The life of an asteroid is lonely. The rocks spend eons drifting through the cold vacuum of space.
But on Wednesday, the asteroid Ryugu welcomed a special visitor: Japan's Hayabusa 2 probe landed successfully at 21:06 on the surface of the asteroid. ET.
The Japan Aerospace Exploration Agency (JAXA) launched Hayabusa-2 into space in December 2014. Their mission: to explore and extract samples from Ryugu, a half-mile-diameter primitive asteroid orbiting the sun at a distance of up to 1 km 211 million kilometers.
The probe reached its target in June 2018, then went to work, taking observations, measuring the gravity of the asteroid and rehearsing the touchdown. He blew up the asteroid in April with a copper plate and a box of explosives to dislodge stones and expose material beneath the surface, and then successfully landed on Ryugu last night to pick up the remains of rock and soil.
The spaceship picked up the images below as it left the surface of the asteroid.
"The first photo was taken at 1
Ancient rock samples
Asteroids are made of rock and metal All kinds of quirky shapes, from pebbles to 600-mile megaliths. Most of them cavort in the asteroid belt between Mars and Jupiter, although Ryugu's orbit sometimes runs between Mars and Earth.
Some asteroids date back to the dawn of our solar system 4.5 billion years ago, when material remnants of planetary formation formed in these rocks. In this sense, asteroids can serve as time capsules: what scientists find in these primitive rocks could tell us much about the history of the solar system.
Ryugu is a C-type asteroid, meaning that it is rich in organic carbon molecules, water, and possibly amino acids. Amino acids are building blocks for proteins and were essential for the development of life on Earth. Some theories assume that an asteroid first brought amino acids here to give our planet the seeds of life, though it is still being discussed.
About three-quarters of the asteroids in our solar system are of type C. Hayabusa-2 is said to be the first mission to return samples of such an asteroid to Earth.
The probe originally landed on Ryugu in February, collecting shallow samples just below the surface. However, the mission leaders decided to also collect some deeper rock samples as this material was not exposed to extreme weather conditions from space. To accomplish this, the probe had to lift the asteroid and then blast a 10-meter crater into the surface to access the rock below.
So in April, Hayabusa-2 released a box of explosives in space and detonated them, firing a copper plate into the asteroid.
The landing on Wednesday then caused a stir in all the released material.
"These images were taken before and after placement with the small monitor camera (CAM-H). The first is 4 seconds before touchdown, the second is at touchdown and the third one is 4 seconds after touchdown, and on the third picture you can see the amount of stones rising, "JAXA tweeted.
After setting up, Hayabusa-2 collected a new set of samples and left Ryugu's surface. The 9-million-kilometer journey home will begin at the end of this year. So far, everything is on schedule.
NASA is on a similar mission.
NASA is also investigating a distant asteroid.
The agency's OSIRIS REx mission reached a much smaller type C, Bennu asteroid in August 2018. However, the probe did not land on Bennu's surface. instead, it revolves at a record-breaking distance.
It is planned that OSIRIS-REx will approach Bennu's surface in July 2020, but the spacecraft will only make contact for about five seconds. During this brief moment nitrogen gas is blown in to stir up dust and pebbles and collect the samples. If everything goes according to plan, it will bring this material back to earth in 2023.
The surface of the asteroid, however, is rougher than expected, and debris flying from space rock can pose a threat to the orbiting spacecraft. So NASA still chooses its location for sampling.
But Bennu already has a significant finding: Before the probe entered orbit around Bennu in December, it discovered that the asteroid contained constituents for water (oxygen and hydrogen atoms bound together). Although Bennu is too small to absorb liquid water, there is a possibility that there was water on its parent asteroid, which Bennu broke free from 700 million to 2 billion years ago.
Although the NASA asteroid exploration mission will collect more sample than the Japanese, the JAXA team hopes that comparing the samples from two different sites on the same asteroid will provide new information about how the asteroids look over a longer period in space change time.
Both Bennu and Ryugu could teach scientists much about the history of the solar system and possibly, if they contain organic materials, about the origins of life on Earth.