Tag: asteroids

OSIRIS-REx on its way back to Earth

10:54 pm

OSIRIS-REx today fired its engines and successfully put itself on course for returning its samples from the asteroid Bennu to Earth on September 24, 2023.

The May 10 departure date was precisely timed based on the alignment of Bennu with Earth. The goal of the return maneuver is to get the spacecraft within about 6,000 miles (approximately 10,000 kilometers) of Earth in September 2023. Although OSIRIS-REx still has plenty of fuel remaining, the team is trying to preserve as much as possible for a potential extended mission to another asteroid after returning the sample capsule to Earth. The team will investigate the feasibility of such a mission this summer.

The spacecraft’s course will be determined mainly by the Sun’s gravity, but engineers will need to occasionally make small course adjustments via engine burns.

The science team has already proposed one option, sending the spacecraft on a rendezvous with the potentially dangerous asteroid Apophis shortly after its 2029 close-fly of Earth. It could be that there are other targets as interesting that they need to choose from.

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New OSIRIS-REx photos of Bennu sample site after sample grab

1:40 pm

Nightingale before and after sample grab
Click here and here for original images.

The OSIRIS-REx science team today released the photos the spacecraft obtained in its last fly-by of the asteroid Bennu on April 7th of the Nightngale sample site, showing how it changed after the sample grab in October 2020.

The two photos to the right compare that site, with the top image taken before the sample grab and the bottom image taken on April 7th.

Comparing the two images reveals obvious signs of surface disturbance. At the sample collection point, there appears to be a depression, with several large boulders evident at the bottom, suggesting that they were exposed by sampling. There is a noticeable increase in the amount of highly reflective material near the TAG [touch-and-go] point against the generally dark background of the surface, and many rocks were moved around.

Where thrusters fired against the surface, substantial mass movement is apparent. Multiple sub-meter boulders were mobilized by the plumes into a campfire ring–like shape — similar to rings of boulders seen around small craters pocking the surface.

Jason Dworkin, the mission’s project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, noticed that one boulder measuring 4 feet (1.25 meters) across on the edge of the sampling site seemed to appear only in the post-TAG image. “The rock probably weighs around a ton, with a mass somewhere between a cow and a car.”

Dante Lauretta, of the University of Arizona and the mission’s principal investigator, later pointed out that this boulder is likely one of those present in the pre-TAG image, but much nearer the sampling location, and estimates it was thrown a distance of 40 feet (about 12 meters) by the sample collection event.

The sample grab arm penetrated the surface by more than a foot, and that event is marked by that dark depression at the center of the site.

OSIRIS-REX will now prepare for its May 10th engine firing that will send it on its route back to Earth to return that sample in September 24, 2023. After that the spacecraft could be sent on another mission, this time to the potentially dangerous asteroid Apophis.

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OSIRIS-REx completes last close-fly of Bennu

12:39 pm

OSIRIS-REx today successfully completed its last close-fly of Bennu before it will fire its engines on May 10th and begin its journey back to Earth to return its samples.

During the flyby, OSIRIS-REx imaged Bennu for 5.9 hours, covering more than a full rotation of the asteroid. It flew within 2.1 miles’ (3.5 kilometers) distance to the surface of Bennu – the closest it’s been since the TAG sample collection event.

It will take until at least April 13 for OSIRIS-REx to downlink all of the data and new pictures of Bennu’s surface recorded during the flyby. It shares the Deep Space Network antennas with other missions like Mars Perseverance, and typically gets 4–6 hours of downlink time per day. “We collected about 4,000 megabytes of data during the flyby,” said Mike Moreau, deputy project manager of OSIRIS-REx at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Bennu is approximately 185 million miles from Earth right now, which means we can only achieve a downlink data-rate of 412 kilobits per second, so it will take several days to download all of the flyby data.”

While they will get images of the asteroid’s entire surface, the region scientists are most interested in is the Nightingale sample return site where the spacecraft grabbed its samples. To best understand the asteroid they need to have before and after shots, and this last fly-by gave them the latter.

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Radar images of Apophis during its March close approach of Earth

9:45 am

Apophis as seen by radar March 9, 2021
Click for full image.

Using two radar dishes, Green Bank in West Virginia and Goldstone in California, astronomers were able to produce radar images of the asteroid Apophis during its most recent close fly-by of Earth on March 10th.

The image to the right, cropped and reduced to post here, shows Apophis on March 9th. If you go to the full image you can also see the March 10th and 11th images, which appear to show the asteroid in different orientations as it rotated.

These images represent radar observations of asteroid 99942 Apophis on March 8, 9, and 10, 2021, as it made its last close approach before its 2029 Earth encounter that will see the object pass our planet by less than 20,000 miles (32,000 kilometers). The 70-meter radio antenna at the Deep Space Network’s Goldstone Deep Space Communications Complex near Barstow, California, and the 100-meter Green Bank Telescope in West Virginia used radar to precisely track Apophis’ motion. At the time of these observations, Apophis was about 10.6 million miles (17 million kilometers) from Earth, and each pixel has a resolution of 127 feet (38.75 meters).

The data obtained has firmly removed any chance Apophis will impact the Earth in the next 100 years. However, it still could hit us late in the 22nd century.

These observations were originally planned to also include data from the Arecibo Observatory, but that telescope was destroyed in December when its instrument platform collapsed. If it had been operational, these radar images would have had much better resolution.

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Meteorite recovered in driveway in UK only days after landing

9:18 am

Meteorite hunters successfully recovered a meteorite only days after it plowed through the atmosphere and landed in a driveway in Gloucestershire in the United Kingdom on February 28th.

The fragment, weighing nearly 300 grams, and other pieces of the space rock were located after scientists reconstructed the flight path of the fireball that unleashed a sonic boom as it tore across the sky shortly before 10pm UK time on Sunday 28 February. The black chunk of rock, a carbonaceous chondrite never seen before in the UK, thumped on to a driveway in the Cotswolds town of Winchcombe, scientists at the Natural History Museum in London said, adding that further fragments were retrieved nearby.

Ashley Green, a scientist at the museum, said it was “a dream come true” to be one of the first people to see and study a meteorite that had been recovered almost immediately after coming down.

Footage of the bright streak captured by the public, and a camera network operated by the Natural History Museum’s UK Fireball Alliance, helped researchers calculate that the meteor had spent most of its orbit between Mars and Jupiter before it ploughed into Earth’s atmosphere.

I seriously doubt that no carbonaceous chondrite asteroids have never been found in Great Britain before. Instead, what the reporter misunderstood was that this was the first such asteroid in the UK recovered immediately after its arrival. Carbonaceous chondrites are very fragile. Much of their material will quickly erode and disappear, preventing researchers from obtaining a complete census of their entire make-up. Grabbing this thing mere days after landing means they will have a sample more closely resembling these kinds of asteroids in space.

In this way this rock is not much different than the samples being brought back from Hayabusa-2 and OSIRIS-REx. It isn’t as pristine, but it certainly carries far more information that meteorites recovered decades or even centuries after landing.

Similar quick recoveries in the past few years have forced some major rethinking about the make-up of the asteroid population. This meteorite will likely add to that revolution.

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OSIRIS-REx begins last approach of Bennu

9:12 am

Approaching Bennu for the last time
Click for full image.

The science team for OSIRIS-REx released today the first picture taken as the spacecraft begins its last approach of the asteroid Bennu. To the right is that picture, cropped and expanded to post here. From the caption:

This image shows a top-down view of asteroid Bennu, with a portion of the asteroid’s equatorial ridge and northern hemisphere illuminated. It was taken by the PolyCam camera on NASA’s OSIRIS-REx spacecraft on March 4, from a distance of about 186 miles (300 km). The spacecraft’s cameras are pointed directly at Bennu’s north pole. Two large equatorial craters are visible on the asteroid’s edge (center and center left).

If all goes well, the probe will fly past the asteroid on April 7th, obtaining high resolution images of its entire surface as it rotates below, including very close-up images of the Nightingale sample grab location during its closest approach.

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Scientists confirm distance to farthest known solar system object

2:46 pm

Scientists have now confirmed that the large asteroid dubbed Farfarout (about 250 miles across) is presently about 132 astronomical units from the Sun (about 12 billion miles), making it the farthest known solar system object.

Its orbit however is far from circular, and it isn’t presently even at its farthest point in that orbit.

[T]he orbit of Farfarout is quite elongated, taking it 175 au from the Sun at its farthest point and around 27 au at its closest, which is inside the orbit of Neptune. Because its orbit crosses Neptune’s, Farfarout could provide insights into the history of the outer Solar System. “Farfarout was likely thrown into the outer Solar System by getting too close to Neptune in the distant past,” said Trujillo. “Farfarout will likely interact with Neptune again in the future since their orbits still intersect.”

The astronomers expect to discover more such objects in the coming years that will even eclipse this one in distance.

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OSIRIS-REx has begun its return to Bennu

2:17 pm

On January 14th the OSIRIS-REx team fired the spacecraft’s engines to halt its drift away from the asteroid Bennu and begin its return for one last reconnaissance before heading to Earth with its samples.

OSIRIS-REx executed the first maneuver on Jan. 14, which acted as a braking burn and put the spacecraft on a trajectory to rendezvous with the asteroid one last time. Since October’s sample collection event, the spacecraft has been slowly drifting away from the asteroid, and ended up approximately 1,635 miles (2,200 km) from Bennu. After the braking burn, the spacecraft is now slowly approaching the asteroid and will perform a second approach maneuver on Mar. 6, when it is approximately 155 miles (250 km) from Bennu. OSIRIS-REx will then execute three subsequent maneuvers, which are required to place the spacecraft on a precise trajectory for the final flyby on Apr. 7.

OSIRIS-REx is scheduled to depart Bennu on May 10 and begin its two-year journey back to Earth. The spacecraft will deliver the samples of Bennu to the Utah Test and Training Range on Sep. 24, 2023.

While they will gather images of the whole asteroid, their number one goal will be to get high resolution photos of the sample-grab site Nightingale to see how it was changed by that sample grab. The spacecraft pushed into the asteroid’s rubble pile about 1.6 feet, and that act certainly disturbed both the interior and surface. By comparing the before and after pictures scientists can garner a lot of information about the asteroid’s make-up, density, and structure. It will also teach future engineers what to expect when next they try to touch another rubble-pile asteroid.

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New radar technology now available for radio astronomy

9:47 am

GreenBank radar image of Apollo 15 landing region

Astronomers have now demonstrated a spectacular new radar technology using radio telescopes and capable of producing high resolution images of all solar system bodies, as far away as Neptune.

[S]cientists built a miniature transmitter, powered at less than a kilowatt and about the size of a refrigerator, Beasley said, and in November hauled it up for a brief stint at the prime focus of Green Bank Telescope, suspended over the large dish.

Then, the team took advantage of the telescope’s superlative: It’s the largest fully steerable radio telescope in the world, able to study objects across 85% of the sky. So the team pointed the telescope and fired the radar system at the moon — more specifically, at the Apollo 15 mission’s landing site in the Hadley-Apennine region [the white dot in the image to the right]. The team used antennas of the NRAO’s Very Long Baseline Array (VLBA) to catch the signal that bounced back.

The image, with its sloping hills, stark crater and slinking rille, offers a hint of what could come. But the moon is our old companion. Scientists would much rather use a shiny new planetary radar system to study more mysterious objects, like the asteroids zipping through our neighborhood of the solar system, most of which are blurs and blobs, or the strange moons of the outer planets that have received few spacecraft visitors.

Without question this technology would be a major breakthrough for the observation of asteroids, especially those that are considered a threat of impacting the Earth for which we have little concrete information.

The article however notes that the technology had been developed with the assumption that the Arecibo radio telescope would be available. That telescope however is now dead, having been destroyed when its instrument platform fell in early December. With a limited number of radio telescopes available, all of which are oversubscribed for other work, it will be difficult to find time for the use of this technology on any of them.

But don’t worry. The Chinese will definitely want to steal it and put it on their giant FAST radio telescope, and I am sure the Biden administration will be agreeable to letting them.

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OSIRIS-REx to make one last observation of Bennu before heading back to Earth

10:56 am

The OSIRIS-REx science team has figured out a way to make one last observation of Bennu and the Nightingale sample return site before heading back to Earth on May 10th.

This activity was not part of the original mission schedule, but the team is studying the feasibility of a final observation run of the asteroid to potentially learn how the spacecraft’s contact with Bennu’s surface altered the sample site. If feasible, the flyby will take place in early April and will observe the sample site, named Nightingale, from a distance of approximately 2 miles (3.2 kilometers). Bennu’s surface was considerably disturbed after the Touch-and-Go (TAG) sample collection event, with the collector head sinking 1.6 feet (48.8 centimeters) into the asteroid’s surface. The spacecraft’s thrusters also disturbed a substantial amount of surface material during the back-away burn.

The mission is planning a single flyby, mimicking one of the observation sequences conducted during the mission’s Detailed Survey phase in 2019. OSIRIS-REx would image Bennu for a full rotation to obtain high-resolution images of the asteroid’s northern and southern hemispheres and equatorial region. The team would then compare these new images with the previous high-resolution imagery of Bennu obtained during 2019.

Getting at look at Nightingale post-sample-grab is critical to better understanding the nature of the asteroid. Knowing how much changed from that contact will tell scientists a lot about the density, interior, and surface of this rubble-pile asteroid.

This last flyby will also give them the chance to assess the spacecraft’s equipment following the touch-and-go sample grab. They want to know if everything still works as designed in order to plan any post-Bennu missions, including the possibility that OSIRIS-REx will rendezvous with the asteroid Apophis in ’29, shortly after the asteroid makes its next close flyby of Earth.

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Hayabusa-2 begins journey to two asteroids

7:59 am

On January 5, 2021, after successfully delivering its samples of Ryugu to Earth, Hayabusa-2 fired up its ion engines and began its ten-year journey to two different asteroids.

Hayabusa2’s first extended-mission destination is the roughly 2,300-foot-wide (700 meters) asteroid (98943) 2001 CC21, which the probe will fly by at high speed in 2026, if all goes according to plan. A more in-depth rendezvous with yet another space rock, 1998 KY26, is scheduled to follow in 2031.

In a previous post I had mistakenly left out the first target asteroid. However, their primary target remains the tiny 100-foot-wide 1998 KY26, since it is so small. This will be the first close-up view of such a small asteroid, in space. Since such asteroids are many, it will tell us much about the make-up and history of the solar system.

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First look at Ryugu samples

8:55 am

Japanese scientists have taken their first look at the Ryugu sample material brought back by Hayabusa-2 and found they resemble charcoal.

The samples Japanese space officials described Thursday are as big as 1 centimeter (0.4 inch) and rock hard, not breaking when picked up or poured into another container. Smaller black, sandy granules the spacecraft collected and returned separately were described last week.

…The sandy granules the Japan Aerospace Exploration Agency described last week were from the spacecraft’s first touchdown in April 2019.

The larger fragments were from the compartment allocated for the second touchdown on Ryugu, said Tomohiro Usui, space materials scientist. To get the second set of samples in July last year, Hayabusa2 dropped an impactor to blast below the asteroid’s surface, collecting material from the crafter so it would be unaffected by space radiation and other environmental factors.

Usui said the size differences suggest different hardness of the bedrock on the asteroid. “One possibility is that the place of the second touchdown was a hard bedrock and larger particles broke and entered the compartment.”

The analysis of these samples has only just begun. Dating them is likely next, and that will probably reveal some startling results.

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Samples from space!

9:16 am

Scientists from both the Japanese Hayabusa-2 mission to the asteroid Ryugu and the Chinese Chang’e-5 mission to the Moon announced yesterday the total amount of material they successfully recovered.

The numbers appear to diminish the Japanese success, but that is a mistake. Getting anything back from a rubble-pile asteroid that had never been touched before and is much farther away from Earth than the Moon was a very great achievement. The 5.4 grams is also more than fifty times the minimum amount they had hoped for.

This is also not to diminish the Chinese achievement, They not only returned almost four pounds, some of that material also came from a core sample. They thus got material both from the surface and the interior of the Moon, no small feat from an unmanned robot craft.

Scientists from both nations will now begin studying their samples. Both have said that some samples will be made available to scientists from other countries, though in the case of China it will be tricky for any American scientist to partner with China in this research, since it is by federal law illegal for them to do so.

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Subaru Telescope photographs Hayabusa-2’s next target asteroid

2:09 pm

In order to better constrain its orbit, the Subaru Telescope in Hawaii has obtained new photographs of Hayabusa-2’s next target asteroid, 100-foot-wide 1998 KY26.

This asteroid is predicted to approach to within 0.47 AU of Earth in mid to late December 2020, giving us a rare opportunity that comes only once every three and a half years. However, the diameter of 1998 KY26 is estimated to be no more than 30 meters, and thus its brightness is so dim that ground-based observations of the asteroid are difficult without a very large telescope.

The observations with the Subaru Telescope were conducted upon the request of the Institute for Space and Astronautical Science (ISAS), JAXA. And as a result, 1998 KY26 was photographed in the direction of the constellation Gemini as a 25.4-magnitude point of light with a measurement uncertainty of 0.7 mag. The positional data collected during these observations will be used to improve the accuracy of the orbital elements of the asteroid. Similar observations were conducted with the Very Large Telescope (VLT) of the European Southern Observatory (ESO).

If all goes right Hayabusa-2 will rendezvous with 1998 KY26 in the summer of 2031.

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Scientists confirm ample Ryugu material in first Hayabuse sample chamber

8:01 am

Japanese scientists have opened the first chamber that stored the Ryugu asteroid samples obtained during its first touch-and-go sample grab, and confirmed that it holds ample material.

They also noted that the chamber itself contained gas from the asteroid as well.

The Japan Aerospace Exploration Agency (JAXA) has confirmed that the gas collected from the sample container inside the re-entry capsule of the asteroid explorer, Hayabusa2, is a gas sample originating from asteroid Ryugu.

The result of the mass spectrometry of the collected gas within the sample container performed at the QLF (Quick Look Facility) established at the Woomera Local Headquarters in Australia on December 7, 2020, suggested that the gas differed from the atmospheric composition of the Earth. For additional confirmation, a similar analysis was performed on December 10 – 11 at the Extraterrestrial Sample Curation Center on the JAXA Sagamihara Campus. This has led to the conclusion that the gas in the sample container is derived from asteroid Ryugu.

They think that this gas must have outgassed from the samples themselves. I suspect it was released either during the long journey or when the samples were subjected to the high accelerations and impact during its return to Earth. Research is going to have to try to pin this down, however.

They plan to open the two remaining sample chambers containing material sometime next week.

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Scientists confirm Hayabusa-2’s return capsule brought back material from Ryugu

8:56 am

Based on their first observations of the return capsule from Hayabusa-1, Japanese scientists yesterday confirmed that it successfully has returned material from the asteroid Ryugu.

JAXA said in a statement that they observed the sandy material at the entrance of the collection chamber, but have yet to look inside to see if more asteroid dust is lurking there. It is only the second time that scientists have returned material from an asteroid.

This find in the entrance portends a gold mine of material in the collection chamber itself.

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Hayabusa-2’s samples from Ryugu land in Australia

2:07 pm

The return capsule carrying the asteroid samples grabbed by Hayabusa-2 from Ryugu successfully parachuted down in the outback of Australia today.

Officials from the Japan Aerospace Exploration Agency, or JAXA, confirmed shortly after 1 p.m. EST (1800 GMT) that the Hayabusa 2’s nearly 16-inch (40-centimeter) sample carrier landed in Australia. Touchdown likely occurred several minutes earlier.

Recovery teams dispatched via helicopter began hunting for the 35-pound (16-kilogram) capsule using estimates of its landing site derived from a radio beacon signal. Mission managers expected it could take several hours to find the capsule and recover it. The landing occurred before dawn in Australia.

Since the article above was posted the capsule was located, and it was found much quicker than first expected.

This was the second sample return mission by the Japanese. The first, Hayabusa-1, successfully returned its capsule in 2010, but because of many technical problems during the mission it only brought back a few microscopic samples. In fact, the technical problems were so bad it was really a miracle the capsule came back at all.

Hayabusa-2 however has been a complete success, showing that they learned from the first mission and applied those lessons to the second.

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Meteorite stolen five years ago from Australian museum recovered

8:45 am

A meteorite that was stolen five years ago from a small Australian museum, only two weeks after it was donated to that museum, was recovered by police two days ago.

While the police have returned the meteorite, they have not yet revealed much else.

On Saturday, Queensland Police executed a search warrant at a Cairns address and recovered the space rock, valued at more than $16,000.

Investigations are underway into the incident, and no charges have been laid, but the sisters are pleased the meteorite is back in their possession.

…Police investigating the incident said they were looking into a number of leads relating to the theft. “I believe it definitely has a story to tell,” Senior Constable Heidi Marek said. “I’ll leave it up to detectives to uncover that story but hopefully we’re able to reveal a bit of information down the track.”

That no charges were file is most puzzling. I hope the full story is soon revealed.

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Apophis: the asteroid that may someday hit the Earth

8:40 am

Apophis' path past the Earth in 2029
From the conference’s logo.

Last week planetary scientists held a three-day virtual conference focused on the asteroid Apophis, whose orbit regularly places it close to the Earth with a real possibility that it might someday hit the Earth.

When Apophis was originally discovered early in 2004, it wasn’t at first seen as an out-of-the-ordinary asteroid. Not much was known about it other than its albedo and that it was not trivial in size, probably around 1,000 feet in diameter. All this changed in December 2004, when further observations suggested that it had a 2.7% chance of impacting the Earth in 2029, making it the most dangerous asteroid ever discovered.

Fortunately, all subsequent observations of the asteroid have since eliminated any possibility of an impact, at least through the year 2068. Depending on what happens during the 2029 and 2036 fly-bys of Earth, there is a very small chance that it could hit the Earth in 2068, though the data says the chances of that happening are quite small (1 in 150,000).

On April 13, 2029 however Apophis will still zip past the Earth less than 20,000 miles above its surface, well within the orbit of all geosynchronous satellites. For viewers in Europe and Africa it will be a naked eye object, with a magnitude of -3.

Because the date of that close fly-by is so well known, and because this asteroid still poses a threat to the Earth, the planetary science community is very much interested in taking advantage of that close approach. From the conference’s webpage:

Knowledge is the first line of planetary defense, and the 2029 Apophis encounter is a once-per-thousand-year opportunity for investigating an asteroid as large as 350 meters passing within 6 Earth-radii. Time is of the essence as we have less than a decade to plan Earth-based and possible in-situ missions whose measurements can deliver unprecedented detailed knowledge on the physical nature of Apophis as the prototype example (poster child) of potentially hazardous asteroids.

I attended that conference, and am here now to give a summary.
» Read more

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Another movie of OSIRIS-REx’s sample-grab-and-go at Bennu

10:08 am

The OSIRIS-REx science team has released another movie showing the sample-grab-and-go at Bennu, this time from a different camera.

The movie, made up of 189 images taken over three hours by the spacecraft’s navigation camera NavCam-2, can be seen at the link.

In the middle of the sequence, the spacecraft slews, or rotates, so that NavCam 2 looks away from Bennu, toward space. OSIRIS-REx then performs a final slew to point the camera (and the sampling arm) toward the surface again.

As the spacecraft nears site Nightingale, the sampling arm’s shadow comes into view in the lower part of the frame. Shortly after, the sampling head impacts site Nightingale (just outside the camera’s field of view to the upper right) and fires a nitrogen gas bottle, which mobilizes a substantial amount of the sample site’s material. Several seconds later, the spacecraft performs a back-away burn and the sampling arm’s shadow is visible against the disturbed surface material.

The team continues to investigate what caused the extremely dark areas visible in the upper and middle parts of the frame. The upper area could be the edge of the depression created by the sampling arm, a strong shadow cast by material lofted from the surface, or some combination of the two. Similarly, the middle dark region that first appears in the lower left of the image could be a depression caused by one of the spacecraft thrusters as it fired, a shadow caused by lofted material, or a combination of both.

It strikes me that getting post impact images of Nightingale is essential, if at all possible.

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OSIRIS-REx completes storage of Bennu sample

2:33 pm

OSIRIS-REx has now completed placing its sample from the asteroid Bennu in the Sample Return Capsule that will bring it back to Earth.

On the afternoon of Oct. 28, following the backout check, the mission team sent commands to disconnect the two mechanical parts on the TAGSAM arm that connect the sampler head to the arm. The spacecraft first cut the tube that carried the nitrogen gas that stirred up the sample through the TAGSAM head during sample collection, and then separated the collector head from the TAGSAM arm itself.

That evening, the spacecraft completed the final step of the sample stowage process –closing the SRC. To secure the capsule, the spacecraft closed the lid and then fastened two internal latches. As of late Oct. 28, the sample of Bennu is safely stored and ready for its journey to Earth.

Because they decided it was better to store the sample immediately and not risk losing it, they were unable to do the spin test that would told them how much sample they obtained. For this reason we will not know the amount until the sample capsule is opened here on Earth, after its return on September 24, ’23.

UPDATE: You can watch if short movie of the Sample Return Capsule closing here.

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Meteor over Alaska sets off volcano sensors

8:49 am

A bright fireball meteor that passed over western Alaska on October 15th caused enough disturbance in the atmosphere to set off volcano sensors throughout the region.

The event, which took place on October 15, triggered six of the sensors’ alarms at a new monitoring station on the Kenai Peninsula. The sensors are built to detect low-frequency sound waves in the atmosphere during volcanic activity, but in this case they picked up waves coming from the meteor that had streaked across the sky around 360 miles away.

In a Facebook post, the USGS said the meteor also triggered an alarm at Mount Spurr—a large, active volcano that sits around 80 miles from Anchorage that last erupted in 1992. However, as other monitoring systems also picked up on the waves, “it quickly became clear that this was not activity at Mount Spur,” the post said.

It is ironic, but those sensors, designed to monitor volcano eruptions, have likely also provided scientists some worthwhile data on asteroids.

Hat tip Commander Cobra of Task Force Gryphon

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Hayabusa-2’s impactor shook Ryugu

8:26 am

When Hayabusa-2 fired an impactor into the asteroid Ryugu in order to access subsurface material in a sample grab, it apparently shook the asteroid, shifting boulders and rocks as far as 130 feet away.

The artificial impactor disturbed boulders within a 30m radius from the center of the impact crater- providing important insight into asteroids’ resurfacing processes.

Professor ARAKAWA Masahiko (Graduate School of Science, Kobe University, Japan) and members of the Hayabusa2 mission discovered more than 200 boulders ranging from 30cm to 6m in size, which either newly appeared or moved as a result of the artificial impact crater created by Japanese spacecraft Hayabusa2’s Small Carry-on Impactor (SCI) on April 5th, 2019. Some boulders were disturbed even in areas as far as 40m from the crater center. The researchers also discovered that the seismic shaking area, in which the surface boulders were shaken and moved an order of cm by the impact, extended about 30m from the crater center. Hayabusa2 recovered a surface sample at the north point of the SCI crater (TD2), and the thickness of ejecta deposits at this site were estimated to be between 1.0mm to 1.8cm using a Digital Elevation Map (DEM).

This data makes all the more important for OSIRIS-REx to get post-sample-grab images of its Nightingale site, if at all possible.

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OSIRIS-REx engineers successfully place sample collector in return capsule

7:55 am

Stowing OSIRIS-REx's sample from Bennu
Click for full image.

OSIRIS-REx engineers have successfully placed the sample collector head holding the material captured from the asteroid Bennu in the return capsule that will bring it back to Earth.

Yesterday, NASA’s OSIRIS-REx mission successfully placed the spacecraft’s sample collector head into its Sample Return Capsule (SRC). The first image shows the collector head hovering over the SRC after the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) arm moved it into the proper position for capture. The second image shows the collector head secured onto the capture ring in the SRC. Both images were captured by the StowCam camera.

Today, after the head was seated into the SRC’s capture ring, the spacecraft performed a “backout check,” which commanded the TAGSAM arm to back out of the capsule. This maneuver is designed to tug on the collector head and ensure that the latches – which keep the collector head in place – are well secured. Following the test, the mission team received telemetry confirming that the head is properly secured in the SRC.

The next step will be to seal the capsule for return to Earth. However, based on the two images above, the sample is now relatively secure, as the opening where material could escape is now held face down in the capsule.

The spacecraft will head back to Earth in March ’21, with the sample capsule landing on Earth on September 24, 2023. I do not know whether it will be possible in the next six months to get new images of the Nightingale touch-and-go site, but have emailed Erin Morton, head of the communications for the science team, and asked. I will update this post when I hear back from her.

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New data: The asteroid Psyche is rusting

9:49 am

Using new ultraviolet data from the Hubble Space Telescope, astronomers now believe that the high density asteroid Psyche, thought to be largely metallic, is rusting because of interaction with the solar wind.

Becker observed the asteroid at two specific points in its rotation to view both sides of Psyche completely and delineate as much as possible from observing the surface at ultraviolet (UV) wavelengths.

“We were able to identify for the first time on any asteroid what we think are iron oxide ultraviolet absorption bands,” she said. “This is an indication that oxidation is happening on the asteroid, which could be a result of the solar wind hitting the surface.”

There will be a U.S. probe to Psyche launched in ’22.

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OSIRIS-REx sample grab so successful they are losing material

2:47 pm

The samples from Bennu
Click for full two frame gif movie.

In a briefing today and press release, the OSIRIS-REx science team announced that they estimate that they have gathered a lot of material from the asteroid Bennu, at least 100s of grams, about twice the minimum of what they hoped to get.

In fact, images of the TAGSAM sample grab equipment suggest that there are some larger rocks lodged in its opening (preventing the flap from closing), and that the small movements they have done to photograph it has caused some of the captured material to escape. The image to the right shows this. You can see floating specks and their shadows (the horizontal streaks) that have escaped. At about 9 o’clock you can see a curve in the contact between a lighter material and blackness to its outside, bending towards the center of the TAGSAM. At other exposures they can clearly see a rock there, distorting the shape and thus preventing the flap from closing properly.

Because of this, they are foregoing the spin maneuver that would have weighed the sample, as well as one engine burst that would have slowed the spacecraft’s movement away from Bennu.

This means they will not know the exact amount captured until the sample gets back to Earth. This is a gamble, but they are confident that they have gotten a lot of material. According to Dante Lauretta, the principal investigator, the sample grab-and-go “got very down” into Bennu, as much as 19 inches. He is also confident that they grabbed more than a 100 grams.

They are therefore going to as quickly as possible store the samples in the Sample Return Capsule for return to Earth, beginning on October 27. They need to do a complex series of steps to make this happen, which is why it cannot happen until then.

One more detail: In their simulations prior to the touch-and-go, they had a range of estimates of how deep the spacecraft would penetrate. According to Lauretta, OSIRIS-REx plunged into Bennu at the softest part of that range, telling them that the asteroid is probably much more loosely packed than expected.

Because they are not doing that last engine burst means that they are moving away from Bennu for good. They will not return to the asteroid. Whether they will be able to get post sample grab images of Nightingale is unknown.

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Images taken during OSIRIS-REx sample grab on Bennu

3:40 pm

Below is an embed of a short eight second video of OSIRIS-REx’s sample grab yesterday from the surface of Bennu, created from 82 images, and covering at high speed the five minutes of approach, contact, and retreat. If you set the speed rate at 0.25, you can get a better view of the whole sequence of events.

From the science team’s press release,

The spacecraft’s sampling arm – called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) – is visible in the lower part of the frame. The round head at the end of TAGSAM is the only part of OSIRIS-REx that contacted the surface during the sample collection event. In the middle of the image sequence, the sampling head positions itself to contact the asteroid’s surface head-on. Shortly after, the sampling head impacts site Nightingale and penetrates Bennu’s regolith. Upon initial contact, the TAGSAM head appears to crush some of the porous rocks underneath it. One second later, the spacecraft fires a nitrogen gas bottle, which mobilizes a substantial amount of the sample site’s material. Preliminary data show the spacecraft spent approximately 5 of the 6 seconds of contact collecting surface material, and the majority of sample collection occurred within the first 3 seconds.

The TAGSAM is designed to catch the agitated surface material, and the mission team will assess the amount of material collected through various spacecraft activities. After touchdown, the spacecraft fired its thrusters to back away from Bennu. As expected, this maneuver also disturbed the Nightingale site, and loose debris is visible near the end of the image sequence. Preliminary telemetry shows the spacecraft remains in good health. The spacecraft was traveling at 0.2 mph (10 cm/sec) when it contacted sample site Nightingale and then backed away at 0.9 mph (40 cm/sec). [emphasis mine]

At the moment it appears they don’t yet know how much sample they have gotten, but they are very optimistic that they have gotten enough, based on the performance above. On October 24th, when they have gotten far enough away from the asteroid, they give the spacecraft a spin to measure its present mass and compare that to a spin done prior to the sample grab. The difference will tell them how much sample they have captured.

They will also be looking at images of TAGSAM over the next few days, which will also indicate what’s been captured.

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Sample grab appears to be a success at Bennu

3:17 pm

OSIRIS-REx has apparently successfully touched the surface of Bennu, grabbed a sample, and backed away without damage.

The link takes you to my embed of NASA’s live stream, which is mostly pr garbage. However, it is providing live updates from the mission control team, as it happens. Most of time, the NASA people running their pr effort even have the sense to shut up when such updates come it.

Right now we do not know how much of a sample was obtained. It will take some analysis of data and images to find out. They will know by the time of tomorrow’s press conference at 5 pm (Eastern).

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Today’s OSIRIS-REx sample grab from Bennu

10:28 am

Nightingale landing site on Bennu
The Nightingale landing site on Bennu, with
OSIRIS-REx superimposed. Click for full image.

Spaceflight Now today published a nicely detailed article summarizing the entire OSIRIS-REx mission to the asteroid Bennu, in anticipation of today’s attempt to grab a sample from that asteroid’s surface.

If you want to understand what is happening today, this article does a nice job of outlining everything.

I have embedded the live stream of the sample grab below the fold. It begins at 5 pm (Eastern) today. Be warned that it will show very little of the actual event, as the spacecraft will not be sending much data back to Earth today, during these operations. All we will really find out is if the grab happened, or was aborted to avoid risks, or occurred but the spacecraft was impacted by flying material during the grab. (Let us hope that this last option does not occur.)

The first images and data will not arrive until tomorrow, to be released during a press conference scheduled for 5 pm (Eastern).
» Read more

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