Apollo Expeditions to the Moon|
PHOTOGRAPHY AND SPACECRAFT ...
... Brought the Moon Closer
The oldest photograph of lunar details on record.
The original of this picture was a "Crystalotype" print
made from a daguerreotype taken in March 1851. As in all
telescopic views of the half Moon, relief features are visible
only near the terminator. The remainder of the image shows
only the contrast in reflectivity between the maria and the
Space photography over a vast range of scales is providing
the raw material for many kinds of study. This view of the
almost-full lunar disk was taken when Apollo 17 was about
2000 miles from the Moon on its way home. More than a third
of the area covered is never visible from the Earth.
Mare Smythii, the dark circular area just to the right of
the center, straddles the 90' east meridian. The crater
Tsiolkovsky is near the terminator at the lower right.
This southward-looking oblique view from an orbital altitude
of 70 miles places lunar features in a new perspective.
The crater in the center is Aristarchus, the brightest
large crater an the Moon. It is 25 miles in diameter and
2 1/4 miles deep. The low Sun angle has brought into bald
relief the deposits of ejected material, as well as the strange
When, finally, man walked the Moon, his footprints symbolized
an enormous new gain in knowledge,
Space has brought dramatic new views of Earth ...
At one point on its coasting path toward the Moon, Apollo 17
lined up with the Sun and the Earth, enabling the astronauts to take
this full-disk view. Since it was December, the beginning of summer
in the Southern Hemisphere, the icecap that covers the Antarctic
continent is brightly illuminated. A most striking feature of the
visible land mass of Africa and southeastern Asia is the transition
from the tawny color of the Sahara, Libyan, and Arabian deserts,
through the dark band of grass-covered savannah, to the cloud-strewn
tropical rain forest.
Shown us mysterious super-canyons on Mars ...
A complex of huge valleys and tributary canyons, now named the
Valles Marineris, can be traced across 2500 miles of the Martian
surface. It is comparable in scale to the Red Sea or the east
African rift valley system and probably originated, like them,
in the pulling part of great plates of the planetary crust.
Tectonic activity of this kind marks a planet that is still
evolving. The tree-like tributary canyons in the picture
(a 275-mile segment of Valles Marineris) may be the result of
water erosion, even though the Martian atmosphere now contains
Given exciting views of giant, turbulent Jupiter ...
Cloud tops high in the atmosphere form the giant planet's
visible surface. This photograph, produced from the red and
blue digital images of Pioneer 11's imaging photopolarimeter,
shows the characteristic banding parallel to the equator and
the elongated circles that mark regions of intense vertical
convective activity. Most prominent among these is the Great
Red Spot, a hurricane-like group of thunderstorms that has
persisted through several centuries of observation.
Jupiter's weather systems are long-lived because their
heat comes mainly from the planet's liquid interior.
Revealed atmospheric circulations on overheated Venus ...
Clouds in its very dense atmosphere completely hide Venus' solid
surface. Although the clouds are nearly featureless at visible
wavelengths, they show a wealth of detail in the near ultraviolet.
This ultraviolet picture, taken by the Mariner 10 television camera,
is one of a post-encounter sequence that shows the cloud-bearing
atmospheric layer in retrograde (right to left) rotation with a
four-day period. The swirling currents of that rotation interact
with convection cells rising from the subsolar point near the left
edge of the disk.
Unveiled the scarred, pocked face of Mercury ...
The surface of Mercury was revealed to science on March 29, 1974,
when Mariner 10 took over 1600 television frames just before
and just after flying past the planet's dark side.
The left and right halves of this picture are mosaics of
the pre-encounter and post-encounter frames. A second
encounter, six months later, provided additional coverage.
Although the crater interiors on this airless planet closely
resemble those on the Moon, study of the highresolution frames
shows external differences that may result from Mercury's stronger
And will soon visit Saturn's strange rings.
We shall have to wait a few more years for a closer view of
Saturn and its rings. Pioneer 11 will encounter the planet
in September 1979. Saturn is second in size only to Jupiter,
with an average density less than that of water. Titan, the
largest of its ten satellites, is the only one in the solar
system known to have an appreciable atmosphere. Saturn's rings
are thin layers of separate particles orbiting in its equatorial
plane. The ring system is probably less than 60 miles thick,
and its total mass is very small compared to that of Saturn's