The orbiting solar laboratory

The Orbiting Solar Laboratory (OSL) is an unmanned NASA space mission which will place a relatively large aperture (1.0 m) solar telescope for optical and near-ultraviolet wavelengths into a slowly precessing polar orbit, such that the spacecraft will see continuous illumination by sunlight for about 260 days per year. Focal-plane instrumentation for this telescope will produce images and spectra from 220–1000 nm with an angular resolution of about 0.13 arcsec at 500 nm. Polarization analysis will allow detailed studies of solar magnetic fields at high resolution. The spacecraft will also carry co-observing instruments to observe at ultraviolet and X-ray wavelengths with sub-arcsecond resolution. The long duration of this mission will permit thorough study of many solar phenomena whose physical behavior is rooted in small-scale dynamical processes. Complemented by a new generation of ground-based solar instrumentation, OSL will revolutionize our observational understanding of MHD processes in the solar atmosphere. The OSL mission now holds the position as the only 1992 new-start candidate in the current NASA five-year strategic plan. Based on a 1992 startup, OSL is scheduled for launch in 1997.