egion of the highest resolution image. Yellow boxes correspond to the region in Figure 1. (Left) The region is shown on the ONC-T global image of Ryugu. (Right) ONC-W1 image, taken at 70 m height. 2018-09-21 13:02(JST). Credit: JAXA
In 2014, the Japanese Space Agency JAXA launched the Hayabusa 2 spacecraft to visit asteroid Ryugu. It arrived at the asteroid in June 2018 and studied it from orbit for over a year. Hayabusa 2 even dispatched four rovers to the asteroid’s surface. After departing, it flew past Earth in December 2020, dropping off a sample of Ryugu.
Of all the scientific results from that impressive mission, the most interesting one might be this: Asteroid Ryugu might not be an asteroid. It might be the remnant of a comet.
Scientists are fortunate enough to have detailed, close-up views of the near-Earth asteroids Bennu and Ryugu. Both asteroids have a diamond shape, for some reason. Why? Up until now, it’s been a puzzle.
Now a team of scientists has tackled the question and may have come up with the answer.
After more than two years in orbit around asteroid Bennu, NASA’s OSIRIS-REx spacecraft is ready to come home. It’s bringing with it a pristine sample of space rocks that geologists here on Earth are eager to study up close. The sample will arrive in September 2023, but we won’t have to wait nearly that long for new data from OSIRIS-REx. Last week, the probe carried out one final flyby of Bennu, in an effort to photograph the sample collection site. The photographs are being downlinked now, and should be here by midweek.
If you’ve been following the OSIRIS-REx mission, you probably already know why scientists are keen to see these photographs, but if you haven’t, hold on to your hats – it’s a wild story.
An artist's conception shows Hayabusa 2's sample return capsule making its atmospheric re-entry as its mothership flies above. (JAXA Illustration)
Japan’s Hayabusa 2 probe zoomed past Earth on December 5th and dropped off a capsule containing bits of an asteroid, finishing a six-year round trip.
But the mission is far from over: While Hayabusa 2’s parachute-equipped sample capsule descended to the Australian Outback, its mothership set a new course for an encounter with yet another asteroid in 2031.
Hayabusa 2’s prime objective was to deliver bits of Ryugu, an asteroid that’s currently 11.6 million kilometers from Earth. Mission controllers at the Japan Aerospace Exploration Agency, or JAXA, cheered and laughed when word came that the capsule had survived atmospheric re-entry.
Imagery captured by tracking cameras — and from the International Space Station — showed the capsule streaking like a fireball across the sky as it decelerated from an initial speed of 43,000 kilometers per hour.
Image taken with Hayabusa2's CAM-H instrument on May 30th, 2019. Credit: JAXA
Japan’s Hayabusa 2 spacecraft is nearly back home, with precious cargo aboard! The sample-return mission departed asteroid Ryugu (162173 Ryugu) a little over a year ago, with soil samples and data that could provide clues to the early days of our Solar System. On December 6, 2020, the sample return container is set to land in the Australian outback.
Artist's impression of the Hayabusa2 taking samples from the surface of the asteroid Ryugu. Credit: Akihiro Ikeshita/JAXA
Japan’s Hayabusa 2 spacecraft is on its way home. The asteroid-visiting, sample-return mission departed asteroid Ryugu (162173 Ryugu) on Wednesday, beginning its year-long journey back to Earth. And it’s carrying some precious cargo.
A screen shot from JAXA's video showing Hayabusa 2's second sample grabbing touchdown. Image Credit: JAXA
A new video shows Japan’s Hayabusa 2 sample return spacecraft collecting samples from asteroid Ryugu. The spacecraft has been at Ryugu for months now, and it’s all been leading up to this. In the video, you can clearly see airborne asteroid dust and particles swirling around in the low gravity.
Hayabusa 2 has collected a sub-surface sample from asteroid Ryugu. Image: JAXA
Japan’s Hayabusa 2 spacecraft is now the first spacecraft to retrieve a subsurface sample from an asteroid. On July 11th, the spacecraft touched down for a second time on asteroid 162173 Ryugu. This time, the probe retrieved a sample from a crater it excavated with its impactor.
Image of the surface of Hayabusha2, taken by Rover-1B on September 23rd, 2018. Credit: JAXA
In December of 2014, the Japanese Aerospace Exploration Agency (JAXA) launched the Hayabusa2 mission. As the second spacecraft to bear this name, Hayabusa2 was deployed by JAXA to conduct a sample-return mission with an asteroid. By studying samples of the near-Earth asteroid 162173 Ryugu, scientists hope to shed new light on the history of the early Solar System
The spacecraft arrived in orbit around Ryugu in July of 2018, where it will spend a total of a year and a half surveying the asteroid before returning to Earth. On September 23rd, the satellite deployed its onboard MINERVA-II rovers onto the surface of Ryugu. According to the latest updates from JAXA, both rovers are in good condition and have recently sent back photographs and a video of the asteroid’s surface.
An artist's image of Hayabusa leaving Earth. Hayabusa was a Japanese sample return mission to the asteroid 25143 Itokawa. The mission was a partial success. A sample mission to Earth's sister planet is the holy-grail for the exploration of Venus. Image credit: JAXA
A space-faring friend pays our fair planet a visit this week on the morning of December 3rd, as the Japanese Space Agency’s Hayabusa 2 spacecraft passes the Earth.
The Flyby
Rick Baldridge on the SeeSat-L message board notes that Hayabusa-2 will pass 9,520 kilometers from the Earth’s center or 3,142 kilometers/1,885 miles from the Earth’s surface at 10:08 UT/5:08 AM EST on Thursday, December 3rd, passing from north-to-south above latitude 18.7 north, longitude 189.8 east just southwest of the Hawaiian Islands.
Unfortunately, the sighting opportunities for Hayabusa-2 aren’t stellar: even at its closest, the 1.5 meter-sized spacecraft is about nine times more distant than the International Space Station and satellites in low Earth orbit. To compound the challenge, Hayabusa-2 passes into the Earth’s shadow from 9:58 UT to 10:19 UT.
The path of Hayabusa-2 past the Earth. Image credit: JAXA
Still, skilled observers with large telescopes and sophisticated tracking rigs based along the Pacific Rim of North America might just catch sight of Hayabusa-2 as it speeds by. The JPL Horizons ephemeris generator is a great resource to create a customized positional chart in right ascension and declination for spacecraft for your given location, including Hayabusa-2.
The Earth-Moon pair snapped by Hayabusa-2 on November 26th from about three million kilometers distant. Image credit: JAXA
Hayabusa-2 won’t crack 20 degrees elevation for observers along the U.S. West Coast, putting it down in the atmospheric murk of additional air mass low to the horizon. This also tends to knock the brightness of objects down a magnitude or so… estimates place Hayabusa-2 at around magnitude +13 shortly before entering the Earth’s shadow. That’s pretty faint, but still, there are some dedicated observers with amazing rigs out there, and it’s quite possible someone could nab it. Hawaii-based observers should have the best shot at it, though again, it’ll be in the Earth’s shadow at its very closest…
Amateur radio satellite trackers are also on the hunt for the carrier-wave signal of the inbound Hayabusa-2 mission. You can also virtually fly along with the spacecraft until December 5th: (H/T @ImAstroNix):
A simulation of tomorrow’s flyby. Image Credit: JAXA
Probably the best eye-candy images will come from the spacecraft itself: already, Hayabusa-2 has already snapped some great images of the Earth-Moon pair using its ONC-T optical navigation camera during its inbound leg.
A close-up of Hayabusa-2’s view of the Earth and Moon. Image credit: JAXA
Other notable missions used Earth flybys en route to their final destinations, including Cassini in 1999, and Juno in 2013. Cassini’s return caused a bit of a stir as it has a plutonium-powered RTG aboard, though Earth and its inhabitants were never in danger. A nuclear RTG actually reentered during the return of Apollo 13, with no release of radioactive material. Meant for the ALSEP science package on the surface of the Moon, it was deposited on the reentry of the Lunar Module over the Marinas Trench in the South Pacific. And no, Hayabusa-2 carries no radioactive material, and in any event, it’s missing the Earth by about a quarter of its girth.
The successor to the Hayabusa (‘Peregrine Falcon’ in Japanese) mission which carried out a historic asteroid sample return from 25143 Itokawa in 2010, Hayabusa-2 launched atop an H-IIA rocket from Tanegashima, Japan exactly a year ago tomorrow on a six year mission to asteroid 162173 Ryugu. This week’s Earth flyby will boost the spacecraft an additional 1.6 kilometers per second to an outbound velocity towards its target of 31.9 kilometers per second post-flyby.
Launch of an H-IIA rocket with Hayabusa-2. Image credit: JAXA
Like its predecessor, Hayabusa-2 is a sample return mission. Unlike the original Hayabusa, however, Hayabusa-2 is more ambitious, also carrying the MASCOT (Mobile Asteroid Surface Scout) lander and an explosive seven kilogram impactor. Hayabusa-2 will deploy a secondary camera in orbit to watch the detonation and will briefly touch down at the impact site to collect material.
If all goes as planned, Hayabusa-2 will return to Earth in late 2020.
NASA has its own future asteroid sample return mission planned, named OSIRIS-REx. This mission will launch in September of next year to rendezvous with asteroid 101955 Bennu in September 2019 and return to Earth in September 2023.
An artist’s conception on Hayabusa 2 at asteroid 162173 Ryugu. Image credit: JAXA
We’re entering the golden age of asteroid exploration, for sure. And this all comes about as the U.S. authorized asteroid mining just last week (or at least, as stated, ‘asteroid utilization’) under the controversial U.S. Commercial Space Launch Competitiveness Act. But the original Hayabusa mission brought back mere micro-meter-sized dust grains, highlighting just how difficult asteroid mining is using present technology…
Perhaps, for now, its more cost effective to simply wait for the asteroids to come to us as meteorites and just scoop ’em up. We’ll be keeping an eye out over the next few days for images of Hayabusa-2 as it speeds by, and more postcards of the Earth-Moon system from the spacecraft as it heads towards its 2018 rendezvous with destiny.
