Student Alert: GRAIL Naming Contest – Essay Deadline November 11

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Student Alert ! – Here’s your once in a lifetime chance to name Two NASA robots speeding at this moment to the Moon on a super science mission to map the lunar gravity field. They were successfully launched from the Earth to the Moon on September 10, 2011. Right now the robots are called GRAIL A and GRAIL B. But, they need real names that inspire. And they need those names real soon. The goal is to “capture the spirit and excitement of lunar exploration”, says NASA – the US Space Agency.

NASA needs your help and has just announced an essay writing contest open to students in Grades K – 12 at schools in the United States. The deadline to submit your essay is November 11, 2011. GRAIL stands for “Gravity Recovery And Interior Laboratory.”

The rules state you need to pick two names and explain your choices in 500 words or less in English. Your essay can be any length up to 500 words – even as short as a paragraph. But, DO NOT write more than 500 words or your entry will be automatically disqualified.

Learn more about the GRAIL Essay Naming Contest here:

Read all the Official Contest Rules here:

Download the Naming Contest Submission Form here:

Students: NASA Wants You to Name that GRAIL !
Write an Essay and name these twin Lunar mapping satellites. NASA’s twin GRAIL A & B science probes are now streaking to the Moon and arrive on New Year’s Day 2012. This picture shows how they looked, mounted side by side, during launch preparations prior to blasting off for the Moon on Sept. 10, 2011 from Florida. Credit: Ken Kremer

The GRAIL A and B lunar spaceships are twins – just like those other awe inspiring robots “Spirit” and “Opportunity” , which were named by a 10 year old girl student and quickly became famous worldwide and forever because of their exciting science missions of Exploration and Discovery.They arrive in Lunar Orbit on New Year’s Day 2012.

Blastoff of twin GRAIL A and B lunar gravity mapping spacecraft on a Delta II Heavy rocket on Sept. 10 from Pad 17B Cape Canaveral Air Force Station in Florida at 9:08 a.m. EDT. Credit: Ken Kremer

And there is another way that students can get involved in NASA’s GRAIL mission.

GRAIL A & B are both equipped with four student-run MoonKAM cameras. Students can suggest targets for the cameras. Then the cameras will take close-up views of the lunar surface, taking tens of thousands of images and sending them back to Earth.

“Over 1100 middle schools have signed up to participate in the MoonKAM education and public outreach program to take images and engage in exploration,” said Prof. Maria Zuber of MIT.

Prof. Zuber is the top scientist on the mission and she was very excited to announce the GRAIL Essay Naming contest right after the twin spaceships blasted off to the Moon on Sep 10, 2011 from Cape Canaveral in Florida.

What is the purpose of GRAIL ?

“GRAIL simply put, is a ‘Journey to the Center of the Moon’,” says Dr. Ed Weiler, NASA Associate Administrator of the Science Mission Directorate in Washington, DC.

“It will probe the interior of the moon and map its gravity field by 100 to 1000 times better than ever before. We will learn more about the interior of the moon with GRAIL than all previous lunar missions combined. Precisely knowing what the gravity fields are will be critical in helping to land future human and robotic spacecraft. The moon is not very uniform. So it’s a dicey thing to fly orbits around the moon.”

“There have been many missions that have gone to the moon, orbited the moon, landed on the moon, brought back samples of the moon,” said Zuber. “But the missing piece of the puzzle in trying to understand the moon is what the deep interior is like.”

So, what are you waiting for.

Start thinking and writing. Students – You can be space explorers too !

Read Ken’s continuing features about GRAIL
GRAIL Lunar Blastoff Gallery
GRAIL Twins Awesome Launch Videos – A Journey to the Center of the Moon
NASA launches Twin Lunar Probes to Unravel Moons Core
GRAIL Unveiled for Lunar Science Trek — Launch Reset to Sept. 10
Last Delta II Rocket to Launch Extraordinary Journey to the Center of the Moon on Sept. 8
NASAs Lunar Mapping Duo Encapsulated and Ready for Sept. 8 Liftoff
GRAIL Lunar Twins Mated to Delta Rocket at Launch Pad
GRAIL Twins ready for NASA Science Expedition to the Moon: Photo Gallery

GRAIL Lunar Blastoff Gallery

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Check out our gallery of more thrilling launch photos of NASA’s twin GRAIL spacecraft departing Earth on Saturday, Sept. 10 at 9:08 a.m. EDT from Pad 17B at Cape Canaveral Air Force Station in Florida.

Although GRAIL’s liftoff was delayed a few days by excessively high upper level winds, it was well worth the wait and put on a spectacular show as the booster thundered away from Space Launch Complex 17. This Delta II rocket was almost certainly the last ever Delta to blastf off from the Florida Space Coast.

Blastoff of Delta II Heavy rocket and twin spacecraft on Sept. 10 from Pad 17B at Cape Canaveral at 9:08 a.m. EDT. View from Press Site 1. Credit: Alan Walters (awaltersphoto.com)

The GRAIL spacecraft continue to function well at the start of their nearly four month journey to the Moon wher they will map the moon gravity in unprecedented detail and provide new insight into the formation and evolution of the rocky bodies of the inner Solar System.

Sept. 10 Blastoff of Delta II and GRAIL gravity mappers. Credit: Ken Kremer (kenkremer.com)
Sept. 10 Blastoff of Delta II and GRAIL gravity mappers. Credit: Alan Walters (awaltersphoto.com)
Sept. 10 Blastoff of Delta II and GRAIL gravity mappers. Credit: Ken Kremer (kenkremer.com)
Sept. 10 Blastoff of Delta II and NASA’s GRAIL spacecraft. Credit: Alan Walters (awaltersphoto.com)
Sept. 10 Blastoff of Delta II and GRAIL gravity mappers. Credit: Ken Kremer
Credit: Alan Walters (awaltersphoto.com)
Credit: Alan Walters (awaltersphoto.com)
Credit: Alan Walters (awaltersphoto.com)
Credit: Alan Walters (awaltersphoto.com)
Credit: Alan Walters (awaltersphoto.com)
GRAIL and Delta II rocket soar to space on Sept 10 from Pad 17B at Cape Canaveral, Florida. Credit: Ken Kremer (kenkremer.com)

NASA GRAIL Launch Images

Read Ken’s continuing features about GRAIL
GRAIL Twins Awesome Launch Videos – A Journey to the Center of the Moon
NASA launches Twin Lunar Probes to Unravel Moons Core
GRAIL Unveiled for Lunar Science Trek — Launch Reset to Sept. 10
Last Delta II Rocket to Launch Extraordinary Journey to the Center of the Moon on Sept. 8
NASAs Lunar Mapping Duo Encapsulated and Ready for Sept. 8 Liftoff
GRAIL Lunar Twins Mated to Delta Rocket at Launch Pad
GRAIL Twins ready for NASA Science Expedition to the Moon: Photo Gallery

GRAIL Twins Awesome Launch Videos – A Journey to the Center of the Moon

Video caption: NASA’s twin GRAIL spacecraft blast off atop a Delta II Heavy booster at 9:08 a.m. EDT on Saturday, September 10, 2011 from Cape Canaveral, Florida, on a mission to explore the moon in unprecedented detail.

Be sure to check out these awesome launch videos showing the Delta II Heavy rocket blasting off with NASA’s GRAIL Lunar Gravity Mapper twins on a “Journey to the Center of the Moon” – as shot by NASA and others – on Sept. 10. from Pad 17 B at Cape Canaveral Air Force Station in Florida at 9:08 a.m. EDT.

Thus began a circuitous 3.5 month voyage from the Earth to the Moon culminating in lunar orbit arrival on New Year’s Eve and Day 2012.

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Liftoff of the $496 Million Gravity Recovery and Interior Laboratory (GRAIL) duo marked the last currently scheduled launch of a United Launch Alliance Delta II from Florida and also the last launch from Space Launch Complex 17. This was the 356th Delta launch overall since the first one in 1960. It was the 110th and final planned flight of a Delta II from Florida.

Watch the NASA GRAIL Launch Video as the 12 story Delta’s 1st stage liquid and solid engines ignite and the rocket’s explosive exhaust and fiery flames instantaneously and dramatically shoot out from below and are vented safely to the side through specially constructed flame ducts to protect the rocket.

Just after the 1 minute mark, the 6 ground lit solid rocket motors are jettisoned and dramatically tumble away from the first stage. Moment later comes the ignition of the three air-lit solid rocket motors.

This dramatic video was shot by Matt Travis of spacearium -from my viewing location with a hoard of photojournalists at Press Site 1 located inside Cape Canaveral Air Force Station.

Press Site 1 is just 1.5 miles away from Pad 17B. It offers the closest and best view of the mighty Delta II rocket which stands 128 feet tall and generates some 1.3 million pounds of liftoff thrust.

Watch this video for post-launch commentary from NASA’s Delta II Launch manager Tim Dunn from the Mission Director’s Center.

Dawn launch on September 27, 2007 by a Delta II Heavy rocket from Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer

The GRAIL Launch video below was taken from Jetty Park Pier, about 2.9 miles south of Pad 17B and shows a completely different perspective from across the waterway of Port Canaveral.

I watched the unforgettable launch of Dawn five years ago from Jetty Park Pier.

Jetty Park and the beaches along Cape Banaveral and Cocoa Beach have been the best place for the public to view Delta rocket launches.


Thousands of spectators lining the Florida Space Coast were absolutely thrilled to witness the historic launch of GRAIL on the final Delta II booster from Florida on a gorgeous morning.

GRAIL’s primary science objectives during the 82 day mission are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon and apply that to the other rocky bodies in our solar system.

Check this short NewBlast Video summary of GRAIL’s launch and objectives from Spaceflight Now

Many of NASA’s recent science missions have launched aboard Delta II rockets, including the outstandingly successful Spirit and Opportunity Mars rovers, Dawn Asteroid Orbiter, MESSENGER Mercury orbiter and Stardust and Deep Impact comet spacecraft.

Congratulations to everyone on the GRAIL team for a superb performance !

GRAIL A and B Lunar gravity mappers rocket to the moon atop a Delta II Heavy booster on Sept. 10 from Cape Canaveral, Florida. View to Space Launch Complex 17 gantry from Press Site 1
Credit: Ken Kremer (kenkremer.com)

Read Ken’s continuing features about GRAIL
NASA launches Twin Lunar Probes to Unravel Moons Core
GRAIL Unveiled for Lunar Science Trek — Launch Reset to Sept. 10
Last Delta II Rocket to Launch Extraordinary Journey to the Center of the Moon on Sept. 8
NASAs Lunar Mapping Duo Encapsulated and Ready for Sept. 8 Liftoff
GRAIL Lunar Twins Mated to Delta Rocket at Launch Pad
GRAIL Twins ready for NASA Science Expedition to the Moon: Photo Gallery

NASA launches Twin Lunar Probes to Unravel Moons Core

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NASA renewed its focus on ground breaking science today with the thunderous blastoff of a pair of lunar bound spacecraft that will map the moons interior with unparalled precision and which will fundamentally alter our understanding of how the moon and other rocky bodies in our solar system – including Earth – formed and evolved over 4.5 Billion years.

Today’s (Sept. 10) launch of the twin lunar Gravity Recovery and Interior Laboratory (GRAIL) spacecraft atop the mightiest Delta II rocket from Cape Canaveral Air Force Station in Florida at 9:08 a.m. EDT was a nail biter to the end, coming after a two day weather delay due to excessively high upper level winds that scrubbed the first launch attempt on Sept. 8, and nearly forced a repeat cancellation this morning.

Liftoff of the nearly identical GRAIL A and B lunar gravity mappers from Space Launch Complex 17B took place on the second of two possible launch attempts after the first attempt was again waived off because the winds again violated the launch constraints.

GRAIL A and B gravity mappers rocket to the moon atop a Delta II Heavy booster on Sept. 10 from Cape Canaveral, Florida. View to Space Launch Complex 17 gantry from Press Site 1.

Credit: Ken Kremer (kenkremer.com)


After the final “GO” was given, the Delta II Heavy booster suddenly roared to life and put on a spectacular show spewing smoke, flames and ash as it pushed off the pad and shot skywards atop a rapidly growing plume of exhaust and rumbling thunder into a nearly cloudless sky.

The solar powered dynamic duo were propelled to space by the last ever Delta II rocket slated to depart Earth from Cape Canaveral, Florida. After more than 50 years of highly reliable service starting in 1960, the venerable Delta II family will be retired after one final launch in October from Vandenberg Air Force Base in California.

GRAIL and Delta II rocket soar to space.
View to Space Launch Complex 17 Pad A & Pad B (right) from Press Site 1. Credit: Ken Kremer

On this special occasion the media were allowed to a witness the launch from Press Site 1 – a location just 1.5 miles away from the pad with a gorgeous and unobstructed view to the base of the pad which magnified the tremendous roar of the rocket engines.

“Since the earliest humans looked skyward, they have been fascinated by the moon,” said GRAIL principal investigator Maria Zuber from the Massachusetts Institute of Technology in Cambridge. “GRAIL will take lunar exploration to a new level, providing an unprecedented characterization of the moon’s interior that will advance understanding of how the moon formed and evolved.”

Delta II arcs over atop long exhaust plume casting shadow for long lunar journey. Credit: Ken Kremer

The spacecraft separation and deployment of the solar arrays worked exactly as planned, the mission team reported at a post launch briefing for reporters. Both probes are power positive and healthy.

GRAIL A and B are now speeding towards the moon on a low energy path that will take about 3.5 months compared to just three days for the Apollo astronauts. The slower and longer path covering more than 2.5 million miles (4 million kilometers) enables the spacecraft to use a smaller engine and carry less fuel for the braking maneuver required to place the probes into a polar elliptical orbit when they arrive at the moon about 25 hours apart on New Year’s Eve and New Year’s Day 2012.

“Our GRAIL twins have Earth in their rearview mirrors and the moon in their sights,” said David Lehman, GRAIL project manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. “The mission team is ready to test, analyze and fine-tune our spacecraft over the next three-and-a-half months on our journey to lunar orbit.”

During the 82 day science phase, the primary objective of is to study the moons interior from crust to core and map its gravity field by 100 to 1000 times better than ever before. GRAIL A and GRAIL B will fly in tandem formation in near circular polar orbit at an altitude of some 50 km above the lunar surface as the moon rotates beneath three times.

GRAIL lunar twins depart Earth for the Moon
All 3 Air-lit solids have ignited after all 6 ground lit solids have been jettisoned.Credit: Ken Kremer

The mission will provide unprecedented insight into the structure and composition of moon from crust to core, unlock the mysteries of the lunar interior and advance our understanding of the thermal evolution of the moon that can be applied to the other terrestrial planets in our solar system, including Mercury, Venus, Earth and Mars.

Read Ken’s continuing features about GRAIL
GRAIL Unveiled for Lunar Science Trek — Launch Reset to Sept. 10
Last Delta II Rocket to Launch Extraordinary Journey to the Center of the Moon on Sept. 8
NASAs Lunar Mapping Duo Encapsulated and Ready for Sept. 8 Liftoff
GRAIL Lunar Twins Mated to Delta Rocket at Launch Pad
GRAIL Twins ready for NASA Science Expedition to the Moon: Photo Gallery

GRAIL Unveiled for Lunar Science Trek — Launch Reset to Sept. 10

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NASA’s Gravity Recovery and Interior Laboratory (GRAIL) moon mapping twins and the mighty Delta II rocket that will blast the high tech physics experiment to space on a lunar science trek were magnificently unveiled in the overnight darkness in anticipation of a liftoff that had originally been planned for the morning of Sept. 8.

Excessively high upper level winds ultimately thwarted Thursday’s launch attempt.

NASA late today has just announced a further postponement by another day to Saturday Sept. 10 to allow engineers additional time to review propulsion system data from Thursday’s detanking operation after the launch attempt was scrubbed to Friday. Additional time is needed by the launch team to review the pertinent data to ensure a safe blastoff of the $496 Million GRAIL mission.

There are two instantaneous launch opportunities at 8:29:45 a.m. and 9:08:52 a.m. EDT at Cape Canaveral, eight minutes earlier than was planned on Sept. 8. The weather forecast for Sept. 10 still shows a 60 percent chance of favorable conditions for a launch attempt.

GRAIL A and B enclosed in nose cone atop Delta II rocket at Cape Canaveral, Florida. Umbilical’s connect from Delta 2 to Fixed Umbilical Tower (FUT).
Credit: Ken Kremer (kenkremer.com)

Despite a rather poor weather prognosis, the heavy space coast cloud cover had almost completely cleared out in the final hours before launch, the surface winds were quite calm and we all expected to witness a thunderous liftoff. But measurements from weather balloons sent aloft indicated that the upper level winds were “red” and violated the launch criteria.

Mobile Service Tower is retracted from around Delta II rocket at Pad 17B. Credit: Ken Kremer

As the launch gantry was quickly retracted at Launch Complex 17B on Sept. 7, the Delta was bathed in xenon spotlights that provided a breathtaking light show as the service structure moved a few hundred feet along rails.

The cocoon like Mobile Service Tower (MST) provides platforms to access the rocket at multiple levels to prepare the vehicle and spacecraft for flight. The MST also protects the rocket from weather and impacts from foreign debris.

The GRAIL A and B mirror image twins ride side by side to space atop the Delta rocket. The washing machine spacecraft weigh about 677 pounds (307 kg) each.

The Delta II rocket stands 128 feet tall and is 8 feet in diameter. The first stage liquid and solid rocket fueled engines will generate about 1.3 million pounds of thrust.

During the Terminal Countdown, the first stage is fueled with cryogenic liquid oxygen and highly refined kerosene (RP-1).

GRAIL is an extraordinary first ever journey to the center of the moon that will — with its instruments from orbit — peer into the moons interior from crust to core and map its gravity field by 100 to 1000 times better than ever before. The mission employs two satellites flying in tandem formation some 50 km in near circular polar orbit above the lunar surface.

GRAIL A and B will perform high precision range-rate measurements between them using a Ka-band instrument. The mission will provide unprecedented insight into the formation and thermal evolution of the moon that can be applied to the other rocky planets in our solar system: Mercury, Venus, Earth and Mars.

After a 3.5 month journey to the moon, the probes will arrive about a day apart on New Year’s Eve and New Year’s Day 2012 for an 82 day science mapping phase as the moon rotates three times beneath the GRAIL orbit.

Photojournalists watch as Mobile Service Tower is retracted from around Delta II rocket at Pad 17B.
Credit: Ken Kremer

Xenon spotlights bathe Delta II rocket as Mobile Service Tower is retracted at Pad 17 and photojournalists watch from nearby at Pad 17B. Credit: Ken Kremer

Read Ken’s continuing features about GRAIL
Last Delta II Rocket to Launch Extraordinary Journey to the Center of the Moon on Sept. 8
NASAs Lunar Mapping Duo Encapsulated and Ready for Sept. 8 Liftoff
GRAIL Lunar Twins Mated to Delta Rocket at Launch Pad
GRAIL Twins ready for NASA Science Expedition to the Moon: Photo Gallery

Last Delta II Rocket to Launch Extraordinary Journey to the Center of the Moon on Sept. 8

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Another American rocket Era is about to end. The venerable Delta II rocket, steeped in history, will fly what is almost certainly its final mission from Cape Canaveral. And it will do so quite fittingly by blasting twin satellites to the moon for NASA on a unique path for a truly challenging mission to do “extraordinary science”.

On Sept. 8, the most powerful version of the Delta II, dubbed the Delta II Heavy, is slated to launch NASA’s duo of GRAIL lunar mappers on an unprecedented science mission to unlock the mysteries of the moons deep interior. There are two instantaneous launch windows at 8:37:06 a.m. and 9:16:12 a.m. EDT lasting one second each.

GRAIL simply put, is a journey to the center of the moon,” said Ed Weiler, NASA Associate Administrator of the Science Mission Directorate in Washington,DC at a pre-launch briefing for reporters on Sept. 6.

“It will probe the interior of the moon and map its gravity field by 100 to 1000 times better than ever before. We will learn more about the interior of the moon with GRAIL than all previous lunar missions combined.”

View of Delta II rocket looking out to Atlantic Ocean from upper level of Launch Complex 17. ULA and GRAIL logos painted on side of 8 ft diameter Delta rocket. Credit: Ken Kremer

GRAIL will depart Earth from Space Launch Complex 17B (SLC-17B) at Cape Canaveral Air Force Station, Florida, which is also the last scheduled use of Pad 17B.

GRAIL logo painted on the side of Delta II Rocket 1st Stage. Photo taken from inside upper level of launch gantry. GRAIL stands for Gravity Recovery and Interior Laboratory. Credit: Ken Kremer

“Trying to understand how the moon formed, and how it evolved over its history, is one of the things we’re trying to address with the GRAIL mission,” says Maria Zuber, principal investigator for GRAIL from the Massachusetts Institute of Technology. “But also, (we’re) trying to understand how the moon is an example of how terrestrial planets in general have formed.”

“GRAIL is a mission that will study the inside of the moon from crust to core,” Zuber says.

Delta II Heavy rocket is augmented by 9 wider diameter solid rocket motors providing more thrust. Credit: Ken Kremer

So far there have been 355 launches of the Delta II family, according to NASA’s Delta II Launch Manager Tim Dunn. The Delta II is built by United Launch Alliance.

“GRAIL is the last contracted Delta II mission to be launched from Complex 17. And it will be the 356th overall Delta to be launched. Complex 17 at the Cape has a proud heritage of hosting 258 of those 355 total Delta launches to date.

Hypergolic propellants have been loaded onto the 2nd stage after assessing all the preparations for the rocket, spacecraft, the range and facilities required for launch.

“The Launch Readiness Review was successfully completed and we can proceed with the countdown,” said Dunn.
The Delta II Heavy is augmented with nine larger diameter ATK solid rocket motors.

The Mobile Service Tower will be rolled back from the Delta II rocket tonight, starting at about 10:30 p.m. EDT depending on the weather.

The weather forecast for launch remains very iffy at a 60% percent chance of “NO GO” according to NASA and Air Force officials.

A launch decision will be made tomorrow morning Sept. 8 right after the weather briefing but before fueling begins at 6:30 a.m.

The weather forecast for rollback of the Mobile Service Tower tonight remains generally favorable. There is a 40% chance of a weather issue at 10:30 p.m. which drops to 30% after midnight. Tower rollback can be pushed back about 2 hours without impacting the countdown, says NASA.

Weather remains at 60% NO GO in case of a 24 hour delay but improves over the weekend. The team has about 42 days time in the launch window.

After entering lunar orbit, the two GRAIL spacecraft will fly in a tandem formation just 55 kilometers above the lunar surface with an average separation of 200 km during the three month science phase.

Stay tuned to Universe Today for updates overnight leading to liftoff at 8:37 a.m.

See my photo album from a recent tour of Launch Complex 17 and the Mobile Service Tower

GRAIL Flying in Formation. Using a precision formation-flying technique, the twin GRAIL spacecraft will map the moon's gravity field. The mission also will answer longstanding questions about Earth's moon, including the size of a possible inner core, and it should provide scientists with a better understanding of how Earth and other rocky planets in the solar system formed. GRAIL is a part of NASA's Discovery Program.

Read Ken’s continuing features about GRAIL

NASAs Lunar Mapping Duo Encapsulated and Ready for Sept. 8 Liftoff
GRAIL Lunar Twins Mated to Delta Rocket at Launch Pad
GRAIL Twins ready for NASA Science Expedition to the Moon: Photo Gallery

NASAs Lunar Mapping Duo Encapsulated and Ready for Sept. 8 Liftoff

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NASA’s powerful lunar mapping duo of GRAIL spacecraft are now poised for liftoff in just one weeks time on Thursday, Sept. 8.

Mission managers held a Flight Readiness Review on Wednesday (Aug.31) and gave a tentative approval to begin fueling the Delta II rockets second stage on Sept. 2 and 3 after evaluating all issues related to the rocket, launch pad and payloads.

Launch preparations are proceeding on schedule towards an early morning lift off from the seaside Space Launch Complex 17B (SLC-17B) at Cape Canaveral Air Force Station, Florida. There are two instantaneous launch windows at 8:37:06 a.m. and 9:16:12 a.m. EDT lasting one second each.

“Launch vehicle and spacecraft closeouts will begin on Tuesday, and the Launch Readiness Review is also scheduled for Tuesday morning,” NASA KSC spokesman George Diller told Universe Today.

“This morning’s launch countdown dress rehearsal went fine.”

“Delta II 2nd stage fueling has been rescheduled for Friday and Saturday [Sept. 2 and 3]. Last evening a software error was found in the launch processing system data base. ULA (United Launch Alliance) decided they would like to look for any additional errors before the fueling begins. There is no impact to the launch date and currently no work is scheduled on Sunday or on Labor Day,” said Diller.

The launch period extends through Oct. 19, with liftoff occurring approximately four minutes earlier each day in case of a delay. The flight plan was designed to avoid a pair of lunar eclipses occurring on December 10th, 2011 and June 4th 2012 which would interfere with the missions operations and science.

The team is keeping a close watch on the weather as the season’s next Atlantic Ocean storm heads westwards. Katia has just been upgraded to Hurricane status and follows closely on the heels of the continuing vast destruction, misery and deaths caused by Hurricane Irene earlier this week.

“The preliminary weather forecast is favorable for launch day as long as the wind remains out of the west as is currently forecast for that time of the morning,” Diller told me.

Twin GRAIL Lunar Mappers are secured atop Delta II rocket and await enclose in the Delta payload fairing. The fairing will protect the spacecraft from the impact of aerodynamic pressure and heating during ascent and will be jettisoned once the spacecraft is outside the Earth's atmosphere. Credit: NASA/Jim Grossmann

The twin probes known as GRAIL-A and GRAIL-B (Gravity Recovery and Interior Laboratory) were encapsulated inside the clamshell like payload fairing on Aug. 23 The nearly identical spacecraft are mounted side by side and sit atop the Centaur upper stage.

The fairing shields the spacecraft from aerodynamic pressures, friction and extreme heating for the first few minutes of flight during ascent through the Earth atmosphere.

This Delta II Heavy booster rocket is the most powerful version of the Delta II family built by ULA. The booster’s first stage is augmented with larger diameter solid rocket motors.

GRAIL was processed for launch inside at the Astrotech payload processing facility in Titusville, Fla. See my GRAIL spacecraft photos from inside the Astrotech clean room facilities here.

“The GRAIL spacecraft inside the handling can departed Astrotech and arrived at the launch pad, SLC-17B on Aug. 18” said Tim Dunn, NASA’s Delta II Launch Director in an interview with Universe Today. “The spacecraft was then hoisted by crane onto the Delta II launch vehicle and the spacecraft mate operation was flawlessly executed by the combined ULA and NASA Delta II Team.”

An Integrated Systems Test (IST) of the mated booster and payload was completed on Aug. 22

Technicians prepare twin GRAIL spacecraft for enclosure in the Delta payload fairing. Credit: NASA/Jim Grossmann

The dynamic duo will orbit the moon in a tandam formation just 50 kilometers above the lunar surface with an average separation of 200 km. During the 90 day science phase the goal is to determine the structure of the lunar interior from crust to core and to advance understanding of the thermal evolution of the moon.

GRAIL-A & GRAIL-B will measure the lunar gravity field with unprecedented resolution up to 100 times improvement on the near side and 1000 times improvement for the far side.

NASA’s twin GRAIL Science Probes ready for Lunar Expedition
GRAIL B (left) and GRAIL A (right) spacecraft are mounted side by side on top of a payload adapter inside the clean room at Astrotech Space Operations facility. The spacecraft await lunar launch on Sept. 8, 2011. Credit: Ken Kremer

Read Ken’s continuing features about GRAIL

GRAIL Lunar Twins Mated to Delta Rocket at Launch Pad
GRAIL Twins ready for NASA Science Expedition to the Moon: Photo Gallery