BPC File

What are BPC files and how to open them

Are you having problems opening a BPC file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your BPC files.

What is a BPC file?

A .BPC file is a SPICE Binary PcK file.

SPICE Binary PcK files hold highly precise information about how natural solar system bodies rotate and orient in space. They store orientation data (attitude) expressed as time-dependent functions, enabling accurate transformation between a body-fixed reference frame and an inertial reference frame. These files support scientific tasks that require precise knowledge of how a planet, moon, or asteroid spins and where its poles and prime meridian are located at different times.

These files are created using the NAIF SPICE Toolkit, typically by experts who need orientation models more detailed than what text format kernels provide. Once produced, binary PCK files are read by SPICE software (for example via CSPICE or SPICELIB routines) to supply orientation data to user applications. When both binary and text PCK files covering the same time span are loaded, the binary one takes priority because it offers higher precision. The bodies with existing binary orientation kernels include the Moon, Earth, and the asteroid Eros.

Internally, the format is built on the SPICE DAF (Double Precision Array File) architecture. Files begin with an identification header ASCII "DAF/PCK " in the first eight bytes. They contain one or more "segments," each covering a specific time span, holding data expressed via Chebyshev polynomials of orientation or angular rate. Different segment types exist (e.g. Type 2, Type 3, Type 20) depending on whether both angles and rates are stored or whether only angular rates are used.

How to open BPC files

Important: Different programs may use files with the BPC file extension for different purposes, so unless you are sure which format your BPC file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested five different BPC openers which you will find listed below.

Last updated: August 24, 2026

Various apps that use files with this extension

These apps are known to open certain types of BPC files. Remember, different programs may use BPC files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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