WASHINGTON, Oct. 27 —The geologist‐astronaut who will go to the moon on Apollo 17 said today there was “a good chance” that the mission would uncover both some of the youngest and some of the oldest lunar rocks ever examined by man.
Dr. Harrison H, Schmitt, the first scientist assigned to an Apollo crew, described Apollo 17's planned landing site during a lunar science briefing at the headquarters here of the National Aeronautics and Space Administration.
Samples to Be Sought
On the nation's final moon mission under the Apollo program, scheduled for launching Dec. 6, Dr. Schmitt and Capt Eugene A. Cernan of the Navy, the flight commander, plan to set their lunar module down in a valley covered with dark cinder‐like soil and surrounded by towering cliffs.
The site, near the southeast edge of the Sea of Serenity, is called Taurus‐Littrow, after the nearby Taurus Mountains and Littrow Crater. While the two astronauts are collecting samples and setting up scientific instruments there, Comdr. Ronald E. Evans of the Navy, the third man in the crew, will be piloting the command ship in orbit.
One objective of the moon explorers will be to gather samples from what appears to be a rock slide at the base of a steep‐walled 7,000‐foot mountain. The rock slide could include debris from the top of the mountain, which Dr. Schmitt said could be early crusal maAerial and possibly well over four billion years old.Continue reading the main story
Some of the dark materials overlaying the valley floor, Dr. Schmitt said, could turn out to be volcanic cinders as relatively young as a billion years old. The general nature of the valley floor has been determined by bouncing radar signals off the surf ace,
A third area that Dr. Schmitt and Captain Cernan hope to explore is called the Sculptured Hills, where the geologist‐astronaut said, “We really don't know what to expect.”
The oldest lunar rocks brought back by the Apollo missions thus far were crystallized about 4.25 billion years ago—about 400 million years after the moon was formed. The youngest were about 3.1 billion years old.
If the Apollo 17 astronauts could bring back even older and younger rocks, scientists should he able to expand their knowledge of the series of cataclysms that shaped the moon's evolution by melting and remelting the surface and gouging deep Into the interior.
Range of Rock Ages
At the briefing, Dr. Oliver Schaeffer of the State University of New York at Stony Brook reported that his analysis of the rocks brought back by Apollo 16 had shown them to range in age from 3.98 billion to 4.25 billion years.
But Dr. Gerald J. Wasserburg of the California Institute of Technology reported finding one Apollo 16 rock that seems to have undergone two distinct melting steps. The bulk of the “two‐history rock,” Dr. Wasserburg said, crystallized 3.93, billion years ago, but it retains some tiny crystals that. were formed 4.4 billion years ago.
The puzzling rock — labeled 65015 — is rich in such radioactive elements as uranium, thorium and potassium, Dr. Wasserburg said. A similar rock was discovered in the Apollo 12 samples.
The first crystallization of the rock was probably associated with the great heat during the moon's formation. But scientists said they had no clue to what had caused the second period of melting and recrystallization.
Dr. Paul W. Gast, a geochemist at the Manned Spacecraft Center in Houston, said that scientists studying some of the Apollo 16 samples suspected that one of the large craters at the landing site may have been carved out by the impact of a comet.
The trapped gases in the samples were similar to those in comets, Dr. Gast said.
Dr. Noel Hinners, chief scientist at the NASA headquarters, said that the wealth of data from the Apollo project should keep scientists busy for about 10 years after the final mission in December.Continue reading the main story