Just what will the GRAIL mission to the Moon do? Find out in just over 3 minutes with this new video about the mission. The launch of GRAIL is scheduled for Sept. 8, 2011 from Cape Canaveral Air Force Station in Florida.
GRAIL Twins ready for NASA Science Expedition to the Moon: Photo Gallery
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NASA’s GRAIL twins – dubbed GRAIL-A & GRAIL-B – are ready to embark on America’s next science expedition to the moon in less than 1 month’s time from Cape Canaveral Air Force Station, Fla.
The twin Gravity Recovery and Interior Laboratory (GRAIL) spacecraft have been exhaustively tested, fueled for flight and mounted side-by-side on a specially designed payload adapter inside the controlled environment of a clean room at the Astrotech Space Operations facility in nearby Titusville, Fla.
The next processing step is to encapsulate the lunar probes inside their protective payload fairing. The duo are set to be shipped from Astrotech to their Cape Canaveral launch pad next week on Aug. 16, where they will be mated to an already assembled Delta II booster.
Liftoff of the GRAIL twins is slated for Sept. 8 at 8:37 a.m. EDT by a Delta II Heavy rocket from Launch Complex 17 at Cape Canaveral for a nearly four month voyage to the moon.
After entering lunar orbit, the two GRAIL spacecraft will fly in a tandam formation just 50 kilometers above the lunar surface with an average separation of 200 km during the 90 day science phase.
The GRAIL spacecraft are mounted to a 3 inch high Launch Vehicle Adapter Assembly and 20 inch Payload Adapter spacer ring on top of a 30-inch high GSE stand. Credit: Ken Kremer (kenkremer.com)
GRAIL’s mission goal is to map the moon’s gravity field to high precision and thereby deduce the structure of the lunar interior from crust to core. This will also lead to a better understanding of the composition of the moon’s interior, according to Sami Asmar, GRAIL co-investigator from NASA’s Jet Propulsion Laboratory in Pasasdena, Calif., during an interview inside the Astrotech clean room at a photo opportunity for the media. A gravity experiment is also aboard the just launched Jupiter bound Juno spacecraft.
GRAIL Photo Album special taken from inside the Astrotech cleanroom facility.
LRO to Move in For Closer Look at the Apollo Landing Sites
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NASA’s Lunar Reconnaissance Orbiter (LRO) is changing our view of the Moon by literally bringing it into sharper focus with its three high resolution cameras. But now, things are about to get even sharper. Today, LRO fired its thrusters to begin dipping down from its usual orbit about 50 km above the surface and moving to an orbit that will allow the spacecraft’s cameras me to image the Apollo sites from about 20 km away.
“This will allow me to obtain images of the Apollo sites that are about 4 times sharper than my current best images,” said the LRO spacecraft on Twitter.
This is just a temporary orbit and the spacecraft will take images of and around the Apollo sites between August 14 and 19, 2011. After that, the spacecraft will return to the 50-km-orbit until December.
LRO has two narrow angle cameras (NACs) and one wide angle camera (WAC).
According to Mark Robinson, LROC Principal Investigator, who spoke at the Lunar Forum at Ames Research Center last month, as of the end of July, 2011 the amount of data returned by LRO has been about 400 gigabits of data every day, which includes 371,027 high resolution images. The WAC has taken about 160,000 images, with about 90,000 in color. In total, the spacecraft has imaged the entire Moon about 20 times with the WAC, and has imaged 20 per cent of the moon with NACs, which provides a narrower but higher resolution view.
“We want to map the whole moon at 50 cm/pixel to 200 cm/pixel, and that would be LROC’s legacy for the next 100 years of lunar exploration and science,” Robinson said.
He noted that all three cameras are performing way better than he had hoped.
“We are very excited about the quality of the data,” Robinson said.
So get ready for a little more quality views of the Apollo landing sites!
Update: as commenter MoonOrBust noted, the LRO Twitter feed had an addendum later in the day, adding that there are several technical challenges associated with getting improved resolution images at the lower altitude orbit. For example, the spacecraft will not slow from its orbital speed of about 1.6 km/s (about 3,500 mph) when it gets closer to the Moon’s surface, which might cause some image blurring, particularly for the LROC Narrow Angle Camera images. “However, it will certainly be fun to compare the images from the different orbits!” the spacecraft Tweeted.
Second Moon May Have Orbited Earth Billions of Years Ago
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It’s a view science fiction fans could only hope for: twin moons in the night sky above Earth. But it might have been reality about 4 billion years ago. A new model suggests the lunar farside highlands could have been created from a collision with a smaller companion moon in what scientists from the University of California, Santa Cruz are calling “the big splat.”
Why the near and far sides of the Moon are so different has long puzzled planetary scientists. The near side is relatively low and flat, while the topography of the far side is high and mountainous, with a much thicker crust.
We actually have a somewhat lopsided Moon.
The new study, published in the August 4 issue of Nature, builds on the “giant impact” model for the origin of the moon, in which a Mars-sized object collided with Earth early in the history of the solar system and ejected debris that coalesced to form the moon.
According to the new computer model, the second moon around Earth would have been about 1,200 kilometers (750 miles) wide and could have formed from the same collision. Later, the smaller moon fell back onto the bigger Moon and coated one side with an extra layer of solid crust tens of kilometers thick.
“Our model works well with models of the Moon-forming giant impact, which predict there should be massive debris left in orbit about the Earth, besides the Moon itself,” said Erik Asphaug, professor of Earth and planetary sciences at UC Santa Cruz. “It agrees with what is known about the dynamical stability of such a system, the timing of the cooling of the moon, and the ages of lunar rocks.”
Other computer models have suggested a companion moon, said Asphaug, who coauthored the paper with UCSC postdoctoral researcher Martin Jutzi.
Asphaug and Jutzi used computer simulations to study the dynamics of the collision between the Moon and a smaller companion, which was about one-thirtieth the mass of the “main” moon. They tracked the evolution and distribution of lunar material in its aftermath.
The impact between the two bodies would have been relatively slow, at about 8,000 kph (5,000 mph) which is slow enough for rocks not to melt and no impact crater to form. Instead, the rocks and crust from the smaller moon would have spread over and around the bigger moon.
“Of course, impact modelers try to explain everything with collisions. In this case, it requires an odd collision: being slow, it does not form a crater, but splats material onto one side,” Asphaug said. “It is something new to think about.”
He and Jutzi hypothesize that the companion moon was initially trapped at one of the gravitationally stable “Trojan points” sharing the Moon’s orbit, and became destabilized after the moon’s orbit had expanded far from Earth. “The collision could have happened anywhere on the Moon,” Jutzi said. “The final body is lopsided and would reorient so that one side faces Earth.”
The model may also explain variations in the composition of the moon’s crust, which is dominated on the near side by terrain comparatively rich in potassium, rare-earth elements, and phosphorus (KREEP). These elements, as well as uranium and thorium, are believed to have been concentrated in the magma ocean that remained as molten rock solidified under the moon’s thickening crust. In the simulations, the collision squishes this KREEP-rich layer onto the opposite hemisphere, setting the stage for the geology now seen on the near side of the moon.
While the model explains many things, the jury is still out among planetary scientists as to the full history of the Moon and what really happened. Scientists say the best way to figure out the Moon’s history is to get more data from lunar orbiting spacecraft and – even better – sample return missions or human missions to study the Moon.
Sources: Nature, UC Santa Cruz
Spectacular View from LRO of Tycho Crater’s Central Uplifts
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Here’s the Moon like you’ve never seen it before: a dramatic sunrise view of Tycho Crater on the Moon, highlighting the peaks and crags of the crater’s central uplifts. On June 10,2011 the Lunar Reconnaissance Orbiter slewed 65° to the west, allowing the Narrow Angle Camera to capture a “sideways” look at Tycho crater, resulting in a spectacular image. The central peak complex is about 15 km wide southeast to northwest (left to right in this view). Below are more images and a video which spans and zooms in to the entire image.
Tycho Crater is a very popular target with amateur astronomers since it is easily seen from Earth. The crater measures about 82 km (51 miles) in diameter, and the summit of the central peak is 2 km (6562 ft) above the crater floor, and the crater floor is about 4700 m (15,420 ft) below the rim.
Central uplifts form in larger impact craters in response to the impact event.
LROC principal investigator Mark Robinson wrote on the LRO website, “Tycho’s features are so steep and sharp because the crater is young by lunar standards, only about 110 million years old….Were these distinctive outcrops formed as a result of crushing and deformation of the target rock as the peak grew? Or do they represent preexisting rock layers that were brought intact to the surface? Imagine future geologists carefully making their way across these steep slopes, sampling a diversity of rocks brought up from depth.”
Here’s a close-up of the summit. The boulder in the background is 120 meters wide, and the image is about 1200 meters wide.
And here’s the entire crater:
Click on the images for larger versions on the LROC website, or see this link for more information on these images.
Source: LROC
ARTEMIS Spacecraft Curlicuing Their Way To Lunar Orbit
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From a Goddard Space Flight Center Press Release:
They’ve almost arrived.
It took one and a half years, over 90 orbit maneuvers, and – wonderfully – many gravitational boosts and only the barest bit of fuel to move two spacecraft from their orbit around Earth to their new home around the Moon.
Along their travels, the spacecraft have been through orbits never before attempted and made lovely curlicue leaps from one orbit to the next. This summer, the two ARTEMIS spacecraft — which began their lives as part of the five-craft THEMIS mission studying Earth’s aurora – will begin to orbit the moon instead. THEMIS is an acronym for the Time History of Events and Macroscale Interaction during Substorms spacecraft.
Even with NASA’s decades of orbital mechanics experience, this journey was no easy feat. The trip required several maneuvers never before attempted, including several months when each craft moved in a kidney-shaped path on each side of the moon around, well, nothing but a gravitational point in space marked by no physical planet or object.
“No one has ever tried this orbit before, it’s an Earth-Moon libration orbit,” says David Folta a flight dynamics engineer at NASA’s Goddard Space Flight Center in Greenbelt, Md. “It’s a very unstable orbit that requires daily attention and constant adjustments.”
The journey for ARTEMIS — short for Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun — began in 2009, after THEMIS had completed some two years of science data collection on the magnetic environment around Earth, the aurora, and how these are affected by the sun.
The spacecraft are solar-powered, but orbits for the two outermost THEMIS spacecraft had slipped over time and were going to be subjected to regular eight-hour periods of darkness. These spacecraft could withstand up to three hours without sunlight, but this much darkness would soon leave the batteries completely discharged.
Teams at UC-Berkeley and Goddard handled the day-to-day control of the THEMIS spacecraft. The Principal Investigator for the mission, Vassilis Angelopoulos of UCLA talked to the teams about moving the two spacecraft to the moon to study the magnetic environment there. But quick models of a conventional boost technique showed that all the remaining fuel would be used simply in transit. There wouldn’t be enough left over for the fuel-hungry process of adjusting direction and speed to actually begin circling the moon.
So Angelopoulos pulled together a new, more complex multi-year-long orbit change plan. The move would rely predominantly on gravity assists from the moon and Earth to move the spacecraft into place. He brought his idea to two engineers who had been involved with launching THEMIS in the first place: David Folta and another flight engineer at Goddard, Mark Woodard. The pair used their own models to validate this new design, and the plan was on.
First step: increase the size of the orbits. The original Earth-centric orbits barely reached half way to the moon. By using small amounts of fuel to adjust speed and direction at precise moments in the orbit, the spacecraft were catapulted farther and farther out into space. It took five such adjustments for ARTEMIS P1 and 27 for ARTEMIS P2.
Next step: make the jump from Earth orbit to the tricky kidney-shaped “Lissajous” orbit, circling what’s known as a Lagrangian point on each side of the moon. These points are the places where the forces of gravity between Earth and the moon balance each other – the point does not actually offer a physical entity to circle around. ARTEMIS P1 made the leap – in a beautiful arc under and around the moon — to the Lagrangian point on the far side of the moon on August 25, 2010. The second craft made the jump to the near side of the moon on October 22. This transfer required a complex series of maneuvers including lunar gravity assists, Earth gravity assists, and deep space maneuvers. The combination of these maneuvers was needed not only to arrive at the correct spot near the moon but also at the correct time and speed.
Using a series of Earth and moon gravity assists – and only the barest bit of fuel – the ARTEMIS spacecraft entered into orbit around the moon’s Lagrangian points in the winter of 2010. Credit: NASA Goddard Space Flight Center/Scientific Visualization Studio
History was made. Numerous satellites orbit Lagrangian points between Earth and the Sun but, while this orbit had been studied extensively, it had never before been attempted.
Not only was this an engineering feat in and of itself, but the spacecraft were now in an ideal spot to study magnetism some distance from the moon. In this position, they could spot how the solar wind – made up of ionized gas known as plasma — flows past the Moon and tries to fill in the vacuum on the other side. A task made complicated since the plasma is forced by the magnetic fields to travel along certain paths.
“It’s a veritable zoo of plasma phenomena,” says David Sibeck, the project manager for THEMIS and ARTEMIS at Goddard. “The Moon carves out a cavity in the solar wind, and then we get to watch how that fills in. It’s anything but boring. There’s microphysics and particle physics and wave particle interaction and boundaries and layers. All things we haven’t had a chance to study before in the plasma.”
Life for the flight engineers was anything but boring too. Keeping something in orbit around a spot that has little to mark it except for the balance of gravity is no simple task. The spacecraft required regular corrections to keep it on track and Folta and Woodard watched it daily.
“We would get updated orbit information around 9 a.m. every day,” says Woodard. “We’d run that through our software and get an estimate of what our next maneuver should be. We’d go back and forth with Berkeley and together we’d validate a maneuver until we knew it was going to work and keep us flying for another week.”
The team learned from experience. Slight adjustments often had bigger consequences than expected. They eventually found the optimal places where corrections seemed to require less subsequent fine-tuning. These sweet spots came whenever the spacecraft crossed an imaginary line joining Earth and the Moon, though nothing in theories had predicted such a thing.
The daily vigilance turned out to be crucial. On October 14, the P1 spacecraft orbit and attitude changed unexpectedly. The first thought was that the tracking system might have failed, but that didn’t seem to be the problem. However, the ARTEMIS team also noticed that the whole craft had begun to spin about 0.001 revolutions per minute faster. One of the instruments that measures electric fields also stopped working. Best guess? The sphere at the end of that instrument’s 82-foot boom had broken off – perhaps because it was struck by something. That sphere was just three ounces on a spacecraft that weighed nearly 190 pounds — but it adjusted ARTEMIS P1’s speed enough that had they caught the anomaly even a few days later they would have had to waste a prohibitive amount of fuel to get back on course.
As it is, ARTEMIS will make it to the moon with even more fuel than originally estimated. There will be enough fuel for orbit corrections for seven to 10 years and then enough left over to bring the two craft down to the moon.
“We are thrilled with the work of the mission planners,” says Sibeck. “They are going to get us much closer to the moon than we could have hoped. That’s crucial for providing high quality data about the moon’s interior, its surface composition, and whether there are pockets of magnetism there.”
On January 9, 2011, ARTEMIS P1 jumped over the moon and joined ARTEMIS P2 on the side of the Moon closest to Earth. Now the last steps are about to begin.
On June 27, P1 will spiral in toward the moon and enter lunar orbit. On July 17, P2 will follow. P2 will travel in the same direction with the Moon, or in prograde; P1 will travel in the opposite direction, in retrograde.
“We’ve been monitoring ARTEMIS every day and developing maneuvers every week. It’s been a challenge, but we’ve uncovered some great things,” says Folta, who will now focus his attention on other NASA flights such as the MAVEN mission to Mars that is scheduled to launch in 2013. “But soon we’ll be done with this final maneuvering and, well, we’ll be back to just being ARTEMIS consultants.”
See additional ARTEMIS imagery and video at this link.
Written by Karen C. Fox at GSFC.
How LRO Plans to Watch the Lunar Eclipse from the Moon
What will the June 15th lunar eclipse look like from the Moon itself? Luckily, we’ve got the Lunar Reconnaissance Orbiter circling the Moon, and we can find out. However, most of the instruments on LRO will be powering down during the eclipse, but one instrument, called Diviner, will stay on. “It will be like a nap with one eye open!” the LRO spacecraft said on Facebook. The Diviner Lunar Radiometer instrument will record how quickly different areas on the moon’s day side cool off during the eclipse. Since large boulders cool more slowly than a fine-grained or dusty surface, Diviner will be able to see what areas are covered with boulders and what regions are blanketed by dust.
Continue reading “How LRO Plans to Watch the Lunar Eclipse from the Moon”
One Year of the Moon in 2.5 Minutes
We don’t always have the time or ability to see the Moon every night of the year, but this video, from the Goddard Space Flight Center Scientific Visualization Studio, uses data from the Lunar Reconnaissance Orbiter and compresses one month into 12 seconds and one year into 2.5 minutes. This is how the Moon will look to us on Earth during the entire year of 2011. While the Moon always keeps the same face to us, it’s not exactly the same face. Because of the tilt in its axis and shape of its orbit, we see the Moon from slightly different angles over the course of a month, and the year. Normally, we don’t see how the Moon “wobbles” in its orbit, but seeing the Moon’s year this quickly, we can see the changes in libration, and axis tilt — as well as the most noticeable changes, the Moon’s phases.
This animation is the most accurate to date, showing shadows and other features on the Moon in incredible detail. This is thanks to the Lunar Orbiter Laser Altimeter (LOLA) aboard LRO. The shadows are based on the global elevation map being developed from measurements by the LOLA, and the instrument has already taken more than 10 times as many elevation measurements as all previous missions combined.
If you want to know what the Moon looks like “right now” this page from the SVC is updated every hour showing the Moon’s geocentric phase, libration, position angle of the axis, and apparent diameter of the Moon. It also has images showing the different phases of the Moon, too.
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Celestial north is up in these images, corresponding to the view from the northern hemisphere. The descriptions of the print resolution stills also assume a northern hemisphere orientation. To adjust for southern hemisphere views, rotate the images 180 degrees, and substitute “north” for “south” in the descriptions.
Source: Goddard Space Flight Center Science Visualization Studio
And The Moon Is Eclipsed By The Earth
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On June 15 there will be a total lunar eclipse visible from Australia, Indonesia, southern Japan, India, a large area of Asia, Africa, Europe and the eastern part of South America. This is expected to be one of the darkest eclipses ever (with a magnitude of 1.7), second only to the July 2000 eclipse.
Sadly it won’t be visible to viewers in North America, but much of the rest of the world should be treated to a wonderful show as the Moon slips into Earth’s shadow. Gradually growing darker from its western limb inwards, the Moon then gains a bluish cast which transitions to orange then deep red as it moves into light passing through the edge of Earth’s atmosphere (the same as what makes the colors of a sunset) and then eventually going almost completely dark before the process then reverses itself from the opposite side.
The entire eclipse will last 5 hours and 39 minutes, with a totality duration of 1 hour and 40 minutes. It will begin at 17:23 UT.
Viewers in Australia and eastern Asia will see the eclipse begin as the Moon is setting while those in Europe and South America will see it as the Moon is rising. Only locations in India, eastern Africa, the Middle East and western Asia will experience the entire eclipse.
This is the first of two total lunar eclipses in 2011; the next will take place on December 10.
I saw my first total lunar eclipse last December, which took place on the night of the winter solstice (December 21). It really was an amazing event to watch… in totality the Moon was colored a deep coppery red and really just seemed to be suspended among the stars – it felt like you could just reach up and pluck it from the sky! If you are in any of the areas where this next one is visible I encourage you to check it out for yourself!
Read more about lunar eclipses on MrEclipse.com.
Image: Jason Major
Water, Water Everywhere… Lunar Samples Show More Water Than Previously Thought
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A team of NASA-funded researchers led by Carnegie Institution’s Erik Hauri has recently announced the discovery of more water on the Moon, in the form of ancient magma that has been locked up in tiny crystals contained within soil samples collected by Apollo 17 astronauts. The amounts found indicate there may be 100 times more water within lunar magma than previously thought… truly a “watershed” discovery!
Orange-colored lunar soil sampled during Apollo 17 EVA missions was tested using a new ion microprobe instrument which measured the water contained within magma trapped inside lunar crystals, called “melt inclusions”. The inclusions are the result of volcanic eruptions on the Moon that occurred over 3.7 billion years ago.
Because these bits of magma are encased in crystals they were not subject to loss of water or “other volatiles” during the explosive eruption process.
“In contrast to most volcanic deposits, the melt inclusions are encased in crystals that prevent the escape of water and other volatiles during eruption. These samples provide the best window we have to the amount of water in the interior of the Moon.”
– James Van Orman of Case Western Reserve University, team member
While it was previously found that water is contained within lunar magma during a 2008 study led by Alberto Saal of Brown University in Providence, Rhode Island, this new announcement is based upon the work of Brown undergraduate student Thomas Weinreich, who located the melt inclusions. By measuring the water content of the inclusions, the team could then infer the amount of water present in the Moon’s interior.
The results also make correlations to the proposed origins of the Moon. Currently-accepted models say the Moon was created following a collision between the newly-formed Earth and a Mars-sized protoplanet 4.5 billion years ago. Material from the Earth’s outer layers was blasted out into space, forming a ring of molten material that encircled the Earth and eventually coalesced, cooled and became the Moon. This would also mean that the Moon should have similarities in composition to material that would have been found in the outer layers of the Earth at that time.
“The bottom line is that in 2008, we said the primitive water content in the lunar magmas should be similar to lavas coming from the Earth’s depleted upper mantle. Now, we have proven that is indeed the case.”
– Alberto Saal, Brown University, RI
The findings also suggest that the Moon’s water may not just be the result of comet or meteor impacts – as was suggested after the discovery of water ice in polar craters by the LCROSS mission in 2009 – but may also have come from within the Moon itself via ancient lunar eruptions.
The success of this study makes a strong case for finding and returning similar samples of ejected volcanic material from other worlds in our solar system.
“We can conceive of no sample type that would be more important to return to Earth than these volcanic glass samples ejected by explosive volcanism, which have been mapped not only on the Moon but throughout the inner solar system.”
– Erik Hauri, lead author, Carnegie’s Department of Terrestrial Magnetism
The results were published in the May 26 issue of Science Express.
Read the full NASA news release here.