NOAA / Space Weather Prediction Center

STEREO Space Weather Beacon Information

What it means to be non-operational

The STEREO mission is run entirely by NASA. Because NASA provides a real-time broadcast of data from the spacecraft, NOAA is able to bring these STEREO data to our forecasters and to the public. NOAA will use STEREO to enhance existing products and forecasts. NOAA cannot create products which rely on STEREO data, because of the limited lifetime of the STEREO mission. In addition, the 'NOAA partner' ground stations, whose support we greatly appreciate, are not receiving monetary compensation for their contributions, and it is not reasonable to expect them to provide support for their systems all day, every day.

Every effort is being made to provide continuous data from STEREO in near-real-time. However, none of the ground stations signed on to guarantee support 24 hours per day, 7 days per week, so it is reasonable to expect the occasional outage or delay in the arrival of data. NOAA forecasters will be keeping an eye on the data flow; there is no need to report an outage to us. If you do have a question or concern, you should e-mail the responsible person at the e-mail address at the bottom of this page.

Who is tracking STEREO?

The Space Weather Prediction Center is extremely grateful to the ground stations that provide tracking of the two STEREO spacecraft. In Japan, the National Institute of Information and Communications Technology (NICT) is providing tracking from Koganei. In Germany, there are two stations: AMSAT-DL from Bochum Observatory and amateur station DL0SHF in Kiel-Ronne. In France, the Centre National D'Etudes Spatial (CNES) is providing tracking from Toulouse. We want to continue to recognize Rutherford Appleton Laboratory (RAL) in the United Kingdom which provided tracking from Chilbolton in the early years of the STEREO mission. We thank the ground station partners for their efforts which are helping to make STEREO a hugely successful mission.

Why is NOAA not providing more access to STEREO data?

The NOAA involvement in STEREO is limited to organizing the ground stations for receipt of the Space Weather Beacon and in providing the relevant data to forecasters. The STEREO Science Center processes the data and has data archive responsibilities. NOAA retrieves the real-time data from the SSC so it only makes sense that all users retrieve data from there. What SWPC has agreed to provide to customers and the general public are those tools developed for use by forecasters. That is, what you see on these STEREO pages is identical to what is being provided to SWPC forecasters.

Magnetic Field Data in RTN Coordinates

For the STEREO spacecraft a natural coordinate system is RTN (Radial-Tangential-Normal). In RTN coordinates, R points away from Sun center through the spacecraft. T is formed by the cross product of the solar rotation axis and R and lies in the solar equatorial plane. N is formed by the cross product of R and T and is the projection of the solar rotational axis on the plane of the sky. Note, this differs from the GSM (Geocentric Solar Magnetospheric) coordinate system used for ACE. In GSM, the X axis points towards the Sun along the Earth-Sun line, Z is the projection of the Earth's north dipole axis, and Y completes the orthogonal coordinate system. For practical purposes, the angle Phi has been rotated 180 degrees on the STEREO displays so that it corresponds, roughly, to Phi as shown on ACE displays.

Note on the 5 Minute Averaged Data

The 5 minute averages of STEREO in-situ data shown on this web site are computed from 1 minute sampled data. The 5 minute averages place equal weight on each minute, with no regard to the amount of data used to compute each 1 minute average.

Questions and comments concerning these pages or the operational use of STEREO Beacon data can be addressed to:

Return to SWPC STEREO main page

Last Page Update: April 18 1, 2011