Month: February 2018

Command Line Arguments

A standard way to access a program’s command line arguments wasn’t added to Fortran until 2003. Command line arguments were one of those things (like environment variables, the file system, and the operating system shell) that the Fortran standards committee

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Another One Bites the Dust: GRAM Atmosphere Model

It looks like the Fortran community has lost another venerable NASA Fortran library to C++. I recently noticed that the latest release of NASA’s Global Reference Atmosphere Model (GRAM) is now C++. From the release link: Earth-GRAM 2016 is now available

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Fehlberg’s Runge-Kutta Methods

Many of the important algorithms we use today in the space business have their origins in NASA’s Apollo program. For example, the Runge-Kutta methods with stepsize control developed by Erwin Fehlberg (1911-1990). These are still used today for propagating spacecraft trajectories. Fehlberg was a

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JSON + SPICE

I have mentioned various kinds of configuration file formats used in Fortran here before. One that I haven’t mentioned is the text PCK file format used by the NAIF SPICE Toolkit. This is a format that is similar in some ways to

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IAU SOFA Version 14

The IAU Standards of Fundamental Astronomy (SOFA) library implements standard models used in fundamental astronomy. Version 14 ( 2018-01-30) has just been released. According to the release notes, this update includes the following: Change in the copyright status of the iau_DAT routine.

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