Fifteen years ago today — April 1, 1998* — a Pegasus XL originating from Vandenberg AFB carried a small satellite to study the Sun’s atmosphere.
(Coronal “loops” above the Sun’s surface, in a false-color image from TRACE. NASA image.)
The Transition Region And Coronal Explorer, or TRACE, carried a single multi-spectral instrument to
examine the three-dimensional magnetic structures which emerge through the Sun’s photosphere (the visible surface of the Sun) and define both the geometry and dynamics of the upper solar atmosphere (the transition region and corona).
In more detail, TRACE was built to achieve three primary objectives:
- follow the evolution of magnetic field structures from the solar interior to the corona;
- investigate the mechanisms of the heating of the outer solar atmosphere; and,
- determine the triggers and onset of solar flares and mass ejections.
The effectiveness of TRACE’s telescopic sensor was due to its sophisticated attitude control system, which combined magnetic-torquers, reaction wheels, and inertial gyros to maintain its pointing accuracy within 5 arc-seconds.
The TRACE mission lasted until June 2010, and produced some stunning images of our Sun.
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*April 2nd UTC.
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