Two small Japanese robots landed on a distant asteroid last weekend.
The robots took small jumps, making it the first time that any device from our planet has moved on the surface of an asteroid.
The two machines, called rovers, landed on the asteroid Ryugu on September 21. The Japan Space Exploration Agency says they were lowered to the surface by an unmanned spacecraft called the Hayabusa2.
Asteroids are small, rocky objects orbiting around the Sun. They sometimes have been described as minor planets.
The Japanese spacecraft first arrived at Ryugu last June. It flew as close as 55 meters to the asteroid before it released the rovers. Hayabusa2 then rose back up to a waiting position about 20 kilometers above the surface.
The next day, Japan’s space agency, known as JAXA, released some pictures the rovers had sent back from the landing area. One shows the dark stone of Ryugu, with a bright line of sunlight lighting up the asteroid’s surface.
“I cannot find words to express how happy I am,” said JAXA project manager Yuichi Tsuda in a statement after the robots arrived.
The rovers are named MINERVA-II 1a and 1b. They are about the size of a can used to hold cookies. Their movements are powered by solar energy from the sun. The low gravity levels on the asteroid make rolling difficult, so the rovers move by taking jumps, up to 15 meters at a time.
They will continue moving across the surface, taking pictures and collecting information about temperature. The Japanese space agency says they will keep jumping as long as their solar equipment and power last.
A larger rover and lander will be released onto the surface from Hayabusa2 in the coming months.
You may be wondering why send a spacecraft millions of kilometers away to land on an ancient piece of rock traveling through space? Scientists believe that asteroids may provide information about the earliest days of our solar system, dating back some 4 billion years.
Ryugu orbits the Sun between Earth and Mars, and is a C-type asteroid—the most common type of asteroid in our solar system. Scientists believe some asteroids may contain organic matter and water. Ryugu may give researchers a window to see all the way back to the beginning of life itself.
JAXA hopes to find out just what Ryugu is made up of by collecting material from the asteroid’s surface and bringing them home to be studied. Hyabusa2 is set to try three brief landings on Ryugu to collect rock samples. The first attempt is expected to be in October.
Later this week, the spacecraft is set to release another lander onto the asteroid. The device is a project of the German and French space agencies. Known as MASCOT, it will be carrying four observation devices. The spacecraft will release a larger rover, called Minerva-II-2, in 2019.
Hyabusa2 will stay at Ryugu until late next year. Then it will fly back to Earth with the asteroid samples. JAXA expects the spacecraft to return home by 2020.
Scientists will study the samples to understand more about how planets were formed around the Sun in the early days of our solar system.
In time, these samples will be compared to ones the American space agency NASA hopes to get from the asteroid Bennu. NASA’s spacecraft was launched two years ago. It is expected to reach Bennu in early December.
NASA’s spacecraft will then take samples from the asteroid in 2020, and three years later they will return to Earth for scientists to study.
I’m Anne Ball.
Anne Ball wrote this story for VOA Learning English with information from The Associated Press. George Grow was the editor.
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Words in This Story
asteroid – n. any one of thousands of small planets that circle around the sun
cookie – n. a sweet baked food that is usually small, flat, and round and is made from flour and sugar
organic – adj. of, relating to, or obtained from living things
sample – n. a small amount of something that gives you information about the thing it was taken from