In December 2020, a small piece of an asteroid was found in the middle of the Australian desert. This was no meteorite, however, but rather the result of one of the most well-choreographed operations in aerospace history. During its six-year-long mission, the Japanese Hayabusa 2 probe rendezvoused with the Ryugu asteroid, chipped and collected a sample from its surface, then launched a capsule containing pieces of the space rock back to Earth for analysis.
The engineering challenge of landing on a fast-moving asteroid in the middle of the solar system was immense, but it was all worth it. Now, Japanese scientists have shared the first results of Ryugu, providing clues about the formation of the early solar system, as well as how water and other basic building blocks made their way to Earth.
Ryugu is a carbon-rich, diamond-shaped, near-Earth asteroid that is about one kilometer in diameter. The distant space rock is classed as a C-type asteroid, where ‘C’ stands for carbon due to these asteroids’ coal-like appearance. These carbonaceous objects are the most common variety, forming around 75% of known asteroids.
The asteroid poses no threat of colliding with our planet — instead, it offers a fantastic opportunity to study carbon-rich space rocks in situ. When pieces of asteroids arrive on Earth, their chemical composition can be heavily altered by the high atmospheric entry temperature and the shock of impact, whereas the 5.4-gram Ryugu sample arrived on Earth unadulterated, protected by a special shielding capsule.
The mass of the sample actually greatly exceeded the Japanese researchers’ expectations, who were prepared to do work with no more than 100 mg. In order to keep physical alterations to the Ryugu samples to a minimum, some of the asteroid pieces were removed from the capsule in vacuum so as to not expose the space rock fragments to terrestrial nitrogen conditions.
After analyzing the sample, Toru Yada and colleagues at the Japan Aerospace Exploration Agency in Sagamihara, Japan found that Ryugu is very dark, reflecting only 2% of the light that hits its surface. Ryugu also has a high porosity of 46%, much greater than any meteorite found thus far, the astronomers reported in Nature Astronomy. C-type asteroids like Ryugu are believed to be possible parent bodies for dark, water- and carbon-bearing meteorites found on Earth known as carbonaceous chondrites, and the analysis suggests that this is indeed the case.
“Curatorial works of returned samples from asteroids are very essential to not only sample return missions themselves, but related science communities like meteorites and asteroids sciences, as well as planetary sciences to reveal the evolution of the solar system. In this sense, our preliminary studies on Ryugu returned samples give us direct proof to connect C-type asteroids to carbonaceous chondrites, which are enriched in water and organics,” Yada told ZME Science.
In a second study published in the same Nature Astronomy, Cédric Pilorget and colleagues at the Université Paris-Saclay in France used special microscopes on Ryugu samples that can acquire images at different wavelengths of light, both in the visible and infrared spectrums.
According to the researchers in France, Ryugu is rich in clay and other organic minerals, linked in a hydrated matrix. However, it also contains carbonates and volatile compounds, making its composition rather heterogeneous.
Since Ryugu’s rocks are thought to be around 4.6 billion years old, their composition reflects the primordial materials found at the dawn of the solar system’s formation, offering a unique opportunity to study the origin and evolution of Earth and other rocky planets.
“Because Ryugu is an asteroid enriched in water and organics, its original body(ies) should be possible sources of water and building blocks of life on ancient Earth,” said Yada.
Yada added that D-type asteroids, which are the main populations in the outer asteroid belt and are thought to be ‘extinct’ comet nuclei, as well as M-type asteroids, which are mainly made of iron, are great targets for future sample return missions, helping fill in the blanks in our understanding. In fact, next year will launch a spacecraft that will do just that, targeting the M-type asteroid Psyche.
It’s difficult to mention the year 2020 without referencing COVID-19, but as more human beings than ever before were wishing they could take a break from the surface of the planet, space research continued to push our knowledge of the stars. Whilst much of the scientific community was consumed with combating a pandemic, physicists, astronomers, cosmologists, and other researchers were further pushing our understanding of space and the objects which dwell there.
These are some of my personal favourite space-related breakthroughs and research that have come about this year. The list is by no means exhaustive.
Black Holes go silent
In terms of black hole science, 2019 was always going to be a difficult year to top being the year that brought us the first direct image of a supermassive black hole (SMBH). That doesn’t mean that 2020 has been a slow year for black hole developments, however.
One of the most striking and memorable examples of black hole research announced this year was the discovery of a ‘silent’ black hole in our cosmic ‘back yard.’ An international team led by researchers from European Southern Observatory (ESO) including found the black hole in the system HR 6819, located within the Milky Way and just 1,000 light-years from the Earth.
The observation marks the closest to Earth a black hole has ever been discovered and Dietrich Baade, Emeritus Astronomer at ESO in Garching believes that it is just ‘the tip of the Iceberg’.
“It’s remarkable because not only is it the first of its kind found, but it’s also so nearby,” said Baade. “Discovering a first only an astronomical stone’s throw away is the biggest surprise one can probably imagine.”
The black hole was described as ‘silent’ by the team because it is not current accreting material — the destructive process that creates powerful x-ray emissions and makes these light-trapping objects observable.
“If there is one, there ‘must’ be more,” Baade remarked in May. “If the Earth is not in a privileged position in the Universe — and all available evidence suggests without a doubt it is not — this means that there must be many more silent black holes.”
Baade also remarked that as current cosmological models suggest that the number of stellar-mass black holes is between 100,000,000 to 1,000,000,000 and we have observed nowhere near this many objects, more quiet black holes are “badly needed” to confirm current models. “HR 6819 is the tip of an iceberg, we do not yet know how big the iceberg is.”
Silent black holes weren’t the only examples of this hind of science making noise in 2020, however. Long-missing Intermediate Mass Black Holes were discovered. And just like a proverbial bus, you wait decades for one and then two turn up at once.
Intermediate mass black holes found and found again
Missing black holes were the subject of another piece of exciting space science in September 2020, when researchers from the VIRGO/LIGO collaboration discovered the tell-tale signal of an intermediate-mass black hole (IMBH) in gravitational-wave signals. To add to the excitement, the signals originated from the largest black hole merger ever observed.
The merger — identified as gravitational wave event GW190521 —was detected in gravitational waves and is the first example of a ‘hierarchical merger’ occurring between two black holes of different sizes, one of which was born from a previous merger.
“This doesn’t look much like a chirp, which is what we typically detect,” Virgo member Nelson Christensen, a researcher at the French National Centre for Scientific Research (CNRS) said when announcing the team’s observation. “This is more like something that goes ‘bang,’ and it’s the most massive signal LIGO and Virgo have seen.”
The black hole birthed in the detected merger appears to have a mass of between 100–1000 times that of the Sun — most likely 142 solar masses — putting it in the mass range of an IMBH — a ‘missing link’ between stellar-mass black holes and much larger SMBHs.
Earlier in 2020, another team had used the Hubble Space Telescope X-ray data collected in 2018 to identify what they believed to be an IMBH with a mass 50,000 times that of the Sun named 3XMM J215022.4−055108 (or J2150−0551 for short).
Whether GW190521 or J2150−0551 will go down in history as the first discovered IMBH is currently a little muddy, but what is less questionable is that 2020 will go down as the year in which these ‘missing link’ black holes were first discovered, bringing with them exciting implications for the future investigation of black holes of all sizes.
“Studying the origin and evolution of the intermediate-mass black holes will finally give an answer as to how the supermassive black holes that we find in the centres of massive galaxies came to exist,” said Natalie Webb of the Université de Toulouse in France, part of the team that found J2150−0551. And IMBHs weren’t the only missing element of the Universe that turned up in 2020.
Discovering the Universe’s missing mass
In May astronomers, including Professor J. Xavier Prochaska of UC Santa Cruz, announced that they had found the missing half of missing baryonic matter demanded by cosmological models.
“The matter in this study is ‘ordinary’ matter — the material that makes up our bodies, the Earth, and the entirety of the periodic table. We refer to this matter as ‘baryonic’–matter made up of baryons like electron and protons,” Prochaska said when he spoke exclusively to ZME Science earlier this year. “Of particular interest to astronomers is to ascertain the fraction of the material that is tightly bound to galaxies versus the fraction that is out in the open Universe — what we refer to as the intergalactic medium or cosmic web.”
The matter the team discovered isn’t ‘dark matter’ — which accounts for roughly 85–90% of the Universe’s matter content — but rather ‘ordinary’ matter that has been predicted to exist by our models of universal evolution but has remained hidden.
The team made the discovery using mysterious Fast Radio Bursts (FRBs) and the measurement of the redshift of the galaxy from which they originate as a detection method. FRBs can be used as a probe for baryonic matter because as they travel across the Universe, every atom they encounter slows them down by a tiny amount.
This means that they carry with them a trace of these encounters along with them in the spectral splitting as seen above. This allowed the team to infer the presence of clouds of ionised gas that are invisible to ‘ordinary’ astronomy because of how diffuse they are.
Asteroid Samples Returned by Hayabusa2
Japan’s Hayabusa2 probe and its continued investigation of the asteroid Ryugu has been the gift that has just kept giving in 2020. Just this month the probe returned to Earth samples collected from an asteroid — which has an orbit that brings it between Earth and Mars — for the first time.
Though probes have landed on asteroids and collected samples before, these samples have been examined in situ. Thus this is the first time researchers have been able to get ‘up close and personal’ with matter from an asteroid.
Hayabusa2 arrived at Ryugu in late June 2018, making its touch-down on the surface of the asteroid in February of the following year after months careful manoeuvring conducted by the Japan Aerospace Exploration Agency (JAXA) and the selection of an optimal region from which to collect samples.
Ahead of the return of samples on December 5th, the probe sent back some stunning images of the asteroid’s surface. These images were more than purely aesthetic, however. Examination of dust grains on the surface of Ryugu gave the team, including Tomokatsu Morota, Nagoya University, Japan, indications of a period of rapid heating by the Sun.
“Our results suggest that Ryugu underwent an orbital excursion near the Sun,” said Morota in May. “This constrains the orbital transition processes of asteroids from the main belt to near-Earth orbit.”
Impressive though this achievement is, its the collection of samples from the asteroid and their subsequent safe return to earth that is the ‘main course’ of the Hayabusa2 mission. “The most important objective of the touchdown is sample collection from Ryugu’s surface,” Morota explained.
It is hoped that access to these samples will help answer lingering questions about asteroid composition as well as assisting researchers to confirm Ryugu’s suspected age of 100 million years old — which actually makes it quite young in terms of other asteroids.
Asteroids like Ryugu can act as a ‘snapshot’ of the system’s in which they form at the time of that formation. This is because whereas planets undergo a lot of interaction with other bodies, asteroids remain pretty much untouched.
Whilst researchers will no doubt be elated by the return of the Ryugu samples and the continuing success of the Hayabusa2 mission, 2020 wasn’t all good news for fans of asteroid research.
Goodbye to Arecibo
The iconic radio telescope at the Arecibo Observatory in Puerto Rico collapsed at the beginning of December, ahead of its planned demolition. The telescope which will be familiar to moviegoers as the setting of the climactic battle in Pierce Brosnan’s first outing as James Bond, 1995’s Goldeneye, had been in operation up until November, playing a role in the detection of near-Earth asteroids and monitoring if they present a threat to the planet.
The collapse of the radio telescope’s 900-tonne platform which was suspended above the telescope’s 305-metre-wide dish, on December 1st, followed the snapping of one of its main cables in November.
The US National Science Foundation (NSF), which operates the observatory had announced that same month that the telescope would be permanently closed citing ‘safety concerns’ after warnings from engineers that it could collapse at any point.
Following the collapse, the NSF release heart-wrenching footage of the radio telescope collapsing recorded by drones. The footage shows cables snapping at the top of one of the three towers from which the instrument platform was suspended. The platform then plummets downward impacting the side of the dish.
The observatory had played a role in several major space-science breakthroughs since its construction in 1963. Most notably, observations made by the instrument formed the basis of Russell A. Hulse and Joseph H. Talyor’s discovery of a new type of pulsar in 1974. The breakthrough would earn the duo the 1993 Nobel Prize in Physics.
Some good could ultimately come out of the collapse of Arecibo. Questions had been asked about the maintenance of the radio telescope for some time and the fact that the cable which snapped in November dated back to the instrument’s construction 57 years ago has not escaped notice and comment.
As a result, various space agencies are being encouraged to make efforts to better maintain large-scale equipment and facilities so that losses like this can be avoided in the future.
For most of us, 2020 is going to be a year that we would rather forget. Whilst very few of us come honestly comment that we have had anything approaching a ‘good year’ space science has plowed ahead, albeit mildly hindered by the global pandemic.
Our knowledge and understanding of space science are better off at the end of 2020 than it was twelve months earlier, and that is at least something positive that has emerged from this painful year.
A Japanese spacecraft has successfully landed on an asteroid. It’s only the second time in history that such a feat has been achieved, the previous success also belonging to the Japanese space agency. Now, the fridge-sized Hayabusa-2 probe is expected to extract samples from the asteroid and bring them back for research.
A closer look at Ryugu. Image credits: JAXA.
The atmosphere was tense at the Japan Aerospace Exploration Agency (Jaxa). Members were observing the landing from a control room when they hear
“The touchdown is successful,” Jaxa spokesman Takayuki Tomobe said, prompting hugs, hurrays, and plenty of “V” victory signs.
The probe first reached the Ryugu asteroid in June 2018, carrying out observations and measurements for months. Because there is virtually no friction in space, the surface of the asteroid isn’t smooth — it’s very rough, and landing on it requires precise calculations.
In April, Hayabusa shot the asteroid with a copper plate projectile, in order to loosen the rocks and expose the material under the surface, making it easier to harvest valuable samples. Last night, the probe Hayabusa-2 latched onto Ryugu, landing in the designated area successfully. The photos are simply stunning.
The photos are also a mythical reference, as Ryugu translates to “Dragon Palace” in Japanese and refers to a castle at the bottom of the ocean in an ancient Japanese tale. In the story, the fisherman Urashima Tarō travels to the palace on the back of a turtle and returns with a mysterious box — an analogy to how Hayabusa will return with samples from the asteroid. Image credits: Jaxa.
“First photo was taken at 10:06:32 JST (on-board time) and you can see the gravel flying upwards. Second shot was at 10:08:53 where the darker region near the centre is due to touchdown,” JAXA tweeted.
The moment of touchdown. Image credits: JAXA.
“These images were taken before and after touchdown by the small monitor camera (CAM-H). The first is 4 seconds before touchdown, the second is at touchdown itself and the third is 4 seconds after touchdown. In the third image, you can see the amount of rocks that rise,” JAXA tweeted.
This is the second touchdown on the asteroid, after earlier this year, two small rovers landed on the Ryugu asteroid. The Hayabusa2 mission includes four rovers with various scientific instruments.
After it touched down, Hayabusa-2 collected a new set of samples and left Ryugu’s surface. If everything goes according to plan (and so far, it has) it will begin the 5.5 million-mile (9 million-kilometer) journey home towards the end of this year.
Subsurface material (such as the one blasted by Hayabusa) is particularly intriguing for scientists, because it has been protected from the harsh effects of cosmic rays and solar wind. By better studying and understanding these asteroids, researchers want to shed more light on the evolution of the solar system
The Hayabusa 2 spacecraft has just bombed an asteroid. It fired a projectile packed with explosives towards the rocky surface, creating a crater from which it can gather samples for analysis.
Image credits: JAXA.
Hovering at 500 meters above the asteroid, Hayabusa 2 just opened fire on an asteroid. It wasn’t a declaration of war but rather a scientific maneuver. The idea was to create an artificial crater on the object known as Ryugu to allow the collection of samples from beneath the surface.
In December 2014, Hayabusa was launched towards the Ryugu asteroid. After three years, it touched down briefly, and last year, it deployed two robots on the surface, which sent back dramatic images and video footage. Now, as the mission progresses, the spacecraft is set to collect samples that will eventually be brought back to Earth. In order to do that, it must first break through the asteroid’s rough surface — which is why the projectile was shot.
It’s not yet entirely clear if the attempt was successful and it could take several days to confirm whether everything went according to plan. However, initial images seem to suggest that the shooting was successful.
Hayabusa 2 seems to have been successful, but it will be a few days before we have confirmation. Image credits: JAXA.
Hayabusa 2 fired the projectile and then navigated to the opposite side of the small asteroid to avoid the dust and pebble ejection. It will return to the site after things have calmed down to gather samples from the newly-formed crater.
“We are excited to see what will happen when the impactor collides with the asteroid,” Takashi Kubota, an engineering researcher at Jaxa, said before the detonation.
The asteroid samples are expected to offer researchers new insights into how the solar system came to be. However, because the surface is constantly bombarded by solar rays which can alter the rock’s properties, samples need to be taken from beneath the surface, hence the need for a crater-creating explosion.
It’s not exactly clear how big the crater will be — it all depends on the asteroid’s composition, which is not fully known. If it’s more sandy, the crater can be up to 10 meters in size, but if it’s more compact, the crater will measure around 3 meters. Researchers believe that the asteroid contains relatively large amounts of organic matter and water from 4.6bn years ago when the solar system was born.
As for Hayabusa 2, it’s expected to make its way back to Earth sometime between November and December, with a landing set for late-2020.
On September 21, two tiny rovers operated by the Japanese space agency JAXA made history by safely landing on the rugged terrain of an asteroid. Not too long after, JAXA released the first image, much to the delight of Earthlings. But it didn’t stop there — more pictures and even a 15-frame short video from the asteroid have been beamed back.
“I cannot find words to express how happy I am that we were able to realize mobile exploration on the surface of an asteroid” enthused Yuichi Tsuda, Hayabusa2 Project Project Manager, “I am proud that Hayabusa2 was able to contribute to the creation of this technology for a new method of space exploration by surface movement on small bodies.”
The two autonomous rovers, unceremoniously named Rover 1A and Rover 1B, were dropped by Hayabusa 2, their mothership, from a distance of 60 meters from the asteroid’s surface. JAXA engineers witnessed the moment with anxiety as rovers encountered rougher than expected conditions, with very few smooth patches around.
But the rovers proved to be sturdy, operating in optimal conditions across the surface of the space rock Ryugu, which measures only 900 meters across.
Taking advantage of Ryugu’s low gravity, the rovers hop across the surface of the space rock using a motor-powered internal mass that rotates to generate inertia.
To snap these unique photos, each rover is equipped with wide-angle and stereo camera. The rovers measure only 1 kilogram, each.
Expect even more amazing developments in the near future from JAXA’s rovers and spacecraft. The next stage will see the Mobile Asteroid Surface Scout (MASCOT) lander released onto the asteroid’s surface. The lander has enough power for a 12-hour mission, in which it will analyze the asteroid’s surface at two different sites.
Also, Hayabusa2 should make a landing itself later in October. Its task will be to collect samples and, hopefully, return them back to Earth.
Ryugu is thought to be billions of years old, a remnant of the early solar system. By studying it, scientists hope to learn more about the origin and evolution of our very own planet, but also what are an asteroid’s biggest weaknesses. At one point in Earth’s history, a giant asteroid wiped out the dinosaurs. Unfortunately for them, they didn’t have science. Next time it happens, we want to be prepared!
After days of gripping suspense, the two small rovers finally landed on the Ryugu asteroid — and they’ve even sent a few postcards back home.
This photo shows the view from asteroid Ryugu from the Minerva-II1A. The probe is one of two that landed on Ryugu from the Japanese Aerospace Exploration Agency’s Hayabusa2 spacecraft. It’s the first time two mobile rovers landed on an asteroid. The image is blurred because it was taken during the rover’s descent. Credit: Japan Aerospace Exploration Agency.
The rovers are part of Japan Aerospace Exploration Agency’s Hayabusa2 asteroid sample-return mission. They were deployed from the spacecraft and successfully landed on Ryugu, and both are still in good condition.
In order to perform the deployment, the Hayabusa2 carefully lowered itself carefully down toward the surface, until it was only 55 meters (180 ft) above. Then, after the rovers were deployed, the shuttle went back up to 20 km (12.5 mi) above the asteroid.
We are sorry we have kept you waiting! MINERVA-II1 consists of two rovers, 1a & 1b. Both rovers are confirmed to have landed on the surface of Ryugu. They are in good condition and have transmitted photos & data. We also confirmed they are moving on the surface. #asteroidlanding
Because Ryugu is so small and doesn’t have a significant gravitational field, the landing was particularly difficult, but this also allows the rovers to hop around the asteroid, taking photos as they go.
The 1kg rovers are equipped with wide-angle and stereo cameras, and are powered internal rotors, which propel the robots across the asteroid. The rovers also feature sensors that measure the surface temperatures, and Hayabusa2 itself carries sensors for remote sensing and sampling.
[panel style=”panel-default” title=”Underwater palace.” footer=””]Ryugu is an asteroid which measures approximately 1 kilometer (0.6 mi) in diameter. Ryugu was discovered in 1999, and its name refers to Ryūgū (Dragon Palace), a magical underwater palace in a Japanese folktale. In the story, a fisherman Urashima Tarō travels to the palace on the back of a turtle, and when he returns, he carries with him a mysterious box — something which is alluding to Hayabusa2 returning with samples[/panel]
Animation of Hayabusa2 orbit from 3 December 2014 to 29 December 2019.
But while this is already a remarkable achievement, the mission is still far from being over: the Japanese space agency still has two more deployments to complete — a larger rover called MASCOT in October and another tiny hopper next year. Then, the rovers have to collect samples, and board the shuttle again, returning to Earth for lab analysis. If everything goes according to plan, the shuttle will leave Ryugu in 2019 and will return back to Earth in 2020.
So far, the asteroid’s surface was rougher than expected, which brought another layer of difficulty to the mission. The surface is blackish-colored, and the asteroid has maintained its original composition for eons, as Ryugu is a particularly primitive asteroid type. Studying it could shed light on the origin and evolution of Earth and even the solar system. For now, we eagerly await the next mission checkpoints.