Tag: asteroids

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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