Retrieving Instantaneous Field of View and Geophysical Information for Atmospheric Limb Sounding with USGNC Near Real-Time Orbit Data

TL;DR

This paper discusses the LITES instrument aboard the ISS, which captures ionospheric data by imaging altitudes from 350 km to 150 km, utilizing near real-time orbit data for atmospheric limb sounding.

Contribution

It introduces the LITES instrument's design and its capability to retrieve geophysical information using USGNC near real-time orbit data for atmospheric limb sounding.

Findings

LITES captures ionospheric structures from 350 km to 150 km altitude.

Instrument's field of view and imaging depend on ISS pitch and orbit data.

Enables near real-time atmospheric and ionospheric observations.

Abstract

The Limb-imaging Ionospheric and Thermospheric Extreme-ultraviolet Spectrograph (LITES) experiment is one of thirteen instruments aboard the Space Test Program Houston 5 (STP-H5) payload on the International Space Station. Along with the complementary GPS Radio Occultation and Ultraviolet Photometry -- Colocated (GROUP-C) experiment, LITES will investigate ionospheric structures and variability relevant to the global ionosphere. The ISS has an orbital inclination of 51.6{\deg} which combined with its altitude of about 410 km enables middle- and low-latitude measurements from slightly above the peak region of the ionosphere. The LITES instrument features a 10{\deg} by 10{\deg} field of view which is collapsed horizontally, combining all information from a given altitude. The instrument is installed such it looks in the wake of the ISS and about 14.5{\deg} downwards in order to image altitudes ranging from about 350 km to 150 km. The actual viewing altitude and geometry is directly dependent on the pitch of the ISS, affecting the geophysical information captured by the instrument.