You know that Apollo astronauts visited craters on the moon, but did you know that some of them also visited Craters of the Moon right here on earth?
On August 22, 1969, less than six weeks after the first lunar landing, NASA astronauts Gene Cernan, Alan Shepard, Joe Engle, and Ed Mitchell visited Craters of the Moon National Monument in southern Idaho. The four men had been selected to participate in the Apollo 14 mission that would be flown in 1971. All were superbly trained astronauts with a wealth of experience to call on. Cernan had, in fact, already paid an orbital visit to the moon. (He was the lunar module pilot of the Apollo 10 mission, the "dress rehearsal" for the Apollo 11 lunar landing.) None of the men was a trained geologist, though, and that was the rub.
Lunar rocks are very difficult and expensive to collect (only about 850 pounds have ever been brought back to earth), so it’s very important that lunar astronauts be able to recognize the most valuable specimens to collect. It’s also essential that astronauts be reasonably skilled at recognizing various volcanic features and forms they might encounter on the moon so they can describe them accurately to geologists back on earth.
To acquire and practice these essential skills, lunar astronauts need hands-on experience with volcanic landforms and rocks similar to those found on the lunar surface. The places best suited to that purpose have reasonably fresh volcanic deposits and a variety of volcanic landforms not badly weathered or obscured by vegetation. Hawaii and Iceland have volcanic landscapes like that, and both have been venues for astronaut training. Another wonderful place to get the job done is Crater of the Moon National Monument.
Proclaimed on May 2, 1924, and subsequently expanded half a dozen times, Craters of the Moon National Monument & Preserve (as the two-unit complex is now called) encompasses three major lava fields sprawling over hundreds of square miles of sparsely-vegetated terrain in southern Idaho’s great Snake River Plain. This volcanic landscape is replete with fissure vents, lava flows, lava lakes, spatter cones, cinder cones, cinder crags, cinder blocks, rafted blocks, lava tubes, explosion pits, subsidence craters, squeeze-ups, basalt mounds, and other volcanic features and forms resulting from eruptions that occurred over the last 15,000 years (including some as recently as 2,000 years ago). The volcanic fissures that contributed the lava are now dormant, but not extinct. This means that they could – at least in the span of another thousand years or so – erupt again.
The four astronauts did not have time to see much of the park during their brief visit on that long-ago August day, but you can rest assured they saw plenty of interesting volcanic features and measurably increased their store of relevant knowledge.
It’s hard to tell precisely how the Craters of the Moon visit contributed to the overall success of the Apollo 14 mission. While everyone knows that Apollo 14 had much better luck than the ill-fated Apollo 13 (and that Apollo 14 commander Alan Shepard hit two golf balls on the moon with a makeshift club), the nuances of rock gathering and related geologic description for that particular mission haven’t been publicized much and don’t seem to relate clearly to the Craters of the Moon training. In any event, lunar terrain photography, including photos taken to document the rock sampling, undoubtedly had much greater scientific value than any personal observations the astronauts could have made.
In case you are interested, the more than 90 pounds of lunar rocks that Apollo 14 brought back were mostly breccias:
The Apollo 14 landing site was in the Fra Mauro formation, which is material ejected by the impact that produced the Imbrium Basin. As one would expect in a region formed by impact-basin debris, most of the 42 kilograms of rocks and soil collected on Apollo 14 are breccias (rocks that are composed of fragments of other, older rocks). The countless impacts that have sculpted the Moon's surface broke many rocks down into small fragments. The heat and pressure of such impacts can sometimes fuse these fragments into new rocks, called breccias. In some cases, the rock fragments that form a breccia are themselves breccias. Such rocks obviously have experienced complex histories with multiple generations of impact events.
Postscript: The four astronauts had careers that certainly did not move in lock step after the August 1969 park visit. Alan Shepard commanded the Apollo 14 mission and became the fifth person to walk on the moon. Ed Mitchell, whose only flight into space was as the lunar module pilot of Apollo 14, became the sixth person to walk on the moon and spent nine hours there. Gene Cernan went to the moon twice (Apollo missions 10 and 17), spent more time there than anyone else, and on December 17, 1972, became “the last man to walk on the moon” while serving as Apollo 17 commander. Joe Engle never did get to the moon, though he was an Apollo 14 backup lunar module pilot and was scheduled to go on Apollo 17 before he was replaced by NASA scientist Harrison Schmitt, who had been scheduled for Apollo 18 (cancelled due to budget cuts). In 1999, Cernan, Mitchell, and Engle all returned to Craters of the Moon to participate in the park’s 75th anniversary celebration. Alan Shepard might have been there too had he not died of leukemia in 1998.