A Step Beyond by Christopher K Anderson

be Colonel Dmitri Komarov, Major Tatiana Pavlova, and Dr. Takashi Satomura.” Unlike the others, Satomura did not acknowledge his name with a nod or a smile. His expression remained unchanged, oddly impatient.
    “The Mars Excursion Modules will separate from the main vehicles and descend to the planet’s surface,” Nelson continued. “We will land at the base of Olympus Mons, approximately two klicks above mean planetary level.” The planet grew several times in size, and Nelson pointed at a spot at the base of a volcano with his pen. “Major Brunnet.”
    “Olympus Mons is the largest known volcano in the solar system,” Brunnet said. A large photograph of the volcano appeared on the screen. “It towers twenty-seven kilometers above the surface—three times higher than Mount Everest. The caldera is eighty-one kilometers across. The base of the volcano spans nearly six hundred kilometers. It also contains some of the youngest lava flows on the planet’s surface. The age of these flows is determined by crater density. This site will answer one very important geological question: When did volcanism cease on Mars? Rock samples from this region will be varied in age and chemical composition. They should provide a good cross section of Martian geological history.”
    “The decision to land on Olympus Mons was not without controversy,” Nelson said. “The elevation was thought by some to be too great to provide sufficient aerobraking, and the site too rocky for a safe landing. But geologically Olympus Mons holds considerable promise, and a majority of our scientists were determined not to pass it up. They chose a site lower than originally considered and reworked the landing strategy to compensate for the elevation. They also redesigned the landing gear to be able to handle less than perfect conditions.” Nelson scrolled the screen eastward and pointed to a spot inside a large, jagged canyon. “The team led by the Russians will land here. Commander Komarov.”
    “Like you,” Komarov said, “we were lured to a spot that holds great potential. Candor Chasma. Six degrees south, seventy-three degrees west. We are to land on a small mesa, one-point-three kilometers high. Candor Chasma belongs to the Valles Marineris canyon system. The system stretches nearly four thousand kilometers in length. To give you a better sense of the size, the Grand Canyon in America is only four hundred and fifty kilometers long. Valles Marineris would stretch the entire length of the United States. It is as much as seven kilometers deep, which is three times deeper than the Grand Canyon. We’ll be using an airship to explore the chasm. A dirigible, I believe you call it. But I will let Dr. Satomura describe the scientific value of this site.”
    “This region is interesting for many reasons,” said Takashi Satomura, stepping forward with a laser pen. “The walls of the canyon are layered. We believe the layers are from different periods of Mars’s geological past. They contain the history of Mars. And to some degree our solar system. To give an example, samples taken from the layers could be used to determine the climatic cycles of Mars. If these cycles correspond with those on Earth, such as the great ice ages, we can assume they were due to variations in the sun’s output.”
    “Or it could lend further credence to Milankovitch’s theory regarding the influence of planetary rotation upon climate,” Endicott remarked.
    “Of course,” Satomura said. “All depends on what we find.” He traced the outer perimeter of the canyon with his laser beam. “There are those who believe that the canyon could have been an ancient lake. We know that life on Earth began in the oceans approximately three and a half billion years ago. We suspect that conditions on Mars at that time were similar to those on Earth, and that Martian life may have lived in the waters that once filled this canyon.”
    Carter listened with amusement as the two