Asteroid approach, Science operations begin! Options

[Daniele_bianchin...]

For years I have imagined the small meteorites that fall to Earth like small-craterized, black, burnt, melted rocks. Only when I was older did I discover that burnt and melt is given by the heat of the impact with the atmosphere. So I imagine that the small meteorites that fall on Earth and give rise a Fireballs, if we observed them before the impact with our terrestrial atmosphere, are common rocks, very similar to the terrestrial ones, one of the many as seen above the Bennu terrain in this picture (Am I saying well?):

http://www.unmannedspaceflight.com/index.p...st&id=45604

[mcaplinger]

Here's a text file with the predicted position of OREx in the Bennu frame every minute for 24 hours starting at 2020-04-14T00:00:00 (time X Y Z) as extracted from orx_200401_200421_200413_od240-N-TR1D-L-TR1BO_v1.bsp

 tagr.txt ( 103.64K ) Number of downloads: 255

[Brian Swift]

Here's a visualization of the March 3, 2020 low (250m) pass over Nightingale. https://youtu.be/Px9JpK9PtZ0

[Marcin600]

Everything went perfectly! And in large part thanks to the remote work of OSIRISRex team, in spite of the f... virus!

Amazing video on the OSIRISRex website: SamCam pictures (covering 10 minutes of descent) from 120 to 65 m (so, a bit lower than the planned 75 m), with extended sampling arm

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[Holder of the Tw...]

The approach test was a success. Here is Spaceflight Now's coverage of the event:

Osiris-Rex sampling rehearsal

[Brian Swift]

If you'd like to walk around Bennu or set it on your desk, I've posted some AR Quick Look (Augmented Reality) globes at:
mandelbits.com/arworlds
These are viewable in Safari on devices running iOS 13 or later.

[JRehling]

So I imagine that the small meteorites that fall on Earth and give rise a Fireballs, if we observed them before the impact with our terrestrial atmosphere, are common rocks, very similar to the terrestrial ones, one of the many as seen above the Bennu terrain in this picture (Am I saying well?)

In at least one case, we have the answer, which is the Moon. Although a small fraction of found meteorites have a lunar origin, we know very well that rocks on the surface of the Moon are not burned or melted looking, and often look rather pristine, at least since the moment when they were last broken, shattered, and refused by impacts.

The diversity of meteorites is a large topic, and certainly Earth is very different from asteroid parent bodies. Stony achondrites, originating from larger parent bodies, including the Moon, sometimes can look a lot like an Earth rock, which is why stony achondrites are extremely hard to find except in locations where meteorites are easily distinguished from the local landscape, such as Antarctic ice. This is why virtually all lunar and martian meteorites have been found either in African deserts or Antarctica.

Chondrites, however, with small, unevolved parent bodies, are pretty easy to tell from Earth rocks, and it would seem like Bennu is composed of the same stuff as carbonaceous chondrites. If so, they may look like Earth rocks from OSIRIS-REx's cameras, but when sliced open will be completely different. It will be nice to get to verify this in 2023!

[Daniele_bianchin...]

In at least one case, we have the answer, which is the Moon. Although a small fraction of found meteorites have a lunar origin, we know very well that rocks on the surface of the Moon are not burned or melted looking, and often look rather pristine, at least since the moment when they were last broken, shattered, and refused by impacts.

The diversity of meteorites is a large topic, and certainly Earth is very different from asteroid parent bodies. Stony achondrites, originating from larger parent bodies, including the Moon, sometimes can look a lot like an Earth rock, which is why stony achondrites are extremely hard to find except in locations where meteorites are easily distinguished from the local landscape, such as Antarctic ice. This is why virtually all lunar and martian meteorites have been found either in African deserts or Antarctica.

Chondrites, however, with small, unevolved parent bodies, are pretty easy to tell from Earth rocks, and it would seem like Bennu is composed of the same stuff as carbonaceous chondrites. If so, they may look like Earth rocks from OSIRIS-REx's cameras, but when sliced open will be completely different. It will be nice to get to verify this in 2023!

Many thanks for the reply. Yes, I know that these rocks will be very different internally than the terrestrial ones. I was surprised to see common rocks, chipped, squared as in any terrain on Earth. In fanasia I expected a little more "alien" landscapes, instead I see landscapes very common and familiar to all of us, :-)

[Marcin600]

... I was surprised to see common rocks, chipped, squared as in any terrain on Earth. In fanasia I expected a little more "alien" landscapes, instead I see landscapes very common and familiar to all of us, :-)

This is because the basic laws of physics are the same throughout the Universe. But if you stood on Bennu and kicked these stones you would immediately see the difference - if you found yourself in a cloud of rock fragments flying everywhere (due to microgravity, like here) - such things on Earth are impossible

[Marcin600]

Nice new pictures from the latest Checkpoint Rehearsal on the OSIRS-REx website, e.g. this one.

Here is my (very limited) play with a view towards Bennu's horizon.

No, this is not a real panorama (it's from 115 m above the surface) - not yet, unfortunately...

[only Harrison Schmitt is missing - that's a request to Neo ]

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[Marcin600]

Just for fun - limited edition of Bennu (for Mars lovers) :

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[Brian Swift]

A simulated panorama and fisheye view from 50m below checkpoint rehearsal lowest point.

Asteroid Bennu from ~25m by bswift, on Flickr

Asteroid Bennu from ~25m by bswift, on Flickr

[Brian Swift]

Checkpoint Rehearsal visualization on YouTube https://youtu.be/y3q9UtEDXOQ

[Explorer1]

Touchdown delayed to October 20th:
https://www.asteroidmission.org/?latest-new...-asteroid-bennu

[Marcin600]

New excellent mosaic of Osprey (backup site) on the OSIRIS-REx website - 347 PolyCam images collected on May 26 from 250 m, stitched together and corrected - 5 mm per pixel at full size!