Michael Mendillo

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Atomic sodium is a useful tracer of the tenuous lunar atmosphere because of its high efficiency in scattering sunlight at the D(1) (5896 angstroms) and D(2) (5890 angstroms) wavelengths. In 1988, Earth-based instruments revealed the presence of sodium at a density of less than 50 atoms per cubic centimeter at lunar altitudes below 100 kilometers. Telescopic(More)
We present an instrumentation plan for spectral imaging of MercuryÏs extended atmosphere. The approach depends upon simultaneous short-exposure images in white light and sodium, with the former used to select the frames for postintegration of the sodium images. The e †ects of atmospheric seeing are thus minimized by the combination of high-speed exposures(More)
Atoll (Marshall Islands) using the ALTAIR incoherent scatter radar and all-sky optical imaging techniques. The major difference between nights when ESF instabilities did not occur (August 14, 1988) and did occur.(August 15, 1988) in the Kwajalein sector was that the northern merid-ional gradient of 6300-A airglow was reduced on the night of limited ESF(More)
Optical diagnostic techniques have been applied to studies of equatorial aeronomy for nearly half a century. The use of scanning photometers and two-dimensional imagers to observe the spatial patterns associated with low-latitude emissions has been an increasingly used approach during the last few decades. In this paper we review the rationale for the use(More)
All planetary atmospheres respond to the enhanced x-rays and ultraviolet (UV) light emitted from the Sun during a flare. Yet only on Earth are observations so continuous that the consequences of these essentially unpredictable events can be measured reliably. Here, we report observations of solar flares, causing up to 200% enhancements to the ionosphere of(More)
 Mars' peak electron density data used to make semi-empirical global model 12  Mars ionosphere model extends from 1964 through 2019 13  Mars ionospheric model available for upcoming NASA MAVEN mission 14 15 16 17 18 19 2 Abstract 20 Observations of the ionosphere of Mars have now reached a sufficient number to 21 begin discussions on how best to create(More)
—Solar-terrestrial interactions produce a rich variety of optical emissions in the Earth's upper atmosphere (100–1000 km). While ground based brightness measurements (i.e., column integrated photon density) provide an important diagnostic of these processes, the more interesting physics is in the associated volume emission rate distribution (i.e., photon(More)
[1] Ionospheric physics deals with the basic structure and variability of plasma within the upper atmospheres of the Earth and planets. Comparative studies foster both exploration and synthesis within diverse settings. In this paper we examine observations of the ionospheric profiles on Mars obtained on 9–27 March 1999 by the radio science experiment(More)
The properties of the Moon's rarefied atmosphere, which can be traced through observations of sodium and potassium, provide important insights into the formation and maintenance of atmospheres on other primitive Solar System bodies. The lunar atmosphere is believed to be composed of atoms from the surface rocks and soil, which might have been sputtered by(More)