Paul Richard Straus

Initial observations with the Global Ultraviolet Imager (GUVI) in the NASA TIMED satellite mission

[1] The Global Ultraviolet Imager (GUVI) instrument carried aboard the NASA TIMED satellite measures the spectral radiance of the Earth’s far ultraviolet airglow in the spectral region from 120 to 180 nm using a cross-track scanning spectrometer design. Continuous operation of the instrument provides images of the Earth’s disk and limb in five selectable spectral bands. Also, spectra at fixed scanning mirror position can be obtained. Initial results demonstrate the quantitative functionality of the instrument for studies of the Earth’s dayglow, aurora, and ionosphere. Moreover, through forward modeling, the abundance of the major constituents of the thermosphere, O, N2, and O2 and thermospheric temperatures can be retrieved from observations of the limb radiance. Variations of the column O/N2 ratio can be deduced from sunlit disk observations. In regions of auroral precipitation not only can the aurora regions be geographically located and the auroral boundaries identified, but also the energy flux Q, the characteristic energy Eo, and a parameter fo that scales the abundance of neutral atomic oxygen can be derived. Radiance due to radiative recombination in the ionospheric F region is evident from both dayside and nightside observations of the Earth’s limb and disk, respectively. Regions of depleted F-region electron density are evident in the tropical Appleton anomaly regions, associated with so-called ionospheric ‘‘bubbles.’’ Access to the GUVI data is provided through the GUVI website www.timed.jhuapl.edu\guvi. INDEX TERMS: 0310 Atmospheric Composition and Structure: Airglow and aurora; 0355 Atmospheric Composition and Structure: Thermosphere—composition and chemistry; 0358 Atmospheric Composition and Structure: Thermosphere—energy deposition; 2407 Ionosphere: Auroral ionosphere (2704); KEYWORDS: airglow, aurora, ultraviolet, imaging, satellite, atmosphere

Instrumentation on the Remote Atmospheric and Ionospheric Detection System Experiment: extreme-ultraviolet spectrometer, photometer, and near-infrared spectrometer

The Remote Atmospheric and Ionospheric Detection System experiment consists of eight instruments spanning the wavelength range from the extreme ultraviolet (55 nm) to the near infrared (800 nm) oriented to view the Earths limb from the National Oceanic and Atmospheric Administration TIROS-J spacecraft to be launched into a circular orbit in 1993. Through measurements of the natural optical emissions and scattered sunlight originating in the upper atmosphere including the mesosphere and thermosphere, state variables such as temperature, composition, density, and ion concentration of this region will be inferred. The subset of instruments fabricated or otherwise provided by the Space and Environment Technology Center (formerly Space Sciences Laboratory) at The Aerospace Corporation are described.

The Remote Atmospheric and Ionospheric Detection System experiment on the ISS: Mission Overview

The Remote Atmospheric and Ionospheric Detection System (RAIDS) is a suite of three photometers, three spectrometers, and two spectrographs which span the wavelength range 50-874 nm and remotely sense the thermosphere and ionosphere by scanning and imaging the limb. RAIDS was originally designed, built, delivered, and integrated onto a NOAA TIROS satellite in 1992. After a series of unfruitful flight opportunities, RAIDS is now certified for flight on the Kibo Japanese Experiment Module-Exposed Facility (JEM-EF) aboard the International Space Station (ISS) in September 2009. The RAIDS mission objectives have been refocused since its original flight opportunity to accommodate the lower ISS orbit and to account for recent scientific progress. RAIDS underwent a fast-paced hardware modification program to prepare for the ISS mission. The scientific objectives of the new RAIDS experiment are to study the temperature of the lower thermosphere (100-200 km), to measure composition and chemistry of the lower thermosphere and ionosphere, and to measure the initial source of OII 83.4 nm emission. RAIDS will provide valuable data useful for exploring tidal effects in the thermosphere and ionosphere system, validating dayside ionospheric remote sensing methods, and studying local time variations in important chemical and thermal processes.

The Remote Atmospheric and Ionospheric Detection System on the ISS: sensor performance and space weather applications from the visible to the near infrared

The RAIDS experiment is a suite of eight instruments to be flown aboard the Japanese Experiment Module-Exposed Facility on the International Space Station (ISS) in late 2009. Originally designed, built, and integrated onto the NOAA TIROS-J satellite in 1993, the original RAIDS hardware and the mission objectives have been modified for this ISS flight opportunity. In this paper we describe the four near infrared instruments on the RAIDS experiment covering the wavelength range of 630 - 870 nm. Over the past two years these instruments have undergone modification, refurbishment, and testing in preparation for flight. We present updated sensor characteristics relevant to this new ISS mission and discuss performance stability in light of the long instrument storage period. The four instruments, operating in a limb scanning geometry, will be used to observe the spectral radiance of atomic and molecular emission from the Earths upper atmospheric airglow. The passbands of the photometers are centered on the atomic lines OI(777.4), OI[630.0], and the 0-0 band of O2 Atmospheric band at 765 nm. The spectrometer scans from 725 to 870 nm. These observations will be used in conjunction with the other RAIDS instruments to investigate the properties of the lower thermosphere and to improve understanding of the connections of the region to the space environment, solar energy flux and the lower atmosphere. These studies are fundamentally important to the understanding the effects of the atmosphere and ionosphere on space systems and their operation in areas such as satellite drag, communications and navigation.

Far-ultraviolet imaging spectrograph and scanning grating spectrometers for the Remote Atmospheric and Ionospheric Detection System

The Remote Atmospheric and Ionospheric Detection System (RAIDS) experiment is an optical remote sensing platform consisting of eight sensors, (spectrographs, spectrometers, and photometers) covering the wavelength range 550 to 8744 A. RAIDS employs a mechanical scan platform to view the Earths limb and measure line-of-sight column emission from tangent altitudes from 50 to 750 km. These measurements provide vertical profiles of atmospheric dayglow and nightglow from the mesosphere to the upper regions of the F-region ionosphere. RAIDS will be flown on the National Oceanographic and Atmospheric Administration (NOAA) J weather satellite through the auspices of the U.S. Air Force Space Test Program. The RAIDS wavelength and altitude coverage allows remote sensing of the major and many minor constituents in the thermosphere and ionosphere. These measurements will be used as part of a proof of concept for remote sensing of ionospheric and neutral density profiles. The RAIDS database will be used to study composition, thermal structure, and couplings between the mesosphere, thermosphere, and ionosphere. RAIDS is a joint venture of the Naval Research Laboratory (NRL) and The Aerospace Corporation. We describe the subset of RAIDS instruments developed at NRL covering the far to near UV regions (1300 to 4000 A).

Instrumentation on the RAIDS experiment II: extreme-ultraviolet spectrometer, photometer, and near-IR spectrometer

The RAIDS experiment consists of eight instruments spanning the wavelength range from the extreme ultraviolet (55 nm) to the near infrared (800 nm) oriented to view the Earths limb from the NOAA-J spacecraft to be launched into a circular orbit in 1993. Through measurements of the natural optical emissions and scattered sunlight origmating in the upper atmosphere including the mesosphere and thermosphere, state variables such as temperature, composition, density and ion concentration of this region will be inferred. This paper describes the subset of instruments fabricated or otherwise provided by the Space and Environment Technology Center (formerly Space Sciences Laboratory) at The Aerospace Corp. The companion to this paper describes the instruments from the Naval Research Laboratory. The Extreme Ultraviolet Spectrograph (EUVS), the three fixed filter photometers 0! (630), 0! (777), and Na (589), and the near infrared spectrometer (NIR) will be described. These are all mounted on a mechanical scan platform that scans the limb from approximately 75 to 750 km in the orbital plane of the satellite every 90 seconds.

Instrumentation on the RAIDS experiment I: far-ultraviolet imaging spectrograph and scanning grating spectrometers for the middle and near ultraviolet

The RAIDS experiment is an optical remote sensing platform consisting of eight sensors (spectrographs, spectrometers and photometers) covering the wavelength range 550 A to 8744 A. RAIDS employs a mechanical scan platform to view the Earths limb and measure vertical profiles of atmospheric dayglow and nightglow from the mesosphere to the upper regions of the F region ionosphere (75 -750 km). RAIDS will be flown on the NOAA J weather satellite through the auspices of the Air Force Space Test Program (STP). The RAIDS wavelength and altitude coverage allows remote sensing of the major, and many minor constituents in the thermosphere and ionosphere. These measurements will be used as part of a proof-of-concept for remote sensing of ionospheric and neutral density profiles. The RAIDS database will be used to study composition, thermal structure and couplings between the mesosphere, thermosphere and ionosphere. RAIDS is a joint venture of the Naval Research Laboratory (NRL) and The Aerospace Corporation. This paper describes the subset of RAIDS instruments developed at NRL covering the far to near ultraviolet (1300 A - 4000 A). A companion paper describes the balance of the experiment complement.