Sample and Return of Asteroid Bennu - live on Oct 20, 2020 at 1720 GMT

  • Thread starter Tom.G
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  • #1
Tom.G
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Yeah, we're trying to get ahold of a physical sample of a pristine asteroid.

Coverage starts at 1720 GMT (1:20pm EDT, 10:20am PDT)
Live landing and capture at 2200 GMT (5pm EDT, 2pm PDT)

https://www.nasa.gov/live/
https://www.space.com/17933-nasa-television-webcasts-live-space-tv.html
https://www.facebook.com/NASA/events/

A little more info at:
https://www.space.com/39958-asteroid-bennu.html
https://www.space.com/nasa-asteroid-bennu-sampling-osiris-rex-webcasts

Cheers,
Tom
 
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Answers and Replies

  • #2
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Live landing and capture at 2200 GMT (5pm EDT, 2pm PDT)
In 45 minutes.
It might take a few hours to confirm that it properly collected samples (camera images), and it will likely take days to determine how much (spinning the spacecraft to measure the mass in the container).
 
  • #3
berkeman
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Tag successful and the craft is backing away safely. Pretty cool. :smile:
 
  • #4
Tom.G
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A few factoids I picked up during the broadcast.

Download link speed from craft: 40 bits per second (that's why no live images, images available tomorrow)

Equatorial rotation speed of asteroid: 10cm per second

Mapping resolution:
. . . Whole surface : 2cm per pixel
. . . Landing area: 3.5mm per pixel

Descent speed:
. . . Lateral drift rate: 0.2cm per second
. . . Vertical speed: 10.2cm per second

The craft is using a "Pogo Stick" landing approach. The sample probe is spring loaded axially so the craft doesn't immediately bounce up on contact. The sample collection is done in the approx. 10 seconds it takes for a rebound.

Sample size is mass limited to the equivalent of a 2cm sphere, odd shapes acceptable.

Once back in orbit, the collection arm will be folded around to the camera for a visual inspection of the collection cup.

A minimum 60g sample is desired. Maximum sample holder capacity is 2kg.

Four days from now (Saturday), they plan to fold the collection arm at 90 degrees to the craft spin axis to measure the change in rotational inertia, thus finding the mass of any collected material. A calibration test was previously executed for a baseline measurement.

If needed, there is enough capability for two more sample events.

Return to Earth is expected in 2013.

There was a brief reference to a Nasa Goddard page on utube for further info; though no details or specific URL were given.

Cheers,
Tom
 
  • #5
berkeman
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Download link speed from craft: 40 bits per second (that's why no live images, images available tomorrow)
Yeah, they mentioned that once the craft was safely away from the asteroid and cooled down some with its solar panels pointing back at the Sun, they would be able to align the high-gain antenna with Earth again to transfer information with a higher datarate.
 
  • #8
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NASA said "tomorrow" 5 hours ago, so Thursday in the US. 26:06 in case the time stamp doesn't work:

 
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  • #9
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NASA’s OSIRIS-REx was so good at grabbing asteroid rocks that they’re overflowing

The images suggest up to 400 gram of material collected. So much material that they couldn't close the lid properly and a few grams of the captured sample escaped again. A bit more might escape until the sample is stored within the main spacecraft.

The spin maneuver is cancelled as it would mean losing more material. We'll only get a good mass estimate when the sample arrives on Earth.
 
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