Tag: asteroids

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

1:57 pm

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.

0 comments

Hayabusa-2’s second touchdown sample grab

9:17 am

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.

0 comments

Hayabusa-2’s second touchdown an apparent success

9:16 am

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.

0 comments

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

8:26 am

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.

0 comments

Astronomers find kilometer-sized asteroid with shortest year

10:10 am

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.

0 comments

Hayabusa’s 2nd sample grab on Ryugu

8:11 am

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.

0 comments

Hayabusa-2 to attempt 2nd sample grab

9:02 am

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.

0 comments

Planning Hayabusa-2’s next sample grab on Ryugu

10:47 am

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.

0 comments

Bennu from 2,200 feet

7:56 am

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.

0 comments

Hayabusa-2 completes close approach of target/manmade crater

9:21 am

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.

0 comments

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

8:39 am

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.

0 comments

Hayabusa-2 making close approach of target/manmade crater

5:56 pm

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.

0 comments
1 … 25 26 27 28 29 … 78