How has the laser influenced our understanding of the Moon? The exploration of space has led to technology developments which use one or more lasers as a means to collect specific data in order to broaden humanity’s understanding of the Moon and neighboring planets. With the Moon being Earth’s nearest neighbor, we’ve come to use this tangible island in space as a laboratory for investigations concerning both the origin and evolution of Earth as well as the all-encompassing solar system. The invention of the laser paved the way for NASA’s advanced space explorations.
On June 18, 2009, NASA launched the Lunar Reconnaissance Orbiter (LRO) along with the Lunar Crater Observation and Sensing Satellite (LCROSS) as the forefront of NASA’s Lunar Precursor Robotic Program. This launch began a four-day trip to the Moon and after a calculated four and a half day journey, LRO finally entered into the Moon’s orbit on June 23, 2009. This success resulted in LRO being the first United States mission to the Moon in over ten years.
For its first three years, LRO traveled in a low polar orbit collecting detailed information about the Moon and its foreign environment. Soon enough, the orbiter transitioned into a more stable orbit, passing low over the lunar south pole. The success of this launch marked NASA’s return to the Moon.
In January 2013, four years after stabilizing its orbit, NASA tested one-way laser communication with LRO by sending an image of the Mona Lisa to the Lunar Orbiter Laser Altimeter (LOLA) instrument on LRO from the Next Generation Satellite Laser Ranging (NGSLR) station at NASA’s Goddard Space Flight Center in Greenbelt, MD. The LOLA Science Team at NGSLR is still currently responsible for deciphering information sent back to Earth from the LOLA instrument.
While the LRO remained in orbit, LOLA was used to gather detailed data about safe landing sites by displaying global, regional, and local models of surface brightness, surface slopes, and surface roughness. These models sent back to Earth by LOLA assisted scientists by collecting information about suitable exploration sites on the Moon through the use of a single laser.
Data is collected from LOLA through the propagation of a laser pulse through a Diffractive Optical Element (DOE) or an element or object that splits a single laser beam into five separate beams. This method allows the shape of a given laser beam to be controlled and manipulated in order to flexibly change according to specific application needs. These beams then strike and scatter across the Moon’s surface. Through this action, LOLA then proceeds to measure surface range, surface roughness, surface reflectance, and slopes.
NASA then uses this information to create 3-D maps which are primarily used to help determine locations of lunar ice, potential resources on the Moon, radiation environment, and safe landing sites for future explorations involving spacecraft. These maps also help NASA to determine how to revise, update, and create new technologies which will lead to more efficient information processing instruments and systems. Since receiving the first data sets from LOLA, NASA has made a 3-D map of the Moon’s surface and has provided high resolution images of various Apollo landing sites. These first images were published on Thursday, July 2, 2009.
One year later, a topographic map, or a detailed surface map, of the Moon was released to the public on Friday, December 17, 2010. This land map was based on data sets gathered by the LOLA instrument.
More recently, in May 2015, LRO’s orbit was slightly altered to fly an estimated 12 mi above the Moon’s south pole. This altered flight has since allowed higher resolution data to be collected from the LOLA instrument over shadowed craters.
Observations made by LRO have enabled groundbreaking and breathtaking discoveries. Images and data collected by LOLA helps scientists to determine past and present strengths and weaknesses of the technologies involved in space-exploration both near and far. The LOLA instrument will continue to provide curious minds with visual maps of our neighboring lunar sphere.