05 December 2023 - Mission Day: 10231 - DOY: 339

Happy 10th Launch Anniversary

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SOHO 10 Years

SOHO was launched on 2 December 1995, for what was originally planned as a two-year mission. Ten years later, it's still going strong. Picture credit: Alex Lutkus
For a collection of SOHO images, see the SOHO Top 10 Images Voting Results
See also the Best of SOHO Movies pages.

Ten years of operation without a single service or tune-up is no piece of cake for a spacecraft. As anyone who has operated scientific instruments in a lab will know, it's amazing how many things can go wrong, requiring some form of intervention or repair. But that has not been an option for SOHO and its instruments - if it breaks, it's broken, and all you can do is adjust to a new reality. But miraculously, we're doing very well even after all these years.

So, while spirits are high at the SOHO operations centre at Goddard Space Flight Center and in the instrument teams around the world as SOHO is embarking on its second decade of operations, we thought we would share with you some astonishing facts about the first decade, and a sample of the diversity of SOHO images:

Some amazing numbers from SOHO's first decade

  • 140 Ph.D. theses have been written on or about SOHO data.
  • 289 scientific meetings on subjects related to SOHO appear on our meetings pages.
  • 944 news stories appear on our newsroom pages (only recorded between 1997 and 2005!).
  • 1000 comets have been found. SOHO is the most prolific comet-finder observatory of all times, and has identified almost half of all comets for which an orbit determination has been made.
  • 2300 reviewed papers using SOHO data have been published.
  • 2300 scientists (approximately) appear in the author lists of those papers (we like to say that every current solar scientist has had the chance to work with SOHO data).
  • 3230 science planning meetings have been held.
  • 2 000 000 command blocks have been sent to the spacecraft by the ground system.
  • 5 000 000 distinct files have been served by the web server.
  • 10 000 000 exposures (almost!) have been made by the CDS instrument.
  • 16 000 000 distinct hosts have been served by the web server.
  • 100 000 000 exposures have been taken by MDI! They're probably quite high on the list of "the world's most durable camera shutters". Don't try to beat it with your favourite SLR camera!
  • 266 000 000 web page requests have been served.
  • 16 000 000 000 000 bytes (16 Terabytes) of data are contained in the SOHO archive (including MDI data at Stanford).
  • 85 000 000 000 000 bytes (85 Terabytes) of web pages/data have been served from the GSFC archive.
  • 114 000 000 000 000 bytes (114 Terabytes) of web pages/data have been served over the internet when the Stanford MDI archive is included. The total amount of data given to users is quite a bit higher when offline requests are accounted for.

A celebration of SOHO images and movies

SOHO 10 Years Poster

Print media: High-res TIFF
For a collection of SOHO images, see the SOHO Top 10 Images Voting Results
Movies: Ten years of SOHO: low res (QuickTime, MPEG), high res (QuickTime, MPEG).
Spectacular cuts: low res (QuickTime, MPEG), high res (QuickTime, MPEG).
Samples from 10 years of EIT observations: low res (QuickTime), medium res (QuickTime, MPEG), high res (QuickTime, MPEG).
See also the Best of SOHO Movies pages.

Related links


• European Site • US Site


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Last modification: July 27, 2020

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