How LRO Will Find Safe Landing Sites on the Moon (No Narration)

  • Released Tuesday, September 2, 2008
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The first attempt to land humans on the moon - Apollo 11 - was a triumph that almost ended in disaster. At just 400 feet from the lunar surface, with only about a minute's worth of fuel remaining, astronauts Neil Armstrong and Edwin 'Buzz' Aldrin saw that their ship's computer was taking them directly into a crater the size of a football field, strewn with SUV-sized boulders. They quickly took control from the computer, flew over the crater and touched down in a smoother area beyond, cutting the engine with just 30 seconds of fuel left.

In general, good landing sites need to be level and free from large boulders that could damage or tip the spacecraft as it attempts to land. And it's up to LRO to make those landings as safe as possible.

Astronauts will want to avoid places with steep slopes that could tip the spacecraft, so LRO includes a laser ranging system that will build an elevation map to show the contours of the polar surface. The instrument, called the Lunar Orbiter Laser Altimeter (LOLA), records the time it takes for a laser pulse to travel from the spacecraft to the lunar surface and back to calculate the height of the lunar terrain. After a year in orbit aboard LRO, LOLA will have created an elevation map of the polar regions that is accurate to within a half-meter (20 inches) vertically and 50 meters (about 160 feet) horizontally.

LRO will also use data from another instrument that measures temperatures to double-check the safe zone map. Temperatures change more rapidly in areas with loose materials (lots of rocks). By analyzing how quickly temperatures change in potential landing zones, planners using the instrument, named Diviner, can rule out areas that appear smooth but actually are likely to be rocky.

LRO also carries a pair of eagle-eyed cameras, called the Narrow Angle Cameras (NACs) which together can take images that reveal details as small as a half-meter (almost 20 inches) over swaths 10 kilometers (about 6.2 miles) wide. As LRO orbits over the poles, the moon rotates beneath the spacecraft, and the NACs will gradually build up a detailed picture of the region. It will be used to identify safe landing zones free of large boulders and craters, allowing astronauts to avoid surprises like Apollo 11.

LRO is scheduled to launch in 2009.

For a 3D stereo version of this visualization, please visit animation #3567: How LRO Will Find Safe Landing Sites on the Moon - Stereoscopic version

For a feature version of this visualization with narration and music, please visit Goddard Multimedia #10349: LRO Scouts for Safe Landing Sites

The crater depicted in this animation is ficticious and only intended for illustrative purposes. The animation begins with the reveal of a digital elevation map showing sample lunar topography illustrating the kind of data that LRO's LOLA instrument will collect. From this topographic data level surface areas can be derived as the first step to determining safe landing sites. Next, an example temperature map of the lunar surface is revealed to show the sort of data Diviner will collect. Changes in surface temperature will help determine small rock hazards, since they retain and release heat at a different rate than the surrounding regolith. Large rock hazards can be found with LROC's surface imagery. Finally, removing rock hazard areas from level surface areas reveals potential safe landing sites for future lunar missions.

Animation of the crater itself without the text background. The raw frames provided have alpha channels, so this element can be overlaid over other visuals.

An artist rendition of topographic data being partially revealed to show a lunar crater. Similar topographic data will be taken by the LOLA instrument onboard LRO.

An artist rendition of topographic data being partially revealed to show a lunar crater. Similar topographic data will be taken by the LOLA instrument onboard LRO.

An artist rendition showing topography of a lunar crater, as the LOLA instrument will eventually generate.

An artist rendition showing topography of a lunar crater, as the LOLA instrument will eventually generate.

An artist rendition showing level surfaces in and around a lunar crater. Although such surfaces may be level, they may not be safe landing sites.

An artist rendition showing level surfaces in and around a lunar crater. Although such surfaces may be level, they may not be safe landing sites.

An artist rendition of Diviner's temperature data being laid over LOLA-like topography and a derived level surface product (depicted in green).

An artist rendition of Diviner's temperature data being laid over LOLA-like topography and a derived level surface product (depicted in green).

An artist rendition of Diviner's temperature data over a lunar crater. Yellow and red indicate areas of high temperatures whereas purple and blue indicate areas with colder temperatures. The green areas depict areas with level surfaces.

An artist rendition of Diviner's temperature data over a lunar crater. Yellow and red indicate areas of high temperatures whereas purple and blue indicate areas with colder temperatures. The green areas depict areas with level surfaces.

One of Diviner's derived products will be detection of small rock hazards. Since small rocks warm and cool slower than the surrounding regolith, Diviner's temperature data over time can reveal potential small rock hazards. This is an artist's rendition of the sort of small rock hazards that might be found around a lunar crater. Small rock hazards are shown in yellow.

One of Diviner's derived products will be detection of small rock hazards. Since small rocks warm and cool slower than the surrounding regolith, Diviner's temperature data over time can reveal potential small rock hazards. This is an artist's rendition of the sort of small rock hazards that might be found around a lunar crater. Small rock hazards are shown in yellow.

An artist rendition of LROC's imaging data being overlaid atop small rock hazards and level surfaces. The LROC camera will provide high resolution images of the lunar surface.

An artist rendition of LROC's imaging data being overlaid atop small rock hazards and level surfaces. The LROC camera will provide high resolution images of the lunar surface.

An artist rendition of LROC imaging data in shades of light to dark gray. Small rock hazards are shown in yellow. Level landing sites are shown in dark green.

An artist rendition of LROC imaging data in shades of light to dark gray. Small rock hazards are shown in yellow. Level landing sites are shown in dark green.

LROC's imaging cameras will provide highly detailed images of the lunar surface. From these images, scientists can determine where large rock hazards exist. Large rock hazards found in or near level surfaces will make landing in those areas unsafe.

LROC's imaging cameras will provide highly detailed images of the lunar surface. From these images, scientists can determine where large rock hazards exist. Large rock hazards found in or near level surfaces will make landing in those areas unsafe.

An artist rendition of safe landing sites around a fictional lunar crator. Safe landing sites are depicted in bright green.

An artist rendition of safe landing sites around a fictional lunar crator. Safe landing sites are depicted in bright green.

For More Information

See http://www.nasa.gov/mission_pages/LRO/news/safe_landing.html

Credits

Please give credit for this item to:
NASA/Goddard Space Flight Center Scientific Visualization Studio Reference DEM data provided by: Jay Friedlander (QSS, Code 672)

This page was originally published on Tuesday, September 2, 2008.
This page was last updated on Sunday, April 21, 2024 at 10:01 PM EDT.

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