Is It Time to Return to the Moon?

Should we pay another visit to the Moon? (From "Le Voyage Dans La Lune" by Georges Méliès, 1902)

Humans haven’t set foot on the Moon — or any other world outside of our own, for that matter — since Cernan and Schmitt departed the lunar surface on December 14, 1972. That will make 40 years on that date this coming December. And despite dreams of moon bases and lunar colonies, there hasn’t even been a controlled landing there since the Soviet Luna 24 sample return mission in 1976 (not including impacted probes.) So in light of the challenges and costs of such an endeavor, is there any real value in a return to the Moon?

Some scientists are saying yes.

Researchers from the UK, Germany and The Netherlands have submitted a paper to the journal Planetary and Space Science outlining the scientific importance of future lunar surface missions. Led by Ian A. Crawford from London’s Birkbeck College, the paper especially focuses on the value of the Moon in the study of our own planet and its formation, the development of the Earth-Moon system as well as other rocky worlds  and even its potential contribution in life science and medicinal research.

Even though some research on the lunar surface may be able to be performed by robotic missions, Crawford et al. ultimately believe that “addressing them satisfactorily will require an end to the 40-year hiatus of lunar surface exploration.”

The team’s paper outlines many different areas of research that would benefit from future exploration, either manned or robotic. Surface composition, lunar volcanism, cratering history — and thus insight into a proposed period of “heavy bombardment” that seems to have affected the inner Solar System over 3.8 billion years ago — as well as the presence of water ice could be better investigated with manned missions, Crawford et al. suggest.

(Read: A New Look At Apollo Samples Supports Ancient Impact Theory)

In addition, the “crashed remains of unsterilized spacecraft” on the Moon warrant study, proposes Crawford’s team. No, we’re not talking about alien spaceships — unless the aliens are us! The suggestion is that the various machinery we’ve sent to the lunar surface since the advent of the Space Age may harbor Earthly microbes that could be returned for study after decades in a lunar environment. Such research could shed new light on how life can — or can’t — survive in a space environment, as well as how long such “contaminants” might linger on another world.

Crawford’s team also argues that only manned missions could offer all-important research on the long-term effects of low-gravity environments on human physiology, as well as how to best sustain exploration crews in space. If we are to ever become a society with the ability to explore and exist beyond our own planet, such knowledge is critical.

And outside of lunar exploration itself, the Moon offers a place from which to perform deeper study of the Universe. The lunar farside, shielded as it is from radio transmissions and other interference from Earth, would be a great place for radio astronomy — especially in the low-frequency range of 10-30 MHz, which is absorbed by Earth’s ionosphere and is thus relatively unavailable to ground-based telescopes. A radio observatory on the lunar farside would have a stable platform from which to observe some of the earliest times of the Universe, between the Big Bang and the formation of the first stars.

Of course, before anything can be built on the Moon or retrieved from its surface, serious plans must be made for such missions. Fortunately, says Crawford’s team, the 2007 Global Exploration Strategy — a framework for exploration created by 13 space agencies from around the world — puts the Moon as the “nearest and first goal” for future missions, as well as Mars and asteroids. Yet with subsequent budget cuts for NASA (a key player for many exploration missions) when and how that goal will be reached still remains to be seen.

See the team’s full paper on arXiv.org here, and check out a critical review on MIT’s Technology Review.

“…this long hiatus in lunar surface exploration has been to the detriment of lunar and planetary science, and indeed of other sciences also, and that the time has come to resume the robotic and human exploration of the surface of the Moon.”

— Ian A. Crawford,  Department of Earth and Planetary Sciences, Birkbeck College, UK

 Top image from “Le Voyage Dans La Lune” by Georges Méliès, 1902. Second image: First photo of the far side of the Moon, acquired by the Soviet Luna-3 spacecraft on Oct. 7, 1959.

On the Edge of Titan

Titan's haze-covered limb seen by Cassini on June 6

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Here’s a quick look at one of my favorite cosmic photo subjects – the varying layers of atmosphere that enshroud Saturn’s enormous moon Titan. The image above is a color-composite made from three raw images acquired by Cassini during its latest flyby.

On June 7 Cassini approached Titan within 596 miles (959 km) and imaged portions of the moon’s northwest quadrant with its radar instrument, as well as conducted further investigations of areas near the equator where surface changes were detected in 2010.

The image here was assembled from three raw images captured in red, green and blue visible light channels. It reveals some structure in the upper hydrocarbon haze layers that extend upwards above the moon’s opaque orange clouds — reaching 400-500 km in altitude, Titan’s atmosphere is ten times thicker than Earth’s!

The June 6 flyby was the second in a series of passes that will take Cassini into a more inclined orbit, where it will reside for the next three years as it investigates Saturn’s polar regions and obtains better views of its ring system.

Read more about the flyby here.

Image: NASA/JPL/Space Science Institute. Composite by J. Major.

Timelapse of a Moonrise as Seen from the ISS

Astronaut Don Pettit continues to ‘wow’ us all with his photographic exploits. In this great timelapse video, not only does Pettit capture a stunning Moonrise over Earth, but he had the presence of mind to set up his video camera in such way that he could also show himself opening the shutters in the space station’s Cupola observation windows just in time to watch all the action. The time-lapse scene was photographed from the airlock of the ISS’s Russian segment.

The Moon Affects the Solar Wind

his is a view of the moon transiting, or passing in front of, the Sun as seen from the STEREO-B spacecraft on Feb. 25, 2007. The Sun is in false color, and the moon appears as a black disk on the upper right. NASA's STEREO mission consists of two spacecraft launched in October, 2006 to study solar storms. Credit: NASA

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From a NASA press release:

With the Moon as the most prominent object in the night sky and a major source of an invisible pull that creates ocean tides, many ancient cultures thought it could also affect our health or state of mind – the word “lunacy” has its origin in this belief. Now, a powerful combination of spacecraft and computer simulations is revealing that the moon does indeed have a far-reaching, invisible influence – not on us, but on the Sun, or more specifically, the solar wind.

The solar wind is a thin stream of electrically conducting gas called plasma that’s constantly blown off the surface of the Sun in all directions at around a million miles per hour. When a particularly fast, dense or turbulent solar wind strikes Earth’s magnetic field, it can generate magnetic and radiation storms that are capable of disrupting satellites, power grids, and communication systems. The magnetic “bubble” surrounding Earth also pushes back on the solar wind, creating a bow shock tens of thousands of miles across over the day side of Earth where the solar wind slams into the magnetic field and abruptly slows from supersonic to subsonic speed.

Unlike Earth, the Moon is not surrounded by a global magnetic field. “It was thought that the solar wind crashes into the lunar surface without any warning or ‘push back’ on the solar wind,” says Dr. Andrew Poppe of the University of California, Berkeley. Recently, however, an international fleet of lunar-orbiting spacecraft has detected signs of the Moon’s presence “upstream” in the solar wind. “We’ve seen electron beams and ion fountains over the Moon’s day side,” says Dr. Jasper Halekas, also of the University of California, Berkeley.

These phenomena have been seen as far as 10,000 kilometers (6,214 miles) above the Moon and generate a kind of turbulence in the solar wind ahead of the Moon, causing subtle changes in the solar wind’s direction and density. The electron beams were first seen by NASA’s Lunar Prospector mission, while the Japanese Kaguya mission, the Chinese Chang’e mission, and the Indian Chandrayaan mission all saw ion plumes at low altitudes. NASA’s ARTEMIS mission has now also seen both the electron beams and the ion plumes, plus newly identified electromagnetic and electrostatic waves in the plasma ahead of the Moon, at much greater distances from the moon. “With ARTEMIS, we can see the plasma ring and wiggle a bit, surprisingly far away from the Moon,” says Halekas. ARTEMIS stands for “Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun”.

This is an artist's concept of the Earth's global magnetic field, with the bow shock. Earth is in the middle of the image, surrounded by its magnetic field, represented by purple lines. The bow shock is the blue crescent on the right. Many energetic particles in the solar wind, represented in gold, are deflected by Earth's magnetic "shield". Credit: Walt Feimer (HTSI)/NASA/Goddard Space Flight Center Conceptual Image Lab

“An upstream turbulent region called the ‘foreshock’ has long been known to exist ahead of the Earth’s bow shock, but the discovery of a similar turbulent layer at the moon is a surprise,” said Dr. William Farrell of NASA’s Goddard Space Flight Center in Greenbelt, Md. Farrell is lead of the NASA Lunar Science Institute’s Dynamic Response of the Environment At the Moon (DREAM) lunar science center, which contributed to the research.

Computer simulations help explain these observations by showing that a complex electric field near the lunar surface is generated by sunlight and the flow of the solar wind. The simulation reveals this electric field can generate electron beams by accelerating electrons blasted from surface material by solar ultraviolet light. Also, related simulations show that when ions in the solar wind collide with ancient, “fossil” magnetic fields in certain areas on the lunar surface, they are reflected back into space in a diffuse, fountain-shaped pattern. These ions are mostly the positively charged ions (protons) of hydrogen atoms, the most common element in the solar wind.

“It’s remarkable that electric and magnetic fields within just a few meters (yards) of the lunar surface can cause the turbulence we see thousands of kilometers away,” says Poppe. When exposed to solar winds, other moons and asteroids in the solar system should have this turbulent layer over their day sides as well, according to the team.

“Discovering more about this layer will enhance our understanding of the Moon and potentially other bodies because it allows information about conditions very near the surface to propagate to great distances, so a spacecraft will gain the ability to virtually explore close to these objects when it’s actually far away,” said Halekas.

The research is described in a series of six papers recently published by Poppe, Halekas, and their colleagues at NASA Goddard, U.C. Berkeley, U.C. Los Angeles, and the University of Colorado at Boulder in Geophysical Research Letters and the Journal of Geophysical Research. The research was funded by NASA’s Lunar Science Institute, which is managed at NASA’s Ames Research Center, Moffett Field, Calif., and oversees the DREAM lunar science center.

In the Shadow of the Moon: A Lunar View of an Eclipse

The LROC turns to capture the Moon's shadow during the May 20 solar eclipse [NASA/GSFC/Arizona State University].

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The May 20 annular eclipse may have been an awesome sight for skywatchers across many parts of the Earth, but it was also being viewed by a robotic explorer around the Moon!

During the event NASA’s Lunar Reconnaissance Orbiter turned its camera to look back home, acquiring several images of the Earth with the Moon’s fuzzy shadow cast onto different regions during the course of the eclipse. The image above is a 4-panel zoom into one particular NAC image showing the Moon’s shadow over the Aleutian Islands.

LRO captured a total of four narrow-angle camera (NAC) images during two of its orbits. During one orbit the Moon’s shadow was over the southern part of Japan, and during the next it had moved northeast to cover the island chain of Alaska.

According to the LROC site run by Arizona State University:

The NAC is a line scanner, meaning that it has only one row of 5064 pixels per camera. Instead of snapping a single frame, an image is built up by the motion of the spacecraft in orbit about the Moon (about 1600 meters per second). To obtain an image of the Earth the spacecraft is turned 180° to face the Earth, then the spacecraft is pitched as quickly as possible (one-tenth of a degree per second), so that the image is built up line by line.

This also explains why some of the images are “clipped” on the edges… LRO ran out of time during its lunar orbit. Still, it’s great to be able to show some photos of the eclipse from quite possibly the most distant viewer anywhere!

Read more on the LROC site here.

Animation of four LROC images of the annular eclipse (click to play) NASA/GSFC/Arizona State University

Going to the Moon? Don’t Touch the Historical Artifacts, NASA Says

NASA recommends an artifact boundary extending 75 m from the Apollo 11 lunar module descent stage. Photo credit: NASA

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Don’t say you haven’t been warned. NASA put out an official document today specifying how close any future spacecraft and astronauts visiting the Moon can come to the artifacts left on the lunar surface by all US space missions, including the Apollo landing sites, any robotic landing sites like Surveyor and impact sites like LCROSS.

While these recommendations are not mandatory (there’s obviously no way to enforce this yet) the document states, “rather, it is offered to inform lunar spacecraft mission planners interested in helping preserve and protect lunar historic artifacts and potential science opportunities for future missions.”

For example, NASA recommends an artifact boundary extending 75 m from the Apollo 11 lunar module descent stage.

NASA isn’t expecting a rush of astro-looters to descend upon the Moon, but with China discussing a Moon landing, and with several Google Lunar X PRIZE teams hoping to send robotic landers, they want to make sure nothing from previous missions is disturbed.

“In the 50 years since the first lunar missions, the spaceflight community has not formally provided recommendations to the next generation of lunar explorers on how to preserve the original artifacts and protect ongoing science from the potentially damaging effects of nearby landers,” NASA said in an accompanying press release, saying that they recognize the steadily increasing technical capabilities of space-faring commercial entities and nations throughout the world that may be on the verge of landing spacecraft on the surface of the Moon.

The document specifies how close another spacecraft can hover, flyover, hop or touchdown near landing sites or spacecraft.

And not just hardware is included in the “don’t touch” areas: “U.S. human, human-robotic lunar presence, including footprints, rover tracks, etc., although not all anthropogenic indicators are protected as identified in the recommendations,” the document says.

NASA’s decisions on proximity boundaries were made from recommendations from external experts from the historic, scientific and flight-planning communities and apply to US government artifacts on the lunar surface.

NASA says they released this document to open discussions with commercial and international space agencies, and seek any improvements to the recommendations.

Read the full document here (pdf file).

Source: NASA

Your ‘Supermoon’ Images from Around the World

San Souci lighthouse and the perigee Moon, in the Dominican Republic. Credit: Goku Abreu.

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We asked for ’em, and you sent ’em in: here are great images of the perigee Moon on May 5, 2012, the largest full Moon of the year taken by our readers.

The perigee Moon as seen in Opelika, Alabama USA. Credit: Jacob Marchio.
The Supermoon on a finger, as seen in Aguilas, Murcia Spain. Credit: Tapani Isomäki
An artist's view of the 'Supermoon.' Credit: Omer Sidat.
Largest Full Moon for 2012 from Dayton, Ohio USA. Credit: John Chumack.
Perigee Moon on May 5, 2012 from Altamonte Springs, Florida USA. Credit: Austin Russie.
A shy supermoon from Brick Landing, North Carolina USA. Credit: Tavi Greiner.
The supermoon from Juiz de Fora, Minas Gerais, Brazil. Credit: jimctu on Flickr
Preparing for a Supermoon, on May 3, 2012 from Wauseon, Ohio. Credit: Bill Schlosser.
A lovely Moonrise at Soldier's Beach off the Central Coast of New South Wales, Australia. Credit: Kerry Middlemiss
'Taken from the Marin Headlands with about 573 other photographer friends. I used my Orion ED Refractor telescope for a lens,' said photographer Ted Judah.
Supermoon over the Pacific, taken at Goblets Beach in Santa Barbara, California, USA. Credit: Jonathan Vail.
Full Super Moon rising over UC Berkeley Sather Tower Campanile and International House. Credit: Ira Serkes.
Super full Moon over Tucson, Arizona, USA. Credit: 'Sifted Reality' on Flickr.
Digiscope of the 2012 Supermoon, São Paulo, Brazil. Credit: Monica, 'MoniBR' on Flickr.
The perigee full Moon from Cocoa Beach, Florida, USA. Credit: Jamie Rich.
The perigee Moon from Toronto, Canada. Credit: Rick Ellis.
The Moon on May 6, 2012 in Mandan, North Dakota, USA. Credit: Jola Boehm

And speaking of images from ‘around the world,’ here’s one from the International Space Station:

The perigee full Moon on May 5, 2012, as seen through Earth’s atmosphere, which bends the light from the Moon, making it appear squished. Credit: Andre Kuipers/ESA/NASA

Thanks to everyone who sent in their images and posted them to our Flickr page. See more images and find more from our contributors at Universe Today’s Flickr page.

How the Hubble Telescope Will Look at the Moon to See Venus Transit the Sun

Scientists used the Hubble Space Telescope to look at the Moon to prepare for special observations of the 2012 Venus transit of the Sun. Credit: NASA, ESA, and D. Ehrenreich (Institut de Planetologie et d'Astrophysique de Grenoble (IPAG)/CNRS/Universite Joseph Fourier)

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Venus moving across the face of the Sun, from our vantage point here on Earth, is such a rare event, that astronomers and observatories around the world have been preparing for this year’s Venus Transit, on June 5-6. And one observatory that is literally “around the world,” – the Hubble Space Telescope — is even planning to make observations of this transit event. What, you say? The Hubble telescope can’t look at the Sun – it would fry every component on board! Hubble scientists are being pretty sneaky, if not resourceful so they too can join in the observations.

Since Hubble can’t look at the Sun directly, astronomers are planning to point the telescope at the Moon, using it as a mirror to capture reflected sunlight and isolate the small fraction of the light that passes through Venus’s atmosphere. Imprinted on that small amount of light are the fingerprints of the planet’s atmospheric makeup.

Scientists say these observations will mimic a technique that is already being used to sample the atmospheres of giant planets outside our solar system passing in front of their stars. In the case of the Venus transit observations, astronomers already know the chemical makeup of Venus’s atmosphere, and that it does not show signs of life on the planet. But the Venus transit will be used to test whether this technique will have a chance of detecting the very faint fingerprints of an Earth-like planet, even one that might be habitable for life, outside our solar system that similarly transits its own star.

Venus is an excellent stand in for Earth because of how similar in size and mass it is to our planet.

Several different instruments on Hubble will be used in this special observation. The Advanced Camera for Surveys, Wide Field Camera 3, and Space Telescope Imaging Spectrograph, to view the transit in a range of wavelengths, from ultraviolet to near-infrared light. During the transit, Hubble will snap images and perform spectroscopy, dividing the sunlight into its constituent colors, which could yield information about the makeup of Venus’s atmosphere.

Hubble will observe the Moon for seven hours, before, during, and after the transit so the astronomers can compare the data. Astronomers need the long observation because they are looking for extremely faint spectral signatures. Only 1/100,000th of the sunlight will filter through Venus’s atmosphere and be reflected off the Moon.

Because the astronomers only have one shot at observing the transit, they had to carefully plan how the study would be carried out. Part of their planning included the test observations of the Moon, such as when they took the top image of Tycho Crater.

Hubble will need to be locked onto the same location on the Moon for more than seven hours, the transit’s duration. For roughly 40 minutes of each 96-minute orbit of Hubble around the Earth, the Earth occults Hubble’s view of the Moon. So, during the test observations, the astronomers wanted to make sure they could point Hubble to precisely the same target area.

This is the last time this century sky watchers can view Venus passing in front of the Sun. The next transit won’t happen until 2117. Venus transits occur in pairs, separated by eight years. The last event was witnessed in 2004.

Find more on how you can observe the Venus transit for yourself in this article by Tammy Plotner.

Source: HubbleSite

Moon Craters 3-D!

A young unnamed crater on the Moon west of Isaev crater. Credit: NASA/GSFC/Arizona State University; Anaglyph by Nathanial Burton-Bradford.

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While many are hoping to see a larger-than-usual view of the Moon this weekend, here’s some great 3-D closeups courtesy of the Lunar Reconnaissance Orbiter and imaging wizard Nathanial Burton Bradford. This great 3-D view (Red/Cyan glasses needed) shows quite an interesting young impact crater on the Moon, (17.682°S, 144.408°E) west of Isaev crater. Click on the image for a larger view, and in 3-D you can dive right in and see all the nooks and crannies – what scientists call complex crater morphology.

Below you can view a Digital Terrain Model, or DTM of this same crater, and find the specifics of how deep the various parts of the crater are and other information critical to scientific investigations of the Moon.

Digital Terrain Model (DTM) of an unnamed crater in the farside highlands. Image is 3.2 km across. Credit: NASA/GSFC/Arizona State University.

Another recent view released by the LRO camera team is of impact melt deposit on another unnamed crater on nearside highlands (38.112°N, 53.052°E; northeast of Mare Tranquillitatis). Again, Nathanial Burton-Bradford provides a 3-D view, and amazingly, the crater walls appear deceptively steep in 3-D as opposed to the regular 2-D view:

3D anaglyph of rim impact melt deposit on Unnamed crater on nearside highlands (38.112°N, 53.052°E; northeast of Mare Tranquillitatis). Credit: NASA/GSFC/Arizona State University; anaglyph by Nathanial Burton-Bradford.

What is impact melt? “So much energy is released when an asteroid or comet slams into the Moon that some of target rock (the Moon) is melted,” wrote Lillian Ostrach on the LRCO website. “For large craters, such as Tycho or Copernicus, the impact event responsible for forming these craters was large enough to generate melt that coated and covered the crater floor, and ejected melt pooled and flowed outside the crater cavity.”

Ostrach says that LROC images show that impact melt is widespread and quite common to lunar impact craters — but as this image shows – take a close look to find channels, flows, and veneers across much of the region.

Here’s LROC’s regular view:

Impact melt started to flow back into the crater cavity before it solidified. Image width is 500 m, from the LROC Narrow Angle Camera. Credit: NASA/GSFC/Arizona State University.

Find out more about these recent LRO images on the LROC website, and see more of Nathanial’s photography handiwork at his DeviantArt page.

Exploration at its Finest: Cassini Visits Dione

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After completing its most recent flyby of Enceladus, Cassini made a pass by Dione — its final visit of the icy moon for the next three years. Coming within  5,000 miles (8000 km) of Dione on May 2, Cassini captured some fantastic images of the moon’s heavily-cratered and frozen surface. Here’s just a few of the raw images that arrived back here on Earth earlier today:

Crescent-lit Dione, with some reflected light via Saturnshine
A nearly fully-lit Dione, with Saturn's rings in the background
Dione's extensively-cratered limb
Some of Dione's signature "wispy lines", bright icy faces of sheer cliffs now known to be tectonic in origin
A color-composite image of an ancient impact crater on the edge of Dione's Saturn-facing side - this could be from the impact that spun the moon 180 degrees. (NASA/JPL/SSI/J. Major)

698 miles (1123 km) in diameter, Dione orbits Saturn at about the same distance that the Moon orbits Earth. Its composition is two-thirds water ice, which at the incredibly cold temperatures found around Saturn behaves like rock does here on Earth.

 

Cassini won’t visit Dione so closely again until June 2015, after spending three years angled high out of the equatorial plane while it studies Saturn’s rings and polar regions.

As Carolyn Porco, Cassini Imaging Team Leader said today, “This is exploration at its finest. It won’t continue forever. So, enjoy it while it lasts!”

See more on the Cassini Imaging Central Laboratory for Operations (CICLOPS) site here.

Image credits: NASA/JPL/Space Science Institute