<title>Student Nitric Oxide Explorer</title>

Abstract

1. Abstract The Student Nitric Oxide Explorer (SNOE) is a small scientific spacecraft designed for launch on a Pegasus™ XL launch vehicle for the USRA Student Explorer Demonstration Initiative. Its scientific goals are to measure nitric oxide density in the lower thermosphere and analyze the energy inputs to that region from the sun and magnetosphere that create it and cause its abundance to vary dramatically. These inputs are energetic solar photons in the EUV and X -ray spectral regions, and energetic electrons that are accelerated into the polar regions, where they cause auroral disturbances and displays. Both of these phenomena are aspects of solar variability; thermospheric nitric oxide responds to that variability and in tum determines key temperature and compositional aspects of the thermosphere and ionosphere through its radiative and chemical properties.The SNOE ("snowy") spacecraft and its instrument complement is being designed, built, and operated entirely at the University of Colorado, Laboratory for Atmospheric and Space Physics (CUILASP). The spacecraft is a compact hexagonal structure, 37" high and 39" across its widest dimension, weighing approximately 220 Ibs. It will be launched into a circular orbit, 550±50 km altitude, at 97.5° inclination for sun-synchronous precession at 10:30-22:30 solar time. It will spin at 5 rpm with the spin axis normal to the orbit plane. It carries three instruments: An ultraviolet spectrometer to measure nitric oxide altitude profiles, a two-channel ultraviolet photometer to measure auroral emissions beneath the spacecraft, and a five-channel solar soft X-ray photometer.The spacecraft structure is aluminum, with a center platform section for the instruments and primary components and truss work to hold the solar arrays. Power is regulated using switched arrays and a partial shunt. The attitude determination and control system uses a magnetometer, two torque rods, and two horizon crossing indicators to measure spin rate and orientation. Attitude control is implemented open-loop by ground commands. The command and data handling system is implemented using a single spacecraft microprocessor that handles all spacecraft and communications functions and instrument data. The communications system is NASA compatible for downlink using the Autonomous Ground Services station at Poker Flat; all mission operations, data processing, and analysis will be performed using a project operations control center (POCC) at the LASP Space Technology Research building.2. Introduction The Student Explorer Demonstration Initiative (STEDI) is a program administrated by the Universities Space Research Association (USRA) and funded by NASA. Its goal is to demonstrate that significant scientific and/or technology experiments can be accomplished with small satellites and constrained budgets. The original design parameters for low-earthorbit experiments were "300 pounds to 300 nautical miles" for one year in polar or near-polar orbit. A firm budget limit of $4.3M was applied to the spacecraft, i...

Relative Importance of Nitric Oxide Physical Drivers in the Lower Thermosphere

“…We also use Student Nitric Oxide Explorer (SNOE) observations (Solomon et al, 1996) to complement and confirm our results. The SNOE satellite determined NO densities with an ultraviolet spectrometer and provided data from 11 March 1998 to 30 September 2000 (ascending phase of SC 23) so observations are almost a decade apart from the SOFIE era.…”

Measurements of the solar soft X‐ray irradiance by the Student Nitric Oxide Explorer: First analysis and underflight calibrations

“…It is a spinning satellite rotating at 5 rpm. Details of the mission, the scientific objectives, the spacecraft, its subsystems, and the instrumentation can be found in Solomon et al [1996] and Bailey et al [1996]. One of the three science instruments on SNOE is designed to measure the solar soft X-ray irradiance from 2 to 20 nm.…”

A fast, parameterized model of upper atmospheric ionization rates, chemistry, and conductivity

“…We have produced a fast, parameterized version of the GLobal AirglOW (GLOW) upper atmospheric model [Solomon et al, 1988], called GLOWfast, and augmented its capabilities by introducing the Nitric Oxide Empirical Model (NOEM) [Solomon et al, 1996] to calculate a priori nitric oxide profiles and first-principles calculations of the Pedersen and Hall conductivities. Two previously derived parameterizations were used to replace the computationally intensive electron transport algorithm in GLOW, namely, Fang et al [2008Fang et al [ , 2010 for electron impact ionization and Solomon and Qian [2005] for photoionization.…”