What’s Next?

Beyond the Moon To Mars

Encore: What’s Next

Dr. Andrew Chaikin, book cover photograph. Banner image of Moon-Mars occultation, copyright, andrewchaikin.com.

Parts 1 * 2 * 3

NASA Research Park (NRP) launched a new Exploration Lecture Series at NASA Ames Research Center, to feature top researchers and academics, who will examine new technologies for human and robot-based exploration, as well as on-going and planned space exploration missions. The first lecture, “The Moon, Mars and Beyond,” featured Dr. Andrew Chaikin, author of “A Man on the Moon: The Triumphant Story of the Apollo Space Program.” The book was the basis for Tom Hanks’ HBO miniseries “From the Earth to the Moon,” which won an Emmy for best miniseries in 1998.

Chaikin has authored and edited several popular books about space, including “The New Solar System,” “Air and Space: The National Air and Space Museum Story of Flight,” “Apollo: An Eyewitness Account,” and ” Full Moon,” a collection of Apollo photography. Chaikin’s most recent book, “SPACE: A History of Space Exploration in Photographs,” was published in 2002 by Carlton Books.

Moon occulting Venus, the morning star, taken by the lunar probe, Clementine.
Credit: NASA/DOD/

A graduate of Brown University, Chaikin served as executive editor for space and science at Space.com until 2001 and was editor of Sky and Telescope magazine for many years. Chaikin is currently a commentator for National Public Radio’s Morning Edition program.

During Dr. Chaikin’s public lecture, he described the Moon-Mars exploration as ‘exciting and tremendously challenging’. His lecture featured a spectacularly symbolic image that he photographed from central Florida during last year’s closest approach between Mars and Earth–the nearest such view towards our sister planet seen in recorded history. Using a Celestron Nexstar 11-inch telescope and a webcam, Chaikin captured an occultation of Mars by our own Moon in silhouette. Six months later, the blue-ribbon Presidential Commission studying transits to the Moon, Mars and beyond formed with the same image in mind: How best to hopscotch humans safely to the moon first, followed by the challenging trek to Mars?

Chaikin’s perspective is unique since he had unparalleled access to the 23 living astronauts who pioneered the Apollo exploration of the Moon. Chaikin noted that humans left the moon for the last time, thirty-one years ago. While posing the question, What can we learn from the Apollo astronauts about going back to the moon and onwards to Mars in the coming decades?, Chaikin recalled a story told to him by Bob Gilruth, a key mission planner at the Johnson Space Center during Apollo. Gilruth was walking on the beach while a full moon was out. He looked up to the light-grey, shining disk and said, “Someday, they’re going to want to go back to the moon, and they’ll realize how difficult it is.”

On December 11, 1972 – thirty-one years ago- the astronauts of Apollo 17 eased their Lunar Module into a landing, beginning the last human excursion to the Moon. Three days later, Eugene Cernan and Harrison Schmitt blasted off from the lunar surface to rejoin crewmate Ronald Evans in the Command/Service Module. The crew circled the Moon for another forty-eight hours or so, fired the spacecraft’s thruster, and left the Moon behind for the next three decades.

During their brief stay on the Moon, Commander Cernan and geologist Schmitt crisscrossed the local terrain in their Lunar Rover, conducting a variety of experiments and gathering Moon rocks to bring home. Thirty year later, there’s a resurgence of interest in returning to the Moon.

The Moon is believed to play an important role in Earth’s habitability . Because the Moon helps stabilize the tilt of the Earth’s rotation, it prevents the Earth from wobbling between climatic extremes. Without the Moon, seasonal shifts would likely outpace even the most adaptable forms of life.

SMART mission surveys the moon.
Credit: ESA

In addition, because our moon is lifeless, it is one of the most appealing places to look for the preserved records of life elsewhere. At least according to recent estimates for the amount of ejected rocks that might survive there, the Moon may hold clues from the early history of Mars, Venus and Earth. Unfortunately, the very early geological history of Earth has been nearly completely obliterated by the actions of tectonics, weathering, and biology; on our home planet the earliest rock records date back about 3.8 billion years but no further.

Scientists John Armstrong and Lloyd Wells of the University of Washington in Seattle and Guillermo Gonzalez of Iowa State University argue for resuming human missions to the Moon to collect not Moon rocks, but Earth rocks. Early in Earth’s history, a rain of comets known as the Late Heavy Bombardment may have blasted bits of Earth’s surface into space; some of the material might now lie strewn across the lunar surface. The rocks might even contain fossil evidence of the earliest life on Earth life, the researchers say.

Earth and Moon
Low resolution animation of simulated flight from Cape Canaveral to lunar orbit. Video in Streaming Video and QuickTime Credit: NASA/GSFC Visualization. The visualization was done by Marit Jentoft-Nilsen working for the NASA’s Earth Science Enterprise in the Visualization and Analysis Lab at Goddard Space Flight Center.

Scientist Kevin Zahnle of NASA Ames Research Center adds that studying the existing collection of Moon rocks returned by Apollo 17 and the five earlier lunar landings could help test techniques for searching for Earth rocks on the Moon. And NASA astrobiologist David McKay of Johnson Space Center has remarked that, to his knowledge, no one has searched the collection of Moon rocks for Earth minerals.

The Moon, however, still retains some of the earliest records of the formation of the Earth-Moon system. Leading models suggest a very early origin of the Moon as a result of the collision of a Mars-sized body with the newly formed Earth. Samples from the Apollo and Luna programs elucidated some of this history, but the nature of these samples, limited to equatorial regions of the lunar near side, leaves many key questions unanswered.

The Moon’s South Pole-Aitken Basin, one of the largest impact structures known within the solar system, exposes material from deep within the crust and possibly even the upper mantle that was excavated by the impact. In addition, the floor of this basin probably retains impact melt rocks created by the giant impact. Apollo experience shows that such melt rocks provide insight into the average composition of the basin, and that by dating such samples we can infer the age of the basin itself. This will help to resolve questions that are raised by the observed cratering record of the lunar highlands, with important implications for the early history of the Moon and all of the terrestrial planets, including Earth. Analysis of ancient lunar material will thus provide critical insights into the processes that occurred on Earth and the other terrestrial planets during their early history.

For more than 40 years, the Moon has been visited by automated space probes and by nine manned expeditions, six of which landed on its surface.

Most recently on the night of September 27th, 2003, Europe’s lunar probe called SMART-1 launched on a technology demonstration mission to the moon. Much remains to be learnt about our closest neighbour, and SMART-1’s payload will conduct observations never performed before in such detail. The Advanced/Moon Micro-Imaging Experiment (AMIE) miniaturized CCD camera will provide high-resolution and high-sensitivity imagery of the surface, even in poorly lit polar areas. The highly compact infrared spectrometer will map lunar materials and look for water and carbon dioxide ice in permanently shadowed craters.

Although the recent history of lunar missions has been dominated by robotic probes, revisions to the future timeline may be forthcoming if the Presidential Commission on Moon to Mars and Beyond continues to develop towards fruition. As Chaikin noted in his lecture series on the subject, it remains a remarkable realization however, that it was 31 years ago that the last human left the moon.

Recent Lunar Timelines

Lunar Clementine mission shows the South Pole of the Moon. The permanently shadowed region center showed earlier evidence of meteor cratering and ice never exposed to direct sunlight, but Arecibo radar reveals dust.
Credit: NASA/DOD Clementine

– Japanese Hiten, Lunar Flyby and Orbiter
– Michael Rampino and Richard Strothers propose Earth could be periodically struck by comets dislodged from orbits when the solar system passes through galactic plane
– US Dept. Defense/NASA Clementine mission, Lunar Orbiter/Attempted Asteroid Flyby
– First commercial lunar mission, AsiaSat 3/HGS-1 , Lunar Flyby
Lunar Prospector launches and enters lunar orbit
Lunar Prospector tries to detect water on the Moon (polar impact)
– Lunar soil samples and computer models by Robin Canup and Erik Asphaug support impact origin of moon
SMART 1, to launch lunar orbiter and test solar-powered ion drive for deep space missions
– Japanese Lunar-A, Lunar Mapping Orbiter and Penetrator, to fire two bullets 3 meters into the lunar soil near Apollo 12 and 14 sites
– Japanese SELENE Lunar Orbiter and Lander, to probe the origin and evolution of the moon

Related Web Pages

JPL Rovers
Spirit’s images and slideshow
Opportunity image gallery and slideshow
Making the Moon
Review of Theories of Moon-Forming Impact (Planetary Science Institute)
Big Bang, New Moon (SwRI)
Ion Drive to the Moon
SMART-1: Chips Off the Terrestrial Block
Treasures from the Lunar Attic
Lunar Scarface
End of an Era, Dawn of Another?

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