The Solar and Heliospheric Observatory or SOHO is by many accounts the granddaddy of modern solar astronomy. SOHO is not the first space based solar observatory but it has truly ushered in a golden age for solar physics. The mission had a primary science phase of 2 years and a overall mission lifetime of 5 years. But it has long surpassed these with enough fuel for at least another 10 years.
It launched on Dec. 2, 1995 and is still going strong, even if two of its instruments have been superseded by ones on the Solar Dynamics Observatory (SDO). Not too many spacecraft achieve this remarkable record of longevity. And its contributions to the field of heliophysics cannot be exaggerated. SDO certainly owes its existence to SOHO, in particular to the EIT and MDI instruments, the predecessors of AIA and HMI respectively.
Our admiration goes to the scientists who conceived, built, and operated the instruments, as well as those who’ve analyzed the data over the last fifteen years; the engineers, who planned and built this sturdy spacecraft and helped construct and test its instruments; and the mission operations team who have been controlling it all these years.
To get a broader perspective based on interviews with SOHO staff, click on this link to read an article about SOHO’anniversary written by Karen Fox, a Goddard Space Flight Center science writer.
So what is next for SOHO? The workhorse that is SOHO has taken a back stage to SDO but it still stands as the 24/7 watchdog of the sun providing invaluable coronagraph observations of coronal mass ejections. This is vital for space weather monitoring and despite its advanced imaging capabilities SDO does not provide coronagraph observations. (Thanks to Steele Hill, George Dimitoglou, Joe Gurman, Bernhard Fleck and the SOHO team for much of this material.)
Below are the results for the SOHO Best 10 Images: 91,257 VOTES FROM 23,990 PARTICIPANTS. This contest ran for the SOHO 10th anniversary. The first 10 images are the top 10 in order and the remaining 20 are the rest of the 30 images from the contest selection set (from the SOHO gallery entry, SOHO Top 10.)