
Over an 18-month period, D. Dirkx led core development for tudat-team/tudatpy, building advanced astrodynamics and simulation features to support high-fidelity space mission analysis. Dirkx engineered robust API exposure, trajectory modeling, and multi-arc propagation workflows, emphasizing maintainability and cross-platform reliability. Using C++ and Python, he refactored core modules, optimized build systems with CMake, and expanded test coverage to reduce regression risk. Dirkx addressed complex challenges in time handling, Doppler modeling, and spherical harmonics, while modernizing CI/CD pipelines and documentation. The work demonstrated deep technical breadth, delivering stable, extensible infrastructure that improved scientific accuracy and accelerated research and onboarding.
March 2026 Tudatpy: Stabilized the build and unit-test pipeline, delivered a final performance optimization pass, cleaned up the codebase, and improved documentation and installation accessibility to accelerate adoption and reduce onboarding overhead. Business value centers on faster, more reliable builds, improved runtime performance, and easier installation for users and contributors.
March 2026 Tudatpy: Stabilized the build and unit-test pipeline, delivered a final performance optimization pass, cleaned up the codebase, and improved documentation and installation accessibility to accelerate adoption and reduce onboarding overhead. Business value centers on faster, more reliable builds, improved runtime performance, and easier installation for users and contributors.
February 2026 Tudatpy monthly summary: The month prioritized delivering UTC-based data handling improvements, strengthening code maintainability, and accelerating feedback through CI enhancements. Key features delivered include UTC-based time range enhancements with epoch alignment for TLE data, along with structural refactors to improve build reliability and modularity. Documentation expanded with project docs and docstring corrections to improve usability and developer onboarding. Build system and CI workflows were modernized, enabling faster and more reliable cross-platform builds. The team also shipped a broad set of bug fixes to stabilize compilation and tests, including long double handling, missing definitions, and regression fixes. Overall, the month established a stronger foundation for future satellite data workflows, with a focus on reliability, performance, and developer productivity.
February 2026 Tudatpy monthly summary: The month prioritized delivering UTC-based data handling improvements, strengthening code maintainability, and accelerating feedback through CI enhancements. Key features delivered include UTC-based time range enhancements with epoch alignment for TLE data, along with structural refactors to improve build reliability and modularity. Documentation expanded with project docs and docstring corrections to improve usability and developer onboarding. Build system and CI workflows were modernized, enabling faster and more reliable cross-platform builds. The team also shipped a broad set of bug fixes to stabilize compilation and tests, including long double handling, missing definitions, and regression fixes. Overall, the month established a stronger foundation for future satellite data workflows, with a focus on reliability, performance, and developer productivity.
January 2026 monthly summary for Tudat projects focusing on delivering higher fidelity dynamics simulations, stronger testing, and improved build/documentation stability across TudatPy and Tudat. Delivered key features and fixes that increase accuracy, robustness, and flexibility for mission analysis and research workflows. Key features delivered: - IAU Rotation Model Enhancements (tudatpy): added support for different base frames, improved angle retrieval, and error handling for unsupported frames to increase accuracy and flexibility. Commits: e69cafd901127c5421282bcb17e37296c27ecfb4; 960cbb7b17346f8f0bec15fcc264b532592d59dd - Doppler Observation Model Improvements (tudatpy): fixed Doppler bias handling in two-way Doppler observations and ensured Doppler partials use the correct observable type for accurate simulations. Commits: eadbf3168bbc5683cf704eda1b9e1a4e84e16c33; ed7131d45aab6bcbee21b8a689f5ff5f4c82712e - Dependent Variable Evaluation Along Trajectories (tudatpy): added capability to evaluate dependent variables along a trajectory (via integrating equations of motion and predefined trajectories) with tests and docs. Commits: 2986524a5b9c71bad5c43ffe72d789b3d11ecf01; d9306bf6cfec460f1bfe376288563d0b90ad295c - Cartesian State Partials Creation Refactor (tudatpy): simplified and clarified partials creation switch for maintainability. Commit: f5d3845c18de2e3995b48620be595f79ee8cf005 - Testing and Warning Improvements (tudatpy): strengthened MPC tests, warnings clarity, and test tolerances for reliability. Commits: multiple (1ef63aee516014dac7d9b9ecf4554f3aa9d60655; 6b2a3b14df7fe479b29fc85b42e722a6aa7348d0; ff076c859f9a977c4cf2652140ba1bfb1e1b02a5; 21c97a467bfa2d4ebe319f4e0af8a2a29f741bfb; d8651b3d877667b1ede370b97f96fc8070e24d55; d741e2db3f53e8a40cbbfb46d0735723fc2dd5ae) - Build and Documentation Stability (tudatpy): reduced Linux build jobs and stabilized docs rendering; commits: 5f88d1a431812ead84e8a7697cfa094894fccc6e; 25941f9c787b346bb5759e68877cb81dad99e9a0 Additional Tudat improvements: - Build and Testing Infrastructure for Tudat (tudat): added build/test configuration files and scripts and updated README to improve usability and maintainability. Commit: c5f3d4f52a04eb514aabe1cdfe3903c15d41152b Overall impact and accomplishments: - Enhanced simulation fidelity and robustness for orbital dynamics through expanded base-frame support, corrected Doppler bias handling, and reliable trajectory-based analytics. - Increased development efficiency and reliability through better tests, clearer partials logic, and stabilized builds/docs, enabling faster onboarding and CI cycles. - Enabled more flexible mission analysis and research workflows with optional observation-set settings and conditional interpolator resets. Technologies/skills demonstrated: - C++ and Python integration (tudat/ TudatPy), numerical integration, derivative/partials computation, trajectory analysis, and Doppler modeling. - Software engineering practices: refactoring for maintainability, rigorous testing, warning management, and build/test infrastructure improvements.
January 2026 monthly summary for Tudat projects focusing on delivering higher fidelity dynamics simulations, stronger testing, and improved build/documentation stability across TudatPy and Tudat. Delivered key features and fixes that increase accuracy, robustness, and flexibility for mission analysis and research workflows. Key features delivered: - IAU Rotation Model Enhancements (tudatpy): added support for different base frames, improved angle retrieval, and error handling for unsupported frames to increase accuracy and flexibility. Commits: e69cafd901127c5421282bcb17e37296c27ecfb4; 960cbb7b17346f8f0bec15fcc264b532592d59dd - Doppler Observation Model Improvements (tudatpy): fixed Doppler bias handling in two-way Doppler observations and ensured Doppler partials use the correct observable type for accurate simulations. Commits: eadbf3168bbc5683cf704eda1b9e1a4e84e16c33; ed7131d45aab6bcbee21b8a689f5ff5f4c82712e - Dependent Variable Evaluation Along Trajectories (tudatpy): added capability to evaluate dependent variables along a trajectory (via integrating equations of motion and predefined trajectories) with tests and docs. Commits: 2986524a5b9c71bad5c43ffe72d789b3d11ecf01; d9306bf6cfec460f1bfe376288563d0b90ad295c - Cartesian State Partials Creation Refactor (tudatpy): simplified and clarified partials creation switch for maintainability. Commit: f5d3845c18de2e3995b48620be595f79ee8cf005 - Testing and Warning Improvements (tudatpy): strengthened MPC tests, warnings clarity, and test tolerances for reliability. Commits: multiple (1ef63aee516014dac7d9b9ecf4554f3aa9d60655; 6b2a3b14df7fe479b29fc85b42e722a6aa7348d0; ff076c859f9a977c4cf2652140ba1bfb1e1b02a5; 21c97a467bfa2d4ebe319f4e0af8a2a29f741bfb; d8651b3d877667b1ede370b97f96fc8070e24d55; d741e2db3f53e8a40cbbfb46d0735723fc2dd5ae) - Build and Documentation Stability (tudatpy): reduced Linux build jobs and stabilized docs rendering; commits: 5f88d1a431812ead84e8a7697cfa094894fccc6e; 25941f9c787b346bb5759e68877cb81dad99e9a0 Additional Tudat improvements: - Build and Testing Infrastructure for Tudat (tudat): added build/test configuration files and scripts and updated README to improve usability and maintainability. Commit: c5f3d4f52a04eb514aabe1cdfe3903c15d41152b Overall impact and accomplishments: - Enhanced simulation fidelity and robustness for orbital dynamics through expanded base-frame support, corrected Doppler bias handling, and reliable trajectory-based analytics. - Increased development efficiency and reliability through better tests, clearer partials logic, and stabilized builds/docs, enabling faster onboarding and CI cycles. - Enabled more flexible mission analysis and research workflows with optional observation-set settings and conditional interpolator resets. Technologies/skills demonstrated: - C++ and Python integration (tudat/ TudatPy), numerical integration, derivative/partials computation, trajectory analysis, and Doppler modeling. - Software engineering practices: refactoring for maintainability, rigorous testing, warning management, and build/test infrastructure improvements.
Monthly summary for tudatpy (2025-12). Focused on delivering stable features, improving API clarity, and strengthening testing and CI processes to reduce risk and accelerate release cycles. Key outcomes include enforcing immutability of critical configuration (ancillary settings), updating API documentation to reflect API exposure changes, and establishing testing groundwork for spherical harmonics and accelerations. Significant bug fixes enhanced reliability and correctness, including proper IFMS base handling and corrected exposure function naming, along with broader error handling improvements. In addition, CI/CD and validation improvements increased test parallelism, re-enabled full test suites, and improved maintainability through documentation and code quality cleanups. This work demonstrates strong proficiency in Python, software architecture, test automation, CI/CD, and documentation discipline, delivering tangible business value through safer APIs, more reliable software, and faster, more confident deployments.
Monthly summary for tudatpy (2025-12). Focused on delivering stable features, improving API clarity, and strengthening testing and CI processes to reduce risk and accelerate release cycles. Key outcomes include enforcing immutability of critical configuration (ancillary settings), updating API documentation to reflect API exposure changes, and establishing testing groundwork for spherical harmonics and accelerations. Significant bug fixes enhanced reliability and correctness, including proper IFMS base handling and corrected exposure function naming, along with broader error handling improvements. In addition, CI/CD and validation improvements increased test parallelism, re-enabled full test suites, and improved maintainability through documentation and code quality cleanups. This work demonstrates strong proficiency in Python, software architecture, test automation, CI/CD, and documentation discipline, delivering tangible business value through safer APIs, more reliable software, and faster, more confident deployments.
November 2025 TudatPy monthly update focused on strengthening reliability, expanding multi-arc capabilities, and enriching documentation and tests. Key work included completing multi-arc testing with added docstrings and .rst updates, introducing exposure functionality, and advancing consider-parameter semantics with covariance propagation. UTC support was added to the differenced time-of-arrival model with expanded unit tests, while the test suite and CI matured through re-enabled tests, adjusted parallelism, and tolerance tuning. Overall, these efforts improved modeling accuracy for multi-arc scenarios, reduced regression risk through comprehensive tests, and enhanced maintainability via clearer docs and exposed internals.
November 2025 TudatPy monthly update focused on strengthening reliability, expanding multi-arc capabilities, and enriching documentation and tests. Key work included completing multi-arc testing with added docstrings and .rst updates, introducing exposure functionality, and advancing consider-parameter semantics with covariance propagation. UTC support was added to the differenced time-of-arrival model with expanded unit tests, while the test suite and CI matured through re-enabled tests, adjusted parallelism, and tolerance tuning. Overall, these efforts improved modeling accuracy for multi-arc scenarios, reduced regression risk through comprehensive tests, and enhanced maintainability via clearer docs and exposed internals.
Month: 2025-10 – TudatPy team performance focused on stability, correctness, and maintainability of the exposure/trajectory module. No new features were released this month for tudat-team/tudatpy; primary activity centered on validating and correcting API exposure functions. The critical change fixed a bug in the departure_node argument naming to align with the intended parameter, reducing runtime error risk and improving code clarity.
Month: 2025-10 – TudatPy team performance focused on stability, correctness, and maintainability of the exposure/trajectory module. No new features were released this month for tudat-team/tudatpy; primary activity centered on validating and correcting API exposure functions. The critical change fixed a bug in the departure_node argument naming to align with the intended parameter, reducing runtime error risk and improving code clarity.
September 2025 Tudatpy monthly summary: Delivered a set of stability and quality improvements across the core library and supporting tooling, with a strong emphasis on robustness, maintainability, and easier release readiness. The month focused on stabilizing the test suite, refactoring core structures for better long-term performance, strengthening CI/CD pipelines, and enhancing documentation and environment configuration to accelerate adoption and reduce operational risk. Key business value: reduced test flakiness and debugging time, more reliable builds and releases, clearer API boundaries, and improved developer onboarding through better tooling and docs. Core outcomes include: - Damped state and damping system adjustments: Refactored the damped state structure by removing the time template and corrected damping object creation and related logic, enabling cleaner state management and fewer runtime issues. - Test suite stabilization: Fixed test cases and adjusted tests to stabilize the suite, reducing flaky test behavior and improving confidence in regressions. - CI/CD and environment improvements: Updated CI workflow and environment configuration (build_and_test.yml, environment.yaml, and ReadTheDocs tooling) to reflect current practices and ensure reliable builds and docs generation. - Code cleanup and modernization: Comprehensive code hygiene work, including correcting imports, updating module headers, deprecation handling, removing legacy dependencies, and improving initialization and exports for better maintainability. - Documentation and packaging enhancements: Added docstrings, updated docs wording, synchronized versioning, and explored CSPICE integration from conda-forge, strengthening external API exposure and release readiness. Selected contributions spanned multiple commits across the feature and bug categories, including core refactors (ccadda3cf3b90a57509a2a0f96cc3345b9814e0b), damping fixes (ae240110728ca76fbe2cfdb3517b12443e7baa15), test stabilization (64ed9cf8f7fc4be0fd2449b055abb4236c88186c, 121b135302e4891c3bc7c190dbd527065bb2dc78, 4dbcfb1a9446fbcce239f82d083ca21e94cb5d40), CI/workflow and docs updates (571fcc04d1aea25040839d4d607b99a42d6ab0c2, 913138b42df3f6f3d23870aa0c1925d4238f93b2, 4e18a5fe409ecd42be48a60582093de392e5862d), and versioning/docs related work (9fba819cac2fd7ef40a1c3384a29dc7a8f4e459f, 0ebed2e6eb630ef640305e016dd219b09c49d013, 821ee328cb2094e516694fc457cda09f18e42003).
September 2025 Tudatpy monthly summary: Delivered a set of stability and quality improvements across the core library and supporting tooling, with a strong emphasis on robustness, maintainability, and easier release readiness. The month focused on stabilizing the test suite, refactoring core structures for better long-term performance, strengthening CI/CD pipelines, and enhancing documentation and environment configuration to accelerate adoption and reduce operational risk. Key business value: reduced test flakiness and debugging time, more reliable builds and releases, clearer API boundaries, and improved developer onboarding through better tooling and docs. Core outcomes include: - Damped state and damping system adjustments: Refactored the damped state structure by removing the time template and corrected damping object creation and related logic, enabling cleaner state management and fewer runtime issues. - Test suite stabilization: Fixed test cases and adjusted tests to stabilize the suite, reducing flaky test behavior and improving confidence in regressions. - CI/CD and environment improvements: Updated CI workflow and environment configuration (build_and_test.yml, environment.yaml, and ReadTheDocs tooling) to reflect current practices and ensure reliable builds and docs generation. - Code cleanup and modernization: Comprehensive code hygiene work, including correcting imports, updating module headers, deprecation handling, removing legacy dependencies, and improving initialization and exports for better maintainability. - Documentation and packaging enhancements: Added docstrings, updated docs wording, synchronized versioning, and explored CSPICE integration from conda-forge, strengthening external API exposure and release readiness. Selected contributions spanned multiple commits across the feature and bug categories, including core refactors (ccadda3cf3b90a57509a2a0f96cc3345b9814e0b), damping fixes (ae240110728ca76fbe2cfdb3517b12443e7baa15), test stabilization (64ed9cf8f7fc4be0fd2449b055abb4236c88186c, 121b135302e4891c3bc7c190dbd527065bb2dc78, 4dbcfb1a9446fbcce239f82d083ca21e94cb5d40), CI/workflow and docs updates (571fcc04d1aea25040839d4d607b99a42d6ab0c2, 913138b42df3f6f3d23870aa0c1925d4238f93b2, 4e18a5fe409ecd42be48a60582093de392e5862d), and versioning/docs related work (9fba819cac2fd7ef40a1c3384a29dc7a8f4e459f, 0ebed2e6eb630ef640305e016dd219b09c49d013, 821ee328cb2094e516694fc457cda09f18e42003).
August 2025 TudatPy monthly summary: Key features delivered include Time handling enhancements with pickling/serialization and a corrected Time constructor for accurate numerical representations, and the acceleration scaling and area-to-mass scaling estimation framework with new parameters and refactored partials. Mars DTM atmosphere tests were consolidated to improve test organization. Major bugs fixed include empirical acceleration parameter naming and robust initialization to prevent crashes, Windows/MSVC build flag issues resolved, and test suite stabilization. Overall impact: improved state persistence and IPC, enhanced orbit estimation fidelity and model fidelity, cross-platform reliability, and maintainable test architecture. Technologies demonstrated: Python TudatPy development, pickling/serialization, numerical precision, C++ Windows build troubleshooting, partial derivatives refactoring, and API parameter exposure.
August 2025 TudatPy monthly summary: Key features delivered include Time handling enhancements with pickling/serialization and a corrected Time constructor for accurate numerical representations, and the acceleration scaling and area-to-mass scaling estimation framework with new parameters and refactored partials. Mars DTM atmosphere tests were consolidated to improve test organization. Major bugs fixed include empirical acceleration parameter naming and robust initialization to prevent crashes, Windows/MSVC build flag issues resolved, and test suite stabilization. Overall impact: improved state persistence and IPC, enhanced orbit estimation fidelity and model fidelity, cross-platform reliability, and maintainable test architecture. Technologies demonstrated: Python TudatPy development, pickling/serialization, numerical precision, C++ Windows build troubleshooting, partial derivatives refactoring, and API parameter exposure.
July 2025 TudatPy monthly summary focusing on delivering robust extrapolation workflows, core stability improvements, and CI/build reliability, while expanding test coverage and documentation. The month emphasized hardening numerical propagation, memory-conscious refactors, and preparatory work for larger Tudat summer milestones.
July 2025 TudatPy monthly summary focusing on delivering robust extrapolation workflows, core stability improvements, and CI/build reliability, while expanding test coverage and documentation. The month emphasized hardening numerical propagation, memory-conscious refactors, and preparatory work for larger Tudat summer milestones.
June 2025 TudatPy monthly summary focusing on robustness, API usability, and diagnostics to strengthen reliability of scientific simulations and ease of use for researchers. Delivered targeted fixes and API enhancements across TudatPy, improving correctness, reusability, and cross-platform stability while demonstrating solid Python engineering, SPICE integration, and testing discipline.
June 2025 TudatPy monthly summary focusing on robustness, API usability, and diagnostics to strengthen reliability of scientific simulations and ease of use for researchers. Delivered targeted fixes and API enhancements across TudatPy, improving correctness, reusability, and cross-platform stability while demonstrating solid Python engineering, SPICE integration, and testing discipline.
May 2025 monthly summary for tudatpy and tudat. Delivered enhanced atmospheric exposure modeling (NRLMSISE) with a new calculation path and expanded test coverage, integrated IAU rotation parameters, and comprehensive spherical harmonics (SH) enhancements including performance optimizations and torque corrections. Major bug fixes addressed exposure calculation accuracy, partial tests, and various test-suite reliability issues. Build and CI modernization reduced friction and improved reliability (upgraded build toolchain, silenced warnings, and CI housekeeping). These changes increase model fidelity, reduce deployment risk, and enable faster future iterations, with a strong emphasis on business value and technical robustness.
May 2025 monthly summary for tudatpy and tudat. Delivered enhanced atmospheric exposure modeling (NRLMSISE) with a new calculation path and expanded test coverage, integrated IAU rotation parameters, and comprehensive spherical harmonics (SH) enhancements including performance optimizations and torque corrections. Major bug fixes addressed exposure calculation accuracy, partial tests, and various test-suite reliability issues. Build and CI modernization reduced friction and improved reliability (upgraded build toolchain, silenced warnings, and CI housekeeping). These changes increase model fidelity, reduce deployment risk, and enable faster future iterations, with a strong emphasis on business value and technical robustness.
April 2025 TudatPy development focused on API reliability, model accuracy, and build/CI improvements. Delivered key API enhancements for rotation model configuration, clarified time handling, and streamlined multi-arc processing, complemented by targeted atmosphere model improvements and solid build-system tweaks.
April 2025 TudatPy development focused on API reliability, model accuracy, and build/CI improvements. Delivered key API enhancements for rotation model configuration, clarified time handling, and streamlined multi-arc processing, complemented by targeted atmosphere model improvements and solid build-system tweaks.
March 2025 (2025-03) delivered solid feature progress, targeted stability fixes, and developer-focused improvements across tudatpy. The team shipped core capabilities, stabilized simulation behavior, and enhanced diagnostics, enabling more reliable space environment modeling and faster iteration on model updates.
March 2025 (2025-03) delivered solid feature progress, targeted stability fixes, and developer-focused improvements across tudatpy. The team shipped core capabilities, stabilized simulation behavior, and enhanced diagnostics, enabling more reliable space environment modeling and faster iteration on model updates.
February 2025 — Delivered code quality tooling, feature enhancements, and stability improvements across tudatpy and tudat. Highlights include tooling and formatting updates; environment updater improvements; ramping and exposure enhancements; Tropo/Doppler/partials work; and ESTRACK meteorological integration. Also completed documentation/licensing updates and fixed critical correctness issues to improve reliability for downstream users.
February 2025 — Delivered code quality tooling, feature enhancements, and stability improvements across tudatpy and tudat. Highlights include tooling and formatting updates; environment updater improvements; ramping and exposure enhancements; Tropo/Doppler/partials work; and ESTRACK meteorological integration. Also completed documentation/licensing updates and fixed critical correctness issues to improve reliability for downstream users.
January 2025 performance summary for TudatPy and Tudat. This month focused on delivering safe, maintainable features, fixing critical data ingestion and build stability issues, and strengthening the codebase hygiene to accelerate future development. The work improves reliability for users running propagation workflows, enhances scientific accuracy in data processing, and clarifies API usage for faster onboarding and integration with downstream systems.
January 2025 performance summary for TudatPy and Tudat. This month focused on delivering safe, maintainable features, fixing critical data ingestion and build stability issues, and strengthening the codebase hygiene to accelerate future development. The work improves reliability for users running propagation workflows, enhances scientific accuracy in data processing, and clarifies API usage for faster onboarding and integration with downstream systems.
2024-12 Tudatpy: Delivered environment configuration updates, Doppler modeling enhancements, and expanded test infrastructure, driving reproducibility, stability, and deeper validation of orbital dynamics simulations.
2024-12 Tudatpy: Delivered environment configuration updates, Doppler modeling enhancements, and expanded test infrastructure, driving reproducibility, stability, and deeper validation of orbital dynamics simulations.
November 2024 Tudatpy monthly summary: Implemented the initial DSN Range Model framework and related fixes, stabilized unit tests and test infrastructure, expanded viability testing, and reinforced CI/CD and documentation. Focused on delivering business value through improved modeling capabilities, more robust tests, and clearer developer tooling.
November 2024 Tudatpy monthly summary: Implemented the initial DSN Range Model framework and related fixes, stabilized unit tests and test infrastructure, expanded viability testing, and reinforced CI/CD and documentation. Focused on delivering business value through improved modeling capabilities, more robust tests, and clearer developer tooling.
October 2024 TudatPy monthly summary focusing on reliability and maintainability improvements in ODF file reading with targeted tests and code hygiene.
October 2024 TudatPy monthly summary focusing on reliability and maintainability improvements in ODF file reading with targeted tests and code hygiene.

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