The Flagships of the Space Fleet; The Future of Space Exploration; Scientific American Presents; by Staff Editors; 14 Page(s)

Few sights are as awe-inspiring as the liftoff of a space shuttle. Propped on its pair of solid-rocket boosters, the shuttle towers over the launchpad at the Kennedy Space Center in Cape Canaveral, Fla. Hundreds of engineers and technicians man the consoles in the Launch Control Center, monitoring the shuttle's systems as the countdown proceeds. Half a minute before liftoff, the shuttle's onboard computers take over the launch sequence, and at T minus six seconds they send the command to start the main engines. Fiery exhaust billows downward from the shuttle's three rocket nozzles. At T minus zero, the solid-rocket boosters ignite, the umbilical lines retract and the shuttle climbs into the sky with 3.6 million kilograms (eight million pounds) of thrust.

The space shuttle grabs the public's attention-and a big share of the budget of the National Aeronautics and Space Administration-because it carries astronauts into orbit. But it is by no means the only vessel in the space fleet. In recent years, NASA has sent unmanned spacecraft to explore Jupiter, Saturn, the asteroid belt and the moon. What these missions lack in personality they make up for with remarkable discoveries. The Galileo spacecraft, for example, has returned spectacular images of Jupiter's moons and that planet's Great Red Spot. Closer to home, the Lunar Prospector probe has found evidence of ice on the poles of Earth's moon.