Mission to Mars
On July 4, 1997, space exploration took a huge step. On that day, a spacecraft called Pathfinder landed on Mars. The National Aeronautics and Space Administration (NASA) sent Pathfinder to discover new information about the Red Planet.
The mission was a complete success. After landing, Pathfinder sent a small rover (漫游机器人), Sojourner, onto the planet's surface. Sojourner explored more than 250 square meters of Mars. Together, designed Sojourner to last for only seven days, but little vehicle ran twelve times longer! Pathfinder surprised scientists, too. It sent back information for almost three months. That was three times longer than it was built to last.
Because Pathfinder and Sojourner ran for so long, scientists got more information than they ever dreamed of getting. For one thing, they discovered that Mars is very sandy. Pictures of sand dunes around the land site hint that Mars once had water. Scientists know that water means life. Was there ever life on Mars? We don't know yet. In addition, the Pathfinder mission told scientists that Mars is dusty. Huge "dust devils" on Mars spit enormous amounts of dust into the Martian air. Pathfinder also discovered frosty Martian temperatures at 200 degrees below zero Fahrenheit. At that temperature, a glass of water would freeze solid in just a few seconds.
In October, scientists lost Pathfinder's signal because the spacecraft's battery had run down. They tried to revive the signal but had no luck. The mission officially ended on November 4.
Scientists hope to use the knowledge from these missions to better understand how life on earth began. They will also use it to plan future Mars missions.
【小题1】What did NASA do to get information about Mars?| A．NASA sent the spacecraft Sojourner to Mars. |
| B．NASA sent engineers on a three-month space mission. |
| C．NASA sent the spacecraft Pathfinder to Mars. |
| D．NASA sent astronauts to run tests for seven days. |
| A．Scientists found out that Mars is very cold and dusty. |
| B．Scientists got more information than they ever dreamed of getting. |
| C．Scientists learned that Mars definitely had water at one time. |
| D．Scientists found out that there was once life on Mars. |
| A．dust devils on Mars made the photographs hard to see. |
| B．Martian temperatures caused Pathfinder's battery to fail. |
| C．scientists suspect that life on Earth began on Mars. |
| D．scientists will look for signs that life existed on Mars. |
