posted December 12, 2007 04:58 PM               

New NASA Mission to Reveal Moon's Internal Structure and Evolution

At a Monday meeting of the American Geophysical Union, NASA's Associate Administrator for Science Alan Stern announced the selection of a new mission that will peer deep inside the moon to reveal its anatomy and history.

The Gravity Recovery and Interior Laboratory, or GRAIL, mission is a part of NASA's Discovery Program. It will cost $375 million and is scheduled to launch in 2011. GRAIL will fly twin spacecraft in tandem orbits around the moon for several months to measure its gravity field in unprecedented detail. The mission also will answer longstanding questions about Earth's moon and provide scientists a better understanding of how Earth and other rocky planets in the solar system formed.

"GRAIL's revolutionary capabilities stood out in this Discovery mission competition owing to its unsurpassed combination of high scientific value and low technical and programmatic risk," Stern said. "GRAIL also offers to bring innovative Earth studies techniques to the moon as a precursor to their possible later use at Mars and other planets."

Scientists will use the gravity field information from the two satellites to X-ray the moon from crust to core to reveal the moon's subsurface structures and, indirectly, its thermal history.

The study technique GRAIL will use was pioneered by the joint U.S.-German Earth observing Gravity Recovery and Climate Experiment, or GRACE, mission launched in 2002. The GRACE satellites measure gravity changes related to the movement of mass within the Earth, such as the melting of ice at the poles and changes in ocean circulation. As with GRACE, both GRAIL spacecraft will be launched on a single launch vehicle.

GRAIL's principal investigator is Maria Zuber of the Massachusetts Institute of Technology. Zuber's team of expert scientists and engineers includes former NASA astronaut Sally Ride, who will lead the mission's public outreach efforts. A camera aboard each spacecraft will allow students and the public to interact with observations from the satellites. Each GRAIL spacecraft will carry the cameras to documents their views from lunar orbits.

GRAIL will support NASA's exploration goals as the agency returns humans to the moon by 2020. In 2008, the agency will launch the Lunar Reconnaissance Orbiter, or LRO, to circle the moon for at least a year and take measurements to identify future robotic and human landing sites. The orbiter also will look for potential lunar resources and document aspects of the lunar radiation environment. After a 30-year hiatus, LRO represents NASA's first step toward returning humans to the moon. The orbiter will be accompanied by another spacecraft, called the Lunar Crater Observation and Sensing Satellite mission, which will impact the lunar south pole to search for evidence of polar water frost.

"As NASA moves forward with exploration endeavors, our lunar science missions will be the light buoy leading the path for future human activities," said Jim Green, director of the Planetary Division, Science Mission Directorate, Washington.

Created in 1992, NASA's Discovery Program sponsors a series of scientist-led, cost-capped solar system exploration missions with highly focused scientific goals. The GRAIL proposal was selected from 24 submissions in response to a 2006 Announcement of Opportunity for the program. Proposals were evaluated for scientific merit, science implementation merit, and technical, management and cost feasibility.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., will manage the GRAIL mission. The spacecraft will be built by Lockheed Martin Space Systems, Denver.

posted December 18, 2007 04:14 PM               

Sally Ride Science to Lead Education Efforts for Grail Mission around the Moon

Sally Ride Science is part of a new NASA mission that will peer deep inside the moon to reveal its anatomy and history — and share its findings with students. The Gravity Recovery and Interior Laboratory, or Grail, mission is a part of NASA's Discovery Program. Sally Ride Science, founded by Dr. Sally Ride, America's first woman in space, will lead the mission's education efforts.

Grail will fly twin spacecraft in tandem orbits around the moon for several months to measure its gravity field in unprecedented detail. Scientists will use the information from the two satellites to study the moon from crust to core to reveal its subsurface structures and, indirectly, its thermal history. The mission will answer longstanding questions about Earth's moon and provide scientists a better understanding of how Earth and other rocky planets in the solar system formed.

Cameras aboard each spacecraft will be dedicated to education — allowing students to photograph the moon from lunar orbit.

According to Ride, Grail will leverage the EarthKAM control center at the University of California, San Diego, where undergraduates will develop the software and procedures to run cameras on the Grail spacecraft. The cameras will be used by middle school students to study the moon from their classrooms.

In addition, as part of the education program, Sally Ride Science will develop workshops about the moon to feature at its science festivals for fifth through eighth grade students. Sally Ride Science will also develop Educator Institutes to train teachers in science activities related to the moon and gravity.

On the Grail mission, Ride will be part of a team of expert scientists and engineers led by Dr. Maria Zuber, of the Massachusetts Institute of Technology, who will serve as Grail's principal investigator. The Grail proposal was selected from 24 submissions in response to a 2006 Announcement of Opportunity for NASA's Discovery Program. The Grail mission will cost $375 million and is scheduled to launch in 2011.

posted May 24, 2011 11:18 AM               

NASA's Twin Craft Arrive In Florida For Moon Mission

NASA's twin lunar probes have arrived in Florida to begin final preparations for a launch in late summer. The two Gravity Recovery And Interior Laboratory spacecraft (GRAIL) were shipped from Lockheed Martin Space Systems, Denver, to the Astrotech payload processing facility in Titusville, Fla., Friday, May 20. NASA's dynamic duo will orbit the moon to determine the structure of the lunar interior from crust to core and to advance understanding of the thermal evolution of the moon.

"NASA's lunar twins have arrived at Cape Canaveral," said Maria Zuber, GRAIL's principal investigator, based at the Massachusetts Institute of Technology, in Cambridge. "We're only a few full moons away from a mission that will reveal clues not only into the history of the moon and Earth, but will provide important data for future lunar exploration."

The GRAIL twins, known as GRAIL-A and GRAIL-B, were removed from their shipping containers Monday, May 23. Later this week, they will begin functional testing to verify their state of health after their ride on an Air Force transport jet from Colorado. Over the next four months at the Astrotech facility, the spacecraft will undergo final testing, fueling and packaging in the shroud that will protect them as the Delta II launch vehicle lifts them into space. The spacecraft will then be transported to the Cape Canaveral Air Force Station for installation atop the rocket that will carry them toward the moon.

GRAIL will be carried into space aboard a United Launch Alliance Delta II Heavy rocket lifting off from Launch Complex-19 at the Cape Canaveral Air Force Station in Florida. The launch period opens Sept. 8, 2011, and extends through Oct. 19. For a Sept. 8 liftoff, the launch window opens at 8:37 a.m. EDT (5:37 a.m. PDT) and remains open through 9:16 a.m. EDT (6:16 a.m. PDT).

GRAIL-A and GRAIL-B will fly in tandem orbits around the moon for several months to measure its gravity field in unprecedented detail. The mission will also answer longstanding questions about Earth's moon, and provide scientists a better understanding of how Earth and other rocky planets in the solar system formed.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the GRAIL mission. The Massachusetts Institute of Technology, Cambridge, is home to the mission's principal investigator, Maria Zuber. The GRAIL mission is part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, built the spacecraft. Launch management for the mission is the responsibility of NASA's Launch Services Program at the Kennedy Space Center in Florida. JPL is a division of the California Institute of Technology in Pasadena.

posted August 11, 2011 07:57 AM               

NASA's twin Gravity Recovery and Interior Laboratory (GRAIL) lunar spacecraft were attached on Aug. 10, 2011, to the spacecraft adapter ring in their launch configuration in Astrotech Space Operation's payload processing facility in Titusville, Fla. Preparations are under way to transport the lunar probes to the launch pad.

GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon.

Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B at the Cape Canaveral Air Force Station is scheduled for Sept. 8.

Credit: NASA/Jim Grossmann

posted August 18, 2011 03:51 PM               

NASA's GRAIL Moon Twins are Joined to Their Booster

NASA's lunar-bound GRAIL twins were mated to their Delta II launch vehicle at the Cape Canaveral Air Force Station's Launch Complex 17 at 8:45 a.m. EDT (5:45 a.m. PDT) today.

The 15-mile (25-kilometer) trip from Astrotech Space Operations in Titusville, Fla., is the last move for GRAIL before it begins its journey to the moon. NASA's dynamic duo will orbit the moon to determine the structure of the lunar interior from crust to core and to advance understanding of the thermal evolution of the moon.

Credit: NASA/Kim Shiflett

"We are about to finish one chapter in the GRAIL story and open another," said Maria Zuber, GRAIL's principal investigator, based at the Massachusetts Institute of Technology in Cambridge. "Let me assure you this one is a real page-turner. GRAIL will rewrite the book on the formation of the moon and the beginning of us."

Now that the GRAIL spacecraft are atop their rocket, a final flurry of checks and tests can begin to confirm that all is go for launch. The final series of checks begins tomorrow, Aug. 19, with an on-pad functional test. The test is designed to confirm that the spacecraft is healthy after the fueling and transport operations. Next week, among all the upcoming final tests, reviews and closeout operations leading up to liftoff, the GRAIL team will install the launch vehicle fairing around the spacecraft.

Credit: NASA/Kim Shiflett

GRAIL's launch period opens Sept. 8 and extends through Oct. 19. On each day, there are two separate instantaneous launch opportunities separated in time by approximately 39 minutes. On Sept. 8, the first launch opportunity is at 8:37 a.m. EDT (5:37 a.m. PDT). The second launch opportunity is 9:16 a.m. EDT (6:16 a.m. PDT).

posted August 25, 2011 10:29 AM               

NASA Moon Mission In Final Preparations For September Launch

NASA's Gravity Recovery And Interior Laboratory (GRAIL), mission to study the moon is in final launch preparations for a scheduled Sept. 8 launch onboard a Delta II rocket from Cape Canaveral Air Force Station in Florida.

GRAIL's twin spacecraft are tasked for a nine-month mission to explore Earth's nearest neighbor in unprecedented detail. They will determine the structure of the lunar interior from crust to core and advance our understanding of the thermal evolution of the moon.

"Yesterday's final encapsulation of the spacecraft is an important mission milestone," said David Lehman, GRAIL project manager for NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Our two spacecraft are now sitting comfortably inside the payload fairing which will protect them during ascent. Next time the GRAIL twins will see the light of day they will be about 95 miles up and accelerating."

The spacecraft twins, GRAIL A and B, will fly a circuitous route to lunar orbit taking 3.5 months and covering approximately 2.6 million miles (4.2 million kilometers) for GRAIL-A, and 2.7 million miles (4.3 million kilometers) for GRAIL-B.

In lunar orbit, the spacecraft will transmit radio signals precisely defining the distance between them. Regional gravitational differences on the moon are expected to expand and contract that distance. GRAIL scientists will use these accurate measurements to define the moon's gravity field. The data will allow mission scientists to understand what goes on below the surface of our natural satellite.

"GRAIL will unlock lunar mysteries and help us understand how the moon, Earth and other rocky planets evolved as well," said Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology in Cambridge.

GRAIL's launch period opens Sept. 8 and extends through Oct. 19. On each day, there are two separate launch opportunities separated by approximately 39 minutes. On Sept. 8, the first launch opportunity is 8:37 a.m. EDT; the second is 9:16 a.m.

posted September 08, 2011 05:59 AM               

GRAIL poised for launch

The mobile service tower on Space Launch Complex 17B at the Cape Canaveral Air Force Station in Florida was rolled away from the United Launch Alliance Delta II heavy rocket starting at about 11:20 p.m. EDT Wednesday in preparation for Thursday's scheduled launch of NASA's GRAIL lunar mapping mission.

GRAIL remains on track for two instantaneous (one-second) launch windows at 8:37:06 a.m. (12:37:36 GMT) or if needed, 9:16:12 a.m. (13:16:12 GMT).

The Delta II's first stage has been loaded with almost 10,000 gallons of refined kerosene, known as RP-1. Liquid oxygen is now being loaded.

Forecasts call for a 40 percent chance of acceptable weather at liftoff time. The concern is the possibility of thick clouds and rain near Launch Complex 17B.

During the 6:30 a.m. weather briefing to the launch team, clouds had not thickened so far, so there is some optimism that conditions will allow a launch.

If not, the same conditions will persist on Friday, with an improving weather picture for the weekend.

Credit: United Launch Alliance/Thom Baur

Above: Delta II-GRAIL rocket as seen just after the Mobile Service Tower was moved back from the vehicle.

posted September 08, 2011 08:13 AM               

Winds postpone GRAIL launch to Friday

Upper level winds above Launch Complex 17B at Cape Canaveral Air Force Station exceeded acceptable limits to launch NASA's GRAIL mission to the moon during the first of two launch opportunities on Thursday.

Liftoff has been re-targeted for Friday, Sept. 9.

GRAIL's launch period opened today (Sept. 8) and extends through Oct. 19. On each day, there are two separate instantaneous launch opportunities separated in time by approximately 39 minutes.

On Friday, Sept. 9, the first launch opportunity is at 8:33:25 a.m. EDT (12:33:25 GMT). The second launch opportunity is 9:12:31 a.m. EDT (13:12:31 a.m. PDT).

posted September 08, 2011 10:22 PM               

GRAIL launch further delayed to Saturday

The launch of a Delta II rocket carrying NASA's Gravity Recovery and Interior Laboratory (GRAIL) has been postponed one day to allow additional time to review propulsion system data from Thursday's detanking operation after the launch attempt was scrubbed due to upper level winds. The postponement will allow the launch team additional time to review the data.

The launch now is planned for Saturday, Sept. 10 from Space Launch Complex-17B at the Cape Canaveral Air Force Station, Fla. There are two instantaneous launch opportunities at 8:29:45 a.m. EDT (12:29:45 GMT) and 9:08:52 a.m. EDT (13:08:52 GMT).

The forecast for Sept. 10 shows a 60 percent chance of favorable weather conditions for a Saturday morning launch.

posted September 10, 2011 05:24 AM               

GRAIL set for Saturday moonshot

NASA's twin GRAIL spacecraft are scheduled to begin their mission to the moon by lifting off today (Sept. 10) from Cape Canaveral Air Force Station's Launch Complex 17B atop a United Launch Alliance Delta II heavy rocket.

There are two instantaneous launch opportunities at 8:29:45 a.m. EDT (12:29:45 GMT) and 9:08:52 a.m. EDT (13:08:52 GMT). The forecast shows a 60 percent chance of favorable weather conditions at liftoff time, with the primary concern being thick clouds and a chance for isolated showers.

Friday the launch team concluded its review of propulsion system data from Thursday's Delta II detanking operations and confirmed there are no issues with the rocket. Unacceptably high upper level winds on Thursday morning scrubbed the first launch attempt for the mission.

posted September 10, 2011 07:26 AM               

Winds delay GRAIL launch to second window

High upper level winds at Complex 17B at Cape Canaveral Air Force Station have again delayed the launch of NASA's GRAIL mission to the moon.

Liftoff has been re-targeted for the second instantaneous window of the day, at 9:08:52 a.m. EDT (13:08:52 GMT).

posted September 10, 2011 08:09 AM               

GRAIL launches on journey to center of the moon

NASA's Gravity Recovery And Interior Laboratory, or GRAIL, mission to study the moon launched on board a Delta II heavy rocket from the Cape Canaveral Air Force Station's Launch Complex 17B in Florida at 9:08:52 a.m. EDT (13:08:52 GMT) on Saturday, Sept. 10, 2011.

"We are on our way, and early indications show everything is looking good," said David Lehman, GRAIL project manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "We will know more about GRAIL's status in a few hours, after an opportunity to analyze telemetry and poll our mission controllers."

GRAIL's twin spacecraft have embarked on a nine-month mission to explore Earth's nearest neighbor in unprecedented detail. They will determine the structure of the lunar interior from crust to core and advance our understanding of the thermal evolution of the moon.

The spacecraft twins, GRAIL A and B, will fly a circuitous route to lunar orbit taking 3.5 months and covering approximately 2.6 million miles (4.2 million kilometers) for GRAIL-A, and 2.7 million miles (4.3 million kilometers) for GRAIL-B. GRAIL-A is scheduled to arrive at the moon on New Year's Eve. GRAIL-B will follow its twin a day later on New Year's Day.

In lunar orbit, the two spacecraft will transmit radio signals precisely defining the distance between them. Gravitational differences on the moon are expected to expand and contract that distance. GRAIL team members will use these accurate measurements to define the moon's gravity field. The data will allow scientists to understand what goes on below the surface of our natural satellite.

GRAIL's launch marked the last scheduled liftoff of a United Launch Alliance (ULA) Delta II from Cape Canaveral after 22 years and 110 launches.

posted September 10, 2011 10:17 AM               

United Launch Alliance Successfully Launches GRAIL Moon Mission for NASA on Final Flight from Space Launch Complex 17

A United Launch Alliance (ULA) Delta II rocket carrying the Gravity Recovery and Interior Laboratory (GRAIL) spacecraft for NASA lifted off from Space Launch Complex (SLC)-17B here at 9:08 a.m. EDT today. This launch marks the 9th flight for ULA in 2011, the 49th Delta II mission for NASA and the last currently-planned flight from this launch complex.

"With the final launch from SLC-17, we reflect on the tremendous historical significance of this complex and the impact of the military and scientific payloads that began their missions from this site," said Michael Gass, ULA president and CEO. "From the Global Positioning System satellites launched for the U.S. Air Force, to NASA's Mars rovers Spirit and Opportunity, in total this complex has been the origin for 259 critical Delta missions to protect our country and explore our universe."

The GRAIL mission was launched aboard a Delta II Heavy 7920H-10 configuration vehicle featuring a ULA first stage booster powered by a Pratt & Whitney Rocketdyne RS-27A main engine and nine Alliant Techsystems (ATK) strap-on solid rocket motors. An Aerojet AJ10-118K engine powered the second stage. The payload was encased by a 10-foot-diameter composite payload fairing.

"ULA is extremely proud to be a part of NASA's team for the GRAIL mission and we sincerely congratulate all of our mission partners," said Jim Sponnick, ULA vice president, Mission Operations. "Today's successful launch is the third NASA mission ULA has launched in just three months with two more to come in October and November. The timing and precision of this campaign along with a one-launch-at-a-time focus are testaments to our commitment to providing reliable and cost-effective space launch services to our customers."

Credit: United Launch Alliance/Thom Baur

posted September 10, 2011 10:56 AM               

GRAIL spacecraft on their way to the moon

Both GRAIL spacecraft, A and B — to be named through a contest to start soon — separated on schedule from the second stage of their Delta II rocket and are now flying to the moon.

All systems are working as expected. It will take the two spacecraft until New Year's Eve and New Year's Day to reach the moon.

The naming contest, which will be open to all U.S. schools, will begin accepting essay submissions Oct. 14 through Nov. 11.

posted October 03, 2011 05:06 PM               

NASA Invites Students To Name Moon-Bound Spacecraft

NASA has a class assignment for U.S. students: help the agency give the twin spacecraft headed to orbit around the moon new names.

The naming contest is open to students in kindergarten through 12th grade at schools in the United States. Entries must be submitted by teachers using an online entry form. Length of submissions can range from a short paragraph to a 500-word essay. The entry deadline is Nov. 11.

NASA's solar-powered Gravity Recovery And Interior Laboratory (GRAIL)-A and GRAIL-B spacecraft lifted off from Cape Canaveral Air Force Station, Fla. on Sept. 10 to begin a three-and-a-half-month journey to the moon. GRAIL will create a gravity map of the moon using two spacecraft that orbit at very precise distances. The mission will enable scientists to learn about the moon's internal structure and composition, and give scientists a better understanding of its origin. Accurate knowledge of the moon's gravity also could be used to help choose future landing sites.

"A NASA mission to the moon is one of the reasons why I am a scientist today," said GRAIL Principal Investigator Maria Zuber from the Massachusetts Institute of Technology (MIT) in Cambridge. "My hope is that GRAIL motivates young people today towards careers in science, math and technology. Getting involved with naming our two GRAIL spacecraft could inspire their interest not only in space exploration but in the sciences, and that's a good thing."

Zuber and former astronaut Sally Ride of Sally Ride Science in San Diego will chair the final round of judging. Sally Ride Science is the lead for GRAIL's MoonKAM program, which enables students to task cameras aboard the two GRAIL spacecraft to take close-up views of the lunar surface.

posted October 06, 2011 06:04 PM               

NASA's Moon Twins Going Their Own Way

NASA's Gravity Recovery And Interior Laboratory (GRAIL)-B spacecraft successfully executed its first flight path correction maneuver Wednesday, Oct. 5. The rocket burn helped refine the spacecraft's trajectory as it travels from Earth to the moon and provides separation between itself and its mirror twin, GRAIL-A. The first burn for GRAIL-A occurred on Sept. 30.

"Both spacecraft are alive and with these burns, prove that they're kicking too, as expected," said David Lehman, GRAIL project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "There is a lot of time and space between now and lunar orbit insertion, but everything is looking good."

GRAIL-B's rocket burn took place on Oct. 5 at 11 a.m. PDT (2 p.m. EDT). The spacecraft's main engine burned for 234 seconds and imparted a velocity change of 56.1 mph (25.1 meters per second) while expending 8.2 pounds (3.7 kilograms) of propellant. GRAIL-A's burn on Sept. 30 also took place at 11 a.m. PDT. It lasted 127 seconds and imparted a 31.3 mph (14 meters per second) velocity change on the spacecraft while expending 4 pounds (1.87 kilograms) of propellant.

These burns are designed to begin distancing GRAIL-A and GRAIL-B's arrival times at the moon by approximately one day and to insert them onto the desired lunar approach paths.

The straight-line distance from Earth to the moon is about 250,000 miles (402,336 kilometers). It took NASA's Apollo moon crews about three days to cover that distance. Each of the GRAIL twins is taking about 30 times that long and covering more than 2.5 million miles (4 million kilometers) to get there. This low-energy, high-cruise time trajectory is beneficial for mission planners and controllers, as it allows more time for spacecraft checkout. The path also provides a vital component of the spacecraft's single science instrument, the Ultra Stable Oscillator, to be continuously powered for several months, allowing it to reach a stable operating temperature long before beginning the collection of science measurements in lunar orbit.

GRAIL-A will enter lunar orbit on New Year's Eve, and GRAIL-B will follow the next day. When science collection begins, the spacecraft will transmit radio signals precisely defining the distance between them as they orbit the moon. Regional gravitational differences on the moon are expected to expand and contract that distance. GRAIL scientists will use these accurate measurements to define the moon's gravity field. The data will allow mission scientists to understand what goes on below the surface of our natural satellite.

posted December 28, 2011 01:50 PM               

NASA twin spacecraft on final approach for moon orbit

NASA's twin spacecraft to study the moon from crust to core are nearing their New Year's Eve and New Year's Day main-engine burns to place the duo in lunar orbit.

Named Gravity Recovery And Interior Laboratory (GRAIL), the spacecraft are scheduled to be placed in orbit beginning at 1:21 p.m. PST (4:21 p.m. EST) for GRAIL-A on Dec. 31, and 2:05 p.m. PST (5:05 p.m. EST) on Jan. 1 for GRAIL-B.

"Our team may not get to partake in a traditional New Year's celebration, but I expect seeing our two spacecraft safely in lunar orbit should give us all the excitement and feeling of euphoria anyone in this line of work would ever need," said David Lehman, project manager for GRAIL at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

The distance from Earth to the moon is approximately 250,000 miles (402,336 kilometers). NASA's Apollo crews took about three days to travel to the moon. Launched from Cape Canaveral Air Force Station Sept. 10, 2011, the GRAIL spacecraft are taking about 30 times that long and covering more than 2.5 million miles (4 million kilometers) to get there.

This low-energy, long-duration trajectory has given mission planners and controllers more time to assess the spacecraft's health. The path also allowed a vital component of the spacecraft's single science instrument, the Ultra Stable Oscillator, to be continuously powered for several months. This will allow it to reach a stable operating temperature long before it begins making science measurements in lunar orbit.

"This mission will rewrite the textbooks on the evolution of the moon," Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology (MIT) in Cambridge, said. "Our two spacecraft are operating so well during their journey that we have performed a full test of our science instrument and confirmed the performance required to meet our science objectives."

As of Dec. 28, GRAIL-A is 65,860 miles (106,000 kilometers) from the moon and closing at a speed of 745 mph (1,200 kph). GRAIL-B is 79,540 miles (128,000 kilometers) from the moon and closing at a speed of 763 mph (1,228 kph).

During their final approaches to the moon, both orbiters move toward it from the south, flying nearly over the lunar south pole. The lunar orbit insertion burn for GRAIL-A will take approximately 40 minutes and change the spacecraft's velocity by about 427 mph (688 kph). GRAIL-B's insertion burn 25 hours later will last about 39 minutes and is expected to change the probe's velocity by 430 mph (691 kph).

The insertion maneuvers will place each orbiter into a near-polar, elliptical orbit with a period of 11.5 hours. Over the following weeks, the GRAIL team will execute a series of burns with each spacecraft to reduce their orbital period from 11.5 hours down to just under two hours. At the start of the science phase in March 2012, the two GRAILs will be in a near-polar, near-circular orbit with an altitude of about 34 miles (55 kilometers).

When science collection begins, the spacecraft will transmit radio signals precisely defining the distance between them as they orbit the moon. As they fly over areas of greater and lesser gravity, caused both by visible features such as mountains and craters and by masses hidden beneath the lunar surface. they will move slightly toward and away from each other. An instrument aboard each spacecraft will measure the changes in their relative velocity very precisely, and scientists will translate this information into a high-resolution map of the Moon's gravitational field. The data will allow mission scientists to understand what goes on below the surface. 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.

JPL manages the GRAIL mission. MIT is home to the mission's principal investigator, Maria Zuber. The GRAIL mission is part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems in Denver built the spacecraft.

posted December 31, 2011 04:51 PM               

NASA's GRAIL-A in orbit around the moon

The first of NASA's two Gravity Recovery And Interior Laboratory (GRAIL) spacecraft, GRAIL-A, entered lunar orbit on New Year's Eve (Dec. 31, 2011), a day ahead of its twin.

"Pop the bubbly and toast the moon! NASA's GRAIL-A spacecraft is in lunar orbit," the agency's Jet Propulsion Laboratory (JPL) wrote on Twitter.

GRAIL-A fired its main thruster at 3:21 p.m. CST (2121 GMT) for 40 minutes, slowing its approach by 427 miles per hour (687 kilometers per hour). Engine cutoff and lunar orbit insertion was confirmed at 4:01 p.m. CST (2201 GMT).

"Burn complete! GRAIL-A is now orbiting the moon and awaiting the arrival of its twin GRAIL-B on New Year's Day," wrote JPL.

Launched aboard the same rocket on Sept. 10, 2011, GRAIL-A's mirror twin, GRAIL-B, is also closing the gap between itself and the moon. GRAIL-B is scheduled to perform its lunar orbit insertion burn on New Year's Day (Jan. 1, 2012) at 4:05 p.m. CST (2205 GMT).

As it will for GRAIL-B, GRAIL-A's insertion maneuver placed it into a near-polar, elliptical orbit with an orbital period of 11.5 hours. Over the following weeks, flight controllers will execute a series of burns with each spacecraft to reduce their period down to just under two hours.

At the start of the science phase in March 2012, the two GRAILs will be in a near-polar, near-circular orbit with an altitude of about 34 miles (55 kilometers).

When science collection begins, the spacecraft will transmit radio signals precisely defining the distance between them as they orbit the moon in formation. Regional gravitational differences on the moon are expected to expand and contract that distance. Scientists will use these accurate measurements to define the moon's gravity field.

The data will allow mission scientists to understand what goes on below the surface of the moon, providing more information about how it, the Earth and other terrestrial planets formed.

posted January 01, 2012 05:47 PM               

NASA's twin GRAIL spacecraft reunite in lunar orbit

The second of NASA's two Gravity Recovery And Interior Laboratory (GRAIL) spacecraft has successfully completed its planned main engine burn and is now in lunar orbit. Working together, GRAIL-A and GRAIL-B will study the moon as never before.

"NASA greets the new year with a new mission of exploration," said NASA Administrator Charles Bolden. "The twin GRAIL spacecraft will vastly expand our knowledge of our moon and the evolution of our own planet. We begin this year reminding people around the world that NASA does big, bold things in order to reach for new heights and reveal the unknown."

GRAIL-B achieved lunar orbit at 4:44 p.m. CST (2244 GMT) on New Year's Day (Jan. 1, 2012). GRAIL-A successfully completed its burn the day before, Dec. 31, 2011, at 4:01 p.m. CST (2201 GMT). The insertion maneuvers placed the spacecraft into a near-polar, elliptical orbit with an orbital period of approximately 11.5 hours.

Over the coming weeks, the GRAIL team will execute a series of burns with each spacecraft to reduce their orbital period to just under two hours. At the start of the science phase in March 2012, the two GRAILs will be in a near-polar, near-circular orbit with an altitude of about 34 miles (55 kilometers).

During GRAIL's science mission, the two spacecraft will transmit radio signals precisely defining the distance between them. 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.

Scientists will translate this information into a high-resolution map of the moon's gravitational field. The data will allow them to understand what goes on below the lunar surface. This information will increase knowledge of how Earth and its rocky neighbors in the inner solar system developed into the diverse worlds we see today.

Each spacecraft carries a small camera called GRAIL MoonKAM (Moon Knowledge Acquired by Middle school students) with the sole purpose of education and public outreach. 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.

GRAIL MoonKAM will engage middle schools across the country in the GRAIL mission and lunar exploration. Thousands of fifth- 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 GRAIL satellites for students to study.

A student contest that began in October 2011 chose new names for the spacecraft, which are scheduled to be announced this month. Ride and Maria Zuber, the mission's principal investigator at the Massachusetts Institute of Technology (MIT), chaired the final round of judging.

posted February 01, 2012 04:36 PM               

NASA Mission Returns First Video From Moon's Far Side

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.

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.

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.

posted March 08, 2012 07:50 AM               

NASA's Twin Grail Spacecraft Begin Collecting Lunar Science Data

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 8:15 p.m. EST (5:15 p.m. PST). During this mission phase, the spacecraft will transmit radio signals precisely defining the distance between them. 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, the distance between the two spacecraft will change slightly. 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)."

posted March 22, 2012 03:22 PM               

NASA'S Grail MoonKam Returns First Student-Selected Lunar Images

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 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 aboard the Ebb spacecraft from March 15-17 and downlinked to Earth on March 20.

"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."

Launched in September 2011, Ebb and Flow 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.