CORSAIR (Coronal Spectropolarimeter for Airborne Infrared Research)

CORSAIR is the acronym for Coronal Spectropolarimeter for Airborne Infrared Research a balloon-borne infrared coronagraph and spectropolarimeter developed at the Smithsonian Astrophysical Observatory for long-duration observations of the solar corona. It combines an internally occulted coronagraph, a rotating-waveplate polarimeterPolarimeterA polarimeter is a scientific instrument used to measure optical rotation: the angle of rotation caused by passing linearly polarized light through an optically active substance. Some chemical substances are optically active, and linearly polarized (uni-directional) light will rotate either to the left (counter-clockwise) or right (clockwise) when passed through these substances. The amount by which the light is rotated is known as the angle of rotation. and a cryogenic spectrometer to obtain two-dimensional spectral imaging of the full polarization state of the corona to one solar radius from the limb. The instrument observes five emission lines at 1.1, 1.4 and 3.9 microns, including density-sensitive Fe XIII, temperature-sensitive Si IX/Si X and He I lines.

CORSAIR measures line-of-sight magnetic-field strength through the longitudinal Zeeman effectZeeman effectRefers to the splitting of a single spectral line into two or more lines of different frequencies observed when radiation (such as light) originates in a magnetic field. It was named after Dutch physicist Pieter Zeeman, who in 1896 observed the field-dependent splitting of optical spectral lines of a sodium flame. Understanding the Zeeman effect has led to advancements in electron paramagnetic resonance studies and magnetic field measurements in space, such as those of the Sun and other stars.-> Mas informacion and plane-of-sky magnetic azimuth through the saturated Hanle effectHanle effectis a reduction in the polarization of light emitted by atoms excited by polarized light, when subjected to a magnetic field. Typically, when atoms are excited by linearly polarized light, the emitted fluorescence is also polarized. If a weak transverse magnetic field is applied, the emitted light becomes depolarized (or its polarization rotates). iIt was named after Wilhelm Hanle, who was the first to explain the effect, in terms of classical physics, in his book Zeitschrift für Physik in 1924.-> Mas informacion. Spectroscopic measurements provide plasma temperature, density, line-of-sight and plane-of-sky velocity, and non-thermal velocity. The spectrometer uses multiple closely spaced slits to acquire the spectral and two spatial dimensions simultaneously, while ultra-narrowband filters minimize background overlap. Operating in multiple spectral orders allows the five emission lines to be measured with similar sensitivity and resolving power. The spectrometer is cooled with liquid nitrogen to approximately -321 °F and enclosed in a vacuum chamber to prevent condensation.

CORSAIR is mounted on the Wallops Arc Second Pointer or WASP, a NASA precision pointing system developed at Wallops Flight Facility for scientific balloon payloads. WASP combines a pointing control system with a star-tracker subsystem and uses a gondola-mounted pitch/yaw articulated gimbal for fine instrument pointing, while the standard NASA gondola rotator provides coarse azimuth positioning. Its pointing system incorporates inner and outer gimbal frames, precision hubs, a fiber-optic gyroscope, avionics, a trim-balance subsystem and a latch mechanism. The system is designed to provide sub-arcsecond pointing, with NASA reporting total pointing error below 1 arcsecond 99.4 percent of the time.

For CORSAIR, WASP provides the line-of-sight pointing required to keep the instrument directed toward the center of the Sun with arcsecond-level stability. The complete assembled CORSAIR payload is reported to weigh approximately 5,000 pounds.

CORSAIR’s development program comprises three balloon flights. The first is a one-day qualification flight from Fort Sumner, New Mexico, in 2026, using only the 3.9-micron Si IX line to demonstrate measurement of line-of-sight magnetic-field strength. The second is a one-day commissioning flight from Fort Sumner in 2028, adding the four near-infrared lines, correction for field-of-view rotation, and ultra-narrowband filters enabling 128 closely spaced slits for nearly continuous spatial coverage. The final mission is a one-month Antarctic circumpolar science flight planned for late 2030, providing uninterrupted solar observations for up to one month and the complete set of CORSAIR measurements.

Balloon launched on: 10/5/2026 at 13:35 UTC
Launch site: Scientific Flight Balloon Facility, Fort Sumner, (NM), US  
Balloon launched by: Columbia Scientific Balloon Facility (CSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon  
Flight identification number: 768N
End of flight (L for landing time, W for last contact, otherwise termination time): 10/5/2026 at 22:00 UTC (L)
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 8 h 15 m
Landing site: NW of Tulia, Texas, US

• For a closer look at the sun, scientists ready 5,000-pound device for balloon launch The FAS current