The space agency may well need to dust off and relearn lessons from the early 1960s into the 1970s. That's when robots ruled the Moon before and after Apollo 11's Neil Armstrong and Buzz Aldrin set foot and flag there.
Year-in-the-making strategy
In early July, the prestigious National Research Council in Washington, D.C. released a seminal report: New Frontiers in the Solar System - An Integrated Exploration Strategy. The study is an intensive look at a decade's worth (2003-2013) of high priority space exploration projects.
Requested by NASA, the year-in-the-making strategy was a major output from the planetary exploration community. High on their collective wish list was a sample return from the Moon's South Pole-Aitken Basin.
The farside South Pole-Aitken (SPA) basin represents the principal major lunar terrain that remains unsampled, the NRC survey report observed. "Analysis of materials from the SPA basin thus is expected to provide key information regarding fundamental problems of the present-day surface of the Moon and its geologic history," the report explained.
High-tech teething
Pulling off such a spacecraft project would also offer engineers a bit of technological teething.
"Such a sample-return mission -- i.e., one of moderate technical difficulty -- is an opportunity to gain relevant experience for much more complex sample-return missions from Mars and, ultimately, Venus," the report said.
It's obvious that any autopilot Moon landing and return sample probe demands a heavy dose of high technology.
Automated descent, hazard avoidance and precision landing gear is critical. So too is advanced on-the-spot sampling, maybe even drilling, age dating and chemical sensing sensors. Then there's requirement for sample transfer into an ascent vehicle and need for Earth-return hardware.
Lastly, a relay satellite put in lunar orbit is also necessary for farside command and control of the spacecraft.
Add all that up, this mission is sure to ring up a good-sized bill.
Ball in NASA's court: love too?
NASA officials were reportedly surprised and somewhat dismayed to learn of the NRC's robotic lunar sample return recommendation.
Space agency officials, of course, could blow off the scientific community counsel, seeing it as misguided advice but that scenario doesn't appear likely.
"The Moon is the cornerstone and keystone for our understanding of the terrestrial planets, including Earth," said James Head, planetary geologist at Brown University in Providence, Rhode Island. "It's a centerpiece, holding together the emerging arch of understanding about the planets," he told SPACE.com.
Getting back to the Moon builds on the past, Head said, given the data yielded by both Apollo and past lunar robotic missions. "We can ask much more sophisticated questions of the Moon because of this important data base. This means that the return on our investment from further lunar exploration can potentially be much greater, and much more synergistic," he said.
Head said that a farside sample mission to the South Pole-Aitken Basin floor could test models of giant impact basin formation, depth of excavation, crustal thickness, impact melt formation, lower crust and perhaps mantle composition, and other parameters.
The ability to return samples from "the other half of the Moon", Head said, requires precursor technology development, ideal equipment for sampling other lunar locales and other airless bodies.
First come, first served
Lest anybody forget, automated landing, followed by touch and go Moon maneuvering, was a specialty honed decades ago by the former Soviet Union.
Luna 16 performed the first robotic sampling of the Moon in 1970. It spent some 26 hours on the lunar surface, rocketing back to Earth fragments of Moon stuff for later analysis.
Luna 20 followed in 1972, soft-landing in a mountainous area known as the Apollonius highlands. It plopped down roughly 75-miles (120 kilometers) from the Luna 16 site. The probe drilled into the lunar terrain and transferred bits and pieces of the Moon into a sealed capsule. Capsule and contents blasted off the Moon and parachuted into the Soviet Union a few days later.
The last in this Soviet series of Moon robots was Luna 24 in 1976. It set down in Mare Crisium, also returning to Earth a small, but treasured load of lunar turf.
For the United States, during 1966 into 1968, NASA's Surveyor Moon landers carried out research duties on the surface. However, these craft were not designed to shoot back samples. The heavy lifting and return of hand picked lunar specimens was assigned to Apollo moonwalkers.
According to Jim Burke, a former Jet Propulsion Laboratory engineer who managed America's first series of crash-landing Ranger lunar flights, a South Pole Aitken Basin mission is technically feasible.
"In an ideal world, we would just go and do it with Soviet technology. But in the real world, the 1970s were a long time ago," Burke said. "Chances are that the whole thing would be a new design, generations of engineers being what they are. I sometimes offer the analogy of little sea turtles hatching and having to find their own way," he said.
Backyard digging
A strong advocate for sampling South Pole-Aitken is Mike Duke, a space geologist at the School of Mines in Golden, Colorado.
"It's an important lunar science mission," Duke said, "to a region of the Moon that is distinctly different from any area sampled by Apollo or Luna missions. It will address some fundamental issues of early solar system evolution, as well as provide the deepest sampling of the early Moon."
Duke said that fresh lunar material to study would reinvigorate the geochemistry/cosmochemistry community of scientists. Antarctic meteorites have saved their day, he said, but a program of new Moon sampling would spur exciting science, including new instruments and research techniques.
"The planetary program is moving from an era of flybys and orbital reconnaissance to an advanced era of surface exploration and sample returns. It is not only scientifically valuable, but logical that NASA should start with the Moon& it's in our backyard," said Wesley Huntress, Jr., Director of the Geophysical Laboratory at the Carnegie Institution of Washington, located in Washington, D.C.
Huntress said that samples returned by Soviet Luna craft and Apollo were all from the upper crustal portion of the Moon's side that faces Earth.
"The USSR accomplished the first robotic sample returns from the Moon in the 1970s, but these missions required special celestial circumstances, allowing return from only very specific sites at very specific times. Now, 30 years later, technology has advanced where this can be achieved from anywhere on the Moon for much less mass and cost," Huntress said.
Getting back to the Moon is of high scientific importance, said lunar scientist David Lawrence of the Los Alamos National Laboratory in New Mexico.
"Unfortunately, I think there may be a general impression that because we have samples from nine locations -- six Apollo and three from Luna -- we already know everything that is to know about the Moon," Lawrence said. "This is quite silly. That's like saying you picked up a few samples from the American Southwest and Midwest and claiming you know all about the Earth from these samples," he said.
"There is still much to learn about the Moon using samples. And the South Pole-Aitken basin is a great place to return and learn more," Lawrence said.
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