IPB

Welcome Guest ( Log In | Register )

10 Pages V  « < 8 9 10  
Reply to this topicStart new topic
Asteroid approach, Science operations begin!
Daniele_bianchin...
post Apr 14 2020, 11:15 AM
Post #136


Member
***

Group: Members
Posts: 115
Joined: 26-May 15
From: Rome - Italy
Member No.: 7482



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

Go to the top of the page
 
+Quote Post
mcaplinger
post Apr 14 2020, 04:45 PM
Post #137


Senior Member
****

Group: Members
Posts: 1936
Joined: 13-September 05
Member No.: 497



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

Attached File  tagr.txt ( 103.64K ) Number of downloads: 27


--------------------
Disclaimer: This post is based on public information only. Any opinions are my own.
Go to the top of the page
 
+Quote Post
Brian Swift
post Apr 14 2020, 06:10 PM
Post #138


Member
***

Group: Members
Posts: 127
Joined: 18-September 17
Member No.: 8250



Here's a visualization of the March 3, 2020 low (250m) pass over Nightingale. https://youtu.be/Px9JpK9PtZ0
Go to the top of the page
 
+Quote Post
Marcin600
post Apr 15 2020, 10:02 PM
Post #139


Member
***

Group: Members
Posts: 152
Joined: 14-December 15
Member No.: 7860



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
Attached thumbnail(s)
Attached Image
Attached Image
Attached Image
 
Go to the top of the page
 
+Quote Post
Holder of the Tw...
post Apr 16 2020, 01:13 PM
Post #140


Member
***

Group: Members
Posts: 498
Joined: 17-November 05
From: Oklahoma
Member No.: 557



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

Osiris-Rex sampling rehearsal
Go to the top of the page
 
+Quote Post
Brian Swift
post Apr 18 2020, 06:14 AM
Post #141


Member
***

Group: Members
Posts: 127
Joined: 18-September 17
Member No.: 8250



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:
Attached Image
mandelbits.com/arworlds

These are viewable in Safari on devices running iOS 13 or later.
Go to the top of the page
 
+Quote Post
JRehling
post Apr 18 2020, 07:59 PM
Post #142


Senior Member
****

Group: Members
Posts: 2234
Joined: 20-April 05
Member No.: 321



QUOTE (Daniele_bianchino_Italy @ Apr 14 2020, 04:15 AM) *
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!
Go to the top of the page
 
+Quote Post
Daniele_bianchin...
post Apr 20 2020, 11:43 AM
Post #143


Member
***

Group: Members
Posts: 115
Joined: 26-May 15
From: Rome - Italy
Member No.: 7482



QUOTE (JRehling @ Apr 18 2020, 08:59 PM) *
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, :-)
Go to the top of the page
 
+Quote Post
Marcin600
post Apr 20 2020, 06:53 PM
Post #144


Member
***

Group: Members
Posts: 152
Joined: 14-December 15
Member No.: 7860



QUOTE (Daniele_bianchino_Italy @ Apr 20 2020, 01:43 PM) *
... 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 smile.gif
Go to the top of the page
 
+Quote Post
Marcin600
post Apr 28 2020, 08:56 PM
Post #145


Member
***

Group: Members
Posts: 152
Joined: 14-December 15
Member No.: 7860



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 smile.gif ]
Attached thumbnail(s)
Attached Image

Attached Image
 
Go to the top of the page
 
+Quote Post
Marcin600
post Apr 28 2020, 11:05 PM
Post #146


Member
***

Group: Members
Posts: 152
Joined: 14-December 15
Member No.: 7860



Just for fun - limited edition of Bennu (for Mars lovers) wink.gif :
Attached thumbnail(s)
Attached Image
 
Go to the top of the page
 
+Quote Post
Brian Swift
post May 12 2020, 12:45 AM
Post #147


Member
***

Group: Members
Posts: 127
Joined: 18-September 17
Member No.: 8250



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
Go to the top of the page
 
+Quote Post
Brian Swift
post May 17 2020, 07:41 AM
Post #148


Member
***

Group: Members
Posts: 127
Joined: 18-September 17
Member No.: 8250



Checkpoint Rehearsal visualization on YouTube https://youtu.be/y3q9UtEDXOQ
Go to the top of the page
 
+Quote Post
Explorer1
post May 21 2020, 12:37 AM
Post #149


Senior Member
****

Group: Members
Posts: 1721
Joined: 13-February 10
From: Ontario
Member No.: 5221



Touchdown delayed to October 20th:
https://www.asteroidmission.org/?latest-new...-asteroid-bennu
Go to the top of the page
 
+Quote Post

10 Pages V  « < 8 9 10
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 1st June 2020 - 06:15 PM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.