Scott Thybony's Canyon Commentary: Island In The Sky

Jul 12, 2019

Flagstaff astrogeologist Eugene Shoemaker played a key role in the early days of lunar exploration as a world-renowned expert on impact craters. But he also had a passion for rivers. Commentator Scott Thybony once took a trip with Shoemaker to Island in the Sky, a mesa within Canyonlands National Park. That’s where Shoemaker told him about swimming Lava Falls Rapid in the Grand Canyon on a trip to retrace John Wesley Powell’s exploration of the Colorado River.  In Scott’s latest Canyon Commentary, he connects next week’s 50th anniversary of the Apollo moon landing with this year’s 150th anniversary of Powell’s historic river trip through the life and work of Eugene Shoemaker.

Flagstaff astrogeologist, Eugene Shoemaker, on the Colorado River
Credit Courtesy of Grand Canyon River Guides


Island in the Sky rises above the confluence of the Green and Colorado Rivers, and a deep crater on top has long puzzled scientists.  Gene Shoemaker, the world’s foremost authority on impact craters, was certain it had resulted from an asteroid colliding with the earth millions of years before.  He was in his natural element among the geologists who had gathered to debate the origin of the enigmatic feature.  I sat next to him, fascinated by the interplay of ideas.  Shoemaker, dressed for the field in a khaki shirt and jeans with a silver Indian buckle, presented a convincing argument.  But knowing how geologists like to keep their feet on the ground, he wasn’t surprised by their resistance to his extraterrestrial theory.

Back in Moab he told me, “Geologists are not comfortable with big things falling out of the sky.  But there’s lots of rocks in the sky.  The earth resides in a vast asteroid swarm.  You can lie on your back and see meteors coming every night.”  Long drawn to the sky above, Shoemaker recounted how he had planned to walk on the moon one day, and how that plan had come to an abrupt end.

After earning a PhD in geology from Princeton, based on a study of Meteor Crater, he expected to be at the front of the line when they began choosing astronauts.  But he had to shift direction when a medical condition kept him from qualifying.  If he couldn’t go to the moon, he would bring the moon to him.  He established the astrogeology branch of the U.S. Geological Survey, and as chief scientist directed the mapping of the moon and helped select the landing sites.  To train the astronauts, they built craterfields in the Verde Valley and outside Flagstaff to simulate the lunar surface.  All of this was in preparation for a wildly ambitious plan to land the first humans on the moon. 

During the run-up to the Apollo 11 voyage, Shoemaker learned of plans to celebrate the centennial of John Wesley Powell’s expedition down the Colorado River.  It was the perfect time to set in motion his idea of retracing the 1869 journey.  The astrogeologist and his friends ended up spending three months floating through the canyons and matching the original photographs taken on Powell’s second trip.  When Shoemaker reached Lava Falls rowing his own boat, he miscalculated and dropped into a huge, crashing hole.  The tremendous power of the water battered his boat, forcing him to swim the rest of the rapid.  Even without going into space, he managed to find an adventure on his home turf.

The Powell expedition reached the confluence of the Green and Colorado Rivers on July 16, 1869.  A hundred years later to the day, astronauts onboard the Apollo 11 spacecraft lifted off for the moon.  During the televised lunar walk, Shoemaker sat next to Walter Cronkite and explained to a global audience the science behind the mission.

In 1992 Gene Shoemaker received the National Medal of Science, the country’s highest scientific award.  And then, while investigating impact craters in Australia five years later, he died in a car accident.  As a tribute to him, NASA placed an ounce of his ashes onboard the Lunar Prospector.  Upon completing its scientific mission the spacecraft was sent crashing into Shoemaker crater, named in his honor.  Half a century after he first dreamed of standing on the lunar surface, the astrogeologist finally reached the moon. 

Scott Thybony is a Flagstaff-based writer. His Canyon Commentaries are produced by KNAU, Arizona Public Radio.