CDX1 File

What are CDX1 files and how to open them

Are you having problems opening a CDX1 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 CDX1 files.

What is a CDX1 file?

A .CDX1 file is a RASAero II Document file.

RASAero II Document files hold rocket design and flight simulation data created by the RASAero II software, a program for aerodynamic analysis and flight prediction. These files capture all information needed to model a rocket: its geometry (nose cone, body tubes, fins etc.), mass distribution, launch conditions (site elevation, temperature, wind), motor nozzle data, and options such as whether boosters are included or ignited. Once the rocket input data are entered or loaded, the design is saved into this file so it can be used for running aerodynamic drag calculations, center of pressure predictions, stability checks, and full flight trajectory simulations.

The RASAero II software both writes and reads this format. New rockets created in RASAero II are saved under this format. Older RASAero (.ALX1) files and RockSim (.RKT) files can be imported; after editing or updating, the rocket designs are saved in the new format.

Files begin with an XML-style signature that includes the ASCII string .RASAeroDocument at the very start. The data inside the file contain many distinct keywords that correspond to properties such as "BOOSTER1NOZZLEDIAMETER", "SUSTAINERLAUNCHWT", "OPTIMUMMAXALT", "EVENTTYPE1", "BODYTUBE", "RAILGUIDEHEIGHT", among others. These field names indicate that the file is structured text (likely XML or similar), with tags matching these keywords to store individual numeric or categorical parameters.

How to open CDX1 files

Important: Different programs may use files with the CDX1 file extension for different purposes, so unless you are sure which format your CDX1 file is, you may need to try a few different programs.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Last updated: August 31, 2026

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