IonStorm

Here is the full high resolution mosaic of the prime sampling site https://www.asteroidmission.org/nightingale-recon-c-mosaic-reduced-size/

You can also look at all the images released to the public in batches 6 months after collection here https://sbib.psi.edu/data/PDS-Bennu/index.html? This doesn't have the mosaics, which are data processed and doesn't yet have Recon C images. I am able to open the giant mosaics with Preview on macOS, btw.

The surface is super dark with a few comparatively bright spots. The dark spots are like coal and the bright spots are like the Moon. You can compare that to the 380MB global mosaic. It has about 1/10 the resolution but the whole asteroid https://www.asteroidmission.org/bennu_global_mosaic/

Successful low recon pass over Osprey (20k x 12k image) https://www.asteroidmission.org/osprey-recon-c-mosaic/ Recall that the medium pass images over Osprey were out of focus due to the OLA failure, so this a big improvement of the imaging of the backup site.

COVID-19 has impacts in space too. TAG delayed from August to October 2020 https://www.asteroidmission.org/?latest-news=nasas-osiris-rex-ready-for-touchdown-on-asteroid-bennu

So, I did a NASA podcast on OSIRIS-REx: https://www.nasa.gov/mediacast/gravity-assist-a-special-delivery-of-life-s-building-blocks-with-jason-dworkin

Flawless execution, even though the team was isolated. Special thanks to the Madrid DSN station who received the data.

The Checkpoint Rehearsal is tomorrow!

We have speculated, "The retention of large craters on Bennu’s equatorial ridge requires that the surface age predates the expected approximately 10-million-year duration as a NEA. There is no clear geologic indication of the process that formed the ridge, and given its relation to the large craters it could be a feature preserved from the formation of Bennu, which would make it the oldest feature on its surface. Bennu’s surface therefore also recorded processes from its time in the main belt; the formation timescales of the largest craters suggest that Bennu recorded hundreds of millions of years of history during this period." (Walsh et al., 2019) https://science.gsfc.nasa.gov/sed/content/uploadFiles/publication_files/Walsh2019.pdf

Here is a Bennu global mosaic at 5cm/px. This is the best global resolution that will be obtained. https://www.asteroidmission.org/bennu_global_mosaic/

So it was something deeper after all, but restricted to the low power laser not the whole instrument. The high power laser will be used instead. It is sufficient resolution for focusing and does not require a big software change:

Here is a 20 cm resolution animation of the shape model and image overlay of Bennu for your amusement. Again this animation is from 100% real data. https://svs.gsfc.nasa.gov/vis/a000000/a004700/a004795/Bennu_spin_full_20cm_1080p30.mp4 This was used in this video:

This can happen either due to random single event errors (i.e. cosmic ray hits) or something deeper. OLA has been asked to do additional work beyond its requirements due to the extra imaging required for the rocky surface. It is expected that some fraction of the images will be out of focus by an unknown amount, we will see when it gets downlinked. There is a Guidance and Navigation LIDAR which was to have been used for sampling--if the asteroid wasn't so rocky. This could be reprogrammed to help PolyCam focus--this will take time. Just reflying the pass to retake the bad images would take less time.

If you want to browse images from the ~six months of Bennu encounter (18 Oct 2018 - 12 April 2019), the complete image data set are public at the Planetary Data System in a simple GUI https://sbib.psi.edu/data/PDS-Bennu/ (unlike the usual PDS distribution method https://pds-smallbodies.astro.umd.edu/data_sb/target_asteroids.shtml#101955_Bennu)

The sample return canister (SRC) is sealed, but not airtight. There is a filter (Figure 1 and 2) allows the pressure inside to equalize with the outside during reentry without introducing water or heatshield ablation products. Upon collection the SRC is kept under N2 purge to prevent ingest of moisture and contaminants. Otherwise, the canister would need to be heavy enough to hold vacuum, which is more expensive than OSIRIS-REx can afford. Also, based on the nitrogen agitation to collect the sample, the warm surface temperature of Bennu, and reentry heating we don't expect a lot of loosely bound gases so it would not have been a good use of resources to build an airtight and thus and heavier return capsule. Instead we will be observing the gases that are evolved upon heating in the laboratory. Fig 1. Note the location of the filter inside the SRC in panel b Fig 2. Diagram of the filter Filter performance and other fussy details can be found at https://rdcu.be/bYXUe

It was a complex series of analyses and models with more than just the topographic models. We also used rock counting to the cm-scale, color variation, local tilts, and spectra. Osprey has slightly better backaway vectors but a lower density of fine material. So the probability of a successful contact times the probability of a successful collection for the two sites was about the same. After vigorous debate we selected Nightingale as prime and Osprey as backup and rejected the other two. We received concurrence from headquarters that our rationale is sound. Yes, we had modeled our pre-launch data based on Itokawa and expected vast smooth regions like the Muses-C regio and assumed worst case would be like the rough areas of Itokawa. Surprise!

Now check out the videos

It is a great site on a challenging asteroid. Next are some low passes to get even better images, then some rehearsals in the spring for sampling in August!

Earth rocks also can show linear cracks, but often with very different types or rocks than Bennu http://maps.unomaha.edu/maher/STEP07/supportinfo/cracks.html There are phyllosilicates (clays) on the surface, they could exhibit a preferred fracture orientation. It may be due to thermal fracturing, and perhaps related to the particle ejection events. So much science to do.

There is still time to count rocks for science! https://bennu.cosmoquest.org/

Here is the real answer:

I'm not sure which image set these are drawn from. A funny thing about fractal rocks is you can't tell the scale by looking at them. I'll need to check with the image team. Anyway, if you can use the boulder tool it is a boulder. If it is too small to draw the line it is a rock.

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..."

Me too! Thanks for posting, I've gotten busy lately...

Indeed. Though the craters don't appear to scale. There is so much to learn about this scree ball. Except for the isolation and death part, yes.