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OSIRIS-REx: Sample Collection at Asteroid Bennu

A spacecraft about the size of an SUV continues operations at an asteroid the size of a mountain. The spacecraft is OSIRIS-REx, the asteroid Bennu, and yesterday’s successful touchdown and sample collection attempt elicits nothing but admiration for the science team that offered up the SUV comparison. They’re collecting materials with a robotic device 321 million kilometers from home. Yesterday’s operations seem to have gone off without a hitch, the only lingering question being whether the sample is sufficient, or whether further sampling in January will be needed.

If all goes well, we will acquire the largest surface sample from another world since Apollo. TAGSAM is the Touch-And-Go Sample Acquisition Mechanism aboard the craft, a 3.35-meter sampling arm extended from the spacecraft as OSIRIS-REx was descending roughly 800 meters to the surface. The ‘Checkpoint’ burn occurred at 125 meters as the craft maneuvered to reach the sample collection site, dubbed ‘Nightingale.’ The ‘Matchpoint’ burn followed ‘Checkpoint’ by 10 minutes to match Bennu’s rotation at point of contact. A coast past the ‘Mount Doom’ boulder was followed by touchdown in a crater relatively free of rocks.

This is dramatic stuff. The image below is actually from August during a rehearsal for the sample collection (images of yesterday’s touchdown are to be downlinked to Earth later today), but it’s an animated view that gets across the excitement of the event. Mission principal investigator Dante Lauretta (University of Arizona. Tucson) had plenty of good things to say about the result:

“After over a decade of planning, the team is overjoyed at the success of today’s sampling attempt. Even though we have some work ahead of us to determine the outcome of the event – the successful contact, the TAGSAM gas firing, and back-away from Bennu are major accomplishments for the team. I look forward to analyzing the data to determine the mass of sample collected.”

Image: Captured on Aug. 11, 2020 during the second rehearsal of the OSIRIS-REx mission’s sample collection event, this series of images shows the SamCam imager’s field of view as the NASA spacecraft approaches asteroid Bennu’s surface. The rehearsal brought the spacecraft through the first three maneuvers of the sampling sequence to a point approximately 40 meters above the surface, after which the spacecraft performed a back-away burn. Credit: NASA/Goddard/University of Arizona.

The goal is 60 grams of material, with the first indication of sample size being new images of the surface to see how much material was disturbed by the TAGSAM activities. Michael Moreau (NASA GSFC) is OSIRIS-REx deputy project manager:

“Our first indication of whether we were successful in collecting a sample will come on October 21 when we downlink the back-away movie from the spacecraft. If TAG made a significant disturbance of the surface, we likely collected a lot of material.”

Images of the TAGSAM head, taken with the camera known as SamCam, should provide evidence of dust and rock in the collector, with some possibility of seeing inside the head to look for evidence of the sample within. Beyond imagery, controllers will try to determine the spacecraft’s moment of inertia by extending the TAGSAM arm and spinning the spacecraft about an axis perpendicular to the arm. Comparison to data from a similar maneuver before the sampling should allow engineers to measure the change in the mass of the collection head.

Between the imagery and the mass measurement, we should learn whether at least 60 grams of surface material have been collected. Once this has been verified, the sample collector head can be placed into the Sample Return Capsule (SRC) and the sample arm retracted as controllers look to a departure from Bennu in March of 2021. If necessary, a second maneuver, at the landing backup site called ‘Osprey,’ could take place on January 12, 2021.

Image: These images show the OSIRIS-REx Touch-and-Go Sample Acquisition Mechanism (TAGSAM) sampling head extended from the spacecraft at the end of the TAGSAM arm. The spacecraft’s SamCam camera captured the images on Nov. 14, 2018 as part of a visual checkout of the TAGSAM system, which was developed by Lockheed Martin Space to acquire a sample of asteroid material in a low-gravity environment. The imaging was a rehearsal for a series of observations that will be taken at Bennu directly after sample collection. Credit: NASA/Goddard/University of Arizona.

Sample return is scheduled for September 24, 2023, with the Sample Return Capsule descending by parachute into the western desert of Utah. So far so good, and congratulations all around to the OSIRIS-REx team!


Comments on this entry are closed.

  • Robert October 21, 2020, 9:57

    A special clean room is being build at the Johnston Space Center to handle the samples and keep them from being contaminated. I just hope they have equally considered the remote possibility that the sample might contaminate the earth’s biosphere with an unknown space born pathogen as Hoyle and Wickramasinghe believed was possible.

    • Michael October 21, 2020, 11:49

      The Andromeda strain…

    • Ron S. October 21, 2020, 13:10

      Bennu is a reservoir of pathogens? I suppose that’s a remote possibility for an arbitrarily chosen non-zero value for “remote”.

    • Alex Tolley October 21, 2020, 14:26

      Or the alien material that contaminated Ceres in “The Expanse”? ;)

      I would be more worried about contamination by resistant Earth microorganisms, although I am sure the engineers did their absolute best to ensure this did not occur.

      If they get a decent sample, this will generate a wealth of analysis about Bennu. I look forward to the early results being published in the mid-2020s.

    • charlie October 21, 2020, 16:51

      don’t worry – they haven’t …

    • Pat October 21, 2020, 18:22

      If there are space born pathogens I would think the Earth’s biosphere has been continuously contaminated since, at least, before the Great Oxidation Event 2 billions years ago. The OSIRIS-REx touch-and-go sample is but a fraction of a drop in an ocean of extraterrestrial contaminants on Earth.

    • Michael Fidler October 22, 2020, 10:05

      It’s is a ruble pile that’s full of eggs and blue water bears from the the giant impact that blow the lithosphere off of Venus 725 million years ago.

  • Robin Datta October 21, 2020, 11:29

    An alien microbe with a physically better genetic machinery that might outcompete and replace DNA-based life as we know it, would be the stuff of nightmares: all familiar biology would all be swept away.

    Then again the cargo may contain the alien equivalent of a pencil stub, or a butane lighter or perhaps a USB drive?

  • ljk October 21, 2020, 12:01

    Ten things you need to know about planetoid Bennu…


    It’s dark, maybe half of it is hollow, it has gold and platinum…

  • Mike Serfas October 21, 2020, 20:47

    Some great ideas here. (a) What if Bennu is infected? (b) Bennu may be hollow ( https://advances.sciencemag.org/content/6/41/eabc3350 ). Let’s put these together — suppose an engineered life form, a Saberhagian berserker, came into the Solar system millions of years ago to hide from the quib-quib while preparing for the cleansing of Earth. It selected a rubble pile asteroid in a convenient orbit and deployed a solar sail to spin Bennu up to the breaking point. Then it muscled its bulk into a void space at the center of the rubble pile, and used the sail to reduce the rotation before withdrawing it. Recharged with power and propellants, the berserker lay dormant, waiting for an all-clear signal that never came. Until an almost inaudible scrabbling at the surface, inconsistent with any natural impact, signalled that confrontation was unavoidable…

  • Ljk October 21, 2020, 23:04

    NASA coverage of the first American landing of sorts on a planetoid…


  • ljk October 22, 2020, 9:36

    The latest episode of Nova on PBS Television is about the OSIRIS-REx mission to Bennu, complete with showing the TAG event which had happened just one day earlier.

    The full episode is available here, at least for now:


    In October 2020, a NASA spacecraft called OSIRIS-REx attempts to reach out and grab a piece of an asteroid named Bennu to bring it back to Earth. The OSIRIS-REx team has just three chances to extend its spacecraft’s specialized arm, touch down for five seconds, and collect material from the surface of Bennu. But if they can pull it off, scientists could gain great insight into Earth’s own origins—and even learn to defend against rogue asteroids that may one day threaten our planet.

    (Premiered October 21, 2020)

  • ljk October 22, 2020, 10:05


    Tagging Bennu

    Image Credit: OSIRIS-REx, University of Arizona, NASA, Goddard Scientific Visualization Studio

    Explanation: On October 20, after a careful approach to the boulder-strewn surface, the OSIRIS-REx spacecraft’s arm reached out and touched asteroid Bennu. Dubbed a Touch-And-Go (TAG) sampling event, the 30 centimeter wide sampling head (TAGSAM) appears to crush some of the rocks in this snapshot.

    The close-up scene was recorded by the spacecraft’s SamCam some 321 million kilometers from planet Earth, just after surface contact. One second later, the spacecraft fired nitrogen gas from a bottle intended to blow a substantial amount of Bennu’s regolith into the sampling head, collecting the loose surface material.

    Data show the spacecraft spent approximately 5 more seconds in contact with Bennu’s Nightingale sample site and then performed its back-away burn. Timelapse frames from SamCam reveal the aftermath.

  • ljk October 22, 2020, 12:26
  • charlie October 22, 2020, 14:35

    So to get right to the point concerning the touchdown on this asteroid- did they in fact successfully collect material from the touchdown site ? Also to can anyone answer the question why is these images from the point of contact always seemingly so stop motion single images threaded together as a movie ?
    Why not just continuously record the actual touchdown in real time and play it back later to rebroadcast back to earth as a continuous movie?
    Certainly they have sufficient amount of memory these days to continuously record such an event so that they can selectively play back whatever they wish to audiences.
    Also if they’re not successful collecting from this site won’t going to another site with the same collecting head because cross-contamination of one sites dust with the new sites dust?

  • ljk October 26, 2020, 9:35

    Scientists Peer Inside an Asteroid – Is Bennu in the Process of Spinning Itself Into Pieces?


    OCTOBER 25, 2020

    New findings from NASA’s OSIRIS-REx mission suggest that the interior of the asteroid Bennu could be weaker and less dense than its outer layers—like a crème-filled chocolate egg flying though space.

    The results appear in a study published in the journal Science Advances and led by the University of Colorado Boulder’s OSIRIS-REx team, including professors Daniel Scheeres and Jay McMahon. The findings could give scientists new insights into the evolution of the solar system’s asteroids—how bodies like Bennu transform over millions of years or more.

    OSIRIS-REx rendezvoused with Bennu, an asteroid orbiting the sun more than 200 million miles from Earth, in late 2018. Since then, the spacecraft, built by Colorado-based Lockheed Martin, has studied the object in more detail than any other asteroid in the history of space exploration.

    So far, however, one question has remained elusive: What’s Bennu like on the inside?

    Full article here:


    • charlie October 26, 2020, 19:53

      ” a crème-filled chocolate egg flying though space.” – yum!

  • ljk October 26, 2020, 9:46
  • ljk October 26, 2020, 11:08

    OSIRIS-REx’s ‘Cup Runneth Over’ with Overflowing Asteroid Samples

    By Paul Scott Anderson, on October 25th, 2020

    Watch the “film” of planetoid debris exiting from the probe surface sample collector.


  • ljk October 26, 2020, 17:29

    Oct. 26, 2020

    RELEASE 20-108

    NASA’s OSIRIS-REx Spacecraft Goes for Early Stow of Asteroid Sample

    NASA’s OSIRIS-REx mission is ready to perform an early stow on Tuesday, Oct. 27, of the large sample it collected last week from the surface of the asteroid Bennu to protect and return as much of the sample as possible.

    On Oct. 22, the OSIRIS-REx mission team received images that showed the spacecraft’s collector head overflowing with material collected from Bennu’s surface – well over the two-ounce (60-gram) mission requirement – and that some of these particles appeared to be slowly escaping from the collection head, called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM).

    A mylar flap on the TAGSAM allows material to easily enter the collector head, and should seal shut once the particles pass through. However, larger rocks that didn’t fully pass through the flap into the TAGSAM appear to have wedged this flap open, allowing bits of the sample to leak out.

    Because the first sample collection event was so successful, NASA’s Science Mission Directorate has given the mission team the go-ahead to expedite sample stowage, originally scheduled for Nov. 2, in the spacecraft’s Sample Return Capsule (SRC) to minimize further sample loss.

    “The abundance of material we collected from Bennu made it possible to expedite our decision to stow,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “The team is now working around the clock to accelerate the stowage timeline, so that we can protect as much of this material as possible for return to Earth.”

    Unlike other spacecraft operations where OSIRIS-REx autonomously runs through an entire sequence, stowing the sample is done in stages and requires the team’s oversight and input. The team will send the preliminary commands to the spacecraft to start the stow sequence and, once OSIRIS-REx completes each step in sequence, the spacecraft sends telemetry and images back to the team on Earth and waits for the team’s confirmation to proceed with the next step.

    Full article here:


  • ljk November 12, 2020, 11:06

    New Mission for OSIRIS-REx Asteroid Explorer?

    By Leonard David

    November 7, 2020

    NASA’s Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission is slated to head back to Earth, delivering its precious cargo of newly acquired Bennu asteroid samples – but the probe may have a new target in 2029.

    “We have developed a mission design that allows us to put the OSIRIS-REx spacecraft into orbit around asteroid Apophis in 2029,” reports Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson.

    Full article here:


    The paper:


    Makes plenty of sense, not to mention saves money and time.

  • ljk January 20, 2021, 14:16

    OSIRIS-REx will fly by Apophis just one week after the NEO makes a very close pass of Earth in 2029!


  • ljk January 26, 2021, 22:48

    Jan. 26, 2021

    RELEASE 21-009

    NASA’s OSIRIS-REx Mission Plans for May Asteroid Departure


  • ljk April 16, 2021, 13:53

    Apr 15, 2021

    NASA’s OSIRIS-REx Leaves its Mark on Asteroid Bennu

    Like boot prints on the Moon, NASA’s OSIRIS-REx spacecraft left its mark on asteroid Bennu. Now, new images — taken during the spacecraft’s final fly-over on April 7 — reveal the aftermath of its historic encounter with the asteroid.