Final answer:
Satellites like the Mars Global Surveyor provide a safer, less costly, and more efficient means of mapping and studying Mars' surface compared to manned missions. They are capable of high precision and autonomy, which is critical due to communication delays across space. These technologies have led to significant discoveries on Mars without the risks associated with astronaut travel.
Step-by-step explanation:
The advantages of using satellites to map the surface of Mars rather than sending astronauts include significant reductions in risk, cost, and complexity. Satellites like the Mars Global Surveyor have facilitated detailed mapping of Mars' topography with precise measurements and high-resolution photography, which has led to crucial discoveries such as gullies potentially formed by surface water and large subsurface hydrogen deposits, likely indicating frozen water. Remote sensing technology, such as laser altimeters on satellites, are efficient tools to gather data about planetary surfaces without the need for human presence, which considerably lowers the potential for human error, such as the unfortunate mishap with NASA's Mars Climate Orbiter due to unit conversion errors.
Moreover, missions to outer planets like Mars necessitate highly reliable spacecraft capable of autonomy due to the delayed communication times across the vast distances of space. Satellites need to carry their own power sources, like solar panels or nuclear generators due to the insufficiency of solar energy when far from the Sun, and must maintain optimal operating temperatures with heaters. These machines can act independently and are equipped with powerful transmitters to relay data back to Earth, making them indispensable for data collection and communication.
Projects such as Pathfinder, Mars Odyssey, and Mars Reconnaissance Orbiter, among others, highlight the successful use of satellite technology in planetary exploration, reinforcing the justification of using satellites for surface mapping and study over the more dangerous and expensive manned missions. These robotic missions offer a prudent approach to exploring and study space, allowing researchers to gather vital information while avoiding the risks that would come with human exploration.