Solar-B Status

ISAS | PPARC | NASA

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Solar-B is a Japanese Institute of Space and Astronautical Science (ISAS) mission proposed as a follow-on to the highly successful Japan/US/UK Yohkoh (Solar-A) collaboration. The mission consists of a coordinated set of optical, EUV and X-ray instruments that will investigate the interaction between the Sun's magnetic field and its corona. The result will be an improved understanding of the mechanisms which give rise to solar magnetic variability and how this variability modulates the total solar output and creates the driving force behind space weather.

ISAS will provide the spacecraft, the launch vehicle (ISAS MV-7), and major elements of each of the scientific instruments. The spacecraft is being developed by Mitsubish Electric Company (MELCO) and will accomodate three major instruments: a large solar optical telescope (SOT), an X-ray telescope (XRT), and an EUV Imaging Spectrograph (EIS).

The Particle Physics and Astronomy Research Council (PPARC) of the U.K. has responsibility for the EIS instrument. Professor Leonard Culhane (Mullard Space Sciences Laboratory, University College of London, U.K.) is the principal investigator. The EIS links the photosphere to the hot corona. PPARC has also invited NASA to provide a U.S. science investigation with some hardware responsibility for this instrument.

NASA will provide the Focal Plane Package (FPP) for the optical telescope as well as components of the X-ray telescope and Extreme Ultraviolet Imaging Spectrograph. NASA has selected three U.S. teams to participate in the development of these science instruments.

Dr. Alan Title (Lockheed Martin Advanced Technology Center, Palo Alto, CA) will be the U.S. principal investigator for the FPP. This package consists of a broadband filter imager, a narrowband filter imager, and a spectro-polarimeter for measuring the magnetic field strength and direction in the photosphere.

Dr. Leon Golub (Smithsonian Astrophysical Observatory, Cambridge, MA) will be the U.S. principal investigator for the XRT. Dr. Golub's team will provide the telescope optics, filters, and structure while ISAS will provide the CCD camera. The XRT will study the million-degree corona. The XRT is an advanced version of a U.S.-Japanese grazing incidence instrument which is currently operating on the ISAS Yohkoh Mission.

Dr. George Doschek (Naval Research Laboratory, Washington, DC) will be the American co-investigator for the EIS instrument. His team will provide the optics for the EIS.

The Solar-B spacecraft is scheduled for launch in the August of 2004. It will be placed in a polar, sun-synchronous orbit about the Earth. This will keep the instruments in continuous sunlight, with no day/night cycling for nine months each year.

Solar-B Schedule from 1999-2004