High Resolution NASA Radar … Maps The Moon

70-meter antenna at the Goldstone complex in California. /// The 70-meter (230-foot) diameter antenna is the largest, and therefore most sensitive, DSN antenna, and is capabile of tracking a spacecraft travelling more than 16 billion kilometers (10 billion miles) from Earth. Image Credit: NASA

High Resolution NASA Radar … Maps The Moon

NASA's Jet Propulsion Laboratory has recently released new high-resolution radar maps of the Moon's south pole. The mapping technique is unique in that it uses digital radar information gleaned from one array of the most sophisticated radar antennae’s in NASA’s arsenal of sensing equipment.

The antenna’s in the array measure three-quarters the size of a football field. From the Mojave desert in California here on the Oblate Spheroid, the antennae send a 500-kilowatt strong, 90-minute long radar stream 231,800 miles to the Moon … and back. The information is then processed with computers at JPL in Pasadena in order to develop detail maps of the Moon’s surface for possible landing sites of possible future Lunar exploration missions. This technique is second only to actually launching a satellite with sophisticated camera equipment and surface sensors.

Digital Elevation Map of Lunar South Pole - Image brightness is generated from the strength of the radar echoes that are bounced of the lunar surface and the color represents the elevation. This map covers an area of 650 kilometers (400 miles) by 450 kilometers (280 miles) with an elevation measurement every 40 meters (130 feet). Image Credit: NASA

This excerpted from Science @ NASA website -

New Radar Maps of the Moon
Science @ NASA - February 29, 2008

NASA has obtained new high-resolution radar maps of the Moon's south pole--a region the space agency is considering as a landing site when astronauts return to the Moon in the years ahead.

"We now know the south pole has peaks as high as Mt. McKinley and crater floors four times deeper than the Grand Canyon," says Doug Cooke, deputy associate administrator for the Exploration Systems Mission Directorate at NASA Headquarters. "These data will be an invaluable tool for advance planning of lunar missions."

New radar imagery of the lunar south pole. The movie simulates solar illumination over the course of a complete lunar day. Video Credit: NASA

Scientists at NASA's Jet Propulsion Laboratory collected the data using the Goldstone Solar System Radar located in California's Mojave Desert. Three times in 2006, JPL scientists targeted the moon's south polar region using Goldstone's 70-meter radar dish. The antenna, three-quarters the size of a football field, sent a 500-kilowatt strong, 90-minute long radar stream 231,800 miles to the Moon. The radar illuminated the rough-hewn lunar surface over an area measuring about 400 by 250 miles. Signals were reflected back to two of Goldstone's 34-meter antennas on Earth. Scientists have been analyzing the echoes ever since, and the data were released by NASA for the first time this week.

NASA has used the data to make a VR movie of a Moon landing from the point of view of the astronaut. Click here to watch. Animation Credit: NASA

"I have not been to the Moon, but this imagery is the next best thing," says Scott Hensley, a scientist at JPL and lead investigator for the study. "With these data we can see terrain features as small as a house without even leaving the office."

NASA is eying the Moon's south polar region as a possible site for future outposts. The location has many advantages; for one thing, there is evidence of water frozen in deep dark south polar craters. Water can be split into oxygen to breathe and hydrogen to burn as rocket fuel--or astronauts could simply drink it. Planners are also looking for "peaks of eternal light." Tall polar mountains where the sun never sets might be a good place for a solar power station.

These are the highest-resolution maps to date. The best images, previously, were generated by the Clementine spacecraft, which could resolve lunar terrain features near the south pole at 1 kilometer per pixel. The JPL radar maps are 50 times more detailed.

As wonderful as they are, however, these images will pale in comparison to next-generation photos from NASA's Lunar Reconnaissance Orbiter. The spacecraft is scheduled to launch in late 2008 and its camera will beam back photos of the moon with details as small as 1 meter.

"The south pole of the Moon," says Cooke, is going to be "a beautiful place to explore."
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Gaps In Saturn’s Rings Formed By Flying Saucer Moons

The moon Pan lies in a gap in Saturn's A ring and Atlas lies just outside the A ring Image Credit: NASA/JPL/University of Colorado

Gaps In Saturn’s Rings Formed By Flying Saucer Moons

When one looks at Saturn, one is struck at how incredibly different it is to our Oblate Spheroid. It is truly spherical and it has a plate of material circling around it at it's equator. The plate, called rings, contains two very unique moons that are shaped like flying saucers.

The exploring satellite, Cassini, recently has given us clues as to how these moons were formed through its cameras.

The fact that the moons, Pan and Atlas are found in the gaps of the rings may give a clue to their unusual “flying saucer” shape.

This excerpted from the New Scientist -

Saturn's 'flying saucer' moons built of ring material
19:00 06 December 2007 - NewScientist.com news service, Maggie McKee

Saturn's moons Pan and Atlas may have formed in two stages - their cores may be remnants of the breakup of a large icy body early in the solar system's history and their ridges may have formed later, as the cores swept up material from Saturn's rings. The scenario might explain why the ridges appear smooth and the polar regions rough.

Two of Saturn's small moons look eerily like flying saucers, new observations by the Cassini spacecraft reveal. The moons, which lie within the giant planet's rings, may have come by their strange shape by gradually accumulating ring particles in a ridge around their equators.
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Both moons have a flattened shape, being wider than they are tall. But their uncanny resemblance to UFOs only became clear recently, when Cassini viewed them with its powerful cameras.
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The images revealed that the smooth ridges girdling the moons' equators lie in the same plane as Saturn's rings and are also as thick as the vertical distance that the moons appear to travel as they move through the rings.

An animation shows how Saturn's moons Pan and Atlas grew by sweeping up particles from Saturn's rings. Animation Video Credit: Courtesy of CEA/ANIMEA

Now, scientists led by Sébastien Charnoz of the University of Paris in France have run computer simulations suggesting that these ridges are made of material swept up from Saturn's rings.
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The origin of the planet's famous rings is still a mystery. But one theory suggests that early in the solar system, one or more large, icy bodies broke up near the planet, creating detritus that then settled into flat rings.

If that is so, Pan and Atlas's cores may have been fragments of this breakup. After the rings flattened into a plane, ring particles may have fallen onto the moons, building up equatorial ridges. The ridges "could be considered as 'fossilised' accretion discs that once may have surrounded Pan and Atlas", the researchers write in the journal Science.

The process probably stopped long ago, since the moons' current orbits are thought to prevent the tenuous material still remaining around them to settle onto their surfaces.
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