Our Level 1 files are in the CDF format.

Click here to access the IMPACT Level 1 Data by HTTP
Note: links to cdf-to-ascii translators provided above.

Click here to access the IMPACT Level 1 Data by FTP

Click here to go to LET L1 Data
Note: This is a link to an alternative ascii data product for LET with identical data to that found the LET Level 1 CDF files.

Click here to go to HET L2 Data (Level 1 not yet available).
Note: This link is for ASCII format files

Click here to go to HET L3 SEP Electron Event Lists
Note: This link is for ASCII format files

Click here for SWEA electron pitch angle distributions in CDF format

Click here for SWEA electron pitch angle distributions and moments in ascii format
Note: These SWEA products include electrons with energies above 45 eV only. Please see the SWEA caveat at the bottom of this page for more information.

Data is currently released for the following instruments and dates:
(please see below for an explanation of our data release schedule)
SWEA (3D Distributions) - through 2023-08-31
LET - through 2023-07-31
SEPT - through 2023-07-31
MAG - through 2023-07-31 - Access to easy downloads of modest periods of ascii data here. See above links for longer data sets via cdf translation.
STE - through 2023-08-31
SWEA (moments, PADs) - to be released soon
HET - through 2023-07-31
SIT - from Mar 15, 2007 through 2023-07-31
SWEA PADs - from Dec 1, 2006 through 2022-11-30

Right now, all calibrations should be considered preliminary. Check this website often for updates to these data files.

Caveats regarding specific data sets:
LET - Caveats are discussed here.
SEPT - Caveats are discussed here. Please be sure to use V06 or higher SEPT data files. SEPT data files in earlier versions had incorrect times.
SIT - Caveats are discussed here.
MAG - The MAG X sensor on the Ahead spacecraft experiences occasional glitches of about 1/2 nT. These glitches are extremely fast (duration of a small fraction of a second. The cause of the glitches is currently not understood and will be corrected in a future data release.
STE - Data are in counts, but IDL routines in our IMPACT SPEDAS library extensions are available for converting to physical units.
Details on the STE instrument can be found here.
SWEA caveat: Since commissioning, the SWEA instruments on both STEREO spacecraft have registered difficult to characterize degradations in the solar wind core electron energies, probably due to charging effects. The nature of the degradations are such that we cannot reliably report electron measurements below 45 eV. However, halo and higher energy electrons are unaffected. Versions 4 and higher of the SWEA 3D distribution data products have these lower energies removed. Similarly, versions 4 and higher of the SWEA pitch angle distribution products also remove these energies. Use of the SWEA pitch angle distributions for most purposes (for example, higher energy heat flux PADs) should be largely unaffected. For more information regarding these issues please contact Peter Schroeder ( IF YOU HAVE DOWNLOADED VERSION 3 or earlier FILES, THOSE FILES CONTAIN UNRELIABLE DATA BELOW 45 EV AND SHOULD BE REPLACED WITH VERSION 4.

Why Level 1 data is released approximately 2 to 3 months after acquisition:

IMPACT (and the rest of STEREO) does not receive “final” Level 0 telemetry files until 30 days after any given date. Our Co-I’s generally validate data one month at a time. This means, for example, that they won’t begin validation of January data until the beginning of March. Then a couple more weeks are needed to validate.

In the meantime, STEREO makes available "Beacon" data. This data is generally not publication quality but can be very useful for identifying events, etc. These data are available in near real-time and archived at the STEREO Science Center here.