Updates GRAIL mission news and updates
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I like the names.
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Very fitting, though I was hoping for something like Action and Reaction.
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NASA / NASA JPL:
Montana Students Pick Winning Names for Moon Craft
January 17, 2012
PASADENA, Calif. -- Twin NASA spacecraft that achieved orbit around the moon New Year's Eve and New Year's Day have new names, thanks to elementary students in Bozeman, Mont. Their winning entry, "Ebb and Flow," was selected as part of a nationwide school contest that began in October 2011.
The names were submitted by fourth graders from the Emily Dickinson Elementary School. Nearly 900 classrooms with more than 11,000 students from 45 states, Puerto Rico and the District of Columbia participated in the contest. Previously named Gravity Recovery And Interior Laboratory, or GRAIL-A and -B, the washing machine-sized spacecraft begin science operations in March, after a launch in September 2011.
"The 28 students of Nina DiMauro's class at the Emily Dickinson Elementary School have really hit the nail on the head," said Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology in Cambridge, Mass. "We were really impressed that the students drew their inspiration by researching GRAIL and its goal of measuring gravity. Ebb and Flow truly capture the spirit and excitement of our mission."
Zuber and Sally Ride, America's first woman in space and CEO of Sally Ride Science in San Diego, selected the names following the contest, which attracted 890 proposals via the Internet and mail. The contest invited ideas from students ages 5 to 18 enrolled in U.S. schools. Although everything from spelling and grammar to creativity was considered, Zuber and Ride primarily took into account the quality of submitted essays.
"With submissions from all over the United States and even some from abroad, there were a lot of great entries to review," Ride said. "This contest generated a great deal of excitement in classrooms across America, and along with it an opportunity to use that excitement to teach science."
GRAIL is NASA's first planetary mission carrying instruments fully dedicated to education and public outreach. Each spacecraft carries a small camera called GRAIL MoonKAM (Moon Knowledge Acquired by Middle school students). Thousands of students in grades five through eight will select target areas on the lunar surface and send requests for study to the GRAIL MoonKAM Mission Operations Center in San Diego.
The winning prize for the Dickinson students is to choose the first camera images. Dickinson is one of nearly 2,000 schools registered for the MoonKAM program, which is led by Ride and her team at Sally Ride Science in collaboration with undergraduate students at the University of California in San Diego.
"These spacecraft represent not only great science, but great inspiration for our future," said Jim Green, director of NASA's Planetary Science Division in Washington. "As they study our lunar neighbor, Ebb and Flow will undergo nearly the same motion as the tides we feel here on Earth."
Launched in September 2011, Ebb and Flow will be placed in a near-polar, near-circular orbit with an altitude of about 34 miles (55 kilometers). During their science mission, the duo will answer longstanding questions about the moon and give scientists a better understanding of how Earth and other rocky planets in the solar system formed.
{...}
NASA Press Release: RELEASE : 12-019 - Montana Students Submit Winning Names for NASA Lunar Spacecraft
SPACE.com: Students Name NASA's Twin Moon Probes 'Ebb' & 'Flow'
collectSPACE: Students name NASA's twin moon probes 'Ebb' and 'Flow'
Florida Today - The Flame Trench: Lunar probes renamed Ebb and Flow
Parabolic Arc: Students Name GRAIL Spacraft “Ebb” and “Flow”
Montana Students Pick Winning Names for Moon Craft
January 17, 2012
PASADENA, Calif. -- Twin NASA spacecraft that achieved orbit around the moon New Year's Eve and New Year's Day have new names, thanks to elementary students in Bozeman, Mont. Their winning entry, "Ebb and Flow," was selected as part of a nationwide school contest that began in October 2011.
The names were submitted by fourth graders from the Emily Dickinson Elementary School. Nearly 900 classrooms with more than 11,000 students from 45 states, Puerto Rico and the District of Columbia participated in the contest. Previously named Gravity Recovery And Interior Laboratory, or GRAIL-A and -B, the washing machine-sized spacecraft begin science operations in March, after a launch in September 2011.
"The 28 students of Nina DiMauro's class at the Emily Dickinson Elementary School have really hit the nail on the head," said Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology in Cambridge, Mass. "We were really impressed that the students drew their inspiration by researching GRAIL and its goal of measuring gravity. Ebb and Flow truly capture the spirit and excitement of our mission."
Zuber and Sally Ride, America's first woman in space and CEO of Sally Ride Science in San Diego, selected the names following the contest, which attracted 890 proposals via the Internet and mail. The contest invited ideas from students ages 5 to 18 enrolled in U.S. schools. Although everything from spelling and grammar to creativity was considered, Zuber and Ride primarily took into account the quality of submitted essays.
"With submissions from all over the United States and even some from abroad, there were a lot of great entries to review," Ride said. "This contest generated a great deal of excitement in classrooms across America, and along with it an opportunity to use that excitement to teach science."
GRAIL is NASA's first planetary mission carrying instruments fully dedicated to education and public outreach. Each spacecraft carries a small camera called GRAIL MoonKAM (Moon Knowledge Acquired by Middle school students). Thousands of students in grades five through eight will select target areas on the lunar surface and send requests for study to the GRAIL MoonKAM Mission Operations Center in San Diego.
The winning prize for the Dickinson students is to choose the first camera images. Dickinson is one of nearly 2,000 schools registered for the MoonKAM program, which is led by Ride and her team at Sally Ride Science in collaboration with undergraduate students at the University of California in San Diego.
"These spacecraft represent not only great science, but great inspiration for our future," said Jim Green, director of NASA's Planetary Science Division in Washington. "As they study our lunar neighbor, Ebb and Flow will undergo nearly the same motion as the tides we feel here on Earth."
Launched in September 2011, Ebb and Flow will be placed in a near-polar, near-circular orbit with an altitude of about 34 miles (55 kilometers). During their science mission, the duo will answer longstanding questions about the moon and give scientists a better understanding of how Earth and other rocky planets in the solar system formed.
{...}
NASA Press Release: RELEASE : 12-019 - Montana Students Submit Winning Names for NASA Lunar Spacecraft
SPACE.com: Students Name NASA's Twin Moon Probes 'Ebb' & 'Flow'
collectSPACE: Students name NASA's twin moon probes 'Ebb' and 'Flow'
Florida Today - The Flame Trench: Lunar probes renamed Ebb and Flow
Parabolic Arc: Students Name GRAIL Spacraft “Ebb” and “Flow”
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NASA / NASA JPL:
NASA Mission Returns First Video From Moon's Far Side
February 01, 2012
PASADENA, Calif. -- A camera aboard one of NASA's twin Gravity Recovery And Interior Laboratory (GRAIL) lunar spacecraft has returned its first unique view of the far side of the moon. MoonKAM, or Moon Knowledge Acquired by Middle school students, will be used by students nationwide to select lunar images for study.
South pole of the far side of the moon as seen from the GRAIL mission’s Ebb spacecraft.
GRAIL consists of two identical spacecraft, recently named Ebb and Flow, each of which is equipped with a MoonKAM. The images were taken as part of a test of Ebb's MoonKAM on Jan. 19. The GRAIL project plans to test the MoonKAM aboard Flow at a later date.
To view the 30-second video clip, visit: http://go.nasa.gov/zZXAPs.
[ame="http://www.youtube.com/watch?v=geWg8mt-Hkg"]GRAIL Mission Returns First Video of Moon's Far Side - YouTube[/ame]
In the video, the north pole of the moon is visible at the top of the screen as the spacecraft flies toward the lunar south pole. One of the first prominent geological features seen on the lower third of the moon is the Mare Orientale, a 560-mile-wide (900 kilometer) impact basin that straddles both the moon's near and far side.
The clip ends with rugged terrain just short of the lunar south pole. To the left of center, near the bottom of the screen, is the 93-mile-wide (149 kilometer) Drygalski crater with a distinctive star-shaped formation in the middle. The formation is a central peak, created many billions of years ago by a comet or asteroid impact.
The quality of the video is excellent and should energize our MoonKAM students as they prepare to explore the moon," said Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology in Cambridge.
The twin spacecraft successfully achieved lunar orbit this past New Year's Eve and New Year's Day. Previously named GRAIL-A and GRAIL-B, the washing machine-sized spacecraft received their new names from fourth graders at the Emily Dickinson Elementary School in Bozeman, Mont., following a nationwide student naming contest.
Thousands of fourth- to eighth-grade students will select target areas on the lunar surface and send requests to the GRAIL MoonKAM Mission Operations Center in San Diego. Photos of the target areas will be sent back by the satellites for students to study. The MoonKAM program is led by Sally Ride, America's first woman in space. Her team at Sally Ride Science and undergraduate students at the University of California in San Diego will engage middle schools across the country in the GRAIL mission and lunar exploration. GRAIL is NASA's first planetary mission carrying instruments fully dedicated to education and public outreach.
"We have had great response from schools around the country; more than 2,500 signed up to participate so far," Ride said. "In mid-March, the first pictures of the moon will be taken by students using MoonKAM. I expect this will excite many students about possible careers in science and engineering."
Launched in September 2011, Ebb and Flow periodically perform trajectory correction maneuvers that, over time, will lower their orbits to near-circular ones with an altitude of about 34 miles (55 kilometers). During their science mission, the duo will answer longstanding questions about the moon and give scientists a better understanding of how Earth and other rocky planets in the solar system formed.
{...}
NASA Press Release: RELEASE : 12-040 - NASA Spacecraft Returns First Video from Far Side Of The Moon
Universe Today: GRAIL Sends Back First Video of the Moon’s Far Side
The Planetary Society Blog: GRAIL MoonKAM's first (released) video of the Moon
SPACE.com: NASA Probe Captures 1st Video of Moon's Far Side
Aviation Week: The Far Side
NASA Mission Returns First Video From Moon's Far Side
February 01, 2012
PASADENA, Calif. -- A camera aboard one of NASA's twin Gravity Recovery And Interior Laboratory (GRAIL) lunar spacecraft has returned its first unique view of the far side of the moon. MoonKAM, or Moon Knowledge Acquired by Middle school students, will be used by students nationwide to select lunar images for study.
Click on image to enlarge
South pole of the far side of the moon as seen from the GRAIL mission’s Ebb spacecraft.Image credit: NASA/JPL-Caltech
GRAIL consists of two identical spacecraft, recently named Ebb and Flow, each of which is equipped with a MoonKAM. The images were taken as part of a test of Ebb's MoonKAM on Jan. 19. The GRAIL project plans to test the MoonKAM aboard Flow at a later date.
To view the 30-second video clip, visit: http://go.nasa.gov/zZXAPs.
[ame="http://www.youtube.com/watch?v=geWg8mt-Hkg"]GRAIL Mission Returns First Video of Moon's Far Side - YouTube[/ame]
In the video, the north pole of the moon is visible at the top of the screen as the spacecraft flies toward the lunar south pole. One of the first prominent geological features seen on the lower third of the moon is the Mare Orientale, a 560-mile-wide (900 kilometer) impact basin that straddles both the moon's near and far side.
The clip ends with rugged terrain just short of the lunar south pole. To the left of center, near the bottom of the screen, is the 93-mile-wide (149 kilometer) Drygalski crater with a distinctive star-shaped formation in the middle. The formation is a central peak, created many billions of years ago by a comet or asteroid impact.
The quality of the video is excellent and should energize our MoonKAM students as they prepare to explore the moon," said Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology in Cambridge.
The twin spacecraft successfully achieved lunar orbit this past New Year's Eve and New Year's Day. Previously named GRAIL-A and GRAIL-B, the washing machine-sized spacecraft received their new names from fourth graders at the Emily Dickinson Elementary School in Bozeman, Mont., following a nationwide student naming contest.
Thousands of fourth- to eighth-grade students will select target areas on the lunar surface and send requests to the GRAIL MoonKAM Mission Operations Center in San Diego. Photos of the target areas will be sent back by the satellites for students to study. The MoonKAM program is led by Sally Ride, America's first woman in space. Her team at Sally Ride Science and undergraduate students at the University of California in San Diego will engage middle schools across the country in the GRAIL mission and lunar exploration. GRAIL is NASA's first planetary mission carrying instruments fully dedicated to education and public outreach.
"We have had great response from schools around the country; more than 2,500 signed up to participate so far," Ride said. "In mid-March, the first pictures of the moon will be taken by students using MoonKAM. I expect this will excite many students about possible careers in science and engineering."
Launched in September 2011, Ebb and Flow periodically perform trajectory correction maneuvers that, over time, will lower their orbits to near-circular ones with an altitude of about 34 miles (55 kilometers). During their science mission, the duo will answer longstanding questions about the moon and give scientists a better understanding of how Earth and other rocky planets in the solar system formed.
{...}
NASA Press Release: RELEASE : 12-040 - NASA Spacecraft Returns First Video from Far Side Of The Moon
Universe Today: GRAIL Sends Back First Video of the Moon’s Far Side
The Planetary Society Blog: GRAIL MoonKAM's first (released) video of the Moon
SPACE.com: NASA Probe Captures 1st Video of Moon's Far Side
Aviation Week: The Far Side
boogabooga
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What exactly are 4th-8th graders going to "study" by looking at pictures of the moon?
NovaSilisko
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NASA / NASA JPL:
NASA's Twin GRAIL Spacecraft Begin Collecting Lunar Data
March 07, 2012
PASADENA, Calif. -- NASA's Gravity Recovery And Interior Laboratory (GRAIL) spacecraft orbiting the moon officially have begun their science collection phase. During the next 84 days, scientists will obtain a high-resolution map of the lunar gravitational field to learn about the moon's internal structure and composition in unprecedented detail. The data also will provide a better understanding of how Earth and other rocky planets in the solar system formed and evolved.
"The initiation of science data collection is a time when the team lets out a collective sigh of relief because we are finally doing what we came to do," said Maria Zuber, principal investigator for the GRAIL mission at the Massachusetts Institute of Technology in Cambridge, "but it is also a time where we have to put the coffee pot on, roll up our sleeves and get to work."
The GRAIL mission's twin, washing-machine-sized spacecraft, named Ebb and Flow, entered lunar orbit on New Year's Eve and New Years Day. GRAIL's science phase began yesterday at 5:15 p.m. PST (8:15 p.m. EST). During this mission phase, the spacecraft will transmit radio signals precisely defining the rate of change of distance between the two. The distance between the spacecraft will change slightly as they fly over areas of greater and lesser gravity caused by visible features such as mountains, craters and masses hidden beneath the lunar surface. Science activities are expected to conclude on May 29, after GRAIL maps the gravity field of the moon three times.
"We are in a near-polar, near-circular orbit with an average altitude of about 34 miles (55 kilometers) right now," said David Lehman, GRAIL project manager from NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "During the science phase, our spacecraft will orbit the moon as high as 31 miles (51 kilometers) and as low as 10 miles (16 kilometers). They will get as close to each other as 40 miles (65 kilometers) and as far apart as 140 miles (225 kilometers)."
{...}
NASA Press Release: RELEASE : 12-070 - NASA's Twin Grail Spacecraft Begin Collecting Lunar Science Data
SPACE.com: Twin NASA Moon Probes Begin Mapping Lunar Gravity
Universe Today: Twin NASA Science Probes Start Lunar Gravity Mapping
NASA's Twin GRAIL Spacecraft Begin Collecting Lunar Data
March 07, 2012
PASADENA, Calif. -- NASA's Gravity Recovery And Interior Laboratory (GRAIL) spacecraft orbiting the moon officially have begun their science collection phase. During the next 84 days, scientists will obtain a high-resolution map of the lunar gravitational field to learn about the moon's internal structure and composition in unprecedented detail. The data also will provide a better understanding of how Earth and other rocky planets in the solar system formed and evolved.
"The initiation of science data collection is a time when the team lets out a collective sigh of relief because we are finally doing what we came to do," said Maria Zuber, principal investigator for the GRAIL mission at the Massachusetts Institute of Technology in Cambridge, "but it is also a time where we have to put the coffee pot on, roll up our sleeves and get to work."
The GRAIL mission's twin, washing-machine-sized spacecraft, named Ebb and Flow, entered lunar orbit on New Year's Eve and New Years Day. GRAIL's science phase began yesterday at 5:15 p.m. PST (8:15 p.m. EST). During this mission phase, the spacecraft will transmit radio signals precisely defining the rate of change of distance between the two. The distance between the spacecraft will change slightly as they fly over areas of greater and lesser gravity caused by visible features such as mountains, craters and masses hidden beneath the lunar surface. Science activities are expected to conclude on May 29, after GRAIL maps the gravity field of the moon three times.
"We are in a near-polar, near-circular orbit with an average altitude of about 34 miles (55 kilometers) right now," said David Lehman, GRAIL project manager from NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "During the science phase, our spacecraft will orbit the moon as high as 31 miles (51 kilometers) and as low as 10 miles (16 kilometers). They will get as close to each other as 40 miles (65 kilometers) and as far apart as 140 miles (225 kilometers)."
{...}
NASA Press Release: RELEASE : 12-070 - NASA's Twin Grail Spacecraft Begin Collecting Lunar Science Data
SPACE.com: Twin NASA Moon Probes Begin Mapping Lunar Gravity
Universe Today: Twin NASA Science Probes Start Lunar Gravity Mapping
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NASA / NASA JPL:
NASA GRAIL Returns First Student-Selected Moon Images
March 22, 2012
PASADENA, Calif. -- One of two NASA spacecraft orbiting the moon has beamed back the first student-requested pictures of the lunar surface from its onboard camera. Fourth grade students from the Emily Dickinson Elementary School in Bozeman, Mont., received the honor of making the first image selections by winning a nationwide competition to rename the two spacecraft.
The image was taken by the MoonKam, or Moon Knowledge Acquired by Middle school students. Previously named Gravity Recovery And Interior Laboratory (GRAIL) A and B, the twin spacecraft are now called Ebb and Flow. Both washing-machine-sized orbiters carry a small MoonKAM camera. Over 60 student-requested images were taken by the Ebb spacecraft from March 15-17 and downlinked to Earth March 20.
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This image of the far side of the lunar surface, with Earth in the background, was taken by the MoonKAM system board the Ebb spacecraft as part of the first image set taken from lunar orbit from March 15 – 18, 2012.
"MoonKAM is based on the premise that if your average picture is worth a thousand words, then a picture from lunar orbit may be worth a classroom full of engineering and science degrees," said Maria Zuber, GRAIL mission principal investigator from the Massachusetts Institute of Technology in Cambridge, Mass. "Through MoonKAM, we have an opportunity to reach out to the next generation of scientists and engineers. It is great to see things off to such a positive start."
GRAIL is NASA's first planetary mission to carry instruments fully dedicated to education and public outreach. Students will select target areas on the lunar surface and request images to study from the GRAIL MoonKAM Mission Operations Center in San Diego.
The MoonKAM program is led by Sally Ride, America's first woman in space, and her team at Sally Ride Science in collaboration with undergraduate students at the University of California in San Diego. More than 2,700 schools spanning 52 countries are using the MoonKAM cameras.
"What might seem like just a cool activity for these kids may very well have a profound impact on their futures," Ride said. "The students really are excited about MoonKAM, and that translates into an excitement about science and engineering."
{...}
NASA Press Release: RELEASE : 12-093 - NASA'S Grail MoonKam Returns First Student-Selected Lunar Images
SPACE.com: NASA Probe Snaps New Moon Photos for Students on Earth
Parabolic Arc: MoonKAMs Begin Operations Aboard GRAIL Lunar Orbiters
Universe Today: 1st Student Selected MoonKAM Pictures Look Inspiringly Home to Earth
NASA GRAIL Returns First Student-Selected Moon Images
March 22, 2012
PASADENA, Calif. -- One of two NASA spacecraft orbiting the moon has beamed back the first student-requested pictures of the lunar surface from its onboard camera. Fourth grade students from the Emily Dickinson Elementary School in Bozeman, Mont., received the honor of making the first image selections by winning a nationwide competition to rename the two spacecraft.
The image was taken by the MoonKam, or Moon Knowledge Acquired by Middle school students. Previously named Gravity Recovery And Interior Laboratory (GRAIL) A and B, the twin spacecraft are now called Ebb and Flow. Both washing-machine-sized orbiters carry a small MoonKAM camera. Over 60 student-requested images were taken by the Ebb spacecraft from March 15-17 and downlinked to Earth March 20.
Click on images for details
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This image of the far side of the lunar surface, with Earth in the background, was taken by the MoonKAM system board the Ebb spacecraft as part of the first image set taken from lunar orbit from March 15 – 18, 2012.Image credit: NASA/Caltech-JPL/MIT/SRS
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How students take pictures from lunar orbit with GRAIL’s MoonKAM (Infographic)
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This image of the lunar surface was taken by the MoonKAM system onboard the Ebb spacecraft on March 15, 2012.Image credit: NASA/Caltech-JPL/MIT/SRS
"MoonKAM is based on the premise that if your average picture is worth a thousand words, then a picture from lunar orbit may be worth a classroom full of engineering and science degrees," said Maria Zuber, GRAIL mission principal investigator from the Massachusetts Institute of Technology in Cambridge, Mass. "Through MoonKAM, we have an opportunity to reach out to the next generation of scientists and engineers. It is great to see things off to such a positive start."
GRAIL is NASA's first planetary mission to carry instruments fully dedicated to education and public outreach. Students will select target areas on the lunar surface and request images to study from the GRAIL MoonKAM Mission Operations Center in San Diego.
The MoonKAM program is led by Sally Ride, America's first woman in space, and her team at Sally Ride Science in collaboration with undergraduate students at the University of California in San Diego. More than 2,700 schools spanning 52 countries are using the MoonKAM cameras.
"What might seem like just a cool activity for these kids may very well have a profound impact on their futures," Ride said. "The students really are excited about MoonKAM, and that translates into an excitement about science and engineering."
{...}
NASA Press Release: RELEASE : 12-093 - NASA'S Grail MoonKam Returns First Student-Selected Lunar Images
SPACE.com: NASA Probe Snaps New Moon Photos for Students on Earth
Parabolic Arc: MoonKAMs Begin Operations Aboard GRAIL Lunar Orbiters
Universe Today: 1st Student Selected MoonKAM Pictures Look Inspiringly Home to Earth
sorindafabico
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An earthrise picture taken from LRO camera would be amazing.
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NASA / NASA JPL:
Flying Formation - Around the Moon at 3,600 MPH
March 27, 2012
The act of two or more aircraft flying together in a disciplined, synchronized manner is one of the cornerstones of military aviation, as well as just about any organized air show. But as amazing as the U.S. Navy's elite Blue Angels or the U.S. Air Force's Thunderbirds are to behold, they remain essentially landlocked, anchored if you will, to our planet and its tenuous atmosphere. What if you could take the level of precision of these great aviators to, say, the moon?
"Our job is to ensure our two GRAIL spacecraft are flying a very, very accurate trail formation in lunar orbit," said David Lehman, GRAIL project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We need to do this so our scientists can get the data they need."
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An artist's depiction of the GRAIL twins (Ebb and Flow) in lunar orbit. During GRAIL's prime mission science phase, the two spacecraft will orbit the moon as high as 31 miles (51 kilometers) and as low as 10 miles (16 kilometers).
Essentially, trail formation means one aircraft (or spacecraft in this case), follows directly behind the other. Ebb and Flow, the twins of NASA's GRAIL (Gravity Recovery And Interior Laboratory) mission, are by no means the first to synch up altitude and "air" speed while zipping over the craters, mountains, hills and rills of Earth's natural satellite. That honor goes to the crew of Apollo 10, who in May 1969 performed a dress rehearsal for the first lunar landing. But as accurate as the astronauts aboard lunar module "Snoopy" and command module "Charlie Brown" were in their piloting, it is hard to imagine they could keep as exacting a position as Ebb and Flow.
"It is an apples and oranges comparison," said Lehman. "Lunar formation in Apollo was about getting a crew to the lunar surface, returning to lunar orbit and docking, so they could get back safely to Earth. For GRAIL, the formation flying is about the science, and that is why we have to make our measurements so precisely."
As the GRAIL twins fly over areas of greater and lesser gravity at 3,600 mph (5,800 kilometers per hour), surface features such as mountains and craters, and masses hidden beneath the lunar surface, can influence the distance between the two spacecraft ever so slightly.
How slight a distance change can be measured by the science instrument beaming invisible microwaves back and forth between Ebb and Flow?
How about one-tenth of one micron? Another way to put it is that the GRAIL twins can detect a change in their position down to one half of a human hair (0.000004 inches, or 0.00001 centimeters). For those of you who are hematologists or vampires (we are not judging here), any change in separation between the two twins greater than one half of a red corpuscle will be duly noted aboard the spacecraft's memory chips for later downlinking to Earth. Working together, Ebb and Flow will make these measurements while flying over the entirety of the lunar surface.
This begs the question, why would scientists care about a change of distance between two spacecraft as infinitesimal as half a red corpuscle a quarter million miles from Earth?
"Mighty oaks from little acorns grow - even in lunar orbit," said Maria Zuber, principal investigator of the GRAIL mission from the Massachusetts Institute of Technology, Cambridge. "From the data collected during these minute distance changes between spacecraft, we will be able to generate an incredibly high-resolution map of the moon's gravitational field. From that, we will be able to understand what goes on below the lunar surface in unprecedented detail, which will in turn increase our knowledge of how Earth and its rocky neighbors in the inner solar system developed into the diverse worlds we see today."
Getting the GRAIL twins into a hyper-accurate formation from a quarter million miles away gave the team quite a challenge. Launched together on Sept. 10, 2011, Ebb and Flow went their separate ways soon after entering space. Three-and-a-half months and 2.5 million miles (4 million kilometers) later, Ebb entered lunar orbit. Flow followed the next day (New Year's Day 2012).
"Being in lunar orbit is one thing, being in the right lunar orbit for science can be something else entirely," said Joe Beerer, GRAIL's mission manager from JPL. "The twins initial orbit carried them as close to the lunar surface as 56 miles (90 kilometers) and as far out as 5,197 miles (8,363 kilometers), and each revolution took approximately 11.5 hours to complete. They had to go from that to a science orbit of 15 by 53 miles (24.5 by 86 kilometers) and took all of 114 minutes to complete."
To reduce and refine Ebb and Flow's orbits efficiently and precisely required the GRAIL team to plan and execute a series of trajectory modification burns for each spacecraft. And each maneuver had to be just right.
"Because each one of these maneuvers was so important, we did a lot of planning and testing for each," said Beerer. "Over eight weeks, we did nine maneuvers with Ebb and 10 with Flow to establish the science formation. We would literally be watching our screens for a signal telling us about an Ebb rocket burn, then go into a meeting about the next burn for Flow. Our schedule was very full."
Today, the calendar for GRAIL's flight team remains a busy one with the day-to-day operations of keeping NASA's lunar twins in synch. But as busy as the team gets, they still have time to peer skyward.
"Next time you look up and see the moon, you might want to take a second and think about our two little spacecraft flying formation, zooming from pole to pole at 3,600 mph," said Lehman. "They're up there, working together, flying together, getting the data our scientists need. As far as I'm concerned, they're putting on quite a show."
{...}
Flying Formation - Around the Moon at 3,600 MPH
March 27, 2012
The act of two or more aircraft flying together in a disciplined, synchronized manner is one of the cornerstones of military aviation, as well as just about any organized air show. But as amazing as the U.S. Navy's elite Blue Angels or the U.S. Air Force's Thunderbirds are to behold, they remain essentially landlocked, anchored if you will, to our planet and its tenuous atmosphere. What if you could take the level of precision of these great aviators to, say, the moon?
"Our job is to ensure our two GRAIL spacecraft are flying a very, very accurate trail formation in lunar orbit," said David Lehman, GRAIL project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We need to do this so our scientists can get the data they need."
Click on images for details
|
An artist's depiction of the GRAIL twins (Ebb and Flow) in lunar orbit. During GRAIL's prime mission science phase, the two spacecraft will orbit the moon as high as 31 miles (51 kilometers) and as low as 10 miles (16 kilometers).Image credit: NASA/Caltech-JPL/MIT
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An artist's depiction of the twin spacecraft that comprise NASA's Gravity Recovery And Interior Laboratory (GRAIL) mission. As the GRAIL twins (Ebb and Flow) fly over areas of greater and lesser gravity at 3,600 mph (5,800 kilometers per hour), surface features such as mountains and craters, and masses hidden beneath the lunar surface, can influence the distance between the two spacecraft.Image credit: NASA/Caltech-JPL/MIT
Essentially, trail formation means one aircraft (or spacecraft in this case), follows directly behind the other. Ebb and Flow, the twins of NASA's GRAIL (Gravity Recovery And Interior Laboratory) mission, are by no means the first to synch up altitude and "air" speed while zipping over the craters, mountains, hills and rills of Earth's natural satellite. That honor goes to the crew of Apollo 10, who in May 1969 performed a dress rehearsal for the first lunar landing. But as accurate as the astronauts aboard lunar module "Snoopy" and command module "Charlie Brown" were in their piloting, it is hard to imagine they could keep as exacting a position as Ebb and Flow.
"It is an apples and oranges comparison," said Lehman. "Lunar formation in Apollo was about getting a crew to the lunar surface, returning to lunar orbit and docking, so they could get back safely to Earth. For GRAIL, the formation flying is about the science, and that is why we have to make our measurements so precisely."
As the GRAIL twins fly over areas of greater and lesser gravity at 3,600 mph (5,800 kilometers per hour), surface features such as mountains and craters, and masses hidden beneath the lunar surface, can influence the distance between the two spacecraft ever so slightly.
How slight a distance change can be measured by the science instrument beaming invisible microwaves back and forth between Ebb and Flow?
How about one-tenth of one micron? Another way to put it is that the GRAIL twins can detect a change in their position down to one half of a human hair (0.000004 inches, or 0.00001 centimeters). For those of you who are hematologists or vampires (we are not judging here), any change in separation between the two twins greater than one half of a red corpuscle will be duly noted aboard the spacecraft's memory chips for later downlinking to Earth. Working together, Ebb and Flow will make these measurements while flying over the entirety of the lunar surface.
This begs the question, why would scientists care about a change of distance between two spacecraft as infinitesimal as half a red corpuscle a quarter million miles from Earth?
"Mighty oaks from little acorns grow - even in lunar orbit," said Maria Zuber, principal investigator of the GRAIL mission from the Massachusetts Institute of Technology, Cambridge. "From the data collected during these minute distance changes between spacecraft, we will be able to generate an incredibly high-resolution map of the moon's gravitational field. From that, we will be able to understand what goes on below the lunar surface in unprecedented detail, which will in turn increase our knowledge of how Earth and its rocky neighbors in the inner solar system developed into the diverse worlds we see today."
Getting the GRAIL twins into a hyper-accurate formation from a quarter million miles away gave the team quite a challenge. Launched together on Sept. 10, 2011, Ebb and Flow went their separate ways soon after entering space. Three-and-a-half months and 2.5 million miles (4 million kilometers) later, Ebb entered lunar orbit. Flow followed the next day (New Year's Day 2012).
"Being in lunar orbit is one thing, being in the right lunar orbit for science can be something else entirely," said Joe Beerer, GRAIL's mission manager from JPL. "The twins initial orbit carried them as close to the lunar surface as 56 miles (90 kilometers) and as far out as 5,197 miles (8,363 kilometers), and each revolution took approximately 11.5 hours to complete. They had to go from that to a science orbit of 15 by 53 miles (24.5 by 86 kilometers) and took all of 114 minutes to complete."
To reduce and refine Ebb and Flow's orbits efficiently and precisely required the GRAIL team to plan and execute a series of trajectory modification burns for each spacecraft. And each maneuver had to be just right.
"Because each one of these maneuvers was so important, we did a lot of planning and testing for each," said Beerer. "Over eight weeks, we did nine maneuvers with Ebb and 10 with Flow to establish the science formation. We would literally be watching our screens for a signal telling us about an Ebb rocket burn, then go into a meeting about the next burn for Flow. Our schedule was very full."
Today, the calendar for GRAIL's flight team remains a busy one with the day-to-day operations of keeping NASA's lunar twins in synch. But as busy as the team gets, they still have time to peer skyward.
"Next time you look up and see the moon, you might want to take a second and think about our two little spacecraft flying formation, zooming from pole to pole at 3,600 mph," said Lehman. "They're up there, working together, flying together, getting the data our scientists need. As far as I'm concerned, they're putting on quite a show."
{...}
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NASA / NASA JPL:
NASA Lunar Spacecraft Complete Prime Mission Ahead of Schedule
May 29, 2012
PASADENA, Calif. -- A NASA mission to study the moon from crust to core has completed its prime mission earlier than expected. The team of NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, with twin probes named Ebb and Flow, is now preparing for extended science operations starting Aug. 30 and continuing through Dec. 3, 2012.
The GRAIL mission has gathered unprecedented detail about the internal structure and evolution of the moon. This information will increase our knowledge of how Earth and its rocky neighbors in the inner solar system developed into the diverse worlds we see today.
Since March 8, the spacecraft have operated around the clock for 89 days. From an orbit that passes over the lunar poles, they have collected data covering the entire surface three times. An instrument called the Lunar Gravity Ranging System onboard each spacecraft transmits radio signals that allow scientists to translate the data into a high-resolution map of the moon's gravitational field. The spacecraft returned their last data set of the prime mission today. The instruments were turned off at 10 a.m. PDT (1 p.m. EDT) when the spacecraft were 37 miles (60 kilometers) above the Sea of Nectar.
"Many of the measurement objectives were achieved from analysis of only half the primary mission data, which speaks volumes about the skill and dedication of our science and engineering teams," said Maria Zuber, principal investigator of GRAIL at the Massachusetts Institute of Technology in Cambridge. "While there is a great deal of work yet to be done to achieve the mission's science, it's energizing to realize that what we traveled from Earth to the moon for is right here in our hands."
"GRAIL delivered to Earth over 99.99 percent of the data that could have been collected, which underscores the flawless performance of the spacecraft, instrument and the Deep Space Network," said Zuber.
Both spacecraft instruments will be powered off until Aug. 30. The spacecraft will have to endure a lunar eclipse on June 4. The eclipse and the associated sudden changes in temperature and the energy-sapping darkness that accompanies the phenomena were expected and do not concern engineers about the spacecraft's health.
"Before launch, we planned for all of GRAIL's primary mission science to occur between lunar eclipses," said David Lehman, project manager of GRAIL from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "But now that we have flown Ebb and Flow for a while, we understand them and are confident they can survive these eclipses in good shape."
The extended mission goal is to take an even closer look at the moon's gravity field. To achieve this, GRAIL mission planners will halve their current operating altitude to the lowest altitude that can be safely maintained.
"Orbiting at an average altitude of 14 miles (23 kilometers) during the extended mission, the GRAIL twins will be clearing some of the moon's higher surface features by about 5 miles (8 kilometers)," said Joe Beerer of JPL, GRAIL's mission manager. "If Ebb and Flow had feet, I think by reflex they'd want to pull them up every time they fly over a mountain."
Along with mission science, GRAIL's MoonKAM (Moon Knowledge Acquired by Middle school students) education and public outreach program is also extended. To date over 70,000 student images of the moon have been obtained. The MoonKAM program is led by Sally Ride, America's first woman in space, and her team at Sally Ride Science in collaboration with undergraduate students at the University of California in San Diego.
{...}
NASA Press Release: RELEASE : 12-175 - NASA Lunar Spacecraft Complete Prime Mission Ahead of Schedule
NASA Lunar Spacecraft Complete Prime Mission Ahead of Schedule
May 29, 2012
PASADENA, Calif. -- A NASA mission to study the moon from crust to core has completed its prime mission earlier than expected. The team of NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, with twin probes named Ebb and Flow, is now preparing for extended science operations starting Aug. 30 and continuing through Dec. 3, 2012.
The GRAIL mission has gathered unprecedented detail about the internal structure and evolution of the moon. This information will increase our knowledge of how Earth and its rocky neighbors in the inner solar system developed into the diverse worlds we see today.
Since March 8, the spacecraft have operated around the clock for 89 days. From an orbit that passes over the lunar poles, they have collected data covering the entire surface three times. An instrument called the Lunar Gravity Ranging System onboard each spacecraft transmits radio signals that allow scientists to translate the data into a high-resolution map of the moon's gravitational field. The spacecraft returned their last data set of the prime mission today. The instruments were turned off at 10 a.m. PDT (1 p.m. EDT) when the spacecraft were 37 miles (60 kilometers) above the Sea of Nectar.
"Many of the measurement objectives were achieved from analysis of only half the primary mission data, which speaks volumes about the skill and dedication of our science and engineering teams," said Maria Zuber, principal investigator of GRAIL at the Massachusetts Institute of Technology in Cambridge. "While there is a great deal of work yet to be done to achieve the mission's science, it's energizing to realize that what we traveled from Earth to the moon for is right here in our hands."
"GRAIL delivered to Earth over 99.99 percent of the data that could have been collected, which underscores the flawless performance of the spacecraft, instrument and the Deep Space Network," said Zuber.
Both spacecraft instruments will be powered off until Aug. 30. The spacecraft will have to endure a lunar eclipse on June 4. The eclipse and the associated sudden changes in temperature and the energy-sapping darkness that accompanies the phenomena were expected and do not concern engineers about the spacecraft's health.
"Before launch, we planned for all of GRAIL's primary mission science to occur between lunar eclipses," said David Lehman, project manager of GRAIL from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "But now that we have flown Ebb and Flow for a while, we understand them and are confident they can survive these eclipses in good shape."
The extended mission goal is to take an even closer look at the moon's gravity field. To achieve this, GRAIL mission planners will halve their current operating altitude to the lowest altitude that can be safely maintained.
"Orbiting at an average altitude of 14 miles (23 kilometers) during the extended mission, the GRAIL twins will be clearing some of the moon's higher surface features by about 5 miles (8 kilometers)," said Joe Beerer of JPL, GRAIL's mission manager. "If Ebb and Flow had feet, I think by reflex they'd want to pull them up every time they fly over a mountain."
Along with mission science, GRAIL's MoonKAM (Moon Knowledge Acquired by Middle school students) education and public outreach program is also extended. To date over 70,000 student images of the moon have been obtained. The MoonKAM program is led by Sally Ride, America's first woman in space, and her team at Sally Ride Science in collaboration with undergraduate students at the University of California in San Diego.
{...}
NASA Press Release: RELEASE : 12-175 - NASA Lunar Spacecraft Complete Prime Mission Ahead of Schedule
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Space News: NASA’s GRAIL Moon Probes Taking the Summer Off
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NASA / NASA JPL:
NASA's GRAIL Moon Twins Begin Extended Mission Science
August 31, 2012
PASADENA, Calif. - NASA's twin, lunar-orbiting Gravity Recovery and Interior Laboratory (GRAIL) spacecraft began data collection for the start of the mission's extended operations.
At 9:28 a.m. PDT (12:28 p.m. EDT) yesterday, while the two spacecraft were 19 miles (30 kilometers) above the moon's Ocean of Storms, the Lunar Gravity Ranging System -- the mission's sole science instrument aboard both GRAIL twins -- was energized.
"The data collected during GRAIL's primary mission team are currently being analyzed and hold the promise of producing a gravity field map of extraordinary quality and resolution," said Maria Zuber, principal investigator for GRAIL from the Massachusetts Institute of Technology in Cambridge. "Mapping at a substantially lower altitude during the extended mission, and getting an even more intimate glimpse of our nearest celestial neighbor, provides the unique opportunity to globally map the shallow crust of a planetary body beyond Earth."
The science phase of GRAIL's extended mission runs from Aug. 30 to Dec. 3. Its goals are to take an even closer look at the moon's gravity field, deriving the gravitational influence of surface and subsurface features as small as simple craters, mountains and rilles. To achieve this unprecedented resolution, GRAIL mission planners are halving the operating altitude - flying at the lowest altitude that can be safely maintained.
During the prime mission, which stretched from March 1 to May 29, the two GRAIL spacecraft, named Ebb and Flow, orbited at an average altitude of 34 miles (55 kilometers). The average orbital altitude during extended mission will be 14 miles (23 kilometers), which places the GRAIL twins within five miles (eight kilometers) of some of the moon's higher surface features.
"Ebb and Flow, and our mission operations team, are both doing great, which is certainly notable considering all the milestones and challenges they have experienced," said David Lehman, GRAIL project manager from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The twins have endured the lunar eclipse of June 4, 2012, and 26 rocket burns since arriving in lunar orbit at the beginning of the year. Down here in our control room, with all the planning and mission operations we have been doing, it feels as though we've been riding right along with them. Of course, they have the better view."
Science data are collected when the Lunar Gravity Ranging System transmit radio signals between the two spacecraft, precisely defining the rate of change of distance between Ebb and Flow. The distance between the twins change slightly as they fly over areas of greater and lesser gravity caused by visible features, such as mountains and craters, and by masses hidden beneath the lunar surface.
Mission scientists calculated that even as the last data were downlinked, four of the mission's six principal science measurement goals had already been achieved. The objective of the GRAIL mission is to generate the most accurate gravity map of the moon and from that derive the internal structure and evolution of Earth's natural satellite.
{...}
NASA's GRAIL Moon Twins Begin Extended Mission Science
August 31, 2012
PASADENA, Calif. - NASA's twin, lunar-orbiting Gravity Recovery and Interior Laboratory (GRAIL) spacecraft began data collection for the start of the mission's extended operations.
At 9:28 a.m. PDT (12:28 p.m. EDT) yesterday, while the two spacecraft were 19 miles (30 kilometers) above the moon's Ocean of Storms, the Lunar Gravity Ranging System -- the mission's sole science instrument aboard both GRAIL twins -- was energized.
"The data collected during GRAIL's primary mission team are currently being analyzed and hold the promise of producing a gravity field map of extraordinary quality and resolution," said Maria Zuber, principal investigator for GRAIL from the Massachusetts Institute of Technology in Cambridge. "Mapping at a substantially lower altitude during the extended mission, and getting an even more intimate glimpse of our nearest celestial neighbor, provides the unique opportunity to globally map the shallow crust of a planetary body beyond Earth."
The science phase of GRAIL's extended mission runs from Aug. 30 to Dec. 3. Its goals are to take an even closer look at the moon's gravity field, deriving the gravitational influence of surface and subsurface features as small as simple craters, mountains and rilles. To achieve this unprecedented resolution, GRAIL mission planners are halving the operating altitude - flying at the lowest altitude that can be safely maintained.
During the prime mission, which stretched from March 1 to May 29, the two GRAIL spacecraft, named Ebb and Flow, orbited at an average altitude of 34 miles (55 kilometers). The average orbital altitude during extended mission will be 14 miles (23 kilometers), which places the GRAIL twins within five miles (eight kilometers) of some of the moon's higher surface features.
"Ebb and Flow, and our mission operations team, are both doing great, which is certainly notable considering all the milestones and challenges they have experienced," said David Lehman, GRAIL project manager from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The twins have endured the lunar eclipse of June 4, 2012, and 26 rocket burns since arriving in lunar orbit at the beginning of the year. Down here in our control room, with all the planning and mission operations we have been doing, it feels as though we've been riding right along with them. Of course, they have the better view."
Science data are collected when the Lunar Gravity Ranging System transmit radio signals between the two spacecraft, precisely defining the rate of change of distance between Ebb and Flow. The distance between the twins change slightly as they fly over areas of greater and lesser gravity caused by visible features, such as mountains and craters, and by masses hidden beneath the lunar surface.
Mission scientists calculated that even as the last data were downlinked, four of the mission's six principal science measurement goals had already been achieved. The objective of the GRAIL mission is to generate the most accurate gravity map of the moon and from that derive the internal structure and evolution of Earth's natural satellite.
{...}
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NASA / NASA JPL:
NASA's GRAIL Creates Most Accurate Moon Gravity Map
December 05, 2012
PASADENA, Calif. -- Twin NASA probes orbiting Earth's moon have generated the highest resolution gravity field map of any celestial body.
The new map, created by the Gravity Recovery and Interior Laboratory (GRAIL) mission, is allowing scientists to learn about the moon's internal structure and composition in unprecedented detail. Data from the two washing machine-sized spacecraft also will provide a better understanding of how Earth and other rocky planets in the solar system formed and evolved.
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The gravity field map reveals an abundance of features never before seen in detail, such as tectonic structures, volcanic landforms, basin rings, crater central peaks and numerous simple, bowl-shaped craters. Data also show the moon's gravity field is unlike that of any terrestrial planet in our solar system.
{colsp=2}
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These are the first scientific results from the prime phase of the mission, and they are published in three papers in the journal Science.
"What this map tells us is that more than any other celestial body we know of, the moon wears its gravity field on its sleeve," said GRAIL Principal Investigator Maria Zuber of the Massachusetts Institute of Technology in Cambridge. "When we see a notable change in the gravity field, we can sync up this change with surface topography features such as craters, rilles or mountains."
{colsp=2}
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According to Zuber, the moon's gravity field preserves the record of impact bombardment that characterized all terrestrial planetary bodies and reveals evidence for fracturing of the interior extending to the deep crust and possibly the mantle. This impact record is preserved, and now precisely measured, on the moon.
{colsp=2}
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The probes revealed the bulk density of the moon's highland crust is substantially lower than generally assumed. This low-bulk crustal density agrees well with data obtained during the final Apollo lunar missions in the early 1970s, indicating that local samples returned by astronauts are indicative of global processes.
{colsp=2}
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"With our new crustal bulk density determination, we find that the average thickness of the moon's crust is between 21 and 27 miles (34 and 43 kilometers), which is about 6 to 12 miles (10 to 20 kilometers) thinner than previously thought," said Mark Wieczorek, GRAIL co-investigator at the Institut de Physique du Globe de Paris. "With this crustal thickness, the bulk composition of the moon is similar to that of Earth. This supports models where the moon is derived from Earth materials that were ejected during a giant impact event early in solar system history."
The map was created by the spacecraft transmitting radio signals to define precisely the distance between them as they orbit the moon in formation. As they fly over areas of greater and lesser gravity caused by visible features, such as mountains and craters, and masses hidden beneath the lunar surface, the distance between the two spacecraft will change slightly.
{colsp=2}
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"We used gradients of the gravity field in order to highlight smaller and narrower structures than could be seen in previous datasets," said Jeff Andrews-Hanna, a GRAIL guest scientist with the Colorado School of Mines in Golden. "This data revealed a population of long, linear gravity anomalies, with lengths of hundreds of kilometers, crisscrossing the surface. These linear gravity anomalies indicate the presence of dikes, or long, thin, vertical bodies of solidified magma in the subsurface. The dikes are among the oldest features on the moon, and understanding them will tell us about its early history."
While results from the primary science mission are just beginning to be released, the collection of gravity science by the lunar twins continues. GRAIL's extended mission science phase began Aug. 30 and will conclude Dec. 17. As the end of mission nears, the spacecraft will operate at lower orbital altitudes above the moon.
{...}
NASA News Release: RELEASE : 12-417 - NASA Twin Spacecraft Create Most Accurate Gravity Map of Moon
Science Daily: NASA Twin Spacecraft Create Most Accurate Gravity Map of Moon
Florida Today: Probes reveal moon's battered interior
SPACE.com: Moon Surprisingly Battered, New Lunar Gravity Map Reveals
Moon Daily: NASA's GRAIL Creates Most Accurate Moon Gravity Map
Universe Today:
Discovery News: Behold! A 'Pounded Moon' Gravity Map: Big Pic
AmericaSpace: NASA's Twin GRAIL Spacecraft Create Highest Resolution Gravity Map Of The Moon
Spaceflight101: First GRAIL Science Data reveals new Feature of Lunar Geology
NASA's GRAIL Creates Most Accurate Moon Gravity Map
December 05, 2012
PASADENA, Calif. -- Twin NASA probes orbiting Earth's moon have generated the highest resolution gravity field map of any celestial body.
The new map, created by the Gravity Recovery and Interior Laboratory (GRAIL) mission, is allowing scientists to learn about the moon's internal structure and composition in unprecedented detail. Data from the two washing machine-sized spacecraft also will provide a better understanding of how Earth and other rocky planets in the solar system formed and evolved.
Click on images for details
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GRAIL's Gravity Tour of the Moon
This movie shows the variations in the lunar gravity field as measured by NASA's Gravity Recovery and Interior Laboratory (GRAIL) during the primary mapping mission from March to May 2012. Very precise microwave measurements between two spacecraft, named Ebb and Flow, were used to map gravity with high precision and high spatial resolution.Image credit: NASA/JPL-Caltech/MIT/GSFC
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Gravity of the Moon's Crust
These maps of the moon show the "Bouguer" gravity anomalies as measured by NASA's GRAIL mission.Image credit: NASA/JPL-Caltech/CSM
The gravity field map reveals an abundance of features never before seen in detail, such as tectonic structures, volcanic landforms, basin rings, crater central peaks and numerous simple, bowl-shaped craters. Data also show the moon's gravity field is unlike that of any terrestrial planet in our solar system.
Click on images for details
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GRAIL's Gravity Gradients
These maps of the near and far side of the moon show gravity gradients as measured by NASA's GRAIL mission.Image credit: NASA/JPL-Caltech/CSM
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Linear Gravity Anomalies
These maps of the near and far side of the moon show the gravity gradients as measured by NASA's GRAIL mission, highlighting a population of linear gravity anomalies.Image credit: NASA/JPL-Caltech/CSM
These are the first scientific results from the prime phase of the mission, and they are published in three papers in the journal Science.
"What this map tells us is that more than any other celestial body we know of, the moon wears its gravity field on its sleeve," said GRAIL Principal Investigator Maria Zuber of the Massachusetts Institute of Technology in Cambridge. "When we see a notable change in the gravity field, we can sync up this change with surface topography features such as craters, rilles or mountains."
Click on images for details
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GRAIL Spots Gravity Anomaly
A 300-mile-long (500 kilometer-long) linear gravity anomaly on the far side of the moon has been revealed by gravity gradients measured by NASA's GRAIL mission.Image credit: NASA/JPL-Caltech/CSM
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Gravity Anomaly Intersects Moon Basin
A linear gravity anomaly intersecting the Crisium basin on the nearside of the moon has been revealed by NASA's GRAIL mission.Image credit: NASA/JPL-Caltech/CSM
According to Zuber, the moon's gravity field preserves the record of impact bombardment that characterized all terrestrial planetary bodies and reveals evidence for fracturing of the interior extending to the deep crust and possibly the mantle. This impact record is preserved, and now precisely measured, on the moon.
Click on images for details
|
GRAIL Identifies Moon Dikes
A profile across one of the linear gravity anomalies found by NASA's GRAIL mission shows that it has higher gravity than the surroundings (the anomaly is the red line in graph at bottom left; its location is shown as a blue line in the center of the GRAIL gravity gradient map at top left).Image credits, Left: NASA/JPL-Caltech/CSM, Right: Photo Copyright © Louis Maher
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Moon Dike Map
This map of one side of the moon shows the location of some of the giant dikes identified by NASA's GRAIL mission. These dikes are solidified magma filled cracks with lengths up to 300 miles (480 kilometers) and widths of up to 24 miles (40 kilometers).Image credit: NASA/JPL-Caltech/CSM
The probes revealed the bulk density of the moon's highland crust is substantially lower than generally assumed. This low-bulk crustal density agrees well with data obtained during the final Apollo lunar missions in the early 1970s, indicating that local samples returned by astronauts are indicative of global processes.
Click on images for details
|
Lunar Gravity Gradients
This moon map shows the gravity gradients calculated by NASA's GRAIL mission. Red and blue correspond to stronger gravity gradients.Image credit: NASA/JPL-Caltech/CSM
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Moon Gravity Field Using Prospector Data
This map shows the gravity field of the moon from the Lunar Prospector mission. The viewing perspective, known as a Mercator projection, shows the far side of the moon in the center and the nearside (as viewed from Earth) at either side.Image credit: NASA/ARC/MIT
"With our new crustal bulk density determination, we find that the average thickness of the moon's crust is between 21 and 27 miles (34 and 43 kilometers), which is about 6 to 12 miles (10 to 20 kilometers) thinner than previously thought," said Mark Wieczorek, GRAIL co-investigator at the Institut de Physique du Globe de Paris. "With this crustal thickness, the bulk composition of the moon is similar to that of Earth. This supports models where the moon is derived from Earth materials that were ejected during a giant impact event early in solar system history."
The map was created by the spacecraft transmitting radio signals to define precisely the distance between them as they orbit the moon in formation. As they fly over areas of greater and lesser gravity caused by visible features, such as mountains and craters, and masses hidden beneath the lunar surface, the distance between the two spacecraft will change slightly.
Click on images for details
|
GRAIL's Gravity Field of the Moon
This map shows the gravity field of the moon as measured by NASA's GRAIL mission. The viewing perspective, known as a Mercator projection, shows the far side of the moon in the center and the nearside (as viewed from Earth) at either side.Image credit: NASA/ARC/MIT
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Olivine Materials Map to Thin Moon Crust
This graphic depicting the crustal thickness of the moon was generated using gravity data from NASA's GRAIL mission and topography data from NASA's Lunar Reconnaissance Orbiter.Image Credit: NASA/JPL-Caltech/ IPGP
"We used gradients of the gravity field in order to highlight smaller and narrower structures than could be seen in previous datasets," said Jeff Andrews-Hanna, a GRAIL guest scientist with the Colorado School of Mines in Golden. "This data revealed a population of long, linear gravity anomalies, with lengths of hundreds of kilometers, crisscrossing the surface. These linear gravity anomalies indicate the presence of dikes, or long, thin, vertical bodies of solidified magma in the subsurface. The dikes are among the oldest features on the moon, and understanding them will tell us about its early history."
While results from the primary science mission are just beginning to be released, the collection of gravity science by the lunar twins continues. GRAIL's extended mission science phase began Aug. 30 and will conclude Dec. 17. As the end of mission nears, the spacecraft will operate at lower orbital altitudes above the moon.
{...}
NASA News Release: RELEASE : 12-417 - NASA Twin Spacecraft Create Most Accurate Gravity Map of Moon
Science Daily: NASA Twin Spacecraft Create Most Accurate Gravity Map of Moon
Florida Today: Probes reveal moon's battered interior
SPACE.com: Moon Surprisingly Battered, New Lunar Gravity Map Reveals
Moon Daily: NASA's GRAIL Creates Most Accurate Moon Gravity Map
Universe Today:
- GRAIL First Results Provide Most Precise Lunar Gravity Map Yet
- Moon’s Inner Crust Almost Completely Pulverized
Discovery News: Behold! A 'Pounded Moon' Gravity Map: Big Pic
AmericaSpace: NASA's Twin GRAIL Spacecraft Create Highest Resolution Gravity Map Of The Moon
Spaceflight101: First GRAIL Science Data reveals new Feature of Lunar Geology
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