Where to Land?

In addition to technology development questions, there was the nettlesome issue of where to land. Soffen, the chief scientist, organized a special team of researchers, including exobiologists, to determine the best places from their point of view. They had Mariner 9 information, but not much else. Throughout 1972, the siting team argued over options. NASA wanted a siting decision by the end of 1972, but the scientists could not agree.

In November 1972, Lederberg came to Fletcher’s office and pounded on his desk. He complained that the polar region was not being given adequate consideration because “the engineers”—Lederberg’s shorthand for Martin and his project management officials—had not done their homework on the po­tential of the polar region for finding life.17 The difficulty “the engineers” had was to balance safety in landing with Lederberg’s preferred site. Indeed, the scientists on the siting team were sharply divided on the polar issue. Sagan, for example, favored equatorial sites as possibly wetter and thus more amenable to life. In a letter to Martin, he pointed out that most water at the poles was frozen, and the biology package could not “detect organisms which extract their water from ice.”18

NASA decided to delay the decision on siting to 1973. In February of that year, Fletcher asked Naugle two questions, reminding him that it was impor­tant to emphasize the “possibility of finding life” in choosing a place to land. Fletcher’s first question was whether Lederberg and the scientists believed that the best chances of finding life were at the 73° polar latitude, and the second was whether liquid water had to exist “now [Fletcher’s emphasis] or could it have existed once, for life ‘signatures’ to be detected?”19

Naugle told Fletcher the answer to his first question was “no!” The optimal place to find life was where there was liquid water. As for Fletcher’s second question, “signatures” of life could be found not only where there was now but where there had been liquid water in “the distant past.” The problem, however, was that Viking might “not be able to distinguish between biological and non­biological types” of signatures.20

In early April, Lederberg conceded that 73°N, his preference, was not viable, or at least not acceptable to those emphasizing safety. That did not end the debate, which one NASA official trying to facilitate agreement called “trau­matic.”21 Finally, in late April 1973, Fletcher got a consensus view, which was announced May 7. There would be two prime sites and two backups. All four were chosen with particular emphasis on the possibility of finding water and life. However, safety in landing took equal or even greater consideration. The debate had lasted one year.

The first region, called Chryse, was at the northeast end of a vast 3000-mile rift canyon near Mars’s equator. The second, called Cydonia, was farther to the north and east, but not as far north as Lederberg had originally wanted. It was near a polar cap (44.3°N) where the scientists hoped water might be left from a previous melting. Backup sites featured similar considerations.22