[music throughout] A historic moment is on the horizon for NASA’s OSIRIS-REx mission
On October 20, the OSIRIS-REx spacecraft will journey to asteroid Bennu’s
Bennu’s boulder-strewn surface and briefly touchdown to gather a sample –
something NASA has never done before.
Right now, you are watching OSIRIS-REx preparing for its descent
to sample site Nightingale, a dark crater near Bennu’s north pole, that you can see below you now.
Site Nightingale is one of the only areas on Bennu that holds
enough fine-grained material for the spacecraft to safely access.
The crater is only 66 ft (20 meters) in diameter, or about the size of a tennis court
The Nightingale site itself is only 26 ft (8 m) wide, nearly the width of 3 parking spaces.
From orbit departure, to the steep descent, to the back-away burn,
the spacecraft will perform the entire sample collection sequence autonomously.
To safely touch the site, the spacecraft has to position itself for the Touch-And-Go sample collection maneuver.
OSIRIS-REx will first stretch out its sampling arm from the folded, parked position.
Then, it will slowly move its solar panels into the “Y-wing” configuration – as you see right now.
Placing the solar panels up and away from the asteroid’s surface during touchdown.
This configuration also places the spacecraft’s center of gravity directly over the TAGSAM collector head,
which is the only part of the spacecraft that will contact Bennu’s surface during the sample collection event.
As OSIRIS-REx descends to Nightingale, it will approach the site and fly over building-sized boulders scattered around the crater’s rim.
The tallest one you see is about the same height as a three-story building.
The spacecraft will spend approximately 22 minutes deeply descending to the rocky surface…
While OSIRIS-REx descends, take a look around sample site Nightingale.
Remember, OSIRIS-REx is aiming to tag a spot no larger than a few parking spaces.
In between these boulders are small patches of relatively clear surface –
enough to allow OSIRIS-REx to collect at least 60 grams of pristine asteroid sample.
With just meters to go, OSIRIS-REx is now ready to collect a sample.
Once the sample collector head senses contact with Bennu’s surface, it will fire a small puff of compressed nitrogen
to kick up debris and capture pieces of the asteroid into the collector head – an event that lasts just a few seconds.
OSIRIS-REx will then fire its thrusters to slowly back-away from the surface and navigate to a safe distance away from Bennu.
A couple days later, the spacecraft will image the inside of the sample collector head to verify that material was collected.
The sample will be delivered to Earth in September 2023.