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Historic Apollo landing sites imaged by new lunar orbiter

Posted: July 17, 2009

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The NASA Lunar Reconnaissance Orbiter (LRO) spacecraft has transmitted the first images in 40 years of the Apollo 11 lunar lander.

The LRO spacecraft also imaged four other Apollo sites showing Grumman lunar module descent stages, and in one case, a trail of astronaut footprints on the Moon.

In addition to Apollo 11, the Apollo 14, 15, 16 and 17 sites were imaged. LRO has not yet flown over the Apollo 12 landing site when lighting was suitable for imagery, but the spacecraft will be commanded to obtain imagery of the Apollo 12 site by late July or early August.

All of the images were taken by the Arizona State University Lunar Reconnaissance Orbiter Camera (LROCC). Once the spacecraft is placed into its final 31 mi. circular mapping orbit, LROC images of the Apollo sites will have two to three times greater resolution than the images shown here.

The spacecraft's current elliptical 23 x 125 mi. orbit resulted in image resolutions that were slightly different for each site, but all around four feet per pixel.

The image of the Apollo 14 landing site (below) , however, had a particularly good lighting condition that allowed visibility of additional details.

Credit: NASA
In the image (above) the Apollo Lunar Surface Experiment Package, set of scientific instruments placed by the Apollo 14 astronauts, is discernable, as are the faint trails between the module Antares and instrument package left by astronauts Alan B. Shepard Jr. and Edgar D. Mitchell in February 1971.

Because the deck of the lunar module descent stage is about 12 feet in diameter, the Apollo relics themselves fill an area of about nine pixels. However, because the sun was low to the horizon when the images were made, even subtle variations in topography create long shadows. Standing slightly more than ten feet above the surface, each Apollo descent stage creates a distinct shadow that fills roughly 20 pixels in size.

The images were taken between July 11-15 . They were processed with unusual speed then released as part of NASA commemoration of the first manned lunar landing by Apollo 11 on July 20, 1969 that carried astronauts Neil Armstrong and Edwin (Buzz) Aldrin to the surface of the moon (image below).

Credit: NASA
The image (above) of the descent stage of Apollo 11 lunar module Eagle was taken with just over 1 meter resolution, showing the small crater just behind the LM that Armstrong had to extend his landing over to avoid. At touchdown Eagle had only 15-30 sec. of descent engine fuel remaining to achieve the landing.

The Apollo 15 landing site (below) was near Hadley Rill, a collapsed lava tube deeper than the grand canyon. The rill is out of view to the east.

Credit: NASA
The Apollo 15 site (above) was the first to be explored with a Boeing Lunar Rover car that enabled astronauts David Scott and the late Jim Irwin to roam widely throughout the area imaged by LRO.

The Apollo 16 site (below) in April, 1972 was in the Descartes highlands.

Credit: NASA
Astronauts John Young and Charles Duke nearly had to abandon the landing when problems arose with the Command/Service Module piloted by Thomas K. Mattingly. But the problem with an engine gimbal were resolved, allowing the landing to proceed after Young and Duke had orbited the moon in the LM longer than planned.

On Apollo 17, the final manned mission to the moon in 1972, astronauts Gene Cernan and Harrison Schmitt explored the Taurus-Littrow region for almost three days. The descent stage of their lunar module Challenger is visible near Camelot crater (below).

Credit: NASA
The Taurus-Littrow valley explored by Apollo 17 (above) was formed 3.9 billion years ago when a mountain-sized asteroid or comet hit the Moon and blasted out a basin nearly 400 mi. in diameter. Around the rim of the Sea of Serenity formed by the impact, great blocks of rock were pushed out and up, forming a ring of mountains. In places, the blocks quickly fell again, and left radial valleys among the mountains. Taurus-Littrow explored by the Apollo 17 crew is one such valley, in the southwestern Taurus Mountains.

The lunar module descent stages (see image below) were quite large carrying the descent engine and its propellant tanks, along with science packages and, on the last three flights, the lunar rover cars.

Credit: NASA
In the Apollo 11 image (above) taken by Neil Armstrong, astronaut Buzz Aldrin works to extract Apollo science hardware from the descent stage of Eagle. This shows the scale of the boxy descent stage with its landing struts in comparison with a person.

The separation of the Apollo 17 ascent stage from the descent stage (below) was imaged by the television on the crew's lunar rover car parked about 100 ft. away.

Credit: NASA
Descent stage (above) shows at ground level what the Lunar Reconnaissance Orbiter was imaging at all of the sites.

The location of the Apollo landing sites is shown (below) on a globe of the moon. The Lunar Reconnaissance Orbiter transmitted its images to antennas at White Sands N. M. which then relayed them to the Goddard Space Flight Center, Md. Which controls the spacecraft.

Credit: NASA
"The LROC team anxiously awaited each image," said LROC principal investigator Mark Robinson at Arizona State. "We were very interested in getting our first peek at the lunar module descent stages just for the thrill - and to see how well the cameras had come into focus. Indeed, the images are fantastic and so is the focus." The lower mission science orbit should enable imaging of the Apollo 11 and 16 sites at double the resolution they are shown here, and images of the Apollo 14, 15 and 17 sites at three times higher resolution that these images Robinson says.

"These are only our first glimpse, from now on the images will only get better," says Mike Wargo, the LRO project scientist at NASA Headquarters.

The spacecraft will also attempt to image the Soviet Lunakhod rovers, each about the size of a Volkswagen beetle car.

The Apollo pictures provide a reminder of past NASA exploration, while LRO's primary focus is on paving the way for the future. By returning detailed lunar data, the mission will help NASA identify safe landing sites for future explorers, locate potential resources, describe the moon's radiation environment and demonstrate new technologies. "Not only do these images reveal the great accomplishments of Apollo, they also show us that lunar exploration continues," said LRO project scientist Richard Vondrak at Goddard. "They demonstrate how LRO will be used to identify the best destinations for the next journeys to the moon."