New moon vistas revealed

Today's first images from NASA's Lunar Reconnaissance Orbiter provide a fresh perspective on the moon, just weeks before the 40th anniversary of the first manned lunar landing.

Lunar Reconnaissance Orbiter, or LRO, was launched on June 18, along with another probe destined to crash into the moon's south pole - known as the Lunar Crater Observation and Sensing Satellite, or LCROSS.

LRO entered lunar orbit just last week, on the same day that LCROSS transmitted its own first imagery of the moon. Mission managers had figured it would take longer for LRO to send back higher-resolution images worth sharing. However, when they activated the orbiter's cameras for a test on Tuesday, they were surprised to find that the pictures they got back were real stunners.

This YouTube video provides a flyover of the region near Mare Nubium (Sea of Clouds), and there's also a zoomable version of the imagery.

"Our first images were taken along the moon's terminator - the dividing line between day and night - making us initially unsure of how they would turn out," Arizona State University's Mark Robinson, the principal investigator for the Lunar Reconnaissance Orbiter Camera, said in today's image advisory.

"Because of the deep shadowing, subtle topography is exaggerated, suggesting a craggy and inhospitable surface," he said. "In reality, the area is similar to the region where the Apollo 16 astronauts safely explored in 1972. While these are magnificent in their own right, the main message is that LROC is nearly ready to begin its mission."

Later today, Robinson explained why the mission team had such low expectations for Tuesday's pictures. "The point of that test was not to take pictures of the lunar surface," he told me. "It was to collect engineering data to make sure that all of our settings are correct for Friday."

Starting Friday, LRO's cameras will be in operation for two and a half days, snapping pictures of some of the lesser-known areas of the moon's far side, Robinson said. Then the cameras will be shut off again for further commissioning. "We still are not completely finished baking out the moisture from the telescope," he said.

By next month, LRO will be in full picture-taking mode, acquiring much sharper views of the lunar surface. The orbiter's camera should be able to make out some of the traces left behind by the Apollo moon missions four decades ago, including lunar module leavings and rover tracks. "I promise you we will get spectacular images of all the Apollo landing sites before all is said and done," Robinson told me.

It's been a whole decade since the last U.S. moon probe smashed into the lunar surface, but it's not as if the moon has been terra incognita over the past few years. Several international spacecraft have been sending back pictures of our nearest celestial neighbor - including Europe's SMART-1, China's Chang'e 1, India's Chandrayaan 1 and Japan's Kaguya probe.

Nevertheless, LRO is a big deal: Its pictures and other data will be used to plan NASA's future push to the moon, designed to climax in a manned lunar landings sometime around 2020.

This month, the world will be remembering the Apollo 11 lunar landing and the explorations that followed between 1969 and 1972. The pictures coming from LRO should remind people that the best is yet to come.

Here's more about LRO's progress from the NASA news release issued today:

"... The satellite also has started to activate its six other instruments. The Lunar Exploration Neutron Detector will look for regions with enriched hydrogen that potentially could have water ice deposits. The Cosmic Ray Telescope for the Effects of Radiation is designed to measure the moon's radiation environment. Both were activated on June 19 and are functioning normally.

"Instruments expected to be activated during the next week and calibrated are the Lunar Orbiter Laser Altimeter, designed to build 3-D topographic maps of the moon's landscape; the Diviner Lunar Radiometer Experiment, which will make temperature maps of the lunar surface; and the Miniature Radio Frequency, or Mini-RF, an experimental radar and radio transmitter that will search for subsurface ice and create detailed images of permanently shaded craters.

"The final instrument, the Lyman Alpha Mapping Project, will be activated after the other instruments have completed their calibrations, allowing more time for residual contaminants from the manufacture and launch of LRO to escape into the vacuum of space. This instrument is an ultraviolet-light imager that will use starlight to search for surface ice. It will take pictures of the permanently-shaded areas in deep craters at the lunar poles.

" 'Accomplishing these significant milestones moves us closer to our goals of preparing for safe human return to the moon, mapping the moon in unprecedented detail, and searching for resources,' said LRO Project Scientist Richard Vondrak of NASA's Goddard Space Flight Center in Greenbelt, Md.

"While its instruments are being activated and tested, the spacecraft is in a special elliptical commissioning orbit around the moon. The orbit takes less fuel to maintain than the mission's primary orbit. The commissioning orbit's closest point to the lunar surface is about 19 miles over the moon's south pole, and its farthest point is approximately 124 miles over the lunar north pole.

"After the spacecraft and instruments have completed their initial calibrations, the spacecraft will be directed into its primary mission orbit in August, a nearly circular orbit about 31 miles above the lunar surface.

"Goddard built and manages LRO, a NASA mission with international participation from the Institute for Space Research in Moscow. Russia provides the neutron detector aboard the spacecraft."

How Martian clouds create snowfall

The planet Mars conjures images of red rocks and arid, dusty plains, but as NASA's Phoenix Mars Lander showed last year, it snows on Mars.

The stationary robot observed ice crystals falling to the Martian surface near the end of its five-month mission in the arctic Vastitas Borealis plains last year. Scientists provided further details on this finding and others in a set of four papers in Friday's issue of the journal Science. The research could help shed light on the past and present action of water on the Martian surface and characterize the potential habitability of the Red Planet.

Phoenix landed on the Red Planet on May 25, 2008, with a mission to dig up and analyze samples of Martian dirt, confirm the existence of a subsurface layer of water ice and observe the weather at its far northern locale.

Cirrus clouds...
Spacecraft orbiting Mars had previously detected clouds high up in the Martian atmosphere and low-level ice fog, "but they've never seen precipitation," said James Whiteway of York University in Canada, the lead scientist for Phoenix's meteorological instruments.

From its vantage point on the Martian surface, Phoenix used its LIDAR (light detection and ranging) instrument, supplied by the Canadian Space Agency, to emit laser pulses upward into the atmosphere. The instrument detected clouds and precipitation above Phoenix's landing site.

The clouds were low-level, wispy clouds made up of ice crystals, similar to the cirrus clouds that form over Earth's polar regions in the winter. Whiteway also likened them to the thin clouds jet planes fly through high in the Earth's atmosphere.

"The thin, wispy clouds up there have a similar water content," he told

The clouds didn't begin forming until around the mission's 80th or 90th Martian day (or sol), when air temperatures were cool enough for water vapor in the atmosphere to condense out, Whiteway explained.

As the mission wore on, the clouds became thicker, lower to the ground and persisted for longer.

...And snow
The snow didn't come until close to the end of the mission. It too is similar to the snow that falls to the ground at Earth's poles, sometimes called "diamond dust." Whiteway describes it as "ice crystals sparkling in the air."

The snow wasn't enough to build a snowmartian with, however, amounting to only a couple micrometers (there are 1,000 micrometers in a millimeter) a day if it was melted on the surface, Whiteway said.

The observations show that "precipitation is a component of the hydrologic cycle" on Mars, which was not suspected before the Phoenix mission, Whiteway said.

How the finding might impact our understanding of the global Mars water cycle — both now and in the distant past, when the planet is suspected to have been warmer and wetter — is not yet known.

The new information can be used to modify Martian climate models, which currently don't feature these newly discovered clouds and precipitation, "and then we'll see what the implications are," Whiteway said.

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