Parsing Packets¶

The spac-parse command converts CCSDS binary data files into Excel spreadsheets with separate sheets for each packet type.

Basic Usage¶

spac-parse --file downlink.bin

This creates downlink.xlsx with one sheet per APID found in the file.

Command-Line Options¶

Required:

--file FILE: Path to the CCSDS binary file

Optional:

--bdsem: Handle BDSEM-specific packet wrappers
--pkt-header: Strip non-CCSDS headers between packets
--json-header: Skip JSON header at file start
--calculate-crc: Validate CRC and include both packet and calculated CRC in output

Examples¶

Parse with CRC validation:

spac-parse --file downlink.bin --calculate-crc

Handle non-CCSDS headers:

spac-parse --file downlink.bin --pkt-header

Output Format¶

The Excel file contains:

One sheet per APID (packet type)
Column headers matching field names
Each row representing one packet

Example:

Sheet: "SensorPacket" (APID 100)
┌───────┬──────────┬─────────────┬────────┐
│ Index │ SHCOARSE │ TEMPERATURE │ STATUS │
├───────┼──────────┼─────────────┼────────┤
│   0   │ 12345678 │    23.45    │   1    │
│   1   │ 12345679 │    23.46    │   1    │
└───────┴──────────┴─────────────┴────────┘

Python API¶

Parse to DataFrames:

from spac_kit.parser.parse_ccsds_downlink import parse_ccsds_file

with open("downlink.bin", "rb") as f:
    dfs = parse_ccsds_file(f, do_calculate_crc=False)

# dfs is a nested dict: {apid: {packet_name: DataFrame}}
for apid, packet_data in dfs.items():
    for packet_name, df in packet_data.items():
        print(f"{packet_name} (APID {apid}): {len(df)} packets")

Parse to Excel:

from spac_kit.parser.downlink_to_excel import export_ccsds_to_excel

export_ccsds_to_excel("downlink.bin", "output.xlsx", do_calculate_crc=True)

Handle non-CCSDS headers:

from spac_kit.parser.remove_non_ccsds_headers import strip_non_ccsds_headers
from spac_kit.parser.parse_ccsds_downlink import parse_ccsds_file

with open("data.bin", "rb") as f:
    clean_file = strip_non_ccsds_headers(f, pkt_header=True)
    dfs = parse_ccsds_file(clean_file)

Troubleshooting¶

No packet definitions found

Ensure you have a plugin installed:

spac-ls  # Check available packets
pip install spac-kit-europa-clipper  # Install if needed

Unknown APID

Packets with unknown APIDs are skipped. Use spac-ls to see supported APIDs.