Transition Region and Coronal Explorer (
TRACE) was a
NASA heliophysics and
solar observatory designed to investigate the connections between fine-scale magnetic fields and the associated plasma structures on the Sun by providing high resolution images and observation of the
solar photosphere and transition region to the
corona. A main focus of the TRACE instrument is the fine structure of
coronal loops low in the solar atmosphere. TRACE is the fourth spacecraft in the
Small Explorer program, launched on April 2, 1998, and obtaining its last science image in 2010.