- NASA orbiter spots Lunokhod 1 on the Moon
Scientists have located on the lunar surface a long lost light reflector attached to the former Soviet Union’s Lunokhod 1 rover.
The French-built laser reflector was sent aboard the robotic Luna 17 mission. That craft landed on the Moon back in mid-November 1970, releasing a robotic rover that roamed the lunar surface, outfitted with scientific gear that included the laser reflector.
Lunokhod 1was last heard from on September 14, 1971. Its true whereabouts on the lunar surface weren’t precisely known. But thanks to new imagery from NASA’s Lunar Reconnaissance Orbiter (LRO), the Lunokhod 1 has been spotted.
That LRO imagery has helped a team of physicists led by a professor at UC San Diego to identify the exact resting spot of Lunokhod 1.
The LRO camera team, spearheaded by Mark Robinson at Arizona State University in Tempe, identified the rover as a sunlit speck on imagery, miles from where researchers had been searching for years.
On target
On April 22, specialists at Apache Point Observatory in New Mexico sent pulses of laser light, zeroing in on the target coordinates provided by the LRO imagery.
Bingo!
The long lost Lunokhod 1 reflector has been pinpointed. In the coming months, it appears possible to establish the reflector’s coordinates to better than one-centimeter precision.
Why all the Earth-to-Moon laser beaming?
Scientists are engaged in a long-term effort to look for deviations of Einstein’s theory of general relativity by measuring the shape of the lunar orbit to within an accuracy of one millimeter, or about the thickness of a paperclip.
This is being accomplished by timing the reflections of pulses of laser light from reflectors left on the Moon by Apollo astronauts and turning the timing measurement into a distance.
Center of the Moon
“Lunokhod 1, by virtue of its location, would provide the best leverage for understanding the liquid lunar core, and for producing an accurate estimate of the position of the center of the Moon—which is of paramount importance in mapping out the orbit and putting Einstein’s gravity to a test,” said Tom Murphy, an associate professor of physics at UCSD.
“We routinely use the three hardy reflectors placed on the moon by the Apollo 11, 14 and 15 missions,” said Murphy, “and occasionally the Soviet-landed Lunokhod 2 reflector…though it does not work well enough to use when illuminated by sunlight. But we yearned to find Lunokhod 1,” he said in a press statement.
Three reflectors are required to lock down the orientation of the Moon. A fourth adds information about tidal distortion of the Moon, and a fifth enhances that information.
Murphy’s project, dubbed APOLLO for the Apache Point Observatory Lunar Laser-ranging Operation, is supported by the National Science Foundation and NASA, and includes scientists at the University of Washington, Harvard University, the Massachusetts Institute of Technology, Humboldt State University and the Apache Point Observatory.
For more information on this impressive tale of lunar lost and found, go to:
http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lroc-20100318.html
By Leonard David