutdown the payload computer and/or the laser transmitter to protect the electronics.

USN
Universal Space Network (USN) is responsible for the daily downlink of the CALIPSO high-rate science data.

OCM
Orbit Correction Maneuvers are periodically required to maintain CALIPSO's position in the Afternoon Constellation (A-Train) of Earth Observing Satellites.

X-Band Transmit Error
Downlinking high rate science data through X-BAND takes careful planning and scheduling. Since commands are sent to the payload well in advance of the downlink time, rare mismatches occur.


Last Updated: June 23, 2011



NASA
Last Updated: November 19, 2020
Curator: Charles R. Trepte
NASA Official: Charles R. Trepte

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