JOHNS HOPKINS
U N I V E R S I T Y
Center for Astrophysical Sciences
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FUSE
The Far Ultraviolet Spectroscopic Explorer
Technical Description
FUSE, a PI-class NASA astronomy mission, will explore the Universe
through high-resolution (lambda/delta lambda = 24,000-30,000)
spectroscopy at far ultraviolet wavelengths (905-1195Å), to address
fundamental questions related to the origin of the Universe. FUSE is scheduled
as a three year mission within the NASA
Origins program.
The FUSE Satellite
The FUSE satellite is composed of the spacecraft and the scientific instrument.
The instrument consists of four coaligned telescope mirrors (~ 39 cm x 35 cm
clear aperture). The light from the four optical channels is dispersed by four
spherical, aberration-corrected holographic diffraction gratings, and recorded
by two delay-line microchannel plate detectors. Two channels with SiC coatings
cover the range 905-1100Å and two channels with LiF coatings cover the
range 1000-1195Å.
Actuators on the mirror mountings will keep the focus to 90% encircled energy
within 1.5". A Fine Error Sensor (FES) with a 21' square field will maintain
the spacecraft pointing stability to 0.5 arcseconds.
The FUSE UV channels: the optical path in the instrument.
SPACECRAFT FACTS
| Design | 3 axis inertially stabilized |
| Mass | 580 kg (1276 pounds) |
| Pointing | 0.5 arcsec stability (with FES) |
INSTRUMENT FACTS
| Wavelength Coverage | 905-1195Å |
| Mirrors | Four off axis parabolas |
| Effective area | 20-80 cm2 |
| PSF | 1.5 arcsec (90% encircled energy) |
| Science Aperture Sizes | 1.25 x 20, 4 x 20, and 30 x 30 arcseconds |
| Spectrograph | Rowland Circle (1652mm = 65 inches) |
| Spectral resolution | lambda/Delta lambda = 24,000 - 30,000 |
| Detectors | Double delay-line Micro-channel Plates (2) |
| Fine Error Sensor Camera Field of View | 21 arcmin x 21 arcmin |
| Total Length | 4 meters (13.1 feet) |
| Mass | 780 kg (1700 pounds) |
AUTOCAD DRAWING OF FUSE
The FUSE Instrument: Click on the image to inspect a larger version
(220 Kb JPG file).
The Johns Hopkins University (Dr. H. Warren Moos, PI) is responsible for developing
the overall mission, in collaboration with: University of Colorado, University of California
(Berkeley), JHU/APL, Canadian Space Agency, CNES (France), Goddard Space Flight
Center, Orbital Sciences Corporation, Swales Aerospace, Interface and Control Systems, Inc.,
and AlliedSignal Technical Services, Inc.
For more detailed technical information:
See the FUSE Observer's Guide.
Last update: 1/98
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