THE MOON

Twin Gravity Spacecraft Set to Enter Lunar Orbit

Dec. 30, 2011: NASA's twin GRAIL spacecraft, on a mission to study the moon's gravitational field, 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 into 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 2012 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 we need," said David Lehman,

project manager for GRAIL

at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

An artist's concept of the GRAIL spacecraft in action. [more]

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," said Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology (MIT) in Cambridge. "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."

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).

Click to download the GRAIL mission iPhone app

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.

For more information about GRAIL, visit: http://www.nasa.gov/grail

Production Editor: Dr. Tony Phillips | Credit: Science@NASA

THE ASTRONOMY PICTURE OF THE DAY FOR 2011 April 23

Shadows at the Lunar South Pole

Credit: NASA / GSFC / Arizona State Univ. / Lunar Reconnaissance Orbiter

Explanation: What is it? It's a multi-temporal illumination map, of course. To make it, the wide angle camera on the Lunar Reconnaissance Orbiter spacecraft collected 1,700 images over a period of 6 lunar days (6 Earth months), repeatedly covering an area centered on the Moon's south pole. Converted to binary values (shadowed pixels set to 0, illuminated pixels set to 1) the images were stacked to produce a map representing the percentage of time each spot on the surface was illuminated by the Sun. Remaining convincingly in shadow, the floor of the 19 kilometer diameter Shackleton crater is seen near the center of the map. The lunar south pole itself is at about 9 o'clock on the crater's rim. Since the Moon's axis of rotation stays almost perpendicular to the ecliptic plane, crater floors near the lunar south and north poles can remain in permanent shadow and mountain tops in nearly continuous sunlight.

Useful to future outposts, the shadowed crater floors could offer reservoirs of water ice, and the sunlit mountain tops ideal locations for solar power arrays.

THE ASTRONOMY PICTURE OF THE DAY FOR 2009 March 11

Lunar X

Credit & Copyright: Jerry Lodriguss (Catching the Light)

Explanation: The striking X near the center of this lunarscape is easily visible in binoculars or a small telescope. Yet, not too many have seen it. The catch is, this lunar X is only apparent during a four hour period just before the Moon's first quarter phase. At the terminator, or shadow line between lunar day and night, the X illusion is produced by a configuration of the craters Blanchinus, La Caille and Purbach. Near the Moon's first quarter phase, an astronaut standing close to the craters' position would see the slowly rising Sun very near the horizon. Temporarily, the crater walls would be in sunlight while the crater floors were still in darkness. Seen from planet Earth, contrasting sections of bright walls against the dark floors by chance look remarkably like an X. This sharp image of the Lunar X was captured at approximately 11:59 UT on March 3, 2009. The Moon's first quarter phase was at 7:46 UT on March 4.

THE ASTRONOMY PICTURE OF THE DAY FOR 2010 September 29

An Airplane in Front of the Moon

Credit & Copyright: Chris Thomas

Explanation: If you look closely at the Moon, you will see a large airplane in front of it. Well, not always. OK, hardly ever. But if you wait for days with your camera attached to a Moon tracker in a place where airplanes are known to pass, you might catch a good photograph of it. Well, if you're lucky. OK, extremely lucky. The above image was taken in mid-Sept 2010 over South East Queensland, Australia using an exposure time of 1/250th of a second and, in the words of the photographer, "a nerve of steel".

January 22nd, 2009

Has the Moon Changed Its Face?

Written by Nancy Atkinson

The moon's "near side" always faces Earth, because the moon spins once on its axis in precisely the same amount of time it takes to revolve around the Earth. But things could have been different billions of years ago. A computer analysis of the amount of craters on the different hemispheres of the Moon shows that the far side may have once been facing Earth. A large asteroid impact may caused the moon to change the way its faces Earth.

One consequence of the Moon being locked in a spin-orbit resonance of synchronous rotation is that more impacts should occur on the Moon's western hemisphere than the eastern, as that side would be facing into orbit, making it more likely to be hit by debris.

But Mark Wieczorek and Matthieu Le Feuvre at the Paris Institute of Earth Physics in France compared the relative ages of the craters, using data about the sequence in which ejected material was deposited on the surface, and they found the opposite to be true. Although the youngest impact basins were concentrated in the western hemisphere, as expected, the older craters were mostly congregated in the east. This suggests that the eastern face had once been bombarded more than the western face.

This could have happened if a large asteroid impact caused the moon to do an about face. The researchers estimate after the impact, the moon would have appeared to turn slowly as viewed from Earth, and slowly would have come into its current position.

In looking at several of the largest lunar impact basins, there are several suspects for impacts that could have temporarily unlocked the Moon from synchronous rotation.

"We show that there is less than a 2% probability that the oldest lunar impact basins are randomly distributed across the lunar surface," the researchers say. "Furthermore, these basins are preferentially located near the Moon's antapex of motion, and this configuration has less than a 0.3% probability of occurring by chance."

The team studied the relative age and distribution of 46 known craters. Wieczorek says the Chandrayaan-1 or Kaguya orbiters could provide information on more craters that would help in further research in this area.

For more information, see the abstract.

Sources: New Scientist

Obama Will Retire Shuttle in 2010 - US Will Go Back to the Moon in 2020

Written by Ian O'Neill --From UniverseToday.com

In a budget blueprint released by the White House on Thursday, President Barack Obama has confirmed his intent to carry out the planned retirement of the ageing Space Shuttle next year. Additionally, the the blueprint affirms Obama's stance on a return trip to the Moon. The US will return to the lunar surface by the year 2020, following the time scale set out by George W. Bush's 2004 Vision for Space Exploration. However, there is no mention that the next manned lunar mission will be carried out by the Constellation Program, a project plagued by criticism about its design and technology.

Although the blueprint may differ from the final budget submitted to Congress in April, it looks like there is some certainty about the future of the shuttle and the direction NASA will be taking over the next decade. And now the space agency has a little bit more money to do something about that troublesome 5-year gap in US manned access to space…

So, any hope to extend the life of the Shuttle looks to have been dashed. Although there could still be a chance for a shuttle extension when the final budget is submitted, it seems as if President Obama has made his intent very clear; the 25 year-old space launch system will be mothballed, as planned, in 2010. This may come as a relief to many as extending the operational lifetime of the shuttle could be a safety risk, however, many on Florida's Space Coast won't be so happy as they could be looking at losing their jobs sooner than they would have hoped.

Generally, these decisions have been welcomed, including the extra $2.4 billion NASA will receive for the 2010 fiscal year (when compared with 2008):

Combined with $1 billion provided to NASA in the $787 billion stimulus package signed into law Feb. 17, the agency would receive $2 billion more than in the $17.7 billion 2009 NASA budget that was passed by the House - an increase that equals an Obama campaign promise. — Florida Today

It remains uncertain how the gap between shuttle retirement and Constellation launch could be shortened from the minimum of five years, but the extra cash is bound to boost confidence. But where does the blueprint say Constellation is even part of the plan? It doesn't, sparking some media sources to point out that it remains a possibility that the Ares rocket system could be abandoned in favour of making the existing Atlas V or Delta IV rockets human rated. However, space policy specialists are advising not to read too much into the omission.

"The budget doesn't say a whole lot about any specific system," said John Logsdon, a space policy analyst at the National Air and Space Museum in Washington, DC. "I wouldn't interpret the absence of the words 'Constellation', 'Ares', and 'Orion' one way or another. That's really up to the the new management team, when it gets there."

After all, since the departure of Michael Griffin as NASA Administrator, the space agency has been without a leader. Acting NASA Administrator Christopher Scolese is currently at the helm, saying that the new budget "is fiscally responsible and reflects the administration's desire for a robust and innovative agency." Unfortunately the details about the use of Constellation may remain sketchy until the final budget is submitted.

This may be the case, but President Obama has obviously seen the merit in the original plans to get man back to the Moon by the year 2020, despite criticism from a guy who has actually stood on the Moon, Buzz Aldrin. In an "alternative" proposal for the future of NASA, Aldrin and two co-authors posted a draft of the "Unified Space Vision" on the National Space Society's website this week (Update: the draft has now been "Removed At Request of the Authors"), urging the administration not to mount an unnecessary lunar mission (been there, done that) and go straight for manned exploration of the asteroids and Mars. The Unified Space Vision, unfortunately, was probably too hard on NASA's accomplishments, saying that "post-Apollo NASA" has become a "visionless jobs-providing enterprise that achieves little or nothing," in developing a viable space transportation system. Many of the points raised are valid (and occasionally very tough), but would require a complete change in NASA's structure to accomplish. I doubt we'll see any radical changes being enacted any time soon.

So, we now have a pretty good idea as to what's going to happen to the shuttle next year; it looks like the plan to get the US back to the Moon by 2020 is still on and NASA has been given an extra $2 billion to play with. I hope they spend it wisely, perhaps on private space launch contracts?

THE ASTRONOMY PICTURE OF THE DAY FOR 2009 September 28

Water Discovered on the Moon

Credit: ISRO/NASA/JPL-Caltech/USGS/Brown U.

Explanation: Water has been discovered on the surface of the Moon. No lakes have been found, but rather NASA's Moon Mineralogy Mapper aboard India's new Chandrayaan-1 lunar orbiter radios back that parts of the Moon's surface absorb a very specific color of light identified previously only with water. Currently, scientists are trying to fit this with other facts about the Moon to figure out how much water is there, and even what form this water takes. Unfortunately, even the dampest scenarios leave our moon dryer than the driest of Earth's deserts. A fascinating clue being debated is whether the water signal rises and falls during a single lunar day. If true, the signal might be explainable by hydrogen flowing out from the Sun and interacting with oxygen in the lunar soil. This could leave an extremely thin monolayer of water, perhaps only a few molecules thick. Some of the resulting water might subsequently evaporate away in bright sunlight. Pictured above, the area near a crater on the far side of the Moon shows a relatively high abundance of water-carrying minerals in false-color blue. Next week, the new LCROSS satellite will release an impactor that will strike a permanently shadowed crater near the lunar south pole to see if any hidden water or ice sprays free there.

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January 23rd, 2009

Chandrayaan-1 Instrument Detects First X-ray Signature from Moon

Written by Nancy Atkinson

The X-ray instrument on board the Chandrayaan-1 spacecraft orbiting the moon was switched on and successfully detected its first X-ray signature from the moon. The C1XS X-ray camera, (pronounced like "kicks") detected the X-ray signal from a region near the Apollo landing sites on December 12th 2008 at 02:36 UT. The solar flare that caused the X-ray fluorescence was exceedingly weak, approximately 20 times smaller than the minimum C1XS was designed to detect, which is good news for the sensitivity of the instrument. "C1XS has exceeded expectations as to its sensitivity and has proven by its performance that it is the most sensitive X-ray spectrometer of its kind in history," said Ms. Shyama Narendranath, Instrument Operations Scientist at the Indian Space Research Organisation (ISRO).

The instrument will help map out the composition of the Moon in much greater detail than has ever been done, and could help settle a long-running debate about how the Moon formed.

The leading theory of how the Moon was created is that a Mars-sized object slammed into the Earth early in its history, creating our orbiting moon. A better accounting of the Moon's makeup is needed to solidify the theory.

A few other spacecraft, like Chandra have taken X-ray images of the moon, but X-ray imaging from Earth is impossible because our atmosphere cuts out X-rays from space.

The C1XS will work by looking at the X-rays from our sun that have been absorbed by atoms in the lunar soil, then re-emitted in such a way as to reveal the chemistry of the surface. The spectrometer is sensitive to magnesium, aluminium and silicon x-rays.

The X-ray camera collected 3 minutes of data from the Moon just as the flare started and the camera finished its observation. The signal reveals the X-ray fingerprint of a part of the lunar surface. As the mission continues, C1XS will build up a detailed picture of the ingredients that have gone into the Moon.

Barry Kellett, instrument scientist from the UK's Science and Technologies Facilities Council said, "Despite the small quantity of data, our initial analysis and modeling shows that C1XS has identified the chemistry of this area of the Moon."

The instrument was jointly developed by the UK's STFC Rutherford Appleton Laboratory and ISRO.

Professor Richard Holdaway, Director of STFC's Space Science and Technology Department, said, "We are thrilled that C1XS has started its mission so successfully and is exceeding expectations. This sophisticated instrument will not only help us better understand the origin of the Earth-Moon system but will ensure that the UK plays an important role in this international activity."

Source: STFC

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THE CLOSEST FULL MOON SINCE 1993 MARCH 8 OCCURRED ON

FRIDAY 2008 DECEMBER 12 at 4:39 PM EST JUST AFTER MOONRISE.

THE DISTANCE FROM EARTH WAS ONLY 221,559 MILES.

THE GREAT BELGIAN CALCULATING ASTRONOMER EXTRAORDINAIRE

JEAN MEEUS CELEBRATED HIS 80th BIRTHDAY ON THIS DAY

THE MAXIMUM APOGEE CAN REACH 406,720 KM AND THE MINIMUM PERIGEE CAN

BE AS SMALL AS 356,371 KM. ON 2008 DEC 12 PERIGEE WAS 356,566 KM AND

THEREFORE LARGER THAN SHOWN ABOVE WITH A PERIGEE OF 357,448 KM

(DIVIDE KILOMETERS BY 1.609344 TO GET MILES)

MOON PHOTO COMPARISONS IN 2008 ABOVE ARE BY BILL BRADLEY . THE DISTANCES IN KILOMETERS ARE 406,327 & 356,590

AND THE ANGULAR DIAMETERS ARE 29' 23.9" AND 33' 30.0" ON MAY 19 AND DECEMBER 12 RESPECTIVELY.

CLOSEST FULL MOON IN 2009 OCCURRED ON JAN 10 (222,431 MILES) AT 10:27PM EST.

THIS CLOSE FULL MOON COMBINED WITH THE SUN BEING CLOSEST TO THE EARTH AND

WITH THE SUN AND MOON BEING FAR FROM THE EQUATORIAL PLANE IN THE SKY

(CALLED THE CELESTIAL EQUATOR) HAS THE POTENTIAL OF CAUSING VERY HIGH TIDES.

THE SIMULTANEOUS CLOSENESS OF BOTH THE SUN AND MOON STRENGHTENS THE TIDAL FORCE WHILE THE SEPARATION OF THEIR POSITIONS AWAY FROM THE CELESTIAL EQUATOR MOVES THE TIDAL BULGE NEAR OUR LATITUDE. THE COMBINATION OF THESE FACTORS GIVES US WHAT ARE CALLED PROXIGEAN TIDES WHICH BECOME SIGNIFICANT IF A STORM ALSO OCCURS AT THE SAME TIME.

THE NEXT CLOSER FULL MOON THAN ON 2008 DEC 12

OCCURS ON 2016 NOV 14 - 221,531 MILES - 900 MILES CLOSER THAN IN 2009.

THE CLOSEST FULL MOON IN 2010 OCCURRED ON JAN 30 - 221,585 MILES - 1:18AM EST

ONLY 26 KM FARTHER THAN THE 2008 DEC 12 FULL MOON WAS.

VERY CLOSE FULL MOON OF 2010 JANUARY 29-30

The moon was full at 1:18 AM EST on January 30. Perigee occurred about

3 hours later at 4:04 AM EST and will only be 356,592.9 km from the

earth (221,576.5 miles).

There was an extraordinary close full moon on 1912 Jan 4 at 356,375.4 km.

Next closest full moon came on 1948 Jan 26 at 356,490.5 km.

Third closest full moon came on 1975 Feb 25 - 356,517 km.

Fourth closest full moon was on 1993 March 8 at 356,530.8 km.

Fifth closest full moon was on 1992 Jan 19 at 356,549.9 km.

Sixth one occurred on 1990 Dec 2 - 356,550.9 km

Seventh one was on 2008 Dec 12 - 356,565.7 km

2010 January 30 came in at 8th place at 356,593 km.

Next closer one about to occur is on 2011 March 19 at 356,575.0 km.

An even closer one in the future will occur on 2016 Nov 14 at 356,520.2 km.

2034 Nov 25 will have a still closer full moon at 356,445.7 km and

THE CLOSEST FULL MOON FOR THE ENTIRE 21st CENTURY will occur

on 2052 December 6 at a distance of only about 356,424 km.

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ASTRONOMY PICTURE OF THE DAY FOR 2008 December 12

Lick Observatory Moonrise

Credit & Copyright: Rick Baldridge

Explanation: As viewed from a well chosen location at sunset, October's gorgeous Full Moon rose behind Mount Hamilton, east of San Jose, California. Captured in this lovely telescopic view, historic Lick Observatory is perched on the mountain's 4,200 foot summit, observatory and rising Moon momentarily sharing the warm color of filtered sunlight. Of course, tonight Dec 12 those blessed with clear skies can also enjoy a glorious Full Moon. In fact, tonight's Moon reaches its full phase at 11:37 AM EST, within only a few hours of perigee, at 4;39 PM EST, the closest point in its elliptical orbit. The close approach really will make Dec 2008 Full Moon the largest Full Moon not only in 2008 but since 1993 March 8, even when it rises high above the horizon.