Descartes is selected

On 3 June 1971, the Apollo Site Selection Board approved Descartes as the landing site for Apollo 16. That decision set into motion a series of events that ranged from mission-specific orbital mechanics and lunar landing simulation planning, to field geologic training and traverse simulations in the Grover for Young and Duke, and much more besides. As with Apollo 15, specific station stops and timelines were established for the Lunar Roving Vehicle traverses and the contingency walking traverses for each of the three EVAs.

The main components of the Saturn V eventually used for SA-511 arrived at the Cape between the summer of 1970 and the fall of 1971. LRV-2 arrived from Boeing on 1 September 1971. After a complete checkout, including crew fit and function tests (as had been done with the crew of Apollo 15), the LRV was folded and stowed on Orion in mid-November. The Lunar Module was then secured within the tapered Spacecraft/Lunar Module Adapter. On top of the adapter was then assembled the combined Command and Service Module. This entire assembly was moved to the Vehicle Assembly Building in December. Within the VAB, a crane lifted it more than thirty storeys for it to be attached to the Saturn V's instrument unit. SA-511 was now a complete space vehicle. After several more weeks of checkout, the Saturn V was ready. On 13 December, the crawler-transporter, carrying the Saturn V on the launch platform, left the VAB at its programmed one mile per hour. Weighing a combined 5.7 million kg and towering more than 120 m high, it was the largest and heaviest man-made machine ever to move across the surface of the Earth. It never failed to inspire awe in those who watched it slowly make its way along the crawler way to Launch Complex 39 some 5.6 km away.

Once the Mobile Launch Platform was secured at Pad 39A, several weeks of planned systems integration and testing commenced. However, the failure of a component in the Command Module's Reaction Control System was serious enough to require the entire launch vehicle be returned to the VAB. This and other issues that arose pushed the launch date of Apollo 16 from 17 March back to mid-April. The Apollo 16 prime and backup crews continued their simulator and EVA training and reviews of the mission profile up to the day before the launch.

On 6 April 1972, ten days before the scheduled liftoff of Apollo 16, NASA released the official 176-page Press Kit. It succinctly described the landing site:

"A hilly region north of the Descartes crater in a highlands area of the southeastern quadrant of the visible face of the Moon is the landing site chosen for Apollo 16. The Descartes site appears to have structural characteristics similar to volcanism sites on Earth, and has two separate volcanic features -Cayley Plains and the Descartes mountains - which will be extensively explored and sampled by the Apollo 16 crew.

John Young and Charles Duke participate in a mission traverse simulation on LRV-2 in the Manned Spacecraft Operations Building at Kennedy Space Center. Tests are also being conducted on their Lunar Module Orion. (NASA/KSC)

"The Cayley Plains segment of the landing site is characterized by terrain ranging from smooth to undulating - possibly as a result of fluid volcanic rock flow. The Descartes Mountains, part of the Kant Plateau, are characterized by hilly, furrowed highland plateau material that is thought to have come from a more viscous volcanic flow. Additionally, the Descartes landing site provides an opportunity to study the evolution of young, bright-rayed craters and to extend age-dating to similar craters in other regions of the Moon.

"The landing site has two basic areas which will be explored and sampled: Cayley Plains, including North Ray and South Ray craters; and Stone Mountain and Smoky Mountain of the South and North Descartes Mountains.

"The low crater density in the Cayley Plains suggests an Imbrian age for the rolling, ridged portion of Cayley in the Apollo 16 traverse area. Stone and Smoky mountains, on the other hand, appear to have shapes typical of volcanic formations on Earth - shapes that might be formed by movement of rather viscous material.

"North and South Ray craters appear to penetrate deeply into the Cayley formation and reveal the sequence of layering, perhaps through an overlap of both the Cayley and Descartes formations. Smaller, subdued craters in the landing site seem to have a characteristic concave bottom, which suggests that the substrata underlying the crater impact were more resistant than in other crater fields on the Moon.''

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