Engineering topics

Stewart, A. I.

Publications and source records attributed to Stewart, A. I..

44 records · Page 3

NASA NTRS1972

Mariner 9 ultraviolet spectrometer experiment - Initial results.

The UV airglow spectrum of Mars has been measured from an orbiting spacecraft during a 30-day period in November and December 1971. Significant variations in the scale height of the CO Cameron band airglow have been observed during a period of variable solar activity. The atomic oxygen and hydrogen airglow lines are present during all the observations. Measurements of the reflectance of the lower atmosphere of Mars show the spectral characteristics of particle scattering and a magnitude that is about 50% of that measured during the Mariner 6 and 7 experiments in 1969.

Barth, C. A.↗

NASA NTRS1972

Mariner 6 and 7 ultraviolet spectrometer experiment - Implications of CO2/+/, CO, and O airglow.

The Mariner 6 and 7 UV spectrometer experiments observed intense emissions from CO, O, and CO2(+) in the Martian airglow. Analysis shows that they are excited predominantly by the absorption of solar EUV photons by CO2 and constitute a major energy-loss mechanism for the thermosphere. Models of the thermospheric temperature profile and the airglow layer that demonstrate the effects of neutral chemistry and ionospheric composition are developed. With their aid, the observed CO Cameron-band emission scale height of 19 (plus or minus 4.5) km is shown to suggest an exospheric temperature of 315 (plus or minus 75) K. Consideration of other data suggests a 'best' value of about 350 K. Within the uncertainties in the excitation efficiencies and in the thermospheric cooling mechanisms, the observations are consistent with the measured electron density. There is no indication in the data that the ionosphere is modified by the solar wind below 200 km.

Stewart, A. I.↗

NASA NTRS1971

Mariner 6 and 7 ultraviolet spectrometer experiment - Upper atmosphere data

Upper Martian atmosphere UV emission spectrum observation noting carbon dioxide photoionization, ion fluorescent scattering and photon/electron dissociative excitation

Anderson, G. P.↗

NASA NTRS1971

Mariner 6 and 7 ultraviolet spectrometer experiment - Upper atmosphere data

Ultraviolet emissum spectrum of Mars upper atmosphere from Mariner 6 and 7 spaceprobes

Anderson, G. P.↗

NASA NTRS1970

Photoionization coefficients and photoelectron impact excitation efficiencies in the daytime ionosphere

Photoionization coefficients and photoelectron impact excitation efficiencies in daytime ionosphere, noting role in dayglow

Stewart, A. I.↗

NASA NTRS1969

Mariner 6 - Ultraviolet spectrum of Mars upper atmosphere.

Mars upper atmosphere ionized carbon dioxide and CO emission spectra in 1900-4300 A region measured by Mariner 6, observing atomic hydrogen and oxygen lines

Anderson, G. P.↗

NASA NTRS1969

Electron impact excitation of the dayglow.

Equilibrium velocity distributions of F region photoelectrons produced by solar ionizing radiation, discussing dayglow as impact result

Dalgarno, A.↗

NASA NTRS1969

Ultraviolet spectroscopy

Ultraviolet spectroscopic measurements on Mars upper atmosphere by Mariners 6 and 7

Anderson, G. P.↗