Wednesday, September 25, 2013

LROC updates image tally of human artifacts on the Moon

Luna 17, the spacecraft that carried the Lunokhod-1 rover to the surface of the Moon; debarking ramps for the rover tracks around the lander are visible, extending southeast, to the right. LROC Narrow Angle Camera (NAC) frame M175502049RE, LRO orbit 10998, November 9, 2011; angle of incidence 57.78° at 43 cm per pixel resolution from 30.66 km over 38.23°N, 325.01°E. View the original contextual image with an enlarged inset HERE [NASA/GSFC/Arizona State University].
Samuel Lawrence
LROC News System

Repeat imaging of anthropogenic targets on the Moon remains an LROC priority as the LRO Extended Science Mission continues. These continuing observations of historic hardware and impact craters are not just interesting from a historical standpoint - each image adds to our knowledge of lunar science and engineering, particularly cartography, geology, and photometry.

Making sure that the lunar cartographic network is accurate is a critical component for planning future lunar missions for both human and robotic exploration of the Moon. The historic spacecraft serve as benchmarks (especially the laser retroreflectors). When new images arrive and final ephemeris is in hand we can check if the hardware has moved - well, actually we see the level of uncertainty in computing latitude/longitude coordinates (currently about ±15 meters).

View of the Luna 17 lander from the Lunokhod-1rover (the vehicle descended from its position atop the lander from the opposite side). A wide variety of images, including many other firsts from the Soviet Union's lunar exploration program  of the Cold War era can be viewed HERE.
Currently the United States has no near-term plans to land humans or robotic spacecraft on the Moon, however China is scheduled to launch the Chang'e 3 mission in December. If we are lucky, the LROC team might have a before picture to compare to any after pictures of the Chang'e 3 landing site (the exact planned landing coordinates have not yet been released). Currently all LROC NAC investigations must rely solely on "after" images of landing sites. Obtaining a before and after set of images of the Chang'e 3 will facilitate a much better understanding of the delicate processes involved in regolith redistribution due to lander rocket plumes.

When a spacecraft lands on the Moon in a powered descent, exhaust gases from the descent engine disrupt the surface resulting in visible changes around the landed vehicle. These changes can be better understood with photometric studies using using LROC NAC images taken with different illumination geometries. Close to (or right under) the lander the soil is most disrupted, leading to reduced reflectance. Interestingly a zone of increased reflectance surrounds the lander. This "blast zone" ranges from a few meters for the Surveyor spacecraft, to a few tens of meters for Luna, and a few hundred meters for Apollo.

The Apollo 15 landing site through shifting shadows of a simulated lunar day, courtesy of the LROC Featured Sites Index. Very little appears to have changed since the departure of Scott and Irwin nearly 600 lunar days ago [NASA/GSFC/Arizona State University].
Photometric modeling indicates possible causes for the increased reflectance zones from smoothing of the surface by the exhaust flow, the destruction of micro-scale regolith structure, and/or the redistribution of fine particles from the area beneath the lander to its surroundings. Modeling the dynamics of rocket exhaust plumes and studying the exhaust plume effects of previous landed spacecraft on the Moon are defining safe operational practices for future landing sites and outposts.

Exceptionally detailed photograph of the Ranger 9 impact on the floor of Alphonsus crater appears to include an inner disk of darker material around 10 meters across, possibly melt created by the release of kinetic energy, LROC NAC M170579736R, LRO orbit 10272, September 13, 2011; angle of incidence 16.1° at 49.6 cm per pixel resolution from 44.64 km [NASA/GSFC/Arizona State University].
Selection of spacecraft impact sites imaged from LRO using the LROC twin Narrow Angle Camera instrument, all at the same scale [NASA/GSFC/Arizona State University].
Careful retracing of the Lunokhod 2 traverse dramatically improved our understanding of the surface activities of that intrepid rover. In addition, by accurately determining the locations of the Luna 23 and Luna 24 landers, the LROC team determined not only how the Luna 23 spacecraft failed, but also that the Luna 24 sample was collected on the rim of a small impact crater, providing an explanation for the discrepancies that existed for the past three decades between samples and remote sensing of the Mare Crisium surface.

Check out a map of robotic spacecraft sites on the lunar surface, HERE.

(a) listing of coordinates (mean Earth/polar axis (ME) system) of ... Soviet and American robotic space hardware and craters produced through spacecraft impact (thus far) identified by the LROC Team can be download as an Adobe PDF file is available HERE.

ED NOTE: This is at least a partial update to "Coordinates of Robotic Spacecraft," released April 9, 2010.

To generate the list of observed latitudes and longitudes, we compiled a list of line and sample coordinates for the center of each object in each image. Each image was then initialized using the USGS Integrated Software for Imagers and Spectrometers (ISIS) software package, attaching the appropriate spacecraft position and pointing information, along with the GLD100 lunar shape model for elevation. ISIS routines were then used to compute the latitude and longitude of the spacecraft (or impact crater) in that image.

The LRO spacecraft positions on the list were provided by the latest cross-over corrected spacecraft positioning kernels provided by the LRO LOLA Team, with an orbital position uncertainty of 15 meters. Finally, temperature-corrected NAC camera kernels produced by the LROC team contributed to the high precision and accuracy. The coordinates listed in the table are statistical median from all of the images acquired before April 28, 2013 for a particular site.

Related Posts:
Apollo 12 at 43 Years (November 20, 2012)
Taurus Littrow Oblique (September 29, 2012)
Close-up on the lonely trail of Lunokhod-2 (September 17, 2012)
America's last unmanned lunar lander (September 7, 2012)
"Houston, Tranquility Base here" (August 28, 2012)
Scooping the Soviets (August 8, 2012)
Apollo 15 departs Hadley Rille Delta - 41 years ago (August 2, 2012)
Tranquility Base at high-resolution before Apollo 11 (August 2, 2012)
Ranger 8 impact on restored Lunar Orbiter LOIRP photograph (July 31, 2012)
"O! Say can you see, by the dawn's early light" (July 27, 2012)
New tool for exploring LROC images and Apollo landing observations (July 19, 2012)
Craters bear Lunokhod-1 officially named (July 3, 2012)
Astronaut's eye view of the Apollo 16 landing site (June 19, 2012)
Who discovered water on the Moon (June 1, 2012)
Will China deploy the first lunar rover since 1976? (April 30, 2012)
The discarded extension of the Ranger program, David S.F. Portree (April 30, 2012)
Orion, up close (April 24, 2012)
Forty years ago, 'a big ol' Navy salute' (April 21, 2012)
Forty years ago-Apollo 16 (April 21, 2012)
The Last Sampler: Failure, then Success (March 17, 2012)
Lunokhod-1 revisited, too (March 15, 2012)
Lunokhod-2 revisited (March 13, 2012)
Pinpoint Landing on the Moon - Apollo 12 (March 12, 2012)
How Young is Young? - Apollo 16 (March 9, 2012)
LROC's closest look yet at Tranquility Base (March 8, 2012)
Apollo 12 and its pinpoint landing in the Moon (March 7, 2012)
Follow the tracks - Apollo 15 (March 6, 2012)

From the second of two sequential, exceptionally low periapsis orbital passes, allowing the LROC team at Arizona State University to capture breathtaking views of the Apollo 16 landing site in the nearside Southern Highlands, LRO orbit 10950, November 6, 2011; LROC NAC M175179080, field of view 145 meters, released on the 40th anniversary of the lift-off from the Moon of the Young and Duke expedition, April 22, 2012 [NASA/GSFC/Arizona State University]

Just another crater? (December 13, 2011)
"Boy, that sure looks like Luna 9!" (December 3, 2011)
Cernan says China will be first back to the Moon (November 8, 2011)
Hadley Rille and the Mountains of the Moon (November 8, 2011)
The First Race to the Moon, David S.F. Portree (September 27, 2011)
On the run! - Apollo 14 (September 8, 2011)
New Views of Apollo 12 (September 8, 2011)
Apollo 14 at 25 cm per pixel (September 8, 2011)
Skimming the Moon (September 8, 2011)
LRO Briefing: Latest Close-Ups of Apollo Sites (September 6, 2011)
Low altitude views of Apollo released (September 3, 2011)
First Low Altitude Apollo 12 NAC Image (August 11, 2011)
Crash or Coincidence (July 22, 2011)
Surveyor 7 (February 12, 2011)
New View of Apollo 14 (February 4, 2011)

Surveyor 7: Our Fragile Lunar LDEF (October 27, 2010)
LRO analysis of LCROSS data proves essential (October 21, 2010)
LRO transitions from exploration to science (September 16, 2010)
Apollo 16, Footsteps Under High Sun (July 11, 2010)
Too brief an expedition to a lobate scarp (August 24, 2010)
Re-acquisition: Lunokhod-1 (April 27, 2010)
Apollo 16: 38 years on (April 21, 2010)
Retracing the steps of Apollo 15: Constellation ROI (April 17, 2010)
Value-added LROC (April 16, 2010)
A fundamental point on the Moon (April 13, 2010)
The part of Apollo 13 that made it to the Moon (April 12, 2010)
Coordinates of Robotic Spacecraft (April 9, 2010)
Ranger 9 (April 4, 2010)
Absentee ownership of Lunokhod-2 (April 1, 2010)
LOLA's Tycho and the Apollo era (March 28, 2010)
The first successful robotic sampler, Luna 16 (March 26, 2010)
Apollo 13 SIVB impact (March 23, 2010)
Surveyor 5: A Hole-in-One (March 21, 2010)
Surveyor 6 on the plains of Sinus Medii (March 21, 2010)
Luna 21 Lander (March 19, 2010)
Foot fall around Orion in the mid-day glare (March 19, 2010)
Lunokhod-1 and Lunokhod-2 (March 17, 2010)
The Soviet lunar sampling missions (March 16, 2010)
Alan Bean shares Apollo 12 with community college students in Iowa (March 9, 2010)

The largest of three Apollo lunar laser range reflectors (LLRR), deployed at Hadley Rille by Scott and Irwin of Apollo 15 in February 1971. The instrument is still an active, critical component of on-going experimental science, part of the effort to further constrain the measured distance to the Moon (to within 3 mm) in part determine "locality," if any, of the laws cosmological physics. AS15-85-11468 [NASA/JSC].
Triumph (and disappointment) of Apollo 12 (November 19, 2009)
High Noon over Apollo 11 on YouTube (November 14, 2009)
Midday on Oceanus Procellarum: Apollo 12 (November 5, 2009)
Apollo 12 Second Look: Midday on the Ocean of Storms (November 4, 2009)
Apollo 17 from 50 kilometers (October 28, 2009)
When bombing the Moon was a good idea (October 21, 2009)
Apollo 14 SIVB impact (October 8, 2009)
Lonely Sentinel Abides (October 1, 2009)
Surveyor 1: America's first soft lunar landing (September 30, 2009)
Tranquility Base: a better, second look (September 29, 2009)
Shadow on the Moon (September 24, 2009)
LROC zooms in on Apollo 12 and Surveyor 3 (September 4, 2009)
First Look: Apollo 12 and Surveyor 3 (September 3, 2009)
Lasting boot prints from 1971 (August 21, 2009)
Trail of Discovery at Fra Mauro (August 19, 2009)
The continued importance of lunar laser ranging (August 3, 2009)
Rediscovering Tranquility Base (July 19, 2009)
Five Apollo landing sites photographed (July 17, 2009)
Lunar Orbiter III-154-H2 (LOIRP) (June 16, 2009)
LOIRP recovers early image of Ranger 8 impact (June 9, 2009)
Kaguya to impact June 10 (May 21, 2009)
Chang'e-1 controlled impact in Mare Fecunditatis (March 1, 2009)
More astounding detail (Surveyor 1) from LOIRP (February 26, 2009)
Anniversary of Ranger 8 (February 20, 2009)
Surveyor proved the Moon safe for man (January 4, 2009)

Chandrayaan-1 Moon Impact Probe shoots Shackleton (November 15, 2008)
Tranquility Base from Kaguya (SELENE-1) (March 29, 2008)

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