The NIXT, or Normal Incidence X-ray Telescope, was a sounding rocket

Sounding rocket

A sounding rocket, sometimes called a research rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight. The origin of the term comes from nautical vocabulary, where to sound is to throw a weighted line from a ship into...

 payload flown in the 1990s by Professor Leon Golub of the Smithsonian Astrophysical Observatory

Smithsonian Astrophysical Observatory

The Smithsonian Astrophysical Observatory is a research institute of the Smithsonian Institution headquartered in Cambridge, Massachusetts, where it is joined with the Harvard College Observatory to form the Harvard-Smithsonian Center for Astrophysics .-History:The SAO was founded in 1890 by...

, to prototype normal-incidence (conventional) optical designs in extreme ultraviolet

Extreme ultraviolet

Extreme Ultraviolet radiation is high-energy ultraviolet radiation, generally defined to be electromagnetic radiation in the part of the electromagnetic spectrum spanning wavelengths from 120 nm down to 10 nm, and therefore having photons with energies from 10 eV up to 124 eV...

 (EUV) solar imaging. In the EUV, the surface of the Sun

Sun

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 appears dark, and hot structures in the solar corona

Corona

A corona is a type of plasma "atmosphere" of the Sun or other celestial body, extending millions of kilometers into space, most easily seen during a total solar eclipse, but also observable in a coronagraph...

 appear bright; this allows study of the structure and dynamics of the solar corona near the surface of the Sun, which is not possible using visible light.

NIXT and its sister rocket, the MSSTA

MSSTA

The Multi-spectral solar telescope array, or MSSTA, was a sounding rocket payload built by Professor A.B.C. Walker, Jr. at Stanford University in the 1990s to test EUV/XUV imaging of the Sun using normal incidence EUV-reflective multilayer optics...

, were the prototypes for all normal-incidence EUV imaging instruments in use today, including SOHO/EIT

Extreme ultraviolet Imaging Telescope

The Extreme ultraviolet Imaging Telescope is an instrument on the SOHO spacecraft used to obtain high-resolution images of the solar corona in the ultraviolet range...

, TRACE

TRACE

TRACE was a NASA space telescope designed to investigate the connections between fine-scale magnetic fields and the associated plasma structures on the Sun by providing high resolution images and observation of the solar photosphere and transition region to the corona...

, and STEREO/SECCHI

STEREO

STEREO is a solar observation mission. Two nearly identical spacecraft were launched into orbits that cause them to respectively pull farther ahead of and fall gradually behind the Earth...

.