ALOS Data Users Handbook

ALOS Data Users HandbookAppendix 1.2 Terminology• Command Signal:Orders to the spacecraft such as turn-on/off of an instrument’s switch, and start/end ofobservation.• Telemetry Data:The data which shows a state of each component of spacecraft such as temperature of instrument,turn-on/off of switch, and observation mode.• Light Load Mode:It is an operation mode which is the mode to avoid loosing functions of overall spacecraft in caseof spacecraft or instruments anomaly by turning off all the instruments except the minimum onesand keeping controlling power consumption.• Autonomous/Automatic:The function that shifts to the light load mode immediately by spacecraft onboard softwarewithout waiting for the command transmitted from the ground in case of spacecraft orinstruments anomaly. This function may decrease the probability of the function loss.• CCSDS Advice:The international standard of data processing protocol advised by Consultative Committee forSpace Data Systems (CCSDS) co-established by space agencies of each countries includingJAXA.• MIL-1553B:It is a kind of data transmission method inside spacecraft and one of the standards established byUS Department of Defense.A1-3