# What’s new¶

## poliastro 0.15.2 - 2021-06-27¶

Same as 0.15.1, but fixes error in release artifact.

## poliastro 0.15.1 - 2021-06-27¶

This release fixes some bugs found after 0.15.0.

### Bugs fixed¶

• Issue #1229: Unit conversion error when using newer astroquery

• Issue #1245: Fix incorrect dependency specification for extras

• [No issue number] Allow Plotly 5.0

• [No issue number] Enable intersphinx support for sphinx-hoverxref

Do you want to help with the remaining ones? Check the current list here!

### Contributors¶

This is the complete list of the people that contributed to this release, with a + sign indicating first contribution.

• Javier Tegedor+

• Juan Luis Cano

## poliastro 0.15.0 - 2021-05-14¶

This new major release includes lots of API changes and enhancements, as well as the fruitful results from Google Summer of Code 2020.

### Highlights¶

• Numerous new Earth-specific capabilities! María Eugenia (Meuge) contributed lots of new features useful for studying artificial satellites, including formulas to compute the field of view and ground range in poliastro.twobody.orbit, and new experimental and classes.

• poliastro is now validated! Thanks to a NumFOCS Small Development Grant, we created a validation framework for poliastro to compare our results with GMAT and Orekit.

• Revamped website! We reorganized our domains and gave poliastro a nice front page.

• Support for Python 3.9! We also dropped support for Python 3.6, as anticipated. The next release will add support for Python 3.10, and depending on development effort we will consider dropping Python 3.7.

• Reorganized documentation following the popular Diátaxis Framework! Now our docs are splitted in four sections: Tutorials, How-to guides, Background, and Reference. We thank Daniele Procida for creating it and for being an endless source of inspiration.

• Migrated all documentation to MyST! Markdown has much wider adoption than reStructuredText, so we made the decision to switch to Markedly Structured Text, a superset of CommonMark that adds some nice features. We hope that this will make contributing to poliastro documentation easier.

• Added a community contributions procedure! We now have a top-level contrib/ directory for community contributions that are not yet ready to be part of the poliastro API. Check out the instructions and make yours!

### Bugs fixed¶

And many more smaller documentation and rendering issues introduced during the migration to MyST.

### Contributors¶

This is a complete, alphabetic list of people that contributed to this release, with a + sign indicating first contribution. This release took longer than usual, and therefore the contributors list is larger than ever!

• Abdul Moiz+

• Abhishek Anant+

• Abhishek Chaurasia

• Andrea Carballo+

• Ángel Ramírez Quispe+

• Bryan W. Weber+

• Claudia Millán+

• Dhruv Sondhi+

• Ezequiel Pássaro+

• Giuseppe Di Pasquale+

• Iago Alonso+

• Isabel González+

• Ismael Jiménez+

• Ishan Srivastava+

• Jorge Martínez Garrido

• Jos van ‘t Hof

• Juan Luis Cano Rodríguez

• Matthew Jones+

• María Eugenia Cruz

• Nickolai Belakovski+

• Nidhi Zare+

• Nihar Salunke+

• Ole Streicher

• Orestis Ousoultzoglou+

• Pablo Castro+

• Rafael Araujo Lehmkuhl+

• Rishabh Nanawati+

• Souhit Dey+

• Tomek Mrugalski

• Venkitesh+

• Yash Gondhalekar+

• Zeke Sikelianos+

## poliastro 0.14.0 - 2020-05-08¶

This major release contains crucial new features and bug fixes that have been years in the making, and is by far the most exciting release in the history of the project.

### Highlights¶

• New API to retrieve ephemerides: After a lot of iteration we introduced a new object, , to retrieve and represent ephemerides, as opposed to osculating orbits. Besides, we added convenience methods to plot them so they can be combined with objects.

• Simple API to retrieve mean elements of Solar System planets: There are many use cases for approximate, mean Keplerian elements for planet orbits: computing Spheres of Influence, designing specialized orbits… We introduced a new function that makes it way easier.

• Avoid mixing ephemerides and osculating orbits: The Orbit.from_body_ephem method was very convenient and it was used everywhere in poliastro examples because it was the simplest way to plot and analyze the orbits of the planets. However, it introduced a lot of confusion about the nature of osculating orbits and planetary ephemerides. With the introduction of objects and , this convenience method is no longer necessary, we removed almost all references to it (both in source code and examples) and we will remove it in the next release.

• Robust propagation in all eccentricity regimes: Two years ago we started working on improving our propagators for near parabolic orbits, which occur naturally when studying comets and reentry trajectories. Unfortunately, there were still problems we could not identify and we tried to compensate by adding other propagation algorithms, but none of them worked correctly in all eccentricity regimes. With a big effort and a few sleepless nights we finally fixed the implementation of our default propagator , and is now working correctly for very extreme cases and long term propagations. Give it a try!

• New color palette: We introduced a new color palette to improve the appearance of plots that include the orbits of the planets of the Solar System. We hope you love it as much as we do!

### Bugs fixed¶

• Issue #475: 🎉 Propagator mean_motion hangs for some r, v vectors around Earth (seethe gory details at the Farnocchia propagator pullrequest)

• Issue #716: Prevent Orbit creation with non scalar quantities

• Issue #726: Strange behaviour when plotting some orbits

• Issue #817: CZML extractor: timezone issues (clock.Interval and currentTime not tz-aware)

• Issue #824: Properly plot orbits in different planes

• Issue #829: Long standing typo in equinoctial elements documentation

• Issue #837: Fix R_polar_jupiter{.interpreted-text role=”const”} value

• Issue #840: vallado.lambert fails for long way transfers

• Issue #841: RAAN from LTAN calculation off by 180 degrees

• Issue #849: Changed ss.frame to ss.get_frame in documentation

• Issue #850: Duplicated sphinx extension

• Issue #859: Fix Binder

• Issue #861: Make from_sbdb tests more robust against external changes

• Issue #862: CZML tests failing locally because of non-UTC timezones

• Issue #892: Error in porkchop docstrings

• Issue #901: Fix sampling logic for closed orbits

• Issue #902: Error while reading Halley’s comet from DASTCOM5

• Issue #907: Orbit.propagate_to_anomaly freezes

• Issue #911: CZMLExtractor has no API documentation

• Issue #916: Orbit.from_sbdb raises unhelpful error if no object was found

### Other news¶

• Support for Python 3.8! The next release will add support for Python 3.9 and remove support for 3.6, following NEP29.

• Benchmarks moved to a new location!

• Switched to Azure Pipelines, so we are again testing in all operative systems.

• We do not ship tests anymore! To run the tests, you will now need to clone poliastro repository.

### Contributors¶

This is a complete, alphabetic list of people that contributed to this release, with a + sign indicating first contribution.

• Abdallah+

• Abhishek Chaurasia+

• Andrej Rode+

• Greg Lindahl+

• Ian DesJardin+

• Jorge Martínez

• Jos van ‘t Hof+

• Juan Luis Cano Rodríguez

• María Eugenia Cruz

• Nanubala Gnana Sai+

• Sarthak Jain+

• Shreyas Bapat

• Sundesh Gupta+

• Syed Osama Hussain+

• Tomek Mrugalski+

• Priyanshu Rohilla+

## poliastro 0.13.1 - 2019-12-20¶

This release fixes some bugs found after 0.13.0.

### Bugs fixed¶

• Issue #715: Fix docs and dependencies for most recent nbsphinx release

• Issue #761: Fix unnoticed doctest failures due to unit problems

• Issue #776: Fix typing error in test

• Issue #781: Fix broken binder embedded hyperlinks

• Issue #821: Fix timezone issues in CZML extraction

• [No issue number] Avoid looking for tests in virtual environments

• [No issue number] Remove executable bit from some Python sources

Do you want to help with the remaining ones? Check the current list here!

### Contributors¶

This is the complete list of the people that contributed to this release, with a + sign indicating first contribution.

• Juan Luis Cano

• Ole Streicher

• Shreyas Bapat

## poliastro 0.13.0 - 2019-08-05¶

This major release is packed with new features, especially the new CZML exporting capabilities and miscellaneous additions and important fixes on the algorithmic side. It also sets a new high in terms of contributors, which makes us extremely proud and thankful!

### Highlights¶

• Export Orbit objects to CZML: There is new experimental functionality to export to CZML, the JSON format used by the Cesium visualization system. This complements poliastro capabilities and allows users to produce gorgeous visualizations, like the one below. We also kickstarted a new project called czml3 a Python 3 interface to CZML, to support all these new capabilities, and created a base Cesium application so you can quickly start experimenting. Let us know your thoughts!

• 2D plots are static by default: Getting Plotly properly installed is a bit more difficult than just a pip install nowadays, and it turns out we alienated some of our non-Jupyter users by pushing it too soon (especially those of you that use Spyder). We have tried hard in this release to make the default plotting work everywhere by sticking again to matplotlib, while allowing more proficient users to install all the necessary components to have interactive visualizations going. If you still find issues, tell us!

• New Lambert maneuver: After a long time, Lambert transfers are finally a , which means it shares the same API as Hohmann and bielliptic transfers among others, making it easier to use.

• Lots of new propagators: And when we say _lots_, we mean it! Lots of authors claim their propagator is “universal”, but to our knowledge this is almost always a slight overstatement. To enrich poliastro with new propagation methods and allow users to test them with all kinds of crazy orbits (especially quasy-parabolic ones) we implemented a ton of new propagators, all sharing the same API. You have more information in this article about the new propagators in our blog.

• Python 3.6+ only: Python 3.5 has done a great service and will still be supported by Astropy a few more months, but we already wanted to move on and embrace fixed-order dictionaries, f-strings, and decimal separators, among others. This release of poliastro requires Python 3.6 or higher to work. We are also getting ready for Python 3.8!

• Export Orbit objects to CZML: There is new experimental functionality to export to CZML, the JSON format used by the Cesium visualization system. This complements poliastro capabilities and allows users to produce gorgeous visualizations, like the one below. We also kickstarted a new project called czml3 a Python 3 interface to CZML, to support all these new capabilities, and created a base Cesium application so you can quickly start experimenting. Let us know your thoughts!

• 2D plots are static by default: Getting Plotly properly installed is a bit more difficult than just a pip install nowadays, and it turns out we alienated some of our non-Jupyter users by pushing it too soon (especially those of you that use Spyder). We have tried hard in this release to make the default plotting work everywhere by sticking again to matplotlib, while allowing more proficient users to install all the necessary components to have interactive visualizations going. If you still find issues, tell us!

• New Lambert maneuver: After a long time, Lambert transfers are finally a , which means it shares the same API as Hohmann and bielliptic transfers among others, making it easier to use.

• Lots of new propagators: And when we say _lots_, we mean it! Lots of authors claim their propagator is “universal”, but to our knowledge this is almost always a slight overstatement. To enrich poliastro with new propagation methods and allow users to test them with all kinds of crazy orbits (especially quasy-parabolic ones) we implemented a ton of new propagators, all sharing the same API. You have more information in this article about the new propagators in our blog.

• Python 3.6+ only: Python 3.5 has done a great service and will still be supported by Astropy a few more months, but we already wanted to move on and embrace fixed-order dictionaries, f-strings, and decimal separators, among others. This release of poliastro requires Python 3.6 or higher to work. We are also getting ready for Python 3.8!

### New features¶

• More orbit creation methods: Both to interface with external systems (from_sbdbs()) and to build new special orbits ().

• Non-planar transfer maneuvers: https://github.com/poliastro/poliastro/pull/599

• Arrival velocity contour lines in porkchop plots: Now porkchop plots are a bit richer and display arrival velocity as well.

• Experimental Geocentric Solar Ecliptic frame: We introduced an experimental implementation of a Geocentric Solar Ecliptic frame, which is used for studies of Near Earth Objects. Please help us validating it!

• Plot orbit trails: Apart from plotting orbits as solid or dashed lines, now it’s easier to visualize the actual direction of the orbit using trail=True.

• New :code:change_attractor method: Now it’s easier to translate the origin of an orbit (withing the patched conics framework) to study it from a different perspective using the method.

• New :code:SpheroidLocation: We also added a experimental , which tries to generalize to other bodies.

• New orbital properties: Angular momentum, mean anomaly, time of perifocal passage of are now very easy to compute.

### Other news¶

• Updated minimum Astropy version to 3.2 and Plotly to 4.0.

• Updated planetary poliastro.constants, plan to add more.

• Better development workflow, issue templates on GitHub, tools to reformat the code.

### Contributors¶

This is a complete, alphabetic list of people that contributed to this release, with a + sign indicating first contribution. Again we had an all-time high number of contributors, thanks everybody ❤️

• Angala+

• Divyansh Raina+

• Eleftheria Chatziargyriou+

• Helge Eichhorn

• Himanshu Garg

• Iván Castro+

• Jesús Jiménez+

• Jorge Martinez

• Juan Luis Cano

• Manuel Kaufmann+

• María Eugenia Cruz+

• Ritwik Saha+

• Shreyas Bapat

• Siro Moreno+

• Sky+

• Vedang Naik+

• Emily Selwood

## poliastro 0.12.0 - 2019-02-21¶

This major release brings lots of new features, several breaking changes that improve the overall consistency of the library, and a stronger bet on Plotly as the default plotting backend, as well as the usual bug fixes. This has been the biggest release in terms of contributors so far and we feel we are reaching a tipping point, which makes us extremely proud and also busier!

### Highlights¶

• New defaults for plotting: We are now switching to Plotly for the default plotting backend as it has better interactive capabilities in the notebook, while keeping the matplotlib backend for publication-quality, 2D static plots. There might be some rough edges in the installation or in trying to keep the aspect ratio still, so we ask for user feedback.

• Reorganization of propagation capabilities: We made some changes to the propagation APIs to be more coherent and flexible and simpler to understand for new contributors. We removed some features from to keep it simpler while moving some of them to , and we splitted by adding . At the cost of some breakage, we think this is a positive change that will make the library more maintainable in the future and reduce the number of bugs.

• Better integration with reference frames: We took one step further in our endeavor to integrate better with Astropy reference frames by adding a method that accepts any frame, be it inertial or not.

• Refactor of Orbit objects: The was designed a long time ago and some design choices prevented all its orbital properties to appear in the documentation, while also making people think that they had to use an internal property. After a simple refactor this is no longer the case, and the code is still fast while being much simpler to understand. Did you know that you can compute the semilatus rectum, the modified equinoctial elements, the eccentricity vector or the mean motion of an ? Now there are no excuses!

### Backwards incompatible changes¶

• We now follow the Black style guide 😎

• The API docs are now more organized and should be easier to browse and understand.

• We are working towards documenting how to use poliastro in JupyterLab, please tell us about anything we may have missed.

• poliastro will be presented at the fifth PyCon Namibia 🇳🇦

### Contributors¶

This is the complete list of the people that contributed to this release, with a + sign indicating first contribution.

• Juan Luis Cano

• Shreyas Bapat

• Jorge Martínez+

• Hrishikesh Goyal+

• Sahil Orionis+

• Helge Eichhorn+

• Antonina Geryak

## poliastro 0.11.1 - 2018-12-27¶

This release fixes some bugs found in 0.11.0 and prepares the ground for bigger API and code changes.

### Bugs fixed¶

• Issue #281: Plotly graphs not showing in documentation

• Issue #469: OrbitPlotter.set_frame error

• Issue #476: Error when representing orbits with no reference frame

• Issue #482: Non deterministic legend layout

• Issue #492: Better error for collinear orbits in Lambert and corner case arithmetic

Do you want to help with the remaining ones? Check the current list here! <https://github.com/poliastro/poliastro/issues?q=is%3Aopen+is%3Aissue+label%3Abug>

### Contributors¶

This is the complete list of the people that contributed to this release, with a + sign indicating first contribution.

• Juan Luis Cano

• Shreyas Bapat

• Ole Streicher+

• Antoniya Karpova+

## poliastro 0.11.0 - 2018-09-21¶

This short cycle release brought some new features related to the three body problem, as well as important changes related to how reference frames are handled in poliastro.

### Highlights¶

• Support for Python 3.7 has been added to the library, now that all the depdendencies are easily available there. Currently supported versions of Python are 3.5, 3.6 and 3.7.

### New features¶

• Lagrange points: The new experimental module poliastro.threebody.restricted contains functions to compute the Lagrange points in the circular restricted three body problem (CR3BP). It has been validated only approximately, so use it at your own risk.

• Flybys: New functions to compute the exit velocity and turn angle have been added to the new module poliastro.threebody.flybys. The B-plane aim point can be specified and the result will be returned in the correct reference frame. This feature was motivated by the Parker Solar Probe mission, and you can read an example on how to analyze parts of its trajectory using poliastro.

• Reference frames: We addded experimental support for reference frames in poliastro objects. So far, the objects were in some assumed reference frame that could not be controlled, leading to some confusion by people that wanted some specific coordinates. Now, the reference frame is made out explicit, and there is also the possibility to make a limited set of transformations. This framework will be further developed in the next release and transformations to arbitrary frames will be allowed. Check out the poliastro.frames module for more information.

### Bugs fixed¶

• Issue #450: Angles function of safe API have wrong docstrings

Do you want to help with the remaining ones? Check the current list here! <https://github.com/poliastro/poliastro/issues?q=is%3Aopen+is%3Aissue+label%3Abug>

### Contributors¶

This is the complete list of the people that contributed to this release, with a + sign indicating first contribution.

• Juan Luis Cano

• Nikita Astrakhantsev

• Shreyas Bapat

• Daniel Lubián+

• Emily Selwood+

## poliastro 0.10.0 - 2018-07-21¶

This major release brings important changes from the code perspective (including a major change in the structure of the library), several performance improvements and a new infrastructure for running timing benchmarks, as well as some new features and bug fixes.

### Highlights¶

• Major change in the structure of poliastro codebase: We separated the high level, units safe functions from the low level, fast ones, with the subsequent improvement in code quality. With this change we effectively communicate where “core” algorithms should go, make easier for future contributors to add numerical functions, and improved the overall quality of the library.

• Upgrade to new SciPy ODE solvers: We wrote our own version of Dormand-Prince 8(5,3) based on the new IVP framework in SciPy 1.0 to take advantage of event detection, dense output and other fancy features. In particular, the method now uses dense output when available, therefore removing the need to propagate the orbit repeatedly.

• New infrastructure for benchmarks: We started publishing timing benchmarks results using Airspeed Velocity, a Python framework for writing, running, studying and publishing benchmarks. Besides, we bought a dedicated machine to run them with as much precision as we can. Please check them out and consider adding new benchmarks as well!

• Several performance improvements: Now that we are tracking performance, we dedicated some time during this release to fix some performance regressions that appeared in propagation, improving the behavior near parabolic orbits, and accelerating (even more!) the Izzo algorithm for the Lambert problem as well as some poliastro utilities.

• New Continuous Integration infrastructure: We started to use CircleCI for the Linux tests, the coverage measurements and the documentation builds. This service has faster machines and better support for workflows, which significantly reduced the build times and completely removed the timeouts that were affecting us in Travis CI.

• Plotly backends now stable: We fixed some outstanding issues with the 2D Plotly backend so now it’s no longer experimental. We also started refactoring some parts of the plotting module and prepared the ground for the new interactive widgets that Plotly 3.0 brings.

### New features¶

• New continuous thrust/low thrust guidance laws: We brought some continuous thrust guidance laws for orbital maneuvers that have analytical solution, such as orbit raising combined with inclination change, eccentricity change and so forth. This is based on the Master Thesis of Juan Luis Cano, “Study of analytical solutions for low-thrust trajectories”, which provided complete validation for all of these laws and which can be found on GitHub.

• More natural perturbations: We finished adding the most common orbital perturbations, namely Solar radiation pressure and J3 perturbation. We could not reach agreement with the paper for the latter, so if you are considering using it please read the discussion in the original pull request and consider lending us a hand to validate it properly!

• New dark mode for matplotlib plots: We added a dark parameter to OrbitPlotter objects so the background is black. Handy for astronomical purposes!

### Bugs fixed:¶

Besides some installation issues due to the evolution of dependencies, these code bugs were fixed:

• Issue #345: Bodies had incorrect aspect ratio in OrbitPlotter2D

• Issue #369: Orbit objects cannot be unpickled

• Issue #382: Orbit.from_body_ephem returns wrong orbit for the Moon

• Issue #385: Sun Incorrectly plotted in plot_solar_system

### Backward incompatible changes¶

• Some functions have been moved to :py:mod:poliastro.core.

### Contributors¶

This is the complete list of the people that contributed to this release, with a + sign indicating first contribution.

• Juan Luis Cano

• Nikita Astrakhantsev

• Shreyas Bapat

• jmerskine1+

## poliastro 0.9.1 - 2018-05-11¶

This is a minor release that fixes one single issue:

Thanks to Joan Fort Alsina for reporting.

## poliastro 0.9.0 - 2018-04-25¶

This major release received lots of improvements in the 2D plotting code and propagation functions, introduced the new perturbation framework and paved the way for the Python in Astronomy 2018 workshop and the Google Summer of Code 2018 program.

### New features¶

• New experimental 2D Plotly backend: A new class was introduced that uses Plotly instead of matplotlib for the rendering. There are still some issues that should be resolved when we take advantage of the latest Plotly version, hence the “experimental” nature.

• New propagators: A new Keplerian propagator mean_motion() was introduced that has better convergence properties than kepler(), so now the user can choose.

• New perturbation functions: A new module poliastro.twobody.perturbations was introduced that contains perturbation accelerations that can be readily used with . So far we implemented J2 and atmospheric drag effects, and we will add more during the summer. Check out the User Guide for examples!

• Support for different propagators in sampling: With the introduction of new propagators and perturbation accelerations, now the user can easily sample over a period of time using any of them. We are eager to see what experiments you come up with!

• Easy plotting of the Solar System: A new function plot_solar_system() was added to easily visualize our inner or complete Solar System in 2D plots.

### Other highlights¶

• poliastro participates in Google Summer of Code thanks to OpenAstronomy! More information in the poliastro blog.

• poliastro will be presented at the Python in Astronomy 2018 workshop to be held at Center for Computational Astrophysics at the Flatiron Institute in New York, USA. You can read more details about the event here.

### New contributors¶

This is the complete list of the people that contributed to this release, with a + sign indicating first contribution.

• Juan Luis Cano

• Pablo Galindo+

• Matt Ettus+

• Shreyas Bapat+

• Ritiek Malhotra+

• Nikita Astrakhantsev+

### Bugs fixed:¶

• Issue #294: Default steps 2D plots were too visible

## poliastro 0.8.0 - 2017-11-18¶

This is a new major release, focused on bringing 3D plotting functions and preparing the material for the Open Source Cubesat Workshop.

### New features¶

• Sampling method for objects that returns an array of positions. This was already done in the plotting functions and will help providing other applications, such as exporting an Orbit to other formats.

• 3D plotting functions: finally poliastro features a new high level object, , that uses Plotly to represent orbit and trajectories in 3D. The venerable notebook about the trajectory of rover Curiosity has been updated accordingly.

• Propagation to a certain date: now apart from specifying the total elapsed time for propagation or time of flight, we can directly specify a target date in .

• Hyperbolic anomaly conversion: we implemented the conversion of hyperbolic to mean and true anomaly to complement the existing eccentric anomaly functions and improve the handling of hyperbolic orbits in poliastro.twobody.angles.

### Other highlights¶

• poliastro is now an Astropy affiliated package, which gives the project a privileged position in the Python ecosystem. Thank you, Astropy core developers! You can read the evaluation here.

• poliastro will be presented at the first Open Source Cubesat Workshop to be held at the European Space Operations Centre in Darmstadt, Germany. You can read the full program of the event here.

### New contributors¶

This is the complete list of the people that contributed to this release, with a + sign indicating first contribution.

• Juan Luis Cano

• Antonio Hidalgo

• mattrossman+

• Roshan Jossey+

### Bugs fixed:¶

• Issue #275: Converting from true to mean anomaly fails for hyperbolic orbits

### Backward incompatible changes¶

• The ephem module has been removed in favor of the astropy.coordinates.get_body_barycentric_posvel function.

## poliastro 0.7.0 - 2017-09-15¶

This is a new major release, which adds new packages and modules, besides fixing several issues.

### New features:¶

• NEOS package: a new package has been added to poliastro, neos package. It provides several ways of getting NEOs (Near Earth Objects) data from NASA databases, online and offline.

• New patched conics module. New module containing a function to compute the radius of the Sphere of Influence (SOI).

• Use Astropy for body ephemerides. Instead of downloading the SPK files ourselves, now we use Astropy builtin capabilities. This also allows the user to select a builtin ephemerides that does not require external downloads. See Issue #131 for details.

• Coordinates and frames modules: new modules containing transformations between ICRS and body-centered frame, and perifocal to body_centered, coordinates as well as Heliocentric coordinate frame in frames based on Astropy for NEOs.

• Pip packaging: troublesome dependencies have been released in wheel format, so poliastro can now be installed using pip from all platforms.

• Legend plotting: now label and epoch are in a figure legend, which ends with the ambiguity of the epochs when having several plots in the same figure.

### Other highlights:¶

• Joined Open Astronomy: we are now part of Open Astronomy, a collaboration between open source astronomy and astrophysics projects to share resources, ideas, and to improve code.

• New constants module: poliastro has now a constants module, with GMs and radii of solar system bodies.

• Added Jupyter examples: poliastro examples are now available in the documentation as Jupyter notebooks, thanks to nbsphinx.

• New Code of Conduct: poliastro community now has a Code of conduct.

• Documentation update: documentation has been updated with new installation ways, propagation and NEOs examples, “refactored” code and images, improved contribution guidelines and intersphinx extension.

• New success stories: two new success stories have been added to documentation.

• Bodies now have a parent. It is now possible to specify the attractor of a body.

• Relative definition of Bodies. Now it is possible to define Body parameters with respect to another body, and also add any number of properties in a simple way.

### New contributors¶

Thanks to the generous SOCIS grant from the European Space Agency, Antonio Hidalgo has devoted three months developing poliastro full time and gained write access to the repository.

This is the complete list of the people that contributed to this release, with a + sign indicating first contribution.

• Juan Luis Cano

• MiguelHB+

• Antonio Hidalgo+

• Zac Miller+

• Fran Navarro+

• Pablo Rodríguez Robles+

### Bugs fixed:¶

• Issue #205: Bug when plotting orbits with different epochs.

• Issue #128: Missing ephemerides if no files on import time.

• Issue #131: Slightly incorrect ephemerides results due to improper time scale.

• Issue #130: Wrong attractor size when plotting different orbits.

### Backward incompatible changes:¶

• Non-osculating orbits: removed support for non-osculating orbits. plotting.plot() calls containing osculating parameter should be replaced.

## poliastro 0.6.0 - 2017-02-12¶

This major release was focused on refactoring some internal core parts and improving the propagation functionality.

### Highlights:¶

• Support Python 3.6. See #144.

• Introduced Orbit objects to replace State ones. The latter has been simplified, reducing some functionality, now their API has been moved to the former. See the User Guide and the examples for updated explanations. See #135.

• Allow propagation functions to receive a callback. This paves the way for better plotting and storage of results. See #140.

## poliastro 0.5.0 - 2016-03-06¶

This is a new major release, focused on expanding the initial orbit determination capabilities and solving some infrastructure challenges.

### New features:¶

• Izzo’s algorithm for the Lambert problem: Thanks to this algorithm multirevolution solutions are also returned. The old algorithm is kept on a separate module.

### Other highlights:¶

• Documentation on Read the Docs: You can now browse previous releases of the package and easily switch between released and development versions.

• Mailing list: poliastro now has a mailing list hosted on groups.io. Come and join!

• Clarified scope: poliastro will now be focused on interplanetary applications, leaving other features to the new python-astrodynamics project.

### Bugs fixed:¶

• Issue #110: Bug when plotting State with non canonical units

### Backward incompatible changes:¶

• Drop Legacy Python: poliastro 0.5.x and later will support only Python 3.x. We recommend our potential users to create dedicated virtual environments using conda or virtualenv or to contact the developers to fund Python 2 support.

• Change lambert function API: The functions for solving Lambert’s problem are now [generators](), even in the single revolution case. Check out the User Guide for specific examples.

• Creation of orbits from classical elements: poliastro has reverted the switch to the semilatus rectum $$p$$ instead of the semimajor axis $$a$$ made in 0.4.0, so $$a$$ must be used again. This change is definitive.

## poliastro 0.4.2 - 2015-12-24¶

Fixed packaging problems.

## poliastro 0.4.0 - 2015-12-13¶

This is a new major release, focused on improving stability and code quality. New angle conversion and modified equinoctial elements functions were added and an important backwards incompatible change was introduced related to classical orbital elements.

### New features:¶

• Angle conversion functions: Finally brought back from poliastro 0.1, new functions were added to convert between true $$\nu$$, eccentric $$E$$ and mean $$M$$ anomaly, see #45.

• Equinoctial elements: Now it’s possible to convert between classical and equinoctial elements, as well as from/to position and velocity vectors, see #61.

• Numerical propagation: A new propagator using SciPy Dormand & Prince 8(5,3) integrator was added, see #64.

### Other highlights:¶

• Python 3.5 and NumPy 1.10 compatibility. poliastro retains compatibility with legacy Python (Python 2) and NumPy 1.9. Next version will be Python 3 only.

### Bugs fixed:¶

• Issue #62: Conversion between coe and rv is not transitive

• Issue #69: Incorrect plotting of certain closed orbits

### Backward incompatible changes:¶

• Creation of orbits from classical elements: poliastro has switched to the semilatus rectum $$p$$ instead of the semimajor axis $$a$$ to define State objects, and the function has been renamed to from_classical(). Please update your programs accordingly.

• Removed specific angular momentum $$h$$ property to avoid a name clash with the fourth modified equinoctial element, use norm(ss.h_vec) instead.

## poliastro 0.3.1 - 2015-06-30¶

This is a new minor release, with some bug fixes backported from the main development branch.

### Bugs fixed:¶

• Fixed installation problem in Python 2.

• Issue #49: Fix velocity units in ephem.

• Issue #50: Fixed ZeroDivisionError when propagating with time zero.

## poliastro 0.3.0 - 2015-05-09¶

This is a new major release, focused on switching to a pure Python codebase. Lambert problem solving and ephemerides computation came back, and a couple of bugs were fixed.

### New features:¶

• Pure Python codebase: Forget about Fortran linking problems and nightmares on Windows, because now poliastro is a pure Python package. A new dependency, numba, was introduced to accelerate the algorithms, but poliastro will use it only if it is installed.

• Lambert problem solving: New module iod to determine an orbit given two position vectors and the time of flight.

• PR #42: Planetary ephemerides computation: New module ephem with functions to deal with SPK files and compute position and velocity vectors of the planets.

• PR #38: New method parabolic() to create parabolic orbits.

• New conda package: visit poliastro binstar channel!

• New organization and logo.

### Bugs fixed:¶

• Issue #19: Fixed plotting region for parabolic orbits.

• Issue #37: Fixed creation of parabolic orbits.

## poliastro 0.2.1 - 2015-04-26¶

This is a bugfix release, no new features were introduced since 0.2.0.

• Fixed #35 (failing tests with recent astropy versions), thanks to Sam Dupree for the bug report.

• Updated for recent Sphinx versions.

## poliastro 0.2 - 2014-08-16¶

• Totally refactored code to provide a more pythonic API (see PR #14 and wiki for further information) heavily inspired by Plyades by Helge Eichhorn.

• Mandatory use of physical units through astropy.units.

• Object-oriented approach: State and classes.

• Vector quantities: results not only have magnitude now, but also direction (see for example maneuvers).

• Easy plotting of orbits in two dimensions using matplotlib.

• Module example with sample data to start testing the library.

These features were removed temporarily not to block the release and will see the light again in poliastro 0.3:

• Conversion between anomalies.

• Ephemerides calculations, will look into Skyfield and the JPL ephemerides prepared by Brandon Rhodes (see issue #4).

• Lambert problem solving.

• Perturbation analysis.