Apollo 15 in the context of "Lunar Roving Vehicle"

David Randolph Scott (born June 6, 1932) is an American retired test pilot and NASA astronaut who was the seventh person to walk on the Moon. Selected as part of the third group of astronauts in 1963, Scott flew to space three times and commanded Apollo 15, the fourth lunar landing; he is one of four surviving Moon walkers and the only living commander of a spacecraft that landed on the Moon.

Before becoming an astronaut, Scott graduated from the United States Military Academy at West Point and joined the Air Force. After serving as a fighter pilot in Europe, he graduated from the Air Force Experimental Test Pilot School (Class 62C) and the Aerospace Research Pilot School (Class IV). Scott retired from the Air Force in 1975 with the rank of colonel, and more than 5,600 hours of logged flying time.

The magnetic field of the Moon is very weak in comparison to that of the Earth; the major difference is the Moon does not have a dipolar magnetic field currently (as would be generated by a geodynamo in its core), so that the magnetization present is varied (see picture) and its origin is almost entirely crustal in location; so it's difficult to compare as a percentage to Earth. But, one experiment discovered that lunar rocks formed 1 - 2.5 billion years ago were created in a field of about 5 microtesla (μT), compared to present day Earth's 50 μT. During the Apollo program several magnetic field strength readings were taken with readings ranging from a low of 6γ (6nT) at the Apollo 15 site to a maximum of 313γ (0.31μT) at the Apollo 16 site, note these readings were recorded in gammas(γ) a now outdated unit of magnetic flux density equivalent to 1nT.

One hypothesis holds that the crustal magnetizations were acquired early in lunar history when a geodynamo was still operating. An analysis of magnetized Moon rocks brought to Earth by Apollo astronauts showed that the Moon must have had a strong (above 110 μT) magnetic field at least 4.25 billion years ago, which then fell to 20 μT level in the 3.6 - 3.1 billion years BP period. The small size of the lunar core, however, is a potential obstacle to promoting that hypothesis to the status of theory. However, single silicate grains with magnetic inclusions from Apollo rocks formed at 3.9, 3.6, 3.3, and 3.2 billion years ago have been shown to be capable of recording strong magnetic fields but do not. This supports the alternative hypothesis that the Moon never had a long-lasting core dynamo, consistent with the lack of energy needed to sustain a field.

Having a mean density of 3,346.4 kg/m, the Moon is a differentiated body, being composed of a geochemically distinct crust, mantle, and planetary core. This structure is believed to have resulted from the fractional crystallization of a magma ocean shortly after its formation about 4.5 billion years ago. The energy required to melt the outer portion of the Moon is commonly attributed to a giant impact event that is postulated to have formed the Earth-Moon system, and the subsequent reaccretion of material in Earth orbit. Crystallization of this magma ocean would have given rise to a mafic mantle and a plagioclase-rich crust.

Geochemical mapping from orbit implies that the crust of the Moon is largely anorthositic in composition, consistent with the magma ocean hypothesis. In terms of elements, the lunar crust is composed primarily of oxygen, silicon, magnesium, iron, calcium, and aluminium, but important minor and trace elements such as titanium, uranium, thorium, potassium, sulphur, manganese, chromium, and hydrogen are present as well. Based on geophysical techniques, the crust is estimated to be on average about 50 km thick.

Condon is a lunar impact crater that lies on the eastern shore of the Sinus Successus, a bay along the northeast edge of Mare Fecunditatis. It was named after American physicist Edward U. Condon in 1976. It lies midway between the larger crater Apollonius to the north and the smaller Webb to the south on the Mare Fecunditatis. Condon was previously designated Webb R.

This is a lava-flooded crater remnant with only low rim segments surviving to the east and west. There is a break in the rim to the south and a wider break to the northwest of the crater. The crater interior is nearly level, and mark only by a few low rises in the surface.

Moon rock or lunar rock is rock originating from Earth's Moon. This includes lunar material collected during the course of human exploration of the Moon, and rock that has been ejected naturally from the Moon's surface and landed on Earth as lunar meteorites.

Lunar horizon glow is a phenomenon in which dust particles in the Moon's thin atmosphere create a glow during lunar sunset. The Surveyor program provided the first data and photos of the phenomenon. Astronauts in lunar orbit observed it during the Apollo 15 and Apollo 17 missions.