BOULDER -- The space shuttle Discovery, scheduled for takeoff Thursday, October 29, is carrying a white light coronograph (WLC), an instrument for studying the sun's corona, developed at the High Altitude Observatory of the National Center for Atmospheric Research (NCAR). The WLC is on board the Spartan 201-05, a small satellite laboratory that will be launched from Discovery and then retrieved later during the shuttle mission. The WLC and a companion instrument, an ultraviolet coronal spectrometer (UVCS) developed at Harvard University, will allow researchers to investigate the solar corona and the solar wind. NCAR's primary sponsor is the National Science Foundation.
"The space shuttle program offers a unique opportunity to fly retrievable instruments in space, where there is no scattered light from the earth's atmosphere," explains Michael Knölker. Knölker directs the High Altitude Observatory (HAO), where the WLC was developed and built in collaboration with scientists at the National Aeronautics and Space Administration (NASA).
NCAR researchers will analyze the data brought back by the two instruments to create a better picture of the outermost layer of the sun. Solar storms launched by coronal mass ejections are the cause of geomagnetic storms that can lead to the sudden failure of communications satellites and electric power grids here on earth. With the WLC, researchers have a tool to determine densities of the corona. The coronograph obscures the disk of the sun, revealing the otherwise invisible corona, much the way the moon obstructs the sun during a solar eclipse. By launching the WLC from the space shuttle, researchers avoid the light-scattering caused by dust in the earth's atmosphere, which interferes with ground-based coronographs.
HAO's Gregory Card is project engineer and the HAO-NASA liaison. He spent several years commuting between Boulder, NASA Goddard Space Flight Center, and Kennedy Space Center to prepare the coronograph and integrate it with the spacecraft. Card is at NASA Ground Control in Houston, where he will oversee WLC telemetry during the mission. He can be reached at (281) 483-2410.
The Spartan 201-05 with its solar research instruments on board is scheduled for deployment on Sunday, November 1. If all goes well it will be retrieved on November 3. During the Spartan 201-5 mission, near-real- time images from the WLC will be available on the Web.
NCAR is managed by the University Corporation for Atmospheric Research, a consortium of more than 60 universities offering Ph.D.s in atmospheric and related sciences.