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CCSDSPy provides an IO Interface for reading CCSDS data in Python. The CCSDS format is used for many NASA and ESA missions for low-level telemetry, and often contains tightly packed bits to reduce downlink requirements.

Install ccsdspy

To install ccsdspy from source, you can use

pip install ccsdspy


The CCSDS space packet protocol is a not a self-describing data format. Context for how to interpret the file’s bits must be provided. This information is typically available from the flight software documentation.

Fixed Length Packets

Fixed length packets are one type of packet defined in CCSDS. When provided with a description of data layout, ccsdspy.FixedLength will decode the fields automatically using highly efficient vectorized shifting and masking.

The result is returned as an OrderedDict, containing PacketField names as keys and values are each array of the interpreted data from each packet.

import ccsdspy
from ccsdspy import PacketField

pkt = ccsdspy.FixedLength([
     PacketField(name='SHCOARSE', data_type='uint', bit_length=32),
     PacketField(name='SHFINE',   data_type='uint', bit_length=20),
     PacketField(name='OPMODE',   data_type='uint', bit_length=3),
     PacketField(name='SPACER',   data_type='fill', bit_length=1),
     PacketField(name='VOLTAGE',  data_type='int',  bit_length=8),

result = pkt.load('MyCCSDS.bin')

User Documentation