America's space agency is nearing completion of a vehicle that will search for evidence of past life on Mars. It is too cold and dry for life to exist on the surface of Mars today. But scientists hope the rover will find evidence of life that once lived on the planet.
The rover will make the trip to the red planet later this year, and start preparing for NASA's mission to send humans into deep space.
NASA recently showed off its Mars 2020 rover. It has four wheels and is about the size of a car. The rover will be sent to Florida's Kennedy Space Center in three parts. It will be put together there. The vehicle's official name will be chosen soon.
Launch is set for July. The following February, the rover will land in the 250-meter-deep Jezero Crater – a dry lake bed that is bigger than New York's Manhattan. Billions of years ago, it was a deep lake, but as the climate changed there, it dried up. Scientists believe that the crater holds many sediments in great condition—some may be 3.5 billion years old. They hope the rover will find fossils—remains of plants or animals that once lived on Mars.
"The trick, though, is that we're looking for trace levels of chemicals from billions of years ago on Mars," Mars 2020 deputy project manager Matt Wallace told Reuters. The rover will collect up to 30 samples, or small amounts, of soil. NASA plans to have them picked up and returned to Earth by a future spacecraft.
“不过，诀窍在于，我们正在寻找数十亿年前火星上痕量的化学物质，” 2020年火星项目副经理Matt Wallace告诉路透社。流动站将收集多达30个样品或少量土壤。美国宇航局计划让他们将它们捡起来，并由未来的航天器送回地球。
Mars 2020 research will also be very important for future human missions to the red planet. It is carrying equipment that can turn carbon dioxide, which is everywhere on Mars, into oxygen for breathing.
If successful, Mars 2020 will mark NASA's fifth Martian rover to carry out a soft landing. Important lessons were learned from the most recent Curiosity rover, which landed on the planet's surface in 2012. It continues to move and work on the Martian surface southeast of the Jezero Crater.
The former Soviet Union is the only other country to land a rover on Mars. But it did not deploy. China and Japan have attempted to send orbiters around Mars. India and Europe's space agency have successfully sent an orbiter to the planet.
Words in This Story：
mission – n. a task or a job that someone is giving to do
sediment – n. material like stones and sand that is carried into water by water or wind
trace – n. something, like an object, which shows that someone, or something, was in a particular place