The Multi-spectral solar telescope array, or MSSTA, was a

sounding rocket A sounding rocket or rocketsonde, sometimes called a research rocket or a suborbital rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight. The rockets are used to ...

payload built by Professor A.B.C. Walker, Jr. at

Stanford University Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is conside ...

in the 1990s to test EUV/XUV imaging of the Sun using normal incidence EUV-reflective

multilayer optics An optical coating is one or more thin layers of material deposited on an optical component such as a lens, prism or mirror, which alters the way in which the optic reflects and transmits light. These coatings have become a key technology in t ...

. MSSTA contained a large number of individual telescopes (> 10), all trained on the Sun and all sensitive to slightly different

wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tr ...

s of ultraviolet light. Like all sounding rockets, MSSTA flew for approximately 14 minutes per mission, about 5 minutes of which were in space—just enough time to test a new technology or yield "first results" science. MSSTA is one of the last solar observing instruments to use

photographic film Photographic film is a strip or sheet of transparent film base coated on one side with a gelatin emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of the crystals determine ...

rather than a

digital camera A digital camera is a camera that captures photographs in digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film. Digital cameras are now widely incorporated into mobile devices ...

system such as a CCD. MSSTA used film instead of a CCD in order to achieve the highest possible spatial resolution and to avoid the electronics difficulty presented by the large number of detectors that would have been required for its many telescopes. MSSTA and its sister rocket, NIXT, were prototypes for normal incidence EUV imaging telescopes that are in use today, as well as the historic EIT instrument aboard the

SOHO Soho is an area of the City of Westminster, part of the West End of London. Originally a fashionable district for the aristocracy, it has been one of the main entertainment districts in the capital since the 19th century. The area was deve ...

spacecraft, and the TRACE spacecraft. MSSTA flew three times: once in 1991 (NASA Sounding Rocket flight 36.049), once in 1994 (flight 36.091), and once in 2002 (flight 36.194). While Dr. Walker's 1991 telescope was the first in the series to carry the MSSTA moniker, the precursor to the MSSTA, the Stanford/MSFC Rocket Spectroheliograph (NASA Sounding Rocket flight 27.092), which carried two EUV telescopes in 1987, was the first mission to successfully obtain high-resolution, full-disk solar images utilizing normal incidence EUV optics . The MSSTA I flown in 1991 carried 14 telescopes; the MSSTA II flown in 1994 carried 19 telescopes; and the MSSTA III flown in 2002 carried 11 telescopes. Several Stanford Ph.D. degrees in Physics resulted from the MSSTA program. These include those earned by Dr. Joakim Lindblom, Dr. Maxwell J. Allen, Dr. Ray H. O'Neal, Dr. Craig E. DeForest, Dr. Charles C. Kankelborg, Dr. Hakeem M. Oluseyi, Dr. Dennis S. Martinez-Galarce, and Dr. Paul F.X. Boerner.

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