Friday, November 29, 2013

Chang'e-3 launch window opens 1 December 1730 UT

CCTV video still, released August 2013, shows final tests and loading of China's Chang'e-3, the third mission of China's Lunar Exploration Program [CCTV/CNSA].
Joel Raupe 
Lunar Pioneer
The China National Space Administration (CNSA) Lunar Exploration Program (CLEP) is gearing up for a nighttime launch of it's third unmanned lunar mission, Chang'e-3, Sunday, December 1 (UT), the first of a series of launch windows beginning 1730 UT, December 1; early Monday morning, December 2, at 1:30 am in Beijing.

Chang'e-3 will be launched aboard a modified Long March 3B booster from Xichang Satellite Launch Center, Suchuan Provence. The long-stated goal of the mission is to perform China's first soft-landing beyond Earth and the first such landing on the Moon in the 21st century, the first since the Soviet mission Luna 24 landed and retrieved a sample from Mare Crisium in 1976.

Presuming a successful launch, early Monday local time, Chang'e-3 will land on the Moon as early as Saturday, December 14, or about 30 hours after local sunrise at the targeted landing zone in Sinus Iridum. A landing early into the two-week-long lunar day will allow the mission to take full advantage of its designed use of solar power.

Sunrise at the intended landing zone, in the vicinity of Laplace A crater (43.74°N, 26.935°W), will begin in the early hours of December 12 (UT).

The mission is also designed to deploy the first remote-operated lunar rover on the lunar surface since the Soviet Luna 21 lander deployed Lunokhod-2 and explored Le Monnier crater in 1973. 

Following a national naming contest with 650,000 online participants, China state news sources report the Chang'e-3 lunar rover has been named Yutu, (Jade Rabbit), after the traditional ethereal attendant to the lunar goddess Chang'e.

Tasks for Yutu include "surveying the moon's geological structure and surface substances while looking for natural resources," said Ouyang Ziyuan, a chief scientist of CLEP, in an interview with Xinhua ("China's lunar probe to land on Moon next month," Mo Hong'e, November 26,

A detailed summary of the planned landing zone for the Chang'e-3 mission, near Laplace A crater in east Sinus Iridum, was posted HERE, a discussion written by Lunar Reconnaissance Orbiter Camera (LROC) principal investigator Dr. Mark Robinson of Arizona State University, released November 22.

In cooperation with the International Lunar Observatory Association (ILOA) in Hawaii, an ultra-violet telescope will be operated from the Chang'e-3 lander, a first since a small UV instrument was operated on the Moon by the Apollo 16 expedition in 1972.

China's Lunar Exploration Program, initiated in 2004, consists of five planned missions. Chang'e-1 became that nation's first lunar orbiter November 5, 2007 and was deorbited to a reportedly planned impact in Mare Fecunditatis, March 1, 2009.

The highly-successful Chang'e-2 orbiter was launched from Xichang, October 1, 2009 and was inserted into lunar orbit five days later. Chang'e-2 captured orbital photography later assembled into a global, low-angle illumination mosaic of the Moon, said to be the first of its kind. 

While performing orbital maneuvers critical to the planned Chang'e-3 landing in Sinus Iridum, Chang'e-2 captured high-resolution low-perilune photography of Laplace A crater and its vicinity.

Chang'e-2 was afterward maneuvered beyond Cislunar space, leaving lunar orbit  June 9, 2011. Ground controllers moved the spacecraft to an extended stay in and around Lagrangian Point 2 (L2), one of five stable points in the Earth-Moon-Sun system where the influences of the gravity of the three bodies balance each other out. 

L2 space is beyond the Moon, more or less directly over the farside, and it presumably where communications with surface missions beyond line-of-sight of Earth could be at least partially maintained.

4179 Toutatis Chang'e-2 flyby
Chang'e-2 passed to within 3.2 km of the potentially hazardous asteroid 4179 Toutatis in December 2012, traveling at a relative speed of 11.72 kilometers per second [CNSA/Xinhua].
Still underway, having departed L2 for interplanetary space, Chang'e-2 recently returned photographs of its recent very close encounter with potentially hazardous asteroid 4179 Toutatis, December 13, 2012.

After Chang'e-3, China plans at least two additional unmanned lunar missions designed to retrieve samples, Chang'e 4 in 2015 and Chang'e 5 in 2018.

Related Posts:
'Government Penalty' removed from Google Lunar XPRIZE terms (November 7, 2013)
Chang'e-3 and LADEE: The Role of Serendipity (October 31, 2013)
Outstanding animation celebrates China's Chang'e-3 (October 29, 2013)
LROC updates image tally of human artifacts on the Moon (September 25, 2013)
Chang'e-3 officially enters launch phase (August 31, 2013)
Chang'e-3 undergoing thermal vacuum testing (May 9, 2013)
Chang'e-3: China's rover mission (May 4, 2013)
Chang'e-3 lander and rover expected in 2013 (January 10, 2013)
China's grand plan for lunar exploration (October 11, 2012)
ILOA to study deep space from Chang'e-3 (September 11, 2012)
Will China deploys first lunar rover since 1976? (April 29, 2012)
China's Long March to the Moon (January 14, 2012)
China plans lunar research base (May 11, 2011)
PRC continues methodical program (March 8, 2011)
Chang'e-2 arrives in mission orbit (October 9, 2010)
Dispatch from Chang'e-2: Sinus Iridum (October 4, 2010)
Chang'e-2 takes direct approach (October 1, 2010)
Chang'e-2 sets stage for future lunar missions (September 3, 2010)
Chang'e-1 research reported published (July 22, 2010)

Thursday, November 28, 2013

Excavation of a Thin Dark Layer in Hertzsprung

Eastern rim of an unnamed young crater. LROC NAC M156102528L; image center 4.072°S, 227.294°E; image width is 590 m; incidence angle is 7.2°, illuminated from right side [NASA/GSFC/Arizona State University].
Hiroyuki Sato
LROC News System

Today's Featured Image highlights the eastern rim of an unnamed young crater (about 6.8 km in diameter), observed in the farside highlands, 218 km southwest from the center of Hertzsprung crater (587 km in diameter). The higher reflectance area (left side of image) is the crater wall inside the crater cavity, and the low reflectance area (right side of image) is the outer surface of the crater, covered by a layer of dark impact melt deposits (see next NAC context view). The low incidence angle (Sun overhead, 7.2° from vertical) enhances the strong reflectance contrast between the fresh anorthosite-rich outcrops on the crater wall and fresh impact melt rocks on the crater exterior. During the cratering process, impact melt was ejected from the crater and placed on the crater exterior, forming a thin layer, or veneer, which solidified into solid rock as it cooled.

A NAC context view, highlighting the impact melts along northeastern rim of the unnamed crater. Blue box indicates the location of the LROC Featured Image, released November 27, 2013 [NASA/GSFC/Arizona State University].
Full 5.4 km-wide field of view from full-width mosaic of the left and right frames from LROC Narrow Angle Camera (NAC) observation M156102528RL, LRO orbit 8138, March 30, 2011; angle of incidence 7.23° at 59 cm per pixel resolution from 56.8 km [NASA/GSFC/Arizona State University].

As the crater wall collapses with time, the exterior melt veneer is fractured and collapses into the crater, as seen in the center of the opening image. From the very narrow shadows (2~3 pixels) along the boundaries between the melt layer and the crater wall, the thickness of the melt sheet can be roughly estimated to be 9 to 14 m. The thickness of the impact melt deposits near the crater rim crest is controlled by the viscosity of the melt and local slopes. In addition, melt splashing out of the crater with a high ejection velocity may form thinner melt veneer deposits. High resolution NAC images allow us to examine the changes in melt thickness as impact melt flowed away from the crater, telling part of the story of the spectacular moment of this impact cratering event.

Synoptic view of the unnamed young crater and surrounding areas in LROC WAC monochrome mosaic (100 meters/pixel), centered on 2.07°S, 113.88°W. The NAC footprint (blue box) and the location of opening image (yellow arrow) are illustrated [NASA/GSFC/Arizona State University].
Explore the fresh impact melt sheet around this unnamed young crater in full NAC frame yourself, HERE.

Related Posts:
Fractured Melt Rock
Hole on A Melt Sheet
Dark Impact Melt Sheet
Splash and flow

Orthographic projection (Color-shaded LROC WAC-derived digital terrain model) explicitly shows the location of the aforementioned 'unnamed crater,' between the peak rings of Hertzsprung crater [NASA/GSFC/Arizona State University].

Sunday, November 24, 2013

JFK and the Moon

John Kennedy and Werner VonBraun 1963
Dr. Wernher Von Braun with President John Kennedy at the U.S. Army Redstone Arsenal in 1963, "feigning interest?"
Paul D. Spudis
The Once and Future Moon
Smithsonian Air & Space

The 50th anniversary of the tragic death of President John F. Kennedy has prompted examination of his presidential legacies and in particular, the role he played in our race to the Moon.  In an op-ed, Rand Simberg opines on how space buffs magnify and distort Kennedy’s space legacy – that in fact, JFK really didn’t care one whit for spaceflight and only challenged the Soviets to a Moon race for near-term, earthly political purposes.

No one conversant with the history of the Apollo program could seriously doubt that the impetus for setting the goal of a lunar landing within a decade was driven primarily by geopolitical considerations, rather than by a romantic notion of colonizing the Solar System.  But there’s a bit more to the story.  Simberg’s piece fails to recognize that close, hands-on experience with the unfamiliar often changes attitudes and that prejudices evolve over time.

Upon taking office, Kennedy had little interest in the space program but like Eisenhower with Sputnik, intervening events abruptly forced a change in his outlook.  In April 1961 Yuri Gagarin orbited the Earth  – the first flight of a human in space – engulfing Kennedy in a press feeding frenzy as a triumphant Soviet Union laid claim to one of the most important laurels of the space age.  With recriminations still echoing throughout Washington, a second national security disaster emerged – the Bay of Pigs fiasco, a failed invasion of Cuba by American-sponsored anti-Castro exiles.  The new administration appeared both inept and indecisive.  The Gagarin space flight and the U.S.-backed invasion of Cuba occurred during the build-up of a devastating nuclear arsenal by the Soviet Union, amid bellicose pronouncements from its bombastic leader, Nikita Sergeivich Khrushchev – “We will bury you!”

Khrushchev and Kennedy, Vienna 1961
June 3, 1961 - only two months following the Gagarin's pioneering orbital flight, and less than a month after Alan Shepard's 15 minute suborbital ride, President John Kennedy meets with Soviet Chairman Nikita Khrushchev at the U. S. Embassy residence, Vienna, Austria [Deptartment of State/John Fitzgerald Kennedy Library, Boston].
Against this high-temperature political background, Kennedy looked for a significant technical project with which to challenge the Soviets.  Kennedy thought that the large-scale desalination of seawater would help win the hearts of emerging “Third World” nations.  A key consideration was choosing an effort that the Soviets could not win in the next few years.  True enough, space was not his original choice but in order to give the United States enough time to build up and use its industrial and technical might (as well as provide payback on politically realistic timescales), Kennedy needed a challenging long-term national goal.

By assigning his Vice-President Lyndon Baines Johnson to look into possible space projects and report back to him, Kennedy had placed the decision in the hands of someone already committed to an accelerated and vigorous space effort.  As Senate Majority Leader, Johnson – a vocal advocate for large-scale space projects – had previously helped shepherd the 1958 Space Act (that created NASA) though the Congress.  It was Johnson who asked NASA’s James Webb and Hugh Dryden for options.

In a memo to Johnson, Kennedy specifically asked,  “Is there a space program we can undertake and win?”   With Johnson’s committee working closely with Wernher von Braun on what was technically possible in the near- and far-terms, it became apparent that the Soviets had a clear advantage in rocket boosters, making any attempt to match Soviet space accomplishments in low Earth orbit within the next few years likely to fail.  On the other hand, if the U.S. were to pick a goal which neither country could achieve in the near-term, America’s edge in technology and resources might give them enough of an advantage to win in the long run – making it a real race.

A manned mission to the Moon emerged as the logical goal and was duly reported to the President.  Kennedy was willing but hesitant – initial cost estimates for Apollo were on the order of $40 billion (this was in a saner fiscal era, when a billion dollars meant real money).  Committing to spend that much, while not unprecedented, would give politicians of any stripe pause.  Nonetheless, Kennedy moved forward with the Moon landing challenge, announcing his initiative in a special Joint Session of Congress on May 25, 1961.

So we now have a picture of a U.S. President, due to political circumstances, forced into and agreeing to a program he was reluctant to undertake.  According to Simberg’s piece, this is the meaning of Apollo.  What’s missing is that (as they like to say in Washington) Kennedy “evolved” in his beliefs.  While initially willing (but cool) to the space program, his continued attention to “the race” over the remainder of his presidency suggests that he became more keenly interested over time.  Kennedy, often guided by von Braun who would brief him on technical details, made multiple visits to the new NASA field centers.  Kennedy became a “buff” – just like so many of us in the 1960s, drawn up in the excitement of the new space effort.  Enthralled by events like a static firing test of Saturn engines at the Marshall Space Flight Center in May of 1963, he began soaking up space knowledge.  He was hooked and in it to win it.

Kennedy’s speech at Rice University on September 12, 1962 has become inextricably tied to the American can-do spirit and cited whenever someone wants to capture the inherent romanticism and steely determination of the American effort.  Apollo was not some tiresome political task or a pork-shoveling boondoggle to JFK.  It was about winning a battle in a very real Cold War.  It is in this context that President Kennedy’s September 1963 offer to go to the Moon jointly with the Russians must be understood. Yet, part of a speech given at the United Nations, has been interpreted to show that Kennedy was ambivalent toward space and was attempting to dodge the heavy political and fiscal costs of building the Apollo system.  This notion has led some to surmise that had he lived, Kennedy would not have been as ardent a supporter of the space program as we space cadets believe that he was.

John Kennedy's seminal remarks at Rice University, Houston, Texas, September 12, 1962. It was this speech where, many believe, the 35th President succeeded in placing manned spaceflight in historic and definitively American context. "We choose to go to the Moon," he said, "and do the other things, not because they are easy, but because they are hard. Because that goal will serve to organize and measure the best of our energies and skills. Because that challenge is one we are willing to accept, one we are unwilling to postpone, and one we intend to win."

Words were effective weapons during the Cold War.  At every opportunity, Kennedy contrasted the open, non-military nature of the American space program with the secretive and presumably bellicose nature of the Soviet one.

This contrast was made explicit in Kennedy’s initial rationale for the lunar effort when he said, “Whatever mankind must undertake, free men must fully share” (emphasis added).  By 1963, Kennedy knew Khrushchev’s mind-set as well as any foreign leader.  He knew that Khrushchev and the rest of the Soviet Presidium would never accept a proposal for a joint lunar mission – they were suspicious, paranoid triumphalists, as their never-ending blitz of space propaganda illustrated.  Moreover, at this stage of the space race, the Soviets were clearly ahead, having racked up a number of headline-grabbing “firsts” including simultaneous multiple crews and spacecraft, four-day long missions, and orbiting the first woman in space, Valentina Tereshkova.

By making an offer for a joint American-Soviet lunar mission, Kennedy appeared reasonable and forthcoming.  “See?  America has nothing but peaceful intentions for space.  If our Soviet colleagues have similar intentions, as they claim, why do they not join us when we ask them to?”  Jack Kennedy, a decorated World War II veteran and the consummate Cold Warrior, knew how to play the propaganda card.  His offer did not represent a desire to back away from his U.S. commitment to space.  It was a calculated move by the United States in the ongoing war of words, threats and confrontations that constituted the Cold War.

It’s tempting to retrospectively apply today’s intellectual template to past events, but by doing so it distorts the historical record.  A look at Kennedy’s approach to the Soviet Union shows that his inclination was to confront them when necessary.  The Bay of Pigs fiasco early in his presidency followed by the Berlin crisis led Kennedy to believe that Khrushchev and the Soviets must be opposed on the world stage, up to and including space.  Initially cool to the very idea of human spaceflight, Kennedy took the concept to new heights of accomplishment by setting – and ultimately achieving – a goal that captured the imaginations of war-weary people around the world.

Originally published November 24, 2013 at his Smithsonian Air & Space blog The Once and Future Moon, Dr. Spudis is a senior staff scientist at the Lunar and Planetary Institute. The opinions expressed are those of the author but are better informed than average.

John Kennedy's Final Address, Texas Hotel
Fort Worth, Texas, November 22, 1963

Johnson watches the launch of Apollo 11
Former President and Mrs. Lyndon Johnson witness the launch of Apollo 11 from the VIP stands at Kennedy Space Center, July 16, 1969 [NASA].

Friday, November 22, 2013

A Great Place to Rove: Sinus Iridum and Chang'e 3

China will launch it's third unmanned lunar probe very early in December. Plans for Chang'e 3 include the first soft landing on the Moon since 1976 and the first rover since 1973. The China National Space Agency (CNSA) has long reported the target for this historic mission is Sinus Iridum, "the Bay of Rainbows," on the northwestern frontier of Mare Imbrium.

Meanwhile, following five years of planning, the NASA orbiter
LADEE has begun a 100 day examination of the Moon's tenuous exosphere, its formal science mission, in low equatorial orbit. It's all but certain both missions will be underway at the same time, leading some to jump to conclusions in reporting the two missions will interfere with one another. But, as Dr. Paul Spudis of the Lunar and Planetary Institute reports, nothing could be further from truth. Read his assessment, HERE.

Sinus Iridum
Sinus Iridum - it is likely China will land a rover near Laplace A before the end of 2013. (Arrow shows location of the Soviet Lunokhod 1), LROC Wide Angle Camera mosaic field of view 360 km [NASA/GSFC/Arizona State University].
Mark Robinson
Principal Investigator
Lunar Reconnaissance Orbiter Camera (LROC)
Arizona State University

In the near future China will attempt a robotic landing on the Moon, and will deploy a rover. The launch date and landing dates have not been officially announced. The exact landing spot is also not yet publicly designated, but it seems likely the landing will take place in Sinus Iridum, possibly near the fresh crater Laplace A (8 km diameter).

Why this particular spot on the Moon? Likely there are critical engineering constraints in terms of landing site selection as well as important science goals. And there is the dramatic grandeur of the lunar landscape!

Imagine the first rover-eye view from the crater rim - a sheer drop of 1600 meters at your wheels, and an 8 km view across to the far wall! From LROC NAC images we know rock is exposed in the upper walls and dramatic landslides streamed material down to the crater floor. Speaking of the crater floor - it hosts a now frozen lake of impact melt 2500 meters (1.5 miles) in diameter. Imagine the moments after the crater formed, the floor was a cauldron of molten rock with debris sliding down into the melt, and the crater itself was deforming as the floor uplifted after the initial pressure of the impact was relieved.

Laplace A and wrinkle ridge
Laplace A crater and nearby wrinkle ridge (diagonally across at lower right). The question mark shows a potential landing site from which the rover could traverse northwest across the ridge to the edge of the crater [NASA/GSFC/Arizona State University].
Laplace A is a fascinating scientific target for a rover. It is a great example of a very young crater formed in mare basalt. A rover traversing the crater's ejecta blanket is in essence similar to driving down into the crater (in a geologic sense). We know from studies of terrestrial impact craters (such as Meteor crater) that material ejected from deep in a crater ends up near the rim, and rocks from the pre-impact surface are thrown far from the crater (a crater radius or more). So as a rover drives closer and closer to the rim it can characterize rocks from deeper and deeper below the surface.

Some of the many outstanding questions regarding the nature of the mare basalts include: how thick are individual flows, does the composition of the erupted magma change with time and location, and are pyroclastic (explosive) eruptions intermingled with effusive eruptions? These questions can be directly addressed with the Chang'e 3 rover! No humans or robots have ever visited a fresh crater anywhere near this size on the Moon (or Mars for that matter) so the return from this mission has great potential for advancing our knowledge of the Moon.

Laplace A
LROC NAC view of the interior of Laplace A crater [NASA/GSFC/Arizona State University].
But wait, there's more!

Another key question can be addressed: what is the 3D nature of large contractional ridges on the Moon? The rover is thought to have a ground penetrating radar (GPR) and it just so happens that a large wrinkle ridge (a contractional landform) lies about 10 km east of Laplace A. Although the exact mission plan is not publicly available, one potential scenario is that the lander sets down just east of the wrinkle ridge and deploys the rover. After initial testing of the lander and rover, and geologic characterization of the landing site, the rover could set off to the west towards the crater. As the rover drives up and over the wrinkle ridge the GPR would continuously probe the subsurface, slowly building up a 3D profile down to 100 meters or more (?) beneath the surface. Wrinkle ridges are complex landforms created when mare basalts are compressed, causing them to buckle and break along faults. However, wrinkle ridges have not been fully explored, and the  geometry and number of faults associated with each wrinkle ridge is not known. A subsurface profile of a wrinkle ridge could tell us the number of faults, where the faults are located, and how steeply the faults dip: is it 15°, 30° or 45°?

Laplace A as plotted using photography and digital terrain model gathered from the CNSA orbiter Chang'e 2 [CNSA/CLEP].
From LROC images we have mapped the location of all the mare wrinkle ridges, and measured their surface topography, but all we have for the subsurface are models! Soon we may have actual measurements providing a good first step towards interpreting these poorly understood features. Wrinkle ridges are also found on Mercury and Mars, so better understanding a lunar example will help scientists unravel the tectonic story across the inner Solar System. Since only a handful of human and robotic missions have ever landed on the Moon, the results from the Chang'e 3 mission will provide important new scientific insights into our Moon.

Full resolution segment of the west wall and rim of Laplace A by Chang'e 2 [CNSA/CLEP].
Once Chang'e 3 has landed, LROC should be able to spot the lander and the rover; LRO will be above Laplace A on 25 December, 22 January, and 18 February.  The LROC team looks forward to posting images of the two vehicles!

Coincidentally, Lunokhod 1 landed only 250 km to the southwest of Laplace A over forty years ago (17 November 1970). This intrepid Soviet rover explored for almost a year and traveled a total distance of 10.5 km. Both the lander vehicle (Luna 17) and the rover can be seen on the surface today.

Perhaps the Chang'e 3 lander and rover will look something like this. Lunokhod 1 rover in its final parking place (38.315°N, 324.992°E) on the surface of Mare Imbrium, 250 km southwest of Laplace A. The Soviet rover, and its French-built laser range reflector array, were lost for four decades until relocated by LRO. The addition of the LLR to astrophysicists on Earth critically improved the accuracy of measurements of the distance to the Moon, bringing the uncertainty to within 3 millimeters. LROC NAC observation M175502049RE, spacecraft orbit 10998, resolution 33 cm per pixel. Original LROC Featured Image, HERE [NASA/GSFC/Arizona State University].
Explore the LROC Featured Mosaic of the Laplace region of interest, HERE.

Related Posts:
Lunar Laser Ranging: The Millimeter Range (November 19, 2013)
'Government landing penalty' removed from Google Lunar Xprize terms (November 7, 2013)
Chang'e 3 and LADEE: The Role of Serendipity, Paul Spudis (October 31, 2013)

LADEE begins collecting data

NASA Ames / Dana Berry
NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft, in orbit above the Moon, as dust scatters light during lunar sunset [NASA/ARC/JAXA/Dana Berry].
Rachel Hoover
NASA Ames Research Center

NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) is ready to begin collecting science data about the Moon.

On November 20, the spacecraft successfully entered its planned orbit around the Moon's equator -- a unique position allowing the small probe to make frequent passes from lunar day to lunar night. This will provide a full view of the changes and processes occurring within the moon's tenuous atmosphere.

LADEE now orbits the moon about every two hours at an altitude of 12 to 60 km above the Moon's surface. For about 100 days, the spacecraft will gather detailed information about the structure and composition of the thin lunar atmosphere and determine whether dust is being lofted into the lunar sky.

Scientists will be able to study the conditions in the atmosphere during lunar sunrise and sunset, where previous crewed and robotic missions detected a glow of rays and streamers reaching high into the lunar sky.

“This is what we’ve been waiting for – we are already seeing the shape of things to come,” said Rick Elphic, LADEE project scientist at NASA's Ames Research Center in Moffett Field, California

On November 20, flight controllers in the LADEE Mission Operations Center at Ames confirmed LADEE performed a crucial burn of its orbit control system to lower the spacecraft into its optimal position to enable science collection. Mission managers will continuously monitor the spacecraft's altitude and make adjustments as necessary.

"Due to the lumpiness of the moon's gravitational field, LADEE's orbit requires significant maintenance activity with maneuvers taking place as often as every three to five days, or as infrequently as once every two weeks," said Butler Hine, LADEE project manager at Ames. "LADEE will perform regular orbital maintenance maneuvers to keep the spacecraft’s altitude within a safe range above the surface that maximizes the science return."

In addition to science instruments, the spacecraft carried the Lunar Laser Communications Demonstration, NASA's first high-data-rate laser communication system. It is designed to enable satellite communication at rates similar to those of high-speed fiber optic networks on Earth. The system was tested successfully during the commissioning phase of the mission, while LADEE was still at a higher altitude.

LADEE was launched September 6 on a US Air Force Minotaur V, an excess ballistic missile converted into a space launch vehicle and operated by Orbital Sciences Corporation of Dulles, Virginia. LADEE is the first spacecraft designed, developed, built, integrated and tested at Ames, and it is the first probe launched beyond Earth orbit from NASA's Wallops Flight Facility on the Virginia's Eastern Shore.

NASA's Science Mission Directorate in Washington funds the LADEE mission. Ames manages the overall mission and serves as a base for mission operations and real-time control of the probe. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the science instruments and technology demonstration payload, the science operations center and overall mission support. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages LADEE within the Lunar Quest Program Office.

Thursday, November 21, 2013

Impact Art

Ejecta from a fresh crater impacted upon southeastern wall of Darwin C, field of view roughly 3 km. LROC NAC mosaic M1119341350LR, LRO orbit 16162, March 31, 2013; resolution 78 cm per pixel, angle of incidence 29.72° from 78.73 km  [NASA/GSFC/Arizona State University].
Raquel Nuno
LROC News System

Today's Featured Image shows a small portion of the ejecta blanket of an unnamed fresh impact crater (1 km diameter) located on the southeastern wall of crater Darwin C (15 km diameter, over 2500 meters deep).

The linear reflectance boundary that runs diagonally from lower left to upper right is a break in slope between the steep wall (lower right) and floor (upper left) of Darwin C crater; to the left of that line the floor is essentially flat.

Exposure to space weathering tends to lower the albedo of surface materials on an airless body like the Moon. But compositional differences also affect the reflectance of surface materials. So how can we tell whether the ejecta deposits in today's Featured Image have higher reflectance due to freshness or composition? It helps to look at the parent crater from where the ejecta was delivered. If we look at the context image below, we can see that it is very blocky. This is another clue that the crater is young; the blocks have not been worn down by micrometeorite bombardment. Also, with time, gravity and other disturbances, such as ground shaking from other impacts, pull material down the walls of a crater. But we see that the crater walls are crisp; they have not begun to slump even though this crater formed on an incline. All of these clues let us confidently assume that this is a fresh (young) crater that has not been exposed to the space environment or gravity for very long.

M1116983132LR with M1119341350LR (2485x1150)
LROC NAC double-observation mosaic (M1119341350LR with M1116983132LR) of impact crater located on the wall of crater Darwin C. The floor of Darwin C is the darker circular area to the left of the linear reflectance boundary. Image field of view roughly 13 km [NASA/GSFC/Arizona State University].
The fresh crater is centered at 20.09°S, 70.67°W and is approximately 1 km in diameter, about the size of Meteor crater, Arizona. Darwin C is located at immediately southeast and is approximately 16 km in diameter.

Check out today's Featured Image at full resolution HERE, and explore the whole region using LROC's QuickMAP.

Related Posts:
Debris flow down the wall of Dugan J (November 13, 2013)
Bright and Dark Ejecta (September 10, 2013)
Ejecta interference patterns (February 21, 2013)
Slumping rim of Darwin C (April 29, 2011)
Ejecta sweeps the surface (October 11, 2009)

Apollo 12 ALSEP first to measure dust accumulation

Apollo 12 ALSEP Central Station
Apollo 12 ALSEP, Central Station, with DTREM (Lunar Dust Collector) marked with arrow. Alan J. Bean, EVA-1;  Oceanus Procellarum, November 19, 1969 (AS12-47-6927) [NASA/JSC/ALSJ].
A dataset thought to have been lost, from an ingenious experiment deployed on the Moon by Apollo astronauts more than four decades ago, has been rediscovered and analyzed. As a result, the Lunar Dust Collector deployed as integral to the Apollo 12 ALSEP system, has become the first instrument to record a measurable rate of dust accumulation on the lunar surface. 

The news is timely, of course, coming the beginning of the Lunar Atmosphere and Dust Environment Explorer (LADEE) science mission, and arriving on November 19, the 44th anniversary of the Apollo 12 expedition.

Keith Cowing (LOIRP)

The Lunar Dust Detector, attached to the corner of (the ALSEP Central Station, pictured above), left by the Apollo 12 astronauts, made the first measurement of lunar dust accumulation. As the matchbox-sized device's three solar panels became covered by dust, the voltage they produced dropped.

When Neil Armstrong took humanity's first otherworldly steps in 1969, he didn't know what a nuisance the lunar soil beneath his feet would prove to be. The scratchy dust clung to everything it touched, causing scientific instruments to overheat and, for Apollo 17 astronaut Harrison Schmitt, a sort of lunar dust hay fever. The annoying particles even prompted a scientific experiment to figure out how fast they collect, but NASA's data got lost.

Retrieving a surface sample behind boulders on a crater rim at Apollo 17 Science Station 5, Taurus Littrow valley; December 12, 1972 - Lunar module pilot and geologist Harrison Schmitt already carries a substantial sampling of abrasive, fine lunar dust on his moon suit. Schmitt endorsed development of 'dust mitigation' technology as a high priority for program planners prior to establishing 'extended human activity' on the Moon (Eugene Cernan - AS17-145-22157) [NASA/JSC/ALSJ].
Or, so NASA thought. Now, more than 40 years later, scientists have used the rediscovered data to make the first determination of how fast lunar dust accumulates. It builds up unbelievably slowly by the standards of any Earth-bound housekeeper, their calculations show -- just fast enough to form a layer about a millimeter (0.04 inch) thick every 1,000 years. Yet, that rate is 10 times previous estimates. It's also more than speedy enough to pose a serious problem for the solar cells that serve as critical power sources for space exploration missions.

On the chronology of lunar formation and evolution

The Moon about 3 billion years shy of it's most familiar cratering, more or less as it appeared after the basin-forming-impact that created Mare Orientale. From the Goddard / Science Visualization Studio video 'Evolution of the Moon' (2012) [NASA/GSFC/SVS].
A newly published chronology of the Moon's four and a half billion year history, among other things, addresses why certain of its oldest and most familiar nearside basins did not originate from a 'basin-forming-impact.'

Johannes Geiss, Angelo Pio Rossi
The Astronomy & Astrophysics Review   

An origin of the Moon by a Giant Impact is presently the most widely accepted theory of lunar origin. It is consistent with the major lunar observations: its exceptionally large size relative to the host planet, the high angular momentum of the Earth–Moon system, the extreme depletion of volatile elements, and the delayed accretion, quickly followed by the formation of a global crust and mantle.

According to this theory, an impact on Earth of a Mars-sized body set the initial conditions for the formation and evolution of the Moon. The impact produced a protolunar cloud. Fast accretion of the Moon from the dense cloud ensured an effective transformation of gravitational energy into heat and widespread melting. A “Magma Ocean” of global dimensions formed, and upon cooling, an anorthositic crust and a mafic mantle were created by gravitational separation.

Simulation of a Moon-forming impact [Harvard University].
Several 100 million years after lunar accretion, long-lived isotopes of potassium, uranium and thorium had produced enough additional heat for inducing partial melting in the mantle; lava extruded into large basins and solidified as titanium-rich mare basalt. This delayed era of extrusive rock formation began about 3.9 billion years ago and may have lasted nearly 3 billions years.

A relative crater count timescale was established and calibrated by radiometric dating (i.e., dating by use of radioactive decay) of rocks returned from six Apollo landing regions and three Luna landing spots. Fairly well calibrated are the periods from 4 billion to about 3 billion years before present, 800 million years ago to the present. Crater counting and orbital chemistry (derived from remote sensing in spectral domains ranging from gamma and x-rays to the infrared) have identified mare basalt surfaces in Oceanus Procellarum that appear to be nearly as young as 1 billion years.

Samples returned from this area are needed for narrowing the gap of 2 billion years in the calibrated timescale. The lunar timescale is not only used for reconstructing lunar evolution but serves also as a standard for chronologies of the terrestrial planets, including Mars and possibly early Earth.

Head / Brown 2010 crater count
James W. Head of Brown University performed a global census 5,185 lunar craters less than 20 km in diameter (2010). Not surprisingly, a thinner population of such craters are found in and around familiar near side basins, reconfirming conclusions from long ago that the huge plains represent younger surfaces [NASA/GSFC/LOLA/Brown/SVS].
The Moon holds a historic record of Galactic cosmic-ray intensity, solar wind composition and fluxes and composition of solids of any size in the region of the terrestrial planets. Some of this record has been deciphered. Secular mixing of the Sun was constrained by determining the ratio of helium-3 to helium-4 of solar wind helium stored in lunar fines and ancient breccias. For checking the presumed constancy of the impact rate over the past (roughly) 3.1 billion years, samples of the youngest mare basalts would be needed for determining their radiometric ages.

Radiometric dating and stratigraphy has revealed that many of the large basins on the near side of the Moon were created by impacts about 4.1 to 3.8 billion years ago. The apparent clustering of ages called “Late Heavy Bombardment (LHB)” is thought to result from migration of planets several 100 million years after their accretion.

The bombardment, unexpectedly late in solar system history, must have had a devastating effect on the atmosphere, hydrosphere and habitability on Earth during and following this epoch, but direct traces of this bombardment have been eradicated on our planet by plate tectonics. Indirect evidence about the course of bombardment during this epoch on Earth must therefore come from the lunar record, especially from additional data on the terminal phase of the LHB. For this purpose, documented samples are required for measuring precise radiometric ages of the Orientale basin and the Nectaris and/or Fecunditatis basins in order to compare these ages with the time of the earliest traces of life on Earth.

A crater count chronology is presently being built up for planet Mars and its surface features. The chronology is based on the established lunar chronology whereby differences between the impact rates for Moon and Mars are derived from local fluxes and impact energies of projectiles. Direct calibration of the Martian chronology will have to come from radiometric ages and cosmic-ray exposure ages measured in samples returned from the planet.

The full science paper is behind Springer's paywall, HERE.

Related Posts:
Earth and Moon share primal water source (May 10, 2013)
Thin Crust Moon (April 24, 2013)
Making the Moon: Two New Models (October 25, 2012)
Water from the Sun (October 17, 2012)
Hit-and-Run Science, Paul Spudis (September 30, 2012)
A Sawtooth-like timeline for the first billion years of lunar bombardment (August 28, 2012)
A new 'hit and run' Giant Impact scenario (July 28, 2012)
"Our view of the Moon has turned upside down" (April 26, 2012)
Ti paternity test fingers Earth as Moon's parent (March 28, 2012)
NLSI team sheds light on 'late heavy bombardment' (February 28, 2012)
Cataclysmic Conundrum, Paul Spudis (February 14, 2012)
'Significant change' in bombardment timing (January 6, 2012)
LOLA data improves the crater count (September 19, 2010)

Tuesday, November 19, 2013

Tsiolkovskiy's Central Peak

Oblique Close-Up Tsiolskovskiy's Central Peaks
LROC Narrow Angle Camera (NAC) oblique mosaic M1098059280LR (orbit 14176, July 27, 2012; angle of incidence 60.08°), the central peak of farside landmark Tsiolkovskiy crater. The image field of view is approximately 25 km across, the central peak rises 3.4 km above the mare-inundated crater floor.  Spacecraft and camera slewed 64° far east of nadir, capturing the dramatic scene from 87.66 km over 20.44°S, 121.42°E [NASA/GSFC/Arizona State University].
Raquel Nuno
LROC News System

Today's Featured Image is a spectacular LROC NAC oblique view looking East at the central peak of Tsiolkovskiy crater. This large impact crater, with a diameter of 185 km, is located on the farside at 20.38°S latitude and 128.97°E longitude.

It is classified as a complex crater because of its terraced walls, scalloped rim, and central peak, which rises over 3400 m (11,150 ft) from the crater floor.

Central peaks of craters form in a matter of seconds from very energetic impact events. The tremendous pressure imparted from the impactor on to the target rock causes it to behave like a plastic for a few brief seconds. An imperfect analogy is a water droplet splashing into water, at first which produces a central jet, the fluid-like behavior of rock after the impact causes it to rebound upwards. Another factor assisting in the uplift of a central peak is the gravitational collapse of the crater walls which pushes material in the center upwards.

LROC interferometry and LOLA (laser altimeter) data, a brief tour of an advanced lunar Digital Elevation Model (DEM), in the vicinity of Tsiolkovskiy crater. "Tour of the Moon, Additional Footage," Science Visualization Studio [NASA/GSFC/SVS/ASU].

The floor of Tsiolkovskiy crater is partially flooded by mare basalt, which is the low reflectance smooth material seen in both the Featured Image above and the WAC context image below. The mare basalt on the floor of Tsiolkovskiy crater formed from basaltic lava that erupted after the crater formed and pooled. Mare basalts are predominantly seen on the lunar nearside; they make up the dark plains we are familiar with when we look at the Moon. This uneven distribution of mare basalts is thought to be due to the difference between the crustal thickness on the nearside and farside. The nearside crust is thinner, allowing easier access for basalt to flow up to the surface, whereas the thicker crust on the farside makes it so that only large impacts, like the one that formed Tsiolkovskiy crater, have enough energy to excavate deep enough into the crust to allow the release of basaltic lava.

Tsiolkovskiy Crater
Nearly every feature visible in the NAC oblique mosaic above is visible in this 50 km wide field of view captured from almost directly overhead. LROC Wide Angle Camera (WAC) monochrome (643 nm) observation M49675737CE, spacecraft orbit 7191, January 14, 2011; angle of incidence 74° at 78.4 meters per pixel resolution, from 57.15 km [NASA/GSFC/Arizona State University].
Tsiolkovskiy Crater
Deeper context from a mosaic of orbital passes, as the Moon rotated under the polar orbit of LRO shows the peaks emerging from it's distinctive (for the farside) mare-flooded floor. Terraced walls, slump and hummock of the complex crater come into view in this 145 km-wide field of view [NASA/GSFC/Arizona State University].
It's difficult to step back far enough to grasp the area affected by this super-positioned impact in the farside southern highlands. This context image originally helped illustrate "Tsiolkovskiy central peaks at sunset," July 3, 2013 [NASA/GSFC/Arizona State University].
Tsiolkovskiy Crater
On the left, LROC WAC monochrome mosaic centered at 120 degrees East longitude. On the right, LROC WAC context image of Tsiolkovskiy crater [NASA/GSFC/Arizona State University].

Tsiolkovskiy Crater
Tsiolkovskiy easily stood out, a rare dark spot highlighting the surprising differences between the Moon's near and its farside when it was first photographed by the Soviet Union's Luna 3 in 1959. This LROC WAC mosaic, centered on 180° and the equator, was among the first LROC Wide Angle Camera images released. Tsiolkovskiy is marked by the arrow [NASA/GSFC/Arizona State University].
The Tsiolkovskiy Crater was a Constellation Program region of interest because of the possibility to study the central peak, where astronauts could sample rocks that came from deep beneath the lunar surface.

Explore Tsiolkovskiy's central peak from an orbiting astronaut's perspective, HERE.

Related Posts:

Has NASA 'RESOLVE'd' on Canadian lunar rover?

The Canadian Space Agency test platform "Artemis, Jr.," fitted with NASA's RESOLVE surface materials probe package "RESOLVE," on Day 3 of field testing on Hawai'i, July 2012 [CSA].
Tom Spears
Ottawa Citizen

Neptec Design Group of Ottawa is the front-runner to build the next moon rover — a traveling robot that will hunt for water on an unmanned NASA mission in 2017. NASA has asked the Canadian Space Agency specifically for Neptec’s rover, called Artemis Jr., said Mike Kearns, president of space exploration with the Ottawa aerospace engineering firm.

It has chosen a Canadian drill and Canadian avionics, too.

“One of the missions on that path is called RESOLVE, renamed by some people now as the Lunar Prospector Mission,” Kearns said.“NASA, for funding reasons, has asked CSA to provide the rover and the drill. And they actually asked for our Neptec rover ... and for the drill that is made by a company called Deltion.” (Deltion Innovations of Sudbury took over the design that originated with NORCAT. Its drill developed out of Canadian mining technology.)

What sealed NASA’s interest was a test drive of the rover prototype on the side of a Hawaiian volcano, in 2012. Chosen to simulate the harsh landscape of the moon and Mars, it provided a place for Artemis Jr. to drive, pivot and steer past obstacles using its vision system and navigation software. It passed nine days of tests.It’s called “Jr.” because this is a scaled-down version of a Neptec rover designed to carry astronauts, called Artemis.

Searching for water in space is vital. Not only can astronauts drink it, but it can be broken down into oxygen and hydrogen, both used in rocket propellant. Artemis Jr. could also search for methane.Neptec hopes the 2017 date will resonate with politicians who want some flag-waving in Canada’s 150th year.

“The question that always comes up is: That’s very nice but what’s the financial benefit? What’s the return to the taxpayers. And the answer is that ... for every dollar that CSA gives us, we end up with $10, mostly in export sales. We sell those products around the world.”

While the Canadian Space Agency can open the bidding to include MDA, the CANADARM builders, Kearns says NASA’s preference gives his company’s Artemis Jr. rover a strong chance. MDA officials weren’t available for comment Monday.

NASA is publicly leaning toward the Neptec team. In a description of the mission it writes: “RESOLVE is not just a NASA effort; the Canadian Space Agency provided Artemis Jr., which is the rover for the payload; the onboard drill and sample transfer system; as well as avionics microprocessors.”

Fanciful rendering of the Artemis, Jr. platform on the floor of Mare Crisium. A better view of the system, in the real world and in more detail is available, HERE.
Artemis Jr. is actually the product of a group of Canadian companies: Ontario Drive and Gear, from New Hamburg, Ont.; ComDev and Neptec from Ottawa; Deltion; and NGC from Sherbrooke.

The four-wheeled rover can pivot on one spot, moving the right wheels forward and the left ones in reverse. It has coarse metal treads for traction, and a solar panel on top.

It’s designed for NASA’s Regolith & Environment Science and Oxygen & Lunar Volatile Extraction (RESOLVE) project, which involves heating the “regolith” (loose minerals on the moon’s surface) to extract gas.

Related Posts:
Good things delivered in small packages, Paul Spudis (August 19, 2013)
Geological sampling and planetary exploration, Paul Spudis (February 19, 2013)
'a RESOLVE to mine the Moon,' Brian Shiro (July 15, 2012)