IonStorm
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Posts posted by IonStorm
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7 hours ago, tater said:I love me some asteroid pictures!
Me too! Thanks for posting, I've gotten busy lately...
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13 minutes ago, tater said:
What's so remarkable is the total lack of scale.
Indeed. Though the craters don't appear to scale. There is so much to learn about this scree ball.
13 minutes ago, tater said:Doesn't it make you want to, well, stand there, and look around?
Except for the isolation and death part, yes.
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On 4/5/2019 at 4:43 PM, tater said:
This is an amazing shot:
Here's another
Rocks and Boulders near Bennu’s Equator
This image shows the rocky surface of Bennu in a region just south of the asteroid’s equator. The PolyCam camera on NASA’s OSIRIS-REx spacecraft took the image on March 7 from a distance of 3 miles (4.8 km). The width of the field of view is 185 ft (56.4 m) of Bennu’s surface. For scale, the cracked rock at the top of the image is 69 ft (21 m) long, which is about the length of four parallel parking spots. The image was obtained during Flyby 1 of the mission’s Detailed Survey: Baseball Diamond phase.
Date Taken: Mar. 7, 2019
Instrument Used: OCAMS (PolyCam)
Credit: NASA/Goddard/University of Arizona
https://www.asteroidmission.org/20190307-polycam-cracked-rock/
and another
Northern Boulder Imaged by PolyCam
This image shows one of the largest boulders on asteroid Bennu’s northern hemisphere. It was taken on March 7 by the PolyCam camera on NASA’s OSIRIS-REx spacecraft from a distance of 2.9 miles (4.6 km). The field of view in the image is 191 feet (58.2 meters) and the boulder itself measures 77 feet (23.5 meters) on its longest dimension, which is about the same length as one-fourth of an American football field.
The image was obtained during Flyby 1 of the mission’s Detailed Survey: Baseball Diamond phase while the spacecraft was flying over Bennu’s equator and pointing PolyCam to the north and west of the asteroid.
Date Taken: March 7, 2019
Instrument Used: OCAMS (PolyCam)
Credit: NASA/Goddard/University of Arizona
https://www.asteroidmission.org/20190307-polycam-northern-boulder/
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More data, more stories:
11M of 1B shots.
https://www.asteroidmission.org/bennu-visualized-by-ola-large/
and
And don't forget to watch Hayabusa2 make a crater on Ryugu today http://www.hayabusa2.jaxa.jp/en/galleries/onc/nav20190404/
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This might be good enough for RSS.
This is also the shape model we are superimposing image data on, so it is professional grade (until we get a lidar based one in the summer).
https://www.asteroidmission.org/updated-bennu-shape-model-3d-files/v20_shapea_24fps_sm_1/
Also, if you want the latest science here are a series of manuscripts just published (many behind paywalls, but per NASA policy all will appear here after a proprietary period: https://www.ncbi.nlm.nih.gov/pmc/funder/nasa/)
- The unexpected surface of asteroid (101955) Bennu https://rdcu.be/btlxy
- Craters, boulders and regolith of (101955) Bennu indicative of an old and dynamic surface https://rdcu.be/btlx8
- The dynamic geophysical environment of (101955) Bennu based on OSIRIS-REx measurements https://rdcu.be/btlxX
- The operational environment and rotational acceleration of asteroid (101955) Bennu from OSIRIS-REx observations https://rdcu.be/btlxS
- Evidence for widespread hydrated minerals on asteroid (101955) Bennu https://rdcu.be/btlxR
- Properties of rubble-pile asteroid (101955) Bennu from OSIRIS-REx imaging and thermal analysis https://rdcu.be/btlxL
- Shape of (101955) Bennu indicative of a rubble pile with internal stiffness https://rdcu.be/btlxI
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1 minute ago, tater said:
Fun image. Cross your eyes til you see three images, then focus on the center image that results. (click image to enbiggen it
)
You can also put it on your phone and use a (cheap) VR headset to see it.
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2 minutes ago, ThatGuyWithALongUsername said:
(I wonder if Ryugu has this, too, and if it doesn't maybe that will help us figure out what's causing this, given their similarities and differences)
Ryugu has not been observed to be active, though images at the specific camera angles that made them apparent for OSIRIS-REx (for improving navigation accuracy) have not (yet) been taken by Hayabus2. However, the hydration bands in the infrared are much weaker in Ryugu than Bennu and the magnetite features are absent in Ryugu. This points to a Bennu being wetter, which might be the mechanism for ejecting particles while at perihelion.
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Remember this is a composite. The particles are too dim to see without hugely overexposing Bennu.
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1 minute ago, tater said:
The new sample target area diameter points out that "pond" as a size example---is there any concern (or hope, lol) that such an area might be a site of the outgassing/eruptions?
Have the sites of the eruptions been established well enough to have a feel for any geographical preferences they might have, or are they randomly scattered?
We don’t know yet, but we’re working on it.
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21 minutes ago, tater said:
Wow, that's fascinating.
What are the implications for reducing the data you guys get from sample return, since the surface material is perhaps refreshed at some rate by material ejected from the interior of Bennu? When material erupts, is there any way to do spectroscopy on the (presumed by me) gas doing the ejecting?
We have a campaign this summer, but the particles are small 1 to <30cm
Our earlier plume campaign was negative, so the gas (if that’s the mechanism) isn’t abundant. But we’ll try.
It is exciting for return
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Here’s some news in this thread.
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Various Surface Textures of Bennu’s Boulders
The boulders on Bennu’s surface sport a variety of surface textures, from smooth, to hummocky, striated, and crumbly “cauliflower” in nature. The large boulder in the image center is ~92 ft (~28 m) across and has a somewhat round shape, though many smaller boulders surrounding it are very angular. Some of these appear to be fragments that may have disaggregated from the central boulder and display layering effects that may reflect some of the properties of their mineral composition. Other boulders show signs of surface exfoliation and fractures that may have been caused by impacts, mechanical weathering, and other forms of rock breakdown active on Bennu’s surface.
This image was obtained by the MapCam camera on NASA’s OSIRIS-REx spacecraft on February 27 from a distance of 0.8 miles (1.3 km) and shows a region of the asteroid’s southern hemisphere near its south pole.
Date Taken: Feb. 27, 2019
Instrument Used: OCAMS (MapCam)
Credit: NASA/Goddard/University of Arizona
https://www.asteroidmission.org/20190227t002051s742_map_iofl2pan/
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There will be more exciting information at a press conference next week. https://www.nasa.gov/press-release/nasa-to-host-media-teleconference-on-asteroid-sample-return-mission
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More images https://www.asteroidmission.org/2019-02-25-regolith-image-compilation-3/
A Region of Bennu’s Northern Hemisphere Close Up
This trio of images acquired by NASA’s OSIRIS-REx spacecraft shows a wide shot and two close-ups of a region in asteroid Bennu’s northern hemisphere. The wide-angle image (left), obtained by the spacecraft’s MapCam camera, shows a 590-foot (180-meter) wide area with many rocks, including some large boulders, and a “pond” of regolith that is mostly devoid of large rocks. The two closer images, obtained by the high-resolution PolyCam camera, show details of areas in the MapCam image, specifically a 50-foot (15 meter) boulder (top) and the regolith pond (bottom). The PolyCam frames are 101 feet (31 meters) across and the boulder depicted is approximately the same size as a humpback whale.
The images were taken on February 25 while the spacecraft was in orbit around Bennu, approximately 1.1 miles (1.8 km) from the asteroid’s surface. The observation plan for this day provided for one MapCam and two PolyCam images every 10 minutes, allowing for this combination of context and detail of Bennu’s surface.
Date Taken: Feb. 25, 2019
Instrument Used: OCAMS (MapCam and PolyCam)
Credit: NASA/Goddard/University of Arizona
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2 minutes ago, tater said:
What do you think of the HP3 instrument on Insight (specifically the drill)?
I'm not versed in InSight (beyond it and OSIRIS-REx sharing a highbay for a while) and what I read on public outlets. However, I expect similar rigor and review progress to have been performed by the engineers and the standing review board (as a Discovery class instead of New Frontiers class mission, there is a different risk tolerance).
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11 hours ago, tater said:
True, I hadn't considered that. The ejecta from the burn could likely approach the exhaust velocity of the thruster, which is possibly concerning for delicate spacecraft. I know that Phil Metzger has done a lot of work on lander exhaust/surface interactions using simulants, I tend to think of larger landers on the Moon, when smaller bodies might even be more important to look at from this standpoint given their composition.
An astute observation. He (e.g. https://www.asteroidmission.org/team/team-list/?search=Metzger) and others were brought in to the mission during development in 2013*. They did extensive modeling and testing (e.g. https://dslauretta.com/2014/02/05/riding-the-vomit-comet/) to be sure that the backscatter of regolith from TAG and thrusters in a Bennu environment would not damage the spacecraft (especially guidance, navigation, and control) based on our backaway speed and geometry (this is one of the reasons our solar arrays gimbal into a Y during TAG). We have assumed that OSIRIS-REx instruments could become covered in dust, and thus are not required after sampling. But the Hayabsa2 images suggest that their optics are intact.
*This is an example of why it takes so long to design a spacecraft to visit a novel environment.
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17 minutes ago, tater said:
This video is apparently at ~5X real speed, though the framerate is also apparently variable. Amazing, particularly the swirling debris. @IonStorm do you think the OSIRIS-REx sample collection will be similar?
Possibly more so. The debris looks to be cause by their back-away thrusters. OSIRIS-REx will also have the pneumatic sampling event. There is a meeting between Hayabusa2 and OSIRIS-REx members next month to ask questions. As you can imagine, we are very interested in the details of the burn.
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1 minute ago, tater said:
What happens if there are larger debris that are detected with the SamCam that might interfere with stowage?
Those are two different things. First, the particles observed by NavCam 1 are being studied with great intensity both for scientific discovery and to ensure spacecraft safety. Second, we have done analysis to ensure spacecraft safety when particles are liberated during collection as well as contingency plans if interfering debris is observed prior to stowage by SamCam and StowCam.
We will also be watching our JAXA colleagues for lessons when they collect their sample from Ryugu 2/22/19 06:45-09:15 Japan time (2/21/19 16:45-19:15 Eastern) http://fanfun.jaxa.jp/jaxatv/detail/14034.html
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8 minutes ago, tater said:[snip]
More on Detailed Survey:
https://www.asteroidmission.org/wp-content/uploads/2018/06/SPP-Baseball-Diamond-Poster.pdf
and 2:06-2:55 of:
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Nearly all (OTES is on the way) data from the cruise and Earth gravity assist has been released to the Planetary Data System. https://pds.nasa.gov/datasearch/subscription-service/SS-20190214.shtml To view the image files you need a FITS viewer, such as the free DS9 http://ds9.si.edu/. The best images have been released already, but if you like messing with raw data, here is your chance. If you didn't know, all NASA planetary missions publically release their data to PDS. Bennu data will be in future releases.
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Sometimes the anticipated, but low probability events happens. This will make for some interesting science. https://www.nasa.gov/feature/goddard/2019/osiris-rex-mission-status-update
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Here is the shape model of Bennu from the November data. Good enough for RSS. Lidar shape model will be later.
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Navigation camera images.
Spacecraft pathway.
https://www.asteroidmission.org/galleries/spacecraft-imagery/preliminarysurveynavcam-2/
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1 hour ago, ThatGuyWithALongUsername said:
Congratulations! This sounds pretty tricky, given the low gravity and irregular shape. Out of curiosity, what's OSIRIS-REx's average orbital speed around Bennu? It has to be going pretty slowly, at least in spaceflight terms.
6 cm/s
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NASA's OSIRIS-REx
in Science & Spaceflight
Posted
Thanks! I've elevated your comments and suggestion to the leader the team responsible. Below is the reply:
"Interesting.... the whole world is seeing just how many rocks we have to count! It's a good comment - I will pass it along..."