Engineering topics

Mauersberger, K.

Publications and source records attributed to Mauersberger, K..

43 records · Page 3

NASA NTRS1976

Diurnal variation of atomic nitrogen

When the perigee of the Atmospheric Explorer C satellite reached the northern latitudes (68 deg) by mid-April 1974, descending and ascending portions of the orbits stretched symmetrically across the Northern Hemisphere. Corresponding local solar times at altitudes above 400 km were 1700 hours and 0200 hours, respectively, thus providing the opportunity to study the diurnal variation of the neutral constituents. Atomic nitrogen densities, measured with the open-source neutral mass spectrometer, show a pronounced diurnal variation. At 400 km, the density ratios derived from measurements of the descending and ascending portions are 5.2 for N, 4.9 for N2, and 2.0 for O. Absolute densities of atomic nitrogen agree within a factor of 2 or 3 with densities derived from neutral-ion reactions. Measurements taken close to the geomagnetic pole show a decrease in atomic nitrogen densities when an increase in molecular nitrogen is observed.

Mauersberger, K.↗

NASA NTRS1976

A direct measurement of the winter helium bulge

In late December 1975, the orbital configuration of the Atmosphere Explorer-D satellite made possible the measurement of the winter helium bulge within a single perigee pass. Shortly after the winter solstice, the perigee of the polar-orbiting AE-D satellite crossed the equator, at which time descending and ascending portions of the orbit stretched symmetrically over the Southern and Northern Hemispheres. The open-source neutral mass spectrometer (OSS) on board AE-D measured helium densities between the perigee (about 150 km) and altitudes of 650 km. During the time the perigee was at the equator, altitudes above approximately 550 km were located north and south at latitudes greater than 50-deg. Helium showed, in the winter hemisphere, densities that were a factor of 20 higher than at corresponding altitudes and latitudes in the Southern (summer) Hemisphere. Absolute densities of helium agree well with previous measurements.

Mauersberger, K.↗

NASA NTRS1976

Determination of exospheric neutral gas temperatures

The Atmosphere Explorer satellites (AE-C, -D, and -E) were initially placed into highly elliptical orbits with perigees around 140 km and apogees of 4000 km. As a result of such an orbital geometry, measurements of neutral constituents at high altitudes represent mainly vertical changes in densities. The influence of horizontal density gradients on measurements above 400 km is small. Under geomagnetically quiet conditions, the density profiles can be used to derive scale-height temperatures of the exosphere. The open-source neutral mass spectrometer (OSS) flown on all three AE-satellites measured neutral constituents such as N2, O, and N well above 400 km. The temperatures derived from scale heights show a good agreement among the constituents and the expected close correlation with the F10.7-cm solar flux. Satellites with highly elliptical orbits provide the opportunity to measure simultaneously both densities and temperatures.

Mauersberger, K.↗

NASA NTRS1976

Atomic nitrogen densities in the thermosphere

Recently atomic nitrogen densities of about one million per cu cm were measured at 400 km by the open source mass spectrometer on the Atmosphere Explorer-C satellite (AE-C). Daytime N densities about 50 million per cu cm at 160 km have also been inferred from airglow and other measurements on AE-C. It is shown that atomic nitrogen densities of this magnitude result in significantly lower values for the O2(+) concentration than those measured on AE-C over the altitude range to 160 to 200 km, because of the removal process O2(+) + N k3 yields NO(+) + O. The discrepancy can be explained in terms of latitudinal variations in both the N and O2 densities. Evidence is presented which indicates that k3 could be as low as 0.1 billionth per cu cm at ionospheric temperatures. K3 is the rate constant for the reaction of O2(+) with N(4-S).

Torr, D. G.↗

NASA NTRS1976

Seasonal variation of neutral thermospheric constituents in the Northern Hemisphere

The Atmosphere Explorer-C satellite carries a large number of experiments including an open source neutral mass spectrometer. Among the measurements obtained with this instrument were ones of particle densities of N2, O, and He at northern latitudes in early February and late June 1974. The orbital geometry of the satellite was such that comparisons could be made between the winter and summer values at the same altitudes and latitudes and at similar local solar times. The helium density shows in midmorning a winter to summer enhancement of a factor of 29 at 400 km. The enhancement at other altitudes, both higher and lower, is less. At 250 km the winter/summer oxygen ratio is 1.7, whereas the winter/summer nitrogen ratio is 0.6. Both ratios decrease with increasing altitudes. The analysis identifies an oxygen enhancement at low altitudes in winter and at high altitudes in summer.

Mauersberger, K.↗

NASA NTRS1975

Atomic nitrogen measurements in the upper atmosphere

The open-source neutral mass spectrometer (OSS) on the Atmosphere Explorer-C satellite (AE-C) measures the neutral constituents of the upper atmosphere. It has been found that atomic nitrogen densities can be determined at altitudes above 380 km. Most of the nitrogen atoms combine with oxygen adsorbed on the walls of the ion source to form NO. The measured net peaks at 14 amu and 30 amu show the scale height expected for atomic nitrogen; both peaks have a pronounced diurnal variation. Absolute number densities at 400 km are computed for a time period between February and April 1974 when measurements were taken in the northern hemisphere. Minimum and maximum densities of atomic nitrogen occur between 4 and 6 hr LST in the morning and around 16 hr LST in the afternoon, respectively. At 400 km, the minimum particle density is 100,000/cu cm and the maximum density 1.5 million/cu cm. In contrast to the response of N2 to geomagnetic activity, atomic N shows no appreciable effect.

Mauersberger, K.↗

NASA NTRS1973

The open-source neutral-mass spectrometer on Atmosphere Explorer-C, -D, and -E.

The open-source mass spectrometer will be used to obtain the number densities of the neutral atmospheric gases in the mass range 1 to 48 amu at the satellite location. The ion source has been designed to allow gas particles to enter the ionizing region with the minimum practicable number of prior collisions with surfaces. This design minimizes the loss of atomic oxygen and other reactive species due to reactions with the walls of the ion source. The principal features of the open-source spectrometer and the laboratory calibration system are discussed.

Nier, A. O.↗