On December 6, 2020, the Japanese Hayabusa2 spacecraft dropped a capsule to the ground of the Australian Outback from about 120 miles or 200 kilometres above Earth’s surface. The capsule which reached the Earth contained some of the most precious cargo of the solar system; the rubble sample collected from the surface of asteroid Ryugu.
The spacecraft rendezvoused with asteroid Ryugu on June 27, 2018, and tucked rubble from the space rock fired its engines and started its two-year-long journey back to earth.
Following the story to date, NASA recently received its first sample of the asteroid. This is one of the first samples to leave Japan for preliminary investigation.JAXA decided to disperse samples of Ryugu to six teams of scientists around the globe so that these researchers will dig and inspect these ancient grains to understand more about their origins. The preliminary sample investigations and analyses are continuing at Johnson Space Centre.
A diamond in Space: Ancient Asteroid Ryugu contains ingredients for life
One of the darkest celestial bodies in the solar system, Asteroid Ryugu is an ancient leftover of a larger asteroid that formed in the cloud of gas and dust. The diamond-shaped asteroid is classified as a carbonaceous, or C-type asteroid, it is an intriguing type of rock in space that is rich in carbon which is an essential element considered for life.
The near-Earth asteroid Ryugu was discovered back in 1999 by the Lincoln Near-Earth Asteroid Research (LINEAR) project, a collaborative U.S. based project which aims to catalogue and track space rocks.
The Japanese space agency, JAXA, has estimated the asteroid to be about 2,952 feet or 900 meters in diameter. The space rock is classified as ‘potentially hazardous’ as it is orbiting the sun between Earth and Mars and crosses Earth’s orbit occasionally, although the asteroid poses no imminent danger to our world. According to the Japanese Space Agency, the asteroid spins around like a top, rotating every 7.6 hours.
It is interesting to note that the asteroid Ryugu, which is dark, dense and cold, has a name that means ‘Dragon Palace’ in Japanese. The name gets its origin from a Japanese folktale, referring to a magical underwater castle, where a fisherman visits the palace and returns with a mysterious box, much like the mysterious samples Hayabusa2 will be bringing back to Earth. Furthermore, the small asteroid’s features are all named for fairytales from around the world.
Bringing Samples Home: Mission to understand the genesis of life on Earth
Dust and rubble from Ryugu are currently 9 million miles, or 15 million kilometres, from Earth, and it is one of the most preserved space materials scientists have laid hands on. Before bringing the samples from Ryugu, JAXA brought back tiny particles of asteroid Itokawa in 2010 as part of the first asteroid sampling mission in history. NASA’s OSIRIS-REx departs asteroid Bennu and will reach Earth with the sample by September 2023.
The researchers are looking for organic compounds or carbon-based compounds in order to understand how these compounds first came into existence and spread throughout the solar system. Astrobiologists find organic compounds intriguing because they make up hundreds of thousands of proteins that are responsible for powering some of life’s most essential functions, such as making new DNA.
After analyzing the makeup of Ryugu, scientists will compare it to Asteroid Bennu, the site of a wildly successful sample grab by OSIRIS-REx. The two asteroids have similar shapes, but Bennu appears to have a lot more evidence of past water and of organic compounds, hence, it will be interesting to witness how they differ given they came from different parent bodies in the asteroid belt and have different histories.
Upon sampling the piece of rubble, the pieces of the puzzle will bring the whole story together – a story of the solar system’s evolutionary history.