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Data & Orbit
What is Space Physics?

Space physics is the study of solar and planetary space environments with special focus on the origin, evolution, and interactions of particulate matter and electromagnetic fields in a wide variety of space plasmas. Because they include electrically charged electrons and ions in addition to neutrals, plasmas interact with electric and magnetic fields very differently than gas consisting of only neutral atoms or molecules.

While most gases that we experience in everyday life are composed of neutral particles, most visible matter in the universe exists in the plasma state. Space provides a natural and large scale laboratory for the study of plasma processes.

Among other things, space physics seeks to understand the complex plasma environment of the Earth, ranging from the ionosphere to the very complex magnetosphere controlled by the geomagnetic field to the solar wind blowing nonuniformly away from the sun and enveloping the magnetosphere. Included are studies of aurora, geomagnetic storms and substorms, cosmic ray acceleration and propagation, solar flares, etc.


The SPDF service gateway allows users to access data through a number of different data services while also providing information on which spacecraft are accessible through which service(s) and to which space physics discipline(s) data services and spacecraft belong.

In addition to going directly to data services by name, the data services can be approached from a spacecraft (or discipline) perspective. If users select data service by spacecraft, they first choose a spacecraft resulting in applicable data services (and disciplines) being highlighted. Users then select the data service. Information is available on each spacecraft, including, e.g., instruments on board, launch dates, data held elsewhere. A description of each space physics discipline is also available.

Electronically accessible data reach back to 1963 from the IMP 1 spacecraft held as part of the OMNI data set. Other data start from the early 1970's (e.g., Pioneer 10 and 11, IMP 8) and include much heliospheric, magnetospheric, ionospheric and upper-atmospheric data from all NASA and some non-NASA space physics missions of the subsequent years. NSSDC still holds most data from most 1950's-1970's missions offline. One may read of these through the NSSDC Master Catalog.

Our Space Physics data services are briefly described below. Some data services yield simple file retrieval, while others provide data subsetting, graphical display, etc.

+ CDAWeb

Many data sets are available through the Coordinated Data Analysis Web (CDAWeb) service and the data coverage continues to grow. These are largely, but not exclusively, magnetospheric data and nearby solar wind data of the ISTP era (1992-present) at time resolutions of approximately a minute. The CDAWeb service provides graphical browsing, data subsetting, screen listings, file creations and downloads (ASCII or CDF).

+ OMNI and OMNIWeb

The OMNI data set is an hourly-resolution 1963-near_current data set with near-Earth solar wind magnetic field and plasma data, solar and geomagnetic activity indices, and energetic particle flux data. The data set was created at NSSDC by interspersing, after cross-normalizing, field and plasma data from each of several spacecraft. It continues to be extended. The OMNIWeb interface provides access to this data set with graphical browse and subsetting capability, to ftp-accessible annual ASCII OMNI files, and to higher resolution data sets contributing to OMNI.


COHOWeb is another graphical browse and data subset/retrieval tool. It provides access to a series of spacecraft-specific hourly resolution data sets wherein all records are of a common format and content, with magnetic field, plasma and spacecraft position data. There are data sets for virtually all deep-space spacecraft (Voyager, Ulysses, Pioneer, Helios, etc.)

+ FTP and FTPBrowser

In addition, many additional space physics data sets are ftp-accessible, mostly in ASCII format. Some of these have dataset-specific browse/subset/retrieve interfaces in the family of similar interfaces called FTPBrowser.


The subset of FTP/FTPBrowser-accessible data that relate to the atmosphere and ionosphere are also accessible through ATMOWeb.

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