Category Archives: LROC

Water Movement on the Moon?

The image is our moon, this is the far-side unseen from Earth courtesy of NASA and Arizona State University.

Water movement on the moon?

NASA — Scientists, using an instrument aboard NASA’s Lunar Reconnaissance Orbiter (LRO), have observed water molecules moving around the dayside of the Moon.

A paper published in Geophysical Research Letters describes how Lyman Alpha Mapping Project (LAMP) measurements of the sparse layer of molecules temporarily stuck to the surface helped characterize lunar hydration changes over the course of a day.

Up until the last decade or so, scientists thought the Moon was arid, with any water existing mainly as pockets of ice in permanently shaded craters near the poles. More recently, scientists have identified surface water in sparse populations of molecules bound to the lunar soil, or regolith. The amount and locations vary based on the time of day. This water is more common at higher latitudes and tends to hop around as the surface heats up.

“This is an important new result about lunar water, a hot topic as our nation’s space program returns to a focus on lunar exploration,” said Dr. Kurt Retherford, the principal investigator of the LAMP instrument from Southwest Research Institute in San Antonio, Texas. “We recently converted the LAMP’s light collection mode to measure reflected signals on the lunar dayside with more precision, allowing us to track more accurately where the water is and how much is present.”

Water molecules remain tightly bound to the regolith until surface temperatures peak near lunar noon. Then, molecules thermally desorb and can bounce to a nearby location that is cold enough for the molecule to stick or populate the Moon’s extremely tenuous atmosphere or exosphere, until temperatures drop and the molecules return to the surface. SwRI’s Dr. Michael Poston, now a research scientist on the LAMP team, had previously conducted extensive experiments with water and lunar samples collected by the Apollo missions. This research revealed the amount of energy needed to remove water molecules from lunar materials, helping scientists understand how water is bound to surface materials.

“Lunar hydration is tricky to measure from orbit, due to the complex way that light reflects off of the lunar surface,” Poston said. “Previous research reported quantities of hopping water molecules that were too large to explain with known physical processes. I’m excited about these latest results because the amount of water interpreted here is consistent with what lab measurements indicate is possible.

Scientists have hypothesized that hydrogen ions in the solar wind may be the source of most of the Moon’s surface water. With that in mind, when the Moon passes behind the Earth and is shielded from the solar wind, the “water spigot” should essentially turn off. However, the water observed by LAMP does not decrease when the Moon is shielded by the Earth and the region influenced by its magnetic field, suggesting water builds up over time, rather than “raining” down directly from the solar wind.

“These results aid in understanding the lunar water cycle and will ultimately help us learn about accessibility of water that can be used by humans in future missions to the Moon,” said Amanda Hendrix, a senior scientist at the Planetary Science Institute and lead author of the paper. “Lunar water can potentially be used by humans to make fuel or to use for radiation shielding or thermal management; if these materials do not need to be launched from Earth, that makes these future missions more affordable.”

“This result is an important step in advancing the water story on the Moon and is a result of years of accumulated data from the LRO mission,” said John Keller, LRO deputy project scientist from NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Goddard manages the LRO mission for the Science Mission Directorate at NASA Headquarters in Washington, D.C. Funding for the research came from LRO, and the team received additional support from a NASA Solar System Exploration Research Virtual Institute (SSERVI) cooperative agreement.

NASA is leading a sustainable return to the Moon with commercial and international partners to expand human presence in space and bring back new knowledge and opportunities.

For more information on LRO, visit:
www.nasa.gov/lro

Lunar Swirls

NASA: “These patterns, called ‘lunar swirls,’ appear almost painted on the surface of the moon,” said John Keller of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “They are unique; we’ve only seen these features on the moon, and their origin has remained a mystery since their discovery.” Keller is project scientist for NASA’s Lunar Reconnaissance Orbiter (LRO) mission, which made the observations.

Lunar swirls can be tens of miles across and appear in groups or just as an isolated feature. Previous observations yielded two significant clues about their formation: First, they appear where ancient bits of magnetic field are embedded in the lunar crust (although not every “fossil” magnetic field on the moon has a lunar swirl). Second, the bright areas in the swirls appear to be less weathered than their surroundings. The space environment is harsh; many things can cause material exposed to space to change chemically and darken over time, including impacts from microscopic meteorites and the effects of the solar wind – a million-mile-per-hour stream of electrically conducting gas blown from the surface of the sun.

Those clues led to three prominent theories about how the swirls formed. The swirls and the magnetic fields could both have formed from plumes of material ejected by comet impacts. Alternatively, perhaps when fine dust particles get lofted by micrometeorite impacts, an existing magnetic field over the swirls sorts them according to their susceptibility to magnetism, forming light and dark patterns with different compositions. Finally, since particles in the solar wind (electrons and ions) are electrically charged, they respond to magnetic forces. Perhaps the magnetic field shields the surface from weathering by the solar wind.

In the new research, teams of scientists created computer models that provide new insights into how the magnetic shield hypothesis could work. “The problem with the magnetic shield idea is that the embedded magnetic fields on the moon are very weak – about 300 times weaker than Earth’s magnetic field,” said Bill Farrell of NASA Goddard. “It’s hard to see how they would have the strength to deflect the solar wind ions.” Farrell leads Goddard’s DREAM-2 Center for Space Environments (Dynamic Response of the Environment at Asteroids, the Moon, and moons of Mars) which is funded by NASA’s Solar System Exploration Research Virtual Institute (SSERVI) to conduct the model research. 

The new models reveal that the magnetic field can create a strong electric field when the solar wind attempts to flow through. It is this brawny electric potential of many hundreds of Volts that could deflect and slow particles in the solar wind. This would reduce the weathering from the solar wind, leaving brighter regions over protected areas. The new models are published separately as a series of three papers, one in Icarus on March 1, 2016 by lead author Andrew Poppe of the University of California at Berkeley; one in the Journal of Geophysical Research: Space Physics on June 18, 2015 by lead author Shahab Fatemi of University of California, Berkeley; and one in the Journal of Geophysical Research: Planets on November 25, 2015 by lead author Michael Zimmerman of The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland.

New observations from LRO appear to provide support for the magnetic shield hypothesis, but don’t rule out the other ideas. “Until you have somebody making measurements on the lunar surface we may not get a definitive answer, but the new observations that analyze the swirls in ultraviolet and far-ultraviolet light are consistent with earlier observations that indicate the swirls are less weathered than their surroundings,” said Keller. The new observations are the subject of two papers published in Icarus by lead author Brett Denevi of The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland on January 21, 2016 and lead author Amanda Hendrix of the Planetary Science Institute, Tucson, Arizona on February 4, 2016.

The DREAM-2 teams want to continue to develop their models to see how the magnetic shield responds to different strengths of the solar wind and various times of the lunar day, when the solar wind blows from different directions. They also want to model the physical and chemical processes of space weathering to better understand how it can change the lunar surface. The LRO team plans to modify the LAMP instrument (Lyman Alpha Mapping Project) on LRO to improve its signal-to-noise ratio for dayside observations, which will dramatically improve its ability to study this problem.

The research was funded by the LRO mission and the DREAM-2 center. DREAM-2 is part of SSERVI at NASA’s Ames Research Center in California’s Silicon Valley. LRO is managed by NASA Goddard for the Science Mission Directorate at NASA Headquarters in Washington.

Bill Steigerwald

NASA’s Goddard Space Flight Center, Greenbelt, Md.

Credits: NASA LRO WAC science team

Chang’e 4 on the Farside

The Chinese lander Chang’e 4 on the farside of the moon spotted by the Lunar Reconnaissance Orbiter’s LROC camera.

NASA; Chang’e 4, the second Chinese lunar lander, set down on a relatively small farside mare basalt deposit that is extensively mixed with highland ejecta from the nearby and relatively young Finsen crater (73 kilometer or 45 mile diameter). Scientists have long wanted to know the composition of farside basalts; are they significantly different from the nearside basalts? According to the China National Space Administration, Chang’e 4 instrumentation includes the visible near infrared spectrometer (VNIS) which takes measurements that can be used to address this question. This new information from the surface will provide important ground truth, while the combination of on-surface and orbital measurements provides synergy that will advance knowledge of the farside.

Credit: NASA/GSFC/Arizona State University.

Mark Robinson
Arizona State University

Nancy Neal Jones
NASA’s Goddard Space Flight Center

A Square Corner

Did you ever notice just about every crater is at least a little rounded, some a bit elongated sure but rounded and most are just plain circular. Well “square” corners do occur and while they can be fodder for conspiracy theories, there are perfectly reasonable explanations for their formation.

The lunar crater above (NASA/GSFC/Arizona State University) is a good example. The name of the crater is Lavoisier, named for the famous French Chemist Antoine Lavoisier.

The crater is about 70 km across (42 miles), pretty large and can be seen with even a small telescope – yhe image width is only about 10 percent of the entire crater. The thing about Lavoisier is the location, Longitude: 81.253° West, Latitude: 38.169° North puts it on the northwestern limb so you need something steady to see it well. Yes binoculars would work but not for a decent examination. Plus the moon probably needs to be pretty well full. I will definitely have a look in a couple of weeks.

So how do we get to the squared off corners? Here’s what the LRO / NASA website had to say:

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Giordano Bruno Crater

Here is a wonderful picture of the crater Giaordano Bruno taken by the LROC camera aboard the Lunar Reconnainse Orbiter.

The crater is about 22 x 22 km / 13 x 13 miles and is named for the Italian philospher born in 1548.

I also want to introduce you to a bit of software I have on every computer I own. The program is called the Virtual Moon Atlas. I have used this for YEARS and love it. Oh yes, the cost for this program is ZERO. Yes, free.

I like to pick out a crater on the moon (eyes to binocular to telescope size) and locate it on the Atlas and the wealth of information, well you have to try it. Or do the reverse pick out an crater on the Atlas and locate it.

Download it here at SourceForge and enjoy!

Strange Lunar Image – Meteor Hit

 

NASA/LRO (By Nancy Neal Jones
NASA’s Goddard Space Flight Center in Greenbelt, MD)- On Oct.13, 2014 something very strange happened to the camera aboard NASA’s Lunar Reconnaissance Orbiter (LRO). The Lunar Reconnaissance Orbiter Camera (LROC), which normally produces beautifully clear images of the lunar surface, produced an image that was wild and jittery. From the sudden and jagged pattern apparent in the image, the LROC team determined that the camera must have been hit by a tiny meteoroid, a small natural object in space.

LROC is a system of three cameras mounted on the LRO spacecraft. Two Narrow Angle Cameras (NACs) capture high resolution black and white images. The third Wide Angle Camera captures moderate resolution images using filters to provide information about the properties and color of the lunar surface.

The NAC works by building an image one line at a time. The first line is captured, then the orbit of the spacecraft moves the camera relative to the surface, and then the next line is captured, and so on, as thousands of lines are compiled into a full image.

According to Mark Robinson, professor and principal investigator of LROC at ASU’s School of Earth and Space Exploration, the jittery appearance of the image captured is the result of a sudden and extreme cross-track oscillation of the camera. LROC researchers concluded that there must have been a brief violent movement of the left Narrow Angle Camera.

There were no spacecraft events like solar panel movements or antenna tracking that might have caused spacecraft jitter during this period. “Even if there had been, the resulting jitter would have affected both cameras identically,” says Robinson. “The only logical explanation is that the NAC was hit by a meteoroid.”

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New LRO Image

lroearth

WOW!

Image Credit: NASA/Goddard/Arizona State University

The original caption:
NASA’s Lunar Reconnaissance Orbiter (LRO) recently captured a unique view of Earth from the spacecraft’s vantage point in orbit around the moon.

“The image is simply stunning,” said Noah Petro, Deputy Project Scientist for LRO at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The image of the Earth evokes the famous ‘Blue Marble’ image taken by Astronaut Harrison Schmitt during Apollo 17, 43 years ago, which also showed Africa prominently in the picture.”

In this composite image we see Earth appear to rise over the lunar horizon from the viewpoint of the spacecraft, with the center of the Earth just off the coast of Liberia (at 4.04 degrees North, 12.44 degrees West). The large tan area in the upper right is the Sahara Desert, and just beyond is Saudi Arabia. The Atlantic and Pacific coasts of South America are visible to the left. On the moon, we get a glimpse of the crater Compton, which is located just beyond the eastern limb of the moon, on the lunar farside.

LRO was launched on June 18, 2009, and has collected a treasure trove of data with its seven powerful instruments, making an invaluable contribution to our knowledge about the moon. LRO experiences 12 earthrises every day; however the spacecraft is almost always busy imaging the lunar surface so only rarely does an opportunity arise such that its camera instrument can capture a view of Earth. Occasionally LRO points off into space to acquire observations of the extremely thin lunar atmosphere and perform instrument calibration measurements. During these movements sometimes Earth (and other planets) pass through the camera’s field of view and dramatic images such as the one shown here are acquired.

This image was composed from a series of images taken Oct. 12, when LRO was about 83 miles (134 kilometers) above the moon’s farside crater Compton. Capturing an image of the Earth and moon with LRO’s Lunar Reconnaissance Orbiter Camera (LROC) instrument is a complicated task. First the spacecraft must be rolled to the side (in this case 67 degrees), then the spacecraft slews with the direction of travel to maximize the width of the lunar horizon in LROC’s Narrow Angle Camera image. All this takes place while LRO is traveling faster than 3,580 miles per hour (over 1,600 meters per second) relative to the lunar surface below the spacecraft!

The high-resolution Narrow Angle Camera (NAC) on LRO takes black-and-white images, while the lower resolution Wide Angle Camera (WAC) takes color images, so you might wonder how we got a high-resolution picture of the Earth in color. Since the spacecraft, Earth, and moon are all in motion, we had to do some special processing to create an image that represents the view of the Earth and moon at one particular time. The final Earth image contains both WAC and NAC information. WAC provides the color, and the NAC provides high-resolution detail.

“From the Earth, the daily moonrise and moonset are always inspiring moments,” said Mark Robinson of Arizona State University in Tempe, principal investigator for LROC. “However, lunar astronauts will see something very different: viewed from the lunar surface, the Earth never rises or sets. Since the moon is tidally locked, Earth is always in the same spot above the horizon, varying only a small amount with the slight wobble of the moon. The Earth may not move across the ‘sky’, but the view is not static. Future astronauts will see the continents rotate in and out of view and the ever-changing pattern of clouds will always catch one’s eye, at least on the nearside. The Earth is never visible from the farside; imagine a sky with no Earth or moon – what will farside explorers think with no Earth overhead?”

NASA’s first Earthrise image was taken with the Lunar Orbiter 1 spacecraft in 1966. Perhaps NASA’s most iconic Earthrise photo was taken by the crew of the Apollo 8 mission as the spacecraft entered lunar orbit on Christmas Eve Dec. 24, 1968. That evening, the astronauts — Commander Frank Borman, Command Module Pilot Jim Lovell, and Lunar Module Pilot William Anders — held a live broadcast from lunar orbit, in which they showed pictures of the Earth and moon as seen from their spacecraft. Said Lovell, “The vast loneliness is awe-inspiring and it makes you realize just what you have back there on Earth.”

 

 

LADEE Impact Crater

lrocladee

The LADEE Impact crater on the far-side of the moon was found by the Lunar Reconnaissance Orbiter and the LRO camera called LROC.  Credit: NASA/GSFC/Arizona State University.

The LADEE spacecraft was launched from Wallops Island on 6 September 2013.  The spacecraft was sent to the moon to study the “surface bound exosphere and dust environment” or dust particles that might exist high above the surface to contribute to the Apollo-era debate about the existence – or not.

LADEE did not find any dust particles.  Mission completed LADEE fired its engines to enter a controlled descent that would cause it to impact the far-side of the moon even in the event the eclipse of 15 April 2014 caused the spacecraft to be otherwise uncontrollable.  The risk of not doing so would mean there would be no guarantee the impact would miss any Apollo landing sites.  Sure the odds probably would be slim but those sites are so historically significant that ANY chance is too much and a spacecraft with a mass of 248 kg / 547 pounds could cause damage.

The strategy was successful and LADEE  impacted the eastern rim of Sundman V crater (11.85°N, 266.75°E). The impact site (11.8494°N, 266.7507°E) is about 780 m from the crater rim with an altitude of about 2590 m, and was only about 295 meters north of its originally predicted location (based on tracking data).

There is an excellent LROC page devoted to this Impact image including before and after pictures – have a look.

 

Inside Tycho Crater

tycho

When we look up at the moon we can see the very large Tycho crater as above (image above wiki commons).

I’ve talked some about central peaks in recent posts and the Lunar Reconnaissance Orbiter has taken some spectacular images of Tycho at very close range. Click the image to see the central peak of Tycho from the LRO, that central peak is more than 2 km / 6562 ft high.

Not all craters have central peaks, it depends on the gravitational field of the body and the material being impacted and of course how large the impact is. Here is a very short video of the concept in a fluid. In rocky moons and planets the central peaks can be formed by the rock being pushed back up by the underlying substrate (rock) instead of the fluid in the video. It is very much like a rebound event.

There are lots of variables that play into the formation of central peaks. You can imagine if the impacted surface was say sandy regolith the peak would just fall down on itself and if the impacting body was not large enough material would be just swept away. Likewise an air burst meteor may not leave a central peak becuase the blast might not be concentrated enough. Even the angle of impact makes a difference.

So as you can see there is a lot to consider. Here is a great web page on crater forms from the University of Wisconsin – Green Bay.

The page where the above image of Tycho’s central peak came from gives a nice treatment of Shapes of Craters and there are even better shots of the central peak of Tycho from the LRO here.

Images: LRO / NASA