Tag Archives: asteroids

Hayabusa-2: Carbon-rich asteroids too delicate to reach Earth surface

New data from Hayabusa-2 has confirmed the long-held suspicions of astronomers that the reason they find so few fragments of C-class asteroids, such as Ryugu, on Earth is because they are too delicate to reach the Earth’s surface.

Ryugu and other asteroids of the common ‘C-class’ [chondritic] consist of more porous material than was previously thought. Small fragments of their material are therefore too fragile to survive entry into the atmosphere in the event of a collision with Earth.

…Until now, only a few chondritic meteorites found on Earth have been identified as fragments of C-type asteroids, which are very common in the Solar System (‘C’ is the chemical symbol for the element carbon). …”We can now confirm that fragments of these asteroids are very likely to break up further when they enter Earth’s atmosphere, and then usually burn up completely. This means that only the largest fragments reach the Earth’s surface,” explains Grott. “That is why meteorites from this type of asteroid are so rarely found on Earth.”

The good news is that, because of this, Earth’s atmosphere offers increased protection from C-type asteroids, which account for 75 percent of all asteroids. …However, further research is necessary to determine the maximum asteroid size for which this atmospheric protection is effective.

It is likely that even the largest rubble-pile C-asteroids will not pose much risk. Even if some pieces reach the Earth’s surface they are probably going to be small and unable to do much harm.

Share

Hayabusa-2’s second touchdown sample grab

Hayabusa touchdown sequence

The Hayabusa-2 science team yesterday released a series of close-up images taken just as the spacecraft touched down and then backed off from the surface of Ryugu.

I have cropped and annotated that sequence and placed all three images side-by-side above. The red arrows in the first two images highlight similar shadows in both pictures, with the appearance of dust visible in the lower center of the middle touchdown picture. I have not marked any comparable surface features in the third image because the uplift of material makes it too difficult.

That uplift however is exactly what the Hayabusa-2 science team needs, as it is some of this material that has hopefully been captured. Their fear was that this uplift posed a risk to the spacecraft itself, but they took precautions to minimize the risk and it appears that these precautions have worked.

We now must wait until the samples come back to Earth in December 2020 to see exactly what they caught.

Share

Hayabusa-2’s second touchdown an apparent success

Japan’s Hayabusa-2 probe has successfully completed its second touch-and-go sample grab on the asteroid Ryugu.

Japan’s Hayabusa2 successfully completed its second touchdown on the asteroid Ryugu and probably captured material from its interior that was exposed by firing a projectile into the asteroid earlier this year. It is the first collection of subsurface materials from a solar system body other than the moon.

Engineers and technicians in the spacecraft’s control room near Tokyo could be seen erupting into cheers and applause on a YouTube live stream when Project Manager Yuichi Tsuda proclaimed the operation a success just before 11 a.m. local time. At an afternoon press briefing, Tsuda said, “Everything went perfectly.” He joked that if a score of 100 indicated perfection, “I would give this a score of 1000.”

They will now begin the journey home, with the samples arriving on Earth in December 2020.

Share

Hayabusa-2 begins second touch&go sample grab on Ryugu

The Hayabusa-2 science team has begun the approach to Ryugu for the spacecraft’s second tough-and-go sample grab.

The link outlines the plan and timing of the operation. You can view real-time images taken by the probe’s navigation camera here. The actual touchdown will take place on July 11 (Japan time).

You can also view a set of stereoscopic images of Ryugu produced by Brian May, lead guitarist of Queen who clearly wants to return to his roots as a trained astrophysicist.

As they note at the first link:

The 2nd touchdown is the last big operation at Ryugu for the Hayabusa2 project. We will proceed with caution and the upmost care. Please wish us success…!

If successful, their next big operation will be getting those samples back to Earth.

Share

Astronomers find kilometer-sized asteroid with shortest year

Astronomers have found a kilometer-sized asteroid with a year only 151 days long, the shortest year of any asteroid.

The asteroid has been dubbed 2019 LF6.

In its orbit, the asteroid swings out beyond Venus and, at times, comes closer in than Mercury, which circles the sun every 88 days. 2019 LF6 is one of only 20 known “Atira” asteroids, which are objects whose orbits fall entirely within Earth’s.

Atira asteroids are difficult to find because they are so close to the Sun, which makes observations difficult if not impossible. Expect more such discoveries as the technology to make these observations improves.

Share

Hayabusa’s 2nd sample grab on Ryugu

Target 2nd landing site on Ryugu
Click for full resolution image.

The Hayabusa-2 science team today posted detailed information in two posts about the process that led to the decision to attempt a second touch-and-go sample grab on the surface of Ryugu. The first part outlined in detail what they have learned about the target landing site. The second part described the decision making process.

The image to the right, reduced to post here, is from the second part. It shows the crater they created with a projectile and the target landing site, labeled C01-C. The dark areas show the changes on the surface following the impact. Their analysis of the target site found that, first, they can land there without undue risk to the spacecraft, and, second, they have a high probability of getting ejecta thrown up from the crater in their sample.

Based on all this information, they decided to attempt it, on July 11. I especially like how they stated this decision:

The second touchdown will be attempted on July 11. We will proceed with our mission with care, but boldly go. [emphasis mine]

I am sure my readers will recognize the literary reference.

Share

Hayabusa-2 to attempt 2nd sample grab

The new colonial movement: The Hayabusa-2 science team has decided to attempt a second touch-and-go sample grab from the man-made crater they created on the surface of the rubble-pile asteroid Ryugu.

JAXA engineers confirmed that the probe’s camera and other equipment that were slightly damaged by the first landing are usable, and that there are no big rocks at the candidate site. They gave the go-ahead for a landing on July 11.

Hayabusa2 is scheduled to begin its descent from an altitude of 20,000 meters at around 10 a.m. on July 10 Japan time, and touch down on the asteroid’s surface about 25 hours later.

This is the first time I have heard of any damage to the spacecraft from the first touch-and-go landing. Regardless, they have decided they can risk another sample grab and still have the ability to return the samples to Earth.

Share

Planning Hayabusa-2’s next sample grab on Ryugu

Target and man-made crater on Ryugu
Click for full image.

The Hayabusa-2 science team today released a mosaic image created using the images taken during the four close approaches to the site of the man made crater put there by a projectile fired from the spacecraft. The image on the right, reduced and cropped to post here, shows this area, with the white spot being the target they dropped onto the site during the most recent close approach. As they note in their release:

In order to collect this material, we need a second touchdown for which the project has been steadily preparing. At this point, it has not yet been decided whether or not to go ahead with a second touchdown, but here we will introduce our preparations in the “Approach to the second touchdown”.

After the operation to form the artificial crater, the spacecraft descended a total of four times above or near the crater site. These descent operations allowed us to obtain detailed data of the region near the artificial crater. In addition, we succeeded in dropping a target marker in the area close to the artificial crater on May 30. Combined, these operations mean that the situation around the artificial crater is now well understood.

Figure 1 [the image to the right] shows an image taken during the low altitude descent observation operation (PPTD-TM1B) conducted from June 11 – 13. The target marker was captured in the image and you can get a handle on the state of the surface. [emphasis mine]

Unfortunately they do not show us exactly where the man made crater is located in this mosaic. Nor was I able to locate it by comparing today’s image to a previous image that did indicate the location.

The only place that seems acceptable for their touch-and-go sample grab seems to be just above or to the left of the target. Whether this will get them any interior material thrown up during the impact however is unclear.

Share

Bennu from 2,200 feet

Bennu from about 2,200 feet
Click for full image.

The OSIRIS-REx science team today released one of the first images taken of Bennu after the spacecraft lowered itself into its closest orbit in early June. I have reduced and cropped slightly that image slightly to post here on the right. As they note,

From the spacecraft’s vantage point in orbit, half of Bennu is sunlit and half is in shadow. Bennu’s largest boulder can also be seen protruding from the southern hemisphere. The image was taken from a distance of 0.4 miles (690 m) above the asteroid’s surface by NavCam 1, one of three navigation cameras that comprise the spacecraft’s TAGCAMS (the Touch-and-Go Camera System) suite. At this distance, details as small as 1.6 ft (0.5 m) across can be resolved in the center of the image.

In other words, if a person was moving across the asteroid’s surface you could see them.

Share

Hayabusa-2 completes close approach of target/manmade crater

Target on Ryugu's surface

Hayabusa-2 has successfully completed its close approach and reconnaissance of the positioning target it had placed on May 30 near the crater it had created on Ryugu on April 4.

The image to the right is the last navigational image taken at the spacecraft’s closest point. You can clearly see the navigational target as the bright point near the upper center of the image, to the right of the three larger rocks. This location also appears to be inside the manmade crater, based on earlier reconnaissance of that crater. The crater is in an area they have labeled C01, which is where they have successfully placed the target. It also appears that this is the smoothest area in C01, which will greatly facilitate their planned sample grab.

Share

OSIRIS-REx’s new orbit of Bennu only half mile high

OSIRIS-REx has moved into its next phase of research by lowering its orbit around the asteroid Bennu to only 2,231 feet above the surface.

Upon arrival at Bennu, the team observed particles ejecting into space from the asteroid’s surface. To better understand why this is occurring, the first two weeks of Orbital B will be devoted to observing these events by taking frequent images of the asteroid’s horizon. For the remaining five weeks, the spacecraft will map the entire asteroid using most of its onboard science instruments: the OSIRIS-REx Laser Altimeter (OLA) will produce a full terrain map; PolyCam will form a high-resolution, global image mosaic; and the OSIRIS-REx Thermal Emission Spectrometer (OTES) and the REgolith X-ray Imaging Spectrometer (REXIS) will produce global maps in the infrared and X-ray bands. All of these measurements are essential for selecting the best sample collection site on Bennu’s surface.

The goal is to narrow to four the possible touch-and-go landing sites for grabbing a surface sample. They will pick the final choice in a reconnaissance phase now scheduled for the fall.

The present research phase will last until the middle of August, when they will raise the orbit slightly to give them a different perspective of its surface and the particles being released from it.

Share

Hayabusa-2 making close approach of target/manmade crater

Ryugu during close approach

The Hayabusa-2 science team is right now conducting a close approach of the manmade impact crater they created to get a firm idea of exactly where the navigation target dropped to the surface during the last close approach landed.

The image on the right is the most recent navigation image, taken just a short time ago, and posted here in real time.

Once they have a precise location, they can then plan the touch-and-go sample grab within that man-made crater.

Share

The big water volcano on Ceres

Scientists have proposed a new detailed model to explain the formation of the large mountain Ahuna Mons on the asteroid Ceres.

The new theory doesn’t change the generally accepted idea that this mountain is a ice volcano, formed by the rise of a brine from below. It simply provides some details about the process.

A study involving scientists from the German Aerospace Centre (DLR) has now solved the mystery of how Ahuna Mons, as the mountain is called, was formed, using gravity measurements and investigations of the geometrical form of Ceres. A bubble made of a mixture of salt water, mud and rock rose from within the dwarf planet. The bubble pushed the ice-rich crust upwards, and at a structural weak point the muddy substance, comprising salts and hydrogenated silicates, was pushed to the surface, solidified in the cold of space, in the absence of any atmosphere, and piled up to form a mountain. Ahuna Mons is an enormous mud volcano.

The bubble would be the equivalent of a magma chamber of lava here on Earth.

Share

On the precipice on Bennu

Truck-sized boulder on a crater rim on Bennu
Click for full image.

Cool image from OSIRIS-REx. The picture on the right, cropped to post here, was taken by OSIRIS-REx and shows a square boulder about the size of a 15-passenger van, precariously perched on the rim of a large crater on the asteroid Bennu. The picture was taken April 11 from about 2.9 miles distance.

This scale is human-sized. If that rock is a 15 passenger van, then the small rocks around it are about the size of a person and that cliff is about 20-30 feet high. I can imagine strolling down the slope to check out the cliff face, though I would make sure I gave a wide berth to the part of the cliff directly below that boulder.

Share

VLT snaps image of double asteroid zipping past Earth

Double asteroid imaged by VLT

The Very Large Telescope (VLT) in Chile was successfully able to photograph the double asteroid that flew past the Earth on May 25 at a distance of 3.2 million miles and a speed of 43 thousand miles per hour.

The left image on the right is the raw image, while the right image is their reconstruction after applying adaptive-optics (AO) to the raw image. From the press release:

Bin Yang, VLT astronomer, declared “When we saw the satellite in the AO-corrected images, we were extremely thrilled. At that moment, we felt that all the pain, all the efforts were worth it.” Mathias Jones, another VLT astronomer involved in these observations, elaborated on the difficulties. “During the observations the atmospheric conditions were a bit unstable. In addition, the asteroid was relatively faint and moving very fast in the sky, making these observations particularly challenging, and causing the AO system to crash several times. It was great to see our hard work pay off despite the difficulties!”

To put it mildly, that right image is a fantasy. Astronomers love to tout the wonders of adaptive optics, but no matter how good it might be, it still is garbage-in-garbage-out, a computer simulation based on their guess at what the object would look like if there was no atmosphere in the way. In this particular case, they are being especially fantastic, and guaranteed to be wrong. It is impossible for them to extrapolate such minute surface details from the fuzzy image on the left.

Still, getting an image of this asteroid as it zipped by at that speed using such a large telescope is an achievement, and bodes well for the use of ground-based astronomy of near Earth asteroids.

Share

Hayabusa-2 successfully places reference target at man-made crater

Close-up during Hayabusa-2's close approach

Hayabusa-2 has successfully dropped a small reference target at the man-made crater on Ryugu, getting within 10 meters of the surface.

The image to the right is the last image taken by the spacecraft’s navigation camera during the operation. Unfortunately, the science team did not provide any further information, such as the height from which this image was taken, nor the scale of the features. Based on the sequence of images, it clearly occurred at the moment of closest approach.

I have tried to see if I could pinpoint the crater in the image by comparing it to the planning image post here. Unfortunately, I have been unable to identify comparable features.

Either way with the successful placement of the reference target on the surface, they can now begin planning the sample grab touch-and-go at this location.

Share

Hayabusa-2 has begun approach to Ryugu

Ryugu during approach

Hayabusa-2 has begun its approach to the man-made impact site on Ryugu in order to drop a reflective reference target there in preparation for a later touch-and-go landing.

The link provides real time delivery of the images taken by the spacecraft’s navigation camera, released approximately once every thirty minutes. The image on the right, brightened slightly to post here, is the most recent image as I write this post.

The approach will take almost twenty-four hours, so viewing the changes at the link will be somewhat equivalent to watching paint dry. I suggest returning every few hours to see the closer images of the asteroid.

Share

Hayabusa-2’s second approach to artificial crater scheduled

Ryugu impact site
Click for full image.

Based on images obtained during the aborted early May close-in approach to the asteroid Ryugu, the Hayabusa-2 science team was able to get better imagery of the location of their man-made impact site,, and this has allowed them to both reschedule to May 28-30 the next close approach, as well as more accurately aim the spacecraft at that artificial crater.

The image on the right shows the artificial crater as the dark area inside the box labeled C01, their new target site. The S01 box was the target location for the mid-May aborted approach.

The goal of these close-in approaches is to drop a reflective target at the site, giving them a very precise reference point for the touch-and-go sample grab to follow. They were unable to make the drop on the aborted close-in approach, and will attempt it again in this week’s second attempt.

The second link above provides a detailed minute-by-minute outline of this week’s approach. As before, you can watch it happen with the live download of navigation images every thirty minutes or so. A link to that real-time image delivery will be found here.

Share

OSIRIS-REx moves into new science phase

The OSIRIS-REx science team has shifted the spacecraft’s operation into a new phase aimed at carefully mapping the surface of the asteroid Bennu in preparation for an eventual touch-and-go sample grab.

During Detailed Survey: Equatorial Stations phase, the spacecraft’s instruments will make the scientific observations needed to help the team home in on the best location on Bennu to collect a sample of regolith (loose surface material). To obtain these data, the spacecraft will execute a series of slews between Bennu’s north and south poles while taking observations from seven different stations above the equator. These data will be studied to understand the geology of Bennu. The spacecraft will also conduct searches for dust and gas plumes.

During this phase, planned to last through mid-June, they are asking for the public’s help in mapping the surface and its innumerable rocks.

For this effort, NASA is partnering with CosmoQuest, a project run out of the Planetary Science Institute that supports citizen science initiatives. Volunteers will perform the same tasks that planetary scientists do – measuring Bennu’s boulders and mapping its rocks and craters – through the use of a simple web interface. They will also mark other scientifically interesting features on the asteroid for further investigation.

The boulder mapping work involves a high degree of precision, but it is not difficult. The CosmoQuest mapping app requires a computer with a larger screen and a mouse or trackpad capable of making precise marks. To help volunteers get started, the CosmoQuest team provides an interactive tutorial, as well as additional user assistance through a Discord community and livestreaming sessions on Twitch.

Seems like fun!

Share

Hayabusa-2 aborts close-in drop of visual marker on Ryugu

Japan’s asteroid probe Hayabusa-2 automatically aborted a planned drop of a visual markee on the asteroid Ryugu at the site where the probe created a crater in April.

Thursday’s mission was to observe the targeted area in detail and drop a marker from an altitude of 10 meters. But officials say the probe automatically suspended the operation after it descended to about 50 meters above the surface. It then headed toward its standby position of 20 kilometers above Ryugu. Hayabusa2 is designed to automatically abort its landing if it detected any irregularity. The agency is looking into the cause of the arrested descent.

Once the marker is eventually in place, they will use it for guidance during a a second touchdown to grab further samples, this time hopefully of material churned up by the explosion that created the crater.

Share

Ten secondary craters produced on Ryugu by Hayabusa-2’s manmade impact

The Hayabusa-2 science team has announced that it has found ten additional secondary craters produced from ejecta from the manmade impact the spacecraft created on Ryugu on April 5.

The secondary craters appear to be about a yard across each, while the initial crater is about thirty feet wide with a depth of six to ten feet.

Share

The temperature on Bennu

The OSIRIS-REx science team have released a short movie, compiled from data obtained in November 2018 as the spacecraft was first approaching the asteroid Bennu, that shows the dayside surface temperature and how it changes as the asteroid rotates.

I have embedded the movie below the fold.

Within a distance of only about 850 feet the temperature rises more than 270 degrees, from -99.67 °F to 170.33 °F. This change also occurs at every spot as the asteroid rotates. At dawn it will be that cold, and by noon it will be that hot.
» Read more

Share

Bennu from two miles

Bennu from two miles
Click for full image.

In late March OSIRIS-REx completed its fourth fly-by of the asteroid Bennu. The image on the right, cropped and reduced to post here, was taken when the spacecraft was only 2.1 miles above the surface. If you were standing among these large boulders, we could easily see you.

The image itself shows the asteroid’s southern limb, and thus the shadows are accentuated. This makes it easier to see surface details. Though it is clear once again that Bennu is a pile of boulders and rocks cemented together and floating in space, the photograph also shows that it also has areas where the material is either much larger or fused together more solidly, as shown by the more massive sections in the left center of this picture. We might be looking a very large boulders peeking up from below the surface, or possibly this is the hint of some real bedrock.

The OSIRIS-REx team is continuing the spacecraft’s survey phase, gathering high resolution images in order to compile a detailed map of the surface, prior to planning the touch-and-go sample grab.

Share

Lunar eclipse meteorite hit the Moon at almost 38,000 mph

By analyzing the data obtained of the meteorite impact that hit the Moon during the January 21 lunar eclipse, astronomers now estimate it crashed into the surface at almost 38,000 miles per hour and would have produced a crater about 50 feet across.

They also estimate that the meteorite itself had a mass of about 100 pounds with a diameter of between one to two feet.

The new crater itself has not yet been spotted, and probably can only be photographed with the high resolution camera on Lunar Reconnaissance Orbiter (LRO). I expect the LRO science team has already scheduled observations for this location. It will be interesting to see if the actual crater corresponds to the estimates of these astronomers.

Share

The new man-made crater on Ryugu

Man-made crater on Ryugu

The Hayabusa-2 science team has released before and after images of the spot on Ryugu where the spacecraft’s explosive projectile caused the creation of a small crater.

On the left above is the before, with the new crater indicated by the circle on the right. Note the rocks in both pictures, some now partly covered with debris. They did not give a scale, but this is a very small area, probably less than a few feet across.

They now need to analyze whether they can safely touchdown at this spot and grab a sample.

Share

Hayabusa-2 confirms man-made crater on Ryugu

In a planned fly-over of Ryugu yesterday Hayabusa-2 took its first direct images of the location where it had fired an explosive projectile and thus confirmed the creation of a man-made crater by that projectile.

“The asteroid’s terrain has clearly been altered,” said Yuichi Tsuda, an associate professor at the Japan Aerospace Exploration Agency.

Hayabusa2, which began its descent toward the asteroid Wednesday afternoon, captured images of its surface to determine the existence of the crater after it successfully shot a metal projectile at Ryugu on April 5 in an experiment deemed the first of its kind.

According to the JAXA, the probe photographed the area hit by the projectile from a distance of 1.7 km. The agency compared images of the asteroid’s surface before and after the shooting of the projectile to determine the presence of a man-made crater.

They have not yet released any of these images. They will use them however for planning a touchdown and sample grab within this crater in next few months.

Share

Did an interstellar meteor hit the Earth in 2014?

By analyzing the speed in which it traveled through the atmosphere, astronomers propose that a meteor that hit the ground in 2014 was probably an interstellar object.

The scientists analyzed the Center for Near-Earth Object Studies’ catalog of meteor events detected by U.S. government sensors. They focused on the fastest meteors, because a high speed suggests a meteor is potentially not gravitationally bound to the sun and thus may originate from outside the solar system.

The researchers identified a meteor about 3 feet (0.9 meters) wide that was detected on Jan. 8, 2014, at an altitude of 11.6 miles (18.7 kilometers) over a point near Papua New Guinea’s Manus Island in the South Pacific. Its high speed of about 134,200 mph (216,000 km/h) and its trajectory suggested it came from outside the solar system, the scientists said. “We can use the atmosphere of the Earth as the detector for these meteors, which are too small to otherwise see,” Loeb told Space.com.

The meteor’s velocity suggested it received a gravitational boost during its journey, perhaps from the deep interior of a planetary system, or a star in the thick disk of the Milky Way.

To put it mildly, there are a lot of uncertainties about this conclusion. Nonetheless, their approach and hypothesis is very intriguing, and seems logical.

Share

April 25 set for Hayabusa-2’s first observations of artificial crater

The Hayabusa-2’s science team has scheduled their first observations of the artificial crater the spacecraft made on the surface of the asteroid Ryugu for April 25.

The probe will observe the crater, which was generated during an impact experiment on April 5, from a height of 1.7 kilometers. JAXA will collate the data with photographs of the surface taken near the impact point to measure the size and location of the crater. It will also examine the dispersion of rocks and judge whether Hayabusa2 can land to take samples.

This is only their first assessment. Once they feel comfortable about getting closer, they will then plan the spacecraft’s second touchdown and sample collection, this time hopefully from within that crater.

Share

Bennu’s cobbled equatorial ridge

Bennu as seen by OSIRIS-REx
Click for full image.

The OSIRIS-REx science team has released a new close-up image of Bennu, this time showing the asteroid’s equatorial ridge. The image on the right is that photograph, reduced to post here.

When the image was taken, the spacecraft was positioned over Bennu’s northern hemisphere, looking southward over the asteroid’s equatorial bulge. The field of view shown is 168 ft (51.2 m) wide. For scale, the bright, rectangular rock above the dark region is 8 ft (2.4 m) wide, about the size of a long bed on a pickup truck

Like Ryugu, the scientists for OSIRIS-REx are going to be challenged in finding a location smooth enough for their touchdown sample grab. That surface reminds me of some avalanche scree slopes I’ve hike across, where you’ve got nothing but rough rocks to walk on.

Share
1 2 3 21