Why Look at the Sun from Space?

SDO is one of fleet of satellites watching the Sun and recording the data that we use to study the solar magnetic field. The Sun was one of the first objects observed from above the Earth's atmosphere. One reason is the Sun's brightness — it was easy to see in the cameras. A more important reason was the ability to see wavelengths of light that are absorbed by the Earth's atmosphere. Although these wavelengths of light produce the ozone layer, which absorbs another wavelength, and the ionosphere, they are very useful to solar scientists. For example, the total solar irradiance measurements described in a previous post can only be made from a satellite.

What other satellites can you use to study the Sun?

Here are two sources (from many I could list) that can tell you about solar satellites from the dawn of space flight to today.

The first is Solar Satellites by Drs. Brian Dennis and Ryan Milligan. It is a web article on Scholarpedia with a list of 86 solar research satellites starting with the SOLRAD series that had its first launch in 1960. Dennis and Milligan also describe the instruments and observations on more modern satellites.

Another source is Watching the Sun from Space, which is available as a free download from the linked AJP website. This article starts with Skylab and traces the ways we observe the Sun from space. Links are provided for 27 solar missions, with data available for about 21. It also describes some orbits we haven't yet used to observe the Sun but could in the future.

Since the dawn of the Space Age during the decline of Solar Cycle 19, data from solar missions have been crucial in helping us understand the solar magnetic field and solar activity. Solar observatories in space continue to provide useful solar data and will as long as they keep flying and observing the Sun.

SDO should be around to watch Solar Cycle 25.