Synthetic view of the waxing Moon as viewed from Earth on 2013-10-15 17:00:00 UTC [NASA/GSFC/Arizona State University].
Take a look around the Moon… no, really, take a good look AROUND the Moon! This is a fantastic animation of our planetary partner in space made by the folks on the Lunar Reconnaissance Orbiter team at Arizona State University. Assembled from reflectance maps and digital terrain models created from data gathered by LRO’s wide-angle camera, this full 360-degree portrait of the Moon shows its surface as if it were receiving direct top-down sunlight on all points — a physical impossibility, yes, but it gives us a great view of pretty much everything (including the far side, which for obvious reasons most of us never get a good look at.)
In addition to shining a light on the lunar landscape (pun intended) the vast amounts of data used to create the view above can also be used to calculate the type of illumination that would be found on any point on the Moon, at any time, allowing for better targeted observation planning with LRO’s narrow-angle camera.
Read more about how this process was engineered here, and see a more recent result of these new capabilities below:
While the image above wouldn’t have been visible from anywhere on North America on October 15, 2013 at 2 p.m. EDT, it’s what would have been seen in the night sky above Mumbai — but no international calls to India were needed, as the view could simply be generated from the LRO WAC data and a ray-tracing algorithm that plots the angles of light and shadow across the lunar terrain. Voilà — it’s Insta-Moon*!
*Some assembly required.
Read more on the Arizona State University LROC site here (and to really blow your mind, watch the high-resolution version here.)
The first photo of the lunar far side taken by the Soviet (Russian) spacecraft Luna 3 on Oct. 7, 1959. The right three-quarters of the disk is the far side. A = Mare Moscoviense, B = Tsiolkovsky Crater with central peak, C = Mare Smythii (on the near side-far side border) and D = Mare Crisium (near side). This is the wide-angle view. Credit: Roscosmos
For millennia, human eyes have seen only one face of the moon. Put a dude from the Iron Age in a time machine and whisk him to 2013 and he’d see the same pattern of light lunar highlands punctuated by dark grey spots you see. Night after night after night.
Telephoto view of the far side with Mare Smythii (Sea of Smyth) at left and bright crater Giordano Bruno at center. Credit: Roscosmos
That all changed 54 years ago today when the Soviet Union’s Luna 3 probe opened its camera shutter and snapped the first pictures of the lunar far side. Though blurry and banded with electronic noise, everyone who saw them sat up in surprise. The backside barely resembled the front. It lacked in the familiar lunar maria, the dark spots that we instinctively patch together to form the face of the “man in the moon”.
Telephoto image of Mare Moscoviense is at upper right with Tsiolkovsky and its bright central peak at lower right. You can begin to see vague outlines of many more craters in this picture. Click for more historic photos. Credit: Roscosmos
Only two dark ovals were seen, Mare Moscoviense (Sea of Moscow) and the lava-filled floor of the crater Tsiolkovsky, named for Konstantin Tsiolkovksy, the Russian rocket pioneer. The rest, which looks like dried paste, is jammed with craters and related the near side’s light-toned, cratered highlands. Both are remnants of the original lunar crust that solidified as the moon cooled after formation.
The dramatic difference between near side and far side shows up in this much more recent global map of the map made by Clementine Mission in 1994. The map is centered on the near side with its many lunar “seas” or maria. The far side trails off to the left and right of center. Mare Moscoviense is at upper right. Credit: NASA
Darker areas or “seas” are more recent basaltic lavas that welled up to fill huge impact scars left by colliding asteroids. They contain iron-rich minerals from deep beneath the crust which make them less reflective, hence darker in comparison to the highlands.
Tidal locking results in the moon rotating about its axis in about the same time it takes to orbit the Earth (left side). If the Moon didn’t spin at all, then it would alternately show its near and far sides to the Earth while moving around our planet in orbit, as shown in the figure on the right. Credit: Wikipedia
The moon hides its back or far side through a neat trick – it rotates at the same rate as it revolves around the Earth. Normally, rotation would bring new features into view, but every little bit it turns, it moves an equal amount along its orbit, hiding what would otherwise be exposed. It’s called synchronous rotation or tidal locking. Most of the larger moons in the solar system are tidally locked to their planets. Jupiter’s four biggest and brightest moons are a great example.
Luna 3 probe sent to the moon by the then Soviet Union. It held two cameras and its own film processing lab. Credit: NASA
Equipped with both wide angle (200 mm) and telephoto (500 mm) lenses, Luna 3 took 29 pictures covering about 70 percent of the far side during its loop around the moon. The first picture was shot from 39,500 miles away (63,500 km), the last taken 40 minutes later from 41,445 miles (66,700 km) distant. After the photo session was done, the probe passed over the moon’s north pole and headed back toward Earth.
Temperature and radiation-resistant film used for the photos was automatically moved to an onboard processor where it was developed, fixed and dried. A cathode ray tube then shot a beam of light through the film and onto a photoelectric multiplier, a light-sensitive device that converted the different gradations of tone into electric signals which were then transmitted to Earth. Almost sounds like a fire brigade, but hey it worked!
High resolution photo map of the moon’s far side imaged by NASA’s Lunar Reconnaissance Orbiter. Mare Moscoviense lies at upper left and Tsiolkovsky at lower left. Click for a hi res image. Credit: NASA
So what’s the reason for the moon’s split personality? We know the far side crust is 50 miles (80 km) thick versus 37 miles (60 km) for the near side. A thicker far side crust may have prevented magma from reaching and flooding the surface as they did on the near side. Heat released by the decay of radioactive elements also may play a role. NASA’s Lunar Prospector probe found more on the near side, where they may have encouraged the formation of hot magmas that eventually found their way to the surface.
What caused the fascinating asymmetry is unknown, but it may have to do with the slowing of the moon’s rotation into its present tidally-locked state under the heavy hand of Earth’s dominating gravitational influence.
The CRaTER instrument aboard NASA's Lunar Reconnaissance Orbiter measures the effect of cosmic rays on "human tissue-equivalent" plastic. (NASA)
It could work, say researchers from the University of New Hampshire and the Southwest Research Institute.
One of the inherent dangers of space travel and long-term exploration missions beyond Earth is the constant barrage of radiation, both from our own Sun and in the form of high-energy particles originating from outside the Solar System called cosmic rays. Extended exposure can result in cellular damage and increased risks of cancer at the very least, and in large doses could even result in death. If we want human astronauts to set up permanent outposts on the Moon, explore the dunes and canyons of Mars, or mine asteroids for their valuable resources, we will first need to develop adequate (and reasonably economical) protection from dangerous space radiation… or else such endeavors will be nothing more than glorified suicide missions.
While layers of rock, soil, or water could protect against cosmic rays, we haven’t yet developed the technology to hollow out asteroids for spaceships or build stone spacesuits (and sending large amounts of such heavy materials into space isn’t yet cost-effective.) Luckily, there may be a much easier way to protect astronauts from cosmic rays — using lightweight plastics.
While aluminum has always been the primary material in spacecraft construction, it provides relatively little protection against high-energy cosmic rays and can add so much mass to spacecraft that they become cost-prohibitive to launch.
Using observations made by the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) orbiting the Moon aboard LRO, researchers from UNH and SwRI have found that plastics, adequately designed, can provide better protection than aluminum or other heavier materials.
“This is the first study using observations from space to confirm what has been thought for some time—that plastics and other lightweight materials are pound-for-pound more effective for shielding against cosmic radiation than aluminum,” said Cary Zeitlin of the SwRI Earth, Oceans, and Space Department at UNH. “Shielding can’t entirely solve the radiation exposure problem in deep space, but there are clear differences in effectiveness of different materials.”
Zeitlin is lead author of a paper published online in the American Geophysical Union journal Space Weather.
A block of tissue-equivalent plastic (TEP) Credit: UNH
The plastic-aluminum comparison was made in earlier ground-based tests using beams of heavy particles to simulate cosmic rays. “The shielding effectiveness of the plastic in space is very much in line with what we discovered from the beam experiments, so we’ve gained a lot of confidence in the conclusions we drew from that work,” says Zeitlin. “Anything with high hydrogen content, including water, would work well.”
The space-based results were a product of CRaTER’s ability to accurately gauge the radiation dose of cosmic rays after passing through a material known as “tissue-equivalent plastic,” which simulates human muscle tissue.
(It may not look like human tissue, but it collects energy from cosmic particles in much the same way.)
Prior to CRaTER and recent measurements by the Radiation Assessment Detector (RAD) on the Mars rover Curiosity, the effects of thick shielding on cosmic rays had only been simulated in computer models and in particle accelerators, with little observational data from deep space.
The CRaTER observations have validated the models and the ground-based measurements, meaning that lightweight shielding materials could safely be used for long missions — provided their structural properties can be made adequate to withstand the rigors of spaceflight.
The blue areas show locations on the Moon's south pole where water ice is likely to exist (NASA/GSFC)
The Moon might seem like a poor place to hunt for water, but in fact there’s a decent amount of the stuff dispersed throughout the lunar soil — and even more of it existing as ice deposits in the dark recesses of polar craters. While the LCROSS mission crashed a rocket stage into one of these craters in October 2009 and confirmed evidence of water in the resulting plume of debris, there haven’t been any definitive maps made of water deposits across a large area on the Moon — until now.
Over the course of several years, NASA’s Lunar Reconnaissance Orbiter scanned the Moon’s south pole using its Lunar Exploration Neutron Detector (LEND) to measure how much hydrogen is trapped within the lunar soil. Areas exhibiting suppressed neutron activity — shown above in blue — indicate where hydrogen atoms are concentrated most, strongly suggesting the presence of water molecules… aka H2O.
The incredibly-sensitive LEND instrument measures the flux of neutrons from the Moon, which are produced by the continuous cosmic ray bombardment of the lunar surface. Even a fraction of hydrogen as small as 100 ppm can make a measurable change in neutron distribution from the surface of worlds with negligible atmospheres, and the hydrogen content can be related to the presence of water.
No other neutron instrument with LEND’s imaging capability has ever been flown in space.
Watch the video below for more details as to how LRO and LEND obtained these results:
“While previous lunar missions have observed indications of hydrogen at the Moon’s south pole, the LEND measurements for the first time pinpoint where hydrogen, and thus water, is likely to exist.”
What’s so important about finding water on the Moon? Well besides helping answer the question of where water on Earth and within the inner Solar System originated, it could also be used by future lunar exploration missions to produce fuel for rockets, drinking water, and breathable air. Read more here.
Image Caption: This image of comet ISON (C/2012 S1) ) from NASA’s Deep Impact spacecraft clearly shows the coma and nucleus on Jan. 17/18, 2013 beyond the orbit of Jupiter. See the dramatic new movie sequence below. It combines all 146 80-second clear filter exposures for a total integration time of 11680 seconds (about 3.25 hours). Individual frames were shifted to align the comet at the center before coadding. By keeping the comet centered and adding all of the images together, the stars effectively get smeared so the long streaks are the trails of background stars. Some have called it the “Comet of the Century.” Credit: NASA
NASA’s legendary Deep Impact comet smashing spacecraft has just scored another major coup – Imaging the newly discovered Comet ISON. The comet could possibly become one of the brightest comets ever late this year as it passes through the inner Solar System and swings around the Sun for the very first time in history – loaded with pristine, volatile material just raring to burst violently forth from the eerie surface, and is therefore extremely interesting to scientists. See the Movie below
“Comet ISON was just imaged by Deep Impact out by Jupiter on Jan. 17 and 18,” said Dr. Jim Green, Director of NASA Planetary Sciences at NASA HQ, in an exclusive interview with Universe Today on the campus of Princeton University. “We will try to look at ISON with the Curiosity rover as it flies past Mars, and with other NASA assets in space [along the way]. It should be spectacular!”
“We are all, ops team and science team, thrilled that we were able to make these observations when the comet was still more than 5 AU from the sun,” said Deep Impact Principal Investigator Prof. Michael A’Hearn of the University of Maryland, in an exclusive interview with Universe Today.
ISON could potentially become the next “Great Comet”, according to NASA. Deep Impact is the first spacecraft to observe ISON.
“We are continuing to observe ISON – it is observable from Deep Impact into mid-March 2013,” A’Hearn told me.
ISON will be the 4th comet observed by Deep Impact. On July 4, 2005 the spacecraft conducted a close flyby of Comet Tempel 1 and delivered a comet smashing impactor that made headlines worldwide. Next, it flew near Hartley 2 in Nov. 2010. In January 2012, the spacecraft performed a long distance imaging campaign on comet C/2009 P1 (Garradd). And it has enough fuel remaining for an Asteroid encounter slated for 2020 !
“NASA’s assets at Mars should be able to observe ISON because it will fly really, really close to Mars!” Green said with a big smile – and me too, as he showed me a sneak preview of the brand new Deep Impact movie.
“ISON observations are in the cue for Curiosity from Mars surface and from orbit with NASA’s Mars Reconnaissance Orbiter (MRO) – and we’ll see how it works out. It should be pretty spectacular. We will absolutely try with Curiosity’s high resolution Mastcam 100 camera.”
“LRO (NASA’s Lunar Reconnaissance Orbiter) also has a good shot at ISON.”
“Because of the possibility of observations of for example ISON, with probes like Deep Impact is why we want to keep NASA’s [older] assets viable.”
146 visible light images snapped by Deep Impact just days ago on Jan. 17 and 18, have been compiled into a dramatic video showing ISON speeding through interplanetary space back dropped by distant star fields – see above and below. The new images were taken by the probes Medium-Resolution Imager (MRI) over a 36-hour period from a distance of 493 million miles (793 million kilometers).
“A composite image, combining all of the Jan 17/18 data – after cleaning up the cosmic rays and improving the S/N (signal to noise ratio) clearly shows the comet has a coma and tail,” said Tony Farnham, a Deep Impact research scientist at the University of Maryland, to Universe Today.
Video Caption: This series of images of comet C/2012 S1 (ISON) was taken by the Medium-Resolution Imager (MRI) of NASA’s Deep Impact spacecraft over a 36-hour period on Jan. 17 and 18, 2013. At the time, the spacecraft was 493 million miles (793 million kilometers) from the comet. Credit: NASA/JPL-Caltech/UMD
ISON is a conglomeration of ice and dust and a long period, sun-grazing comet.
“It is coming in from the Solar System’s Oort cloud at the edge of the Solar System”, said Green, and was likely disturbed out of its established orbit by a passing star or other gravitational effects stemming from the Milky Way galaxy. “It will pass within 2.2 solar radii during perihelion and the Sun will either blast it apart or it will survive.”
Despite still being in the outer Solar System and a long distance from the Sun, ISON is already quite “variable” said A’Hearn, and it’s actively spewing material and ‘outgassing”.
The tail extending from the nucleus was already more than 40,000 miles (64,400 kilometers) long on Jan. 18. It’s a science mystery as to why and the Deep Impact team aims to try and determine why.
In addition to imaging, Deep Impact will also begin collecting long range spectral observations in the next week or so to help answer key questions.
“In mid-February, the solar elongation will allow IR (infrared) spectra for a few weeks,” A’Hearn elaborated.
“The 6-7% variability that we observed in the first day of observing shows that there is variable ‘outgassing’, presumably modulated by rotation of the nucleus. We hope to pin down the rotational period with the continuing images.”
“The interesting question is what drives the outgassing!”
Since ISON is still a very great distance away at more than 5 AU, data collection will not be an easy task. The comet is 5.1 AU from the Sun and 5.3 AU from Deep Impact. And the mission could also be imperiled by looming slashes to NASA’s budget if the Federal sequester actually happens in March.
“Getting spectra will be a real challenge because, at these large heliocentric and geocentric distances, the comet is really faint. However, maybe we can test whether CO2 is driving the outgassing,” Ahearn explained.
“Since we have the only facility capable of measuring CO2, it will be important to observe again in our second window in July-August, but that depends on NASA finding a little more money for us.”
“We, both the ops team and the science team, are funded only for the observations through March,” A’Hearn stated.
Although observing predictions for the brightness of comets are sometimes notoriously wrong and they can fade away precipitously, there is some well founded hope that ISON could put on a spectacular sky show for observers in both the northern and southern hemispheres.
The comet will continue to expand in size and grow in brightness as it journeys inward.
“ISON might be pretty spectacular,” said Green. “If things work out it might become bright enough to see during the day and be brighter than the Moon. The tail might be 90 degrees.”
Image caption: This is the orbital trajectory of comet C/2012 S1 (ISON). The comet is currently located just inside the orbit of Jupiter. In November 2013, ISON will pass less than 1.1 million miles (1.8 million kilometers) from the sun’s surface. The fierce heating it experiences during this close approach to the sun could turn the comet into a bright naked-eye object. Credit: NASA/JPL-Caltech
The best times to observe the comets head and growing tail will be from Nov. 2013 to Jan. 2014, if it survives its closest approach to the Sun, known as perihelion, on Nov. 28, 2013 and doesn’t break apart.
There’s no need to worry about doomsday predictions from conspiracy theorists. At its closest approach next Christmas season on Dec. 26, 2013, ISON will pass by Earth at a safe distance of some 40 million miles.
A pair of Russian astronomers only recently discovered the comet on Sept. 21, 2012, using the International Scientific Optical Network’s 16-inch (40-centimeter) telescope near Kislovodsk.
The study of comets has very important implications for understanding the evolution of not just the Solar System but also the origin of life on Earth. Comets delivered a significant portion of the early Earth’s water as well as a range of both simple and complex organic molecules – the building blocks of life.
Image caption. Deep Impact images Comet Tempel 1 alive with light after colliding with the impactor spacecraft on July 4, 2005. CREDIT: NASA/JPL-Caltech/UMD
Color coded shaded relief map of Linné crater (2.2 km diameter) created from an LROC NAC stereo topographic model. The colors represent elevations; cool colors are lowest and hot colors are highest. Credit: NASA/GSFC/Arizona State University.
Linné crater on the Moon is one of the youngest, most well-preserved lunar impact craters. This cone-shaped crater thought to be less than 10 million years old – a mere whippersnapper when it comes to impact craters. Scientists have been studying this crater for years, using it to investigate how cratering occurs in mare basalt. This “barnstorming” flyover video was created with data from the Lunar Reconnaissance Orbiter.
LRO helped discern the actual shape of this crater, and other craters too. It was once thought that the circular Linné crater was bowl-shaped, and that set a precedent for understanding the morphology of craters on the Moon, and also on Earth. But laser-mapping observations by NASA’s Lunar Reconnaissance Orbiter determined Linné is actually more of a truncated inverted cone, with a flattened interior floor surrounded by sloping walls that rise up over half a kilometer to its rim.
It’s a magnificent crater, and enjoy this unique chance to see it up close.
In the ultimate example of science imitating art, engineers working with NASA’s Lunar Reconnaissance Orbiter recently beamed an image of the Mona Lisa to the LRO and back via laser beam in order to measure the rate of transmission between the spacecraft and Earth. This allowed them to then calibrate their software to correct for any discrepancies between the image sent and the one received, resulting in a picture-perfect result.
Leonardo would definitely have approved.
From NASA’s Goddard Space Flight Center:
As part of the first demonstration of laser communication with a satellite at the moon, scientists with NASA’s Lunar Reconnaissance Orbiter (LRO) beamed an image of the Mona Lisa to the spacecraft from Earth.
The iconic image traveled nearly 240,000 miles in digital form from the Next Generation Satellite Laser Ranging (NGSLR) Station at NASA’s Goddard Space Flight Center in Greenbelt, MD, to the Lunar Orbiter Laser Altimeter (LOLA) instrument on the spacecraft. By transmitting the image piggyback on laser pulses that are routinely sent to track LOLA’s position, the team achieved simultaneous laser communication and tracking.
“This test, and the data obtained from it, sets the stage for future high data-rate laser communications demonstrations that will be an essential feature of NASA’s next Moon mission: the Lunar Atmosphere and Dust Environment Explorer.“
When the Moon was receiving its highest number of impacts, so was Earth. Credit: Dan Durda
Some questions about our own planet are best answered by looking someplace else entirely… in the case of impact craters and when, how and how often they were formed, that someplace can be found shining down on us nearly every night: our own companion in space, the Moon.
By studying lunar impact craters both young and old scientists can piece together the physical processes that took place during the violent moments of their creation, as well as determine how often Earth — a considerably bigger target — was experiencing similar events (and likely in much larger numbers as well.)
With no substantial atmosphere, no weather and no tectonic activity, the surface of the Moon is a veritable time capsule for events taking place in our region of the Solar System. While our constantly-evolving Earth tends to hide its past, the Moon gives up its secrets much more readily… which is why present and future lunar missions are so important to science.
Take the crater Linné, for example. A young, pristine lunar crater, the 2.2-km-wide Linné was formed less than 10 million years ago… much longer than humans have walked the Earth, yes, but very recently on lunar geologic terms.
It was once thought that the circular Linné (as well as other craters) is bowl-shaped, thus setting a precedent for the morphology of craters on the Moon and on Earth. But laser-mapping observations by NASA’s Lunar Reconnaissance Orbiter (at right) determined in early 2012 that that’s not the case; Linné is actually more of a truncated inverted cone, with a flattened interior floor surrounded by sloping walls that rise up over half a kilometer to its rim.
On our planet the erosive processes of wind, water, and earth soon distort the shapes of craters like Linné, wearing them down, filling them in and eventually hiding them from plain sight completely. But in the Moon’s airless environment where the only weathering comes from more impacts they retain their shape for much longer lengths of time, looking brand-new for many millions of years. By studying young craters in greater detail scientists are now able to better figure out just what happens when large objects strike the surface of worlds — events that can and do occur quite regularly in the Solar System, and which may have even allowed life to gain a foothold on Earth.
Most of the craters visible on the Moon today — Linné excluded, of course — are thought to have formed within a narrow period of time between 3.8 and 3.9 billion years ago. This period, called the Late Heavy Bombardment, saw a high rate of impact events throughout the inner Solar System, not only on the Moon but also on Mars, Mercury, presumably Venus and Earth as well. In fact, since at 4 times its diameter the Earth is a much larger target than the Moon, it stands to reason that Earth was impacted many more times than the Moon as well. Such large amounts of impacts introduced material from the outer Solar System to the early Earth as well as melted areas of the surface, releasing compounds like water that had been locked up in the crust… and even creating the sorts of environments where life could have begun to develop and thrive.
(It’s been suggested that there was even a longer period of heavy impact rates nicknamed the “late late heavy bombardment” that lingered up until about 2.5 billion years ago. Read more here.)
In the video below lunar geologist David Kring discusses the importance of impacts on the evolution of the Moon, Earth and eventually life as we know it today:
“Impact cratering in Earth’s past has affected not only the geologic but the biologic evolution of our planet, and we were able to deduce that in part by the lessons we learned by studying the Moon… and you just have to wonder what other things we can learn by going back to the Moon and studying that planetary body further.”
It’s these sorts of connections that make lunar exploration so valuable. Keys to our planet’s past are literally sitting on the surface of the Moon, a mere 385,000 km away, waiting for us to just scoop them up and bring them back. While the hunt for a biological history on Mars or resource-mining an asteroid are definitely important goals in their own right, only the Moon holds such direct references to Earth. It’s like an orbiting index to the ongoing story of our planet — all we have to do is make the connections.
Learn more about lunar research at the LPI site here, and see the latest news and images from LRO here.
LROC view looking obliquely of the south rim of Aristarchus from the west (NASA/GSFC/Arizona State University)
Flying over at an altitude of 135 km, NASA’s Lunar Reconnaissance Orbiter captured this lovely oblique view of the crater Aristarchus, looking down at the 40-km (25-mile) -wide crater’s southern rim from the west.
The broad flank of Aristarchus’ 300-meter (980-foot) central peak and surrounding hills can be seen at left, casting lengthening shadows in the setting sun.
Named after the Greek astronomer who first proposed a controversial heliocentric model for the Solar System in the 3rd century BCE, Aristarchus is a prominent crater located near the Moon’s northwestern limb within the geologically-diverse Oceanus Procellarum — the “Ocean of Storms.” Surrounded by rays of bright ejecta that extend down its stepped rim, the floor of Aristarchus drops 3.7 km (2.3 miles) below the surrounding lunar landscape.
The bright material seen in the ejecta streaks seems to echo the patterns of light and dark material lining the slopes of Aristarchus’ central peak, suggesting that they may be the made of similar material.
Detail of the 4.5-km-long central peak of Aristarchus (NASA/GSFC/Arizona State University)
The impact that created Aristarchus an estimated 450 million years ago excavated subsurface material, melting and spraying it tens of kilometers over the surrounding plateau. It’s thought that the central peak is likely composed of the same stuff, dredged up by the impact and frozen in place.
Future lunar explorers, should they ever visit this region, would be able to collect samples from the base of the central peak and compare them to samples from the bright rays to see if they match up, allowing researchers to learn about the composition of the material underlying the plateau from rocks scattered conveniently around the surface… this is the beauty of such (relatively) recent craters! The digging’s already been done for us.
Caption: LROC image showing the illuminated side of the still standing American flag to be captured at the Apollo 17 landing site. Credit: NASA/GSFC/Arizona State University.
Mark Robinson, Principal Investigator of the Lunar Reconnaisance Orbiter Camera (LROC) says the most often-asked questions he gets about the images LRO has taken of the Moon are about pictures of the Apollo landing sites and what is visible. Especially, Robinson said, people want to know if the flags are still standing.
Previously, Robinson has said that while the flag poles are likely still standing, he didn’t think the flags themselves survived the harsh radiation of the lunar surface environment. But new images and video show that at some of the landing sites – Apollo 12, Apollo 16, and Apollo 17 – the flags must still be intact, because they are creating shadows on the surface.
“Personally I was a bit surprised that the flags survived the harsh ultraviolet light and temperatures of the lunar surface, but they did,” Robinson wrote on the LROC website. “What they look like is another question (badly faded?).”
Caption: The flag was captured in this image of the Apollo 16 site with the spacecraft slewed 15° towards the Sun; the shadowed side of the flag is seen by LROC. Credit: NASA/GSFC/Arizona State University.
James Fincannon, a NASA engineer from Glenn Research Center, combined LROC images of each Apollo site taken at roughly the same orientation but with different Sun angles to show the travel of shadows.
“Combined with knowledge of the Apollo site maps which show where the flag was erected relative to the Lander, long shadows cast by the flags at the three sites show that the these flags are still “flying”, held aloft by the poles,” Fincannon wrote.
And so, from the LROC images it is now certain that the American flags are still standing and casting shadows at all of the sites, except Apollo 11. Astronaut Buzz Aldrin reported that the flag was blown over by the exhaust from the ascent engine during liftoff of Apollo 11, and Robinson said that from the images of the Apollo 11 landing site, it looks like he was correct.
Caption: Enlargement of area surrounding Apollo 11 landing site. Credit: NASA/GSFC/Arizona State University
Robinson added that the most convincing way to see that the flags are still there, is to view a time series of LROC images taken at different times of day, and watch the shadow circle the flag (see movie below; the flag is just above the LM descent stage).
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