Introduction

Why another space physics software?

At the moment, there are already a couple of well-developed Python libraries for loading space physics data, such as PySPEDAS, Speasy, and SciQLop. However, there is a lack of Python utility for direct interactions with the RESTful API provided by the MMS Science Data Center (SDC). Inspired by the Python package for CDAS web services, cdasws, this package intends to provide access to the MMS SDC web services at LASP and fills in that gap.

While the core functionality of mmspy does not differ much from that of PySPEDAS, which is to provide data from a repository to space physics researchers, it puts focus on the broader Xarray ecosystem for distributed and parallel computing with Dask, performant I/O with Zarr, and automatic unit handling with Pint. These features aim to make the most out of metadata provided in CDF files and make analysis of MMS data more intuitive, efficient, and scalable.

Installation

Required dependencies

• python (>=3.11)

• numpy (>=2.2.6)

• scipy (>=1.15.3)

• xarray (>=2025.4.0,<2026.0.0)

• dask[distributed] (>=2025.5.1,<2026.0.0)

• zarr (2.18.5)

• cdflib (>=1.3.4,<2.0.0))

• attrs (>=25.3.0,<26.0.0)

• pint-xarray (>=0.4,<0.5)

• tqdm (>=4.67.1,<5.0.0)

• matplotlib (>=3.10.3)

• requests (>=2.32.3)

• pathos (>=0.3.4)

• bigtree (>=0.29.2)

• bs4 (>=0.0.2)

• python-benedict[toml] (>=0.34.1)

• numcodecs (0.15.1)

• rocket-fft (>=0.2.5)

• astropy (>=7.1.0)

Instructions

mmspy is distributed on the Python package Index (PyPI). To install, run:

pip install mmspy