OSIRIS-REx at asteroid Bennu

[lpetrich]

News brief: OSIRIS-REx finds water on Bennu | The Planetary Society
NASA’s Newly Arrived OSIRIS-REx Spacecraft Discovers Water on Bennu | NASA
OSIRIS-REx Mission
 OSIRIS-REx is the Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer, a spacecraft that was sent to an asteroid named Bennu to collect samples of it, then to return home with those samples. Bennu is in an orbit close to the Earth's orbit, making it relatively easy to get to there and back.

Or at least evidence of water in the form of spectra with lines associated with hydroxyl groups -OH. These groups would be part of clay minerals. Such minerals have been found in some meteorites: Clay Minerals in Carbonaceous Chondrites: Characterization by Cryogenic Mössbauer Spectroscopy

This raises the question of how Bennu got to the inner Solar System, because when it formed, it would have to have been cold enough for water to condense.

 

[lpetrich]

OSIRIS-REx completes New Year’s Eve orbit insertion burn at asteroid – Spaceflight Now

OSIRIS-REx arrived at Bennu on Dec. 3, ending a journey from Earth that lasted more than two years and spanned 1.2 billion miles (2 billion kilometers). Since then, the robotic spacecraft has surveyed the 1,600-foot-wide (492-meter) asteroid through a series of flybys as close as 4.4 miles (7 kilometers) over Bennu’s north pole, south pole and equator to measure the asteroid’s gravitational tug on OSIRIS-REx, which helped scientists determine the object’s mass.

The mass estimate helped navigators refine the parameters of OSIRIS-REx’s maneuver to enter orbit around Bennu. The craft’s thrusters ignited for 8 seconds at 2:43:55 p.m. EST (1943:55 GMT) Monday to slightly adjust OSIRIS-REx’s velocity, nudging it just enough for Bennu’s tenuous gravity to capture the probe into orbit.

Then,

OSIRIS-REx will orbit and explore Bennu for more than a year, allowing scientists and mission planners to examine the asteroid and determine a safe location for the craft’s touch-and-go descent in July 2020 to snag samples from the asteroid. The spacecraft will depart Bennu and head back to Earth, releasing its sample carrier for re-entry and landing in Utah in September 2023.

Scientists will take the samples to an ultra-clean facility at NASA’s Johnson Space Center in Houston for detailed analysis.

 

[lpetrich]

Megapixels: Asteroid Bennu is ...exploding? | Popular Science

But new images released on Tuesday reveal much more than a tasty space snack. Bennu appears to be spewing out dusty, gravel-sized debris, which is extremely rare behavior for an asteroid. “It’s one of the biggest surprises of my scientific career,” Dante Lauretta, lead investigator of the mission, told The Atlantic’s Marina Koren

...
Recent photos have also revealed Bennu has a much bumpier and rockier surface than we thought—originally, astronomers predicted it’d be smooth like a river-worn pebble.

Bennu Images Reveal Unexpected Discoveries | NASA
NASA Mission Reveals Asteroid Has Big Surprises | NASA

 

[lpetrich]

OSIRIS-REx Makes Final Course Adjustment Before Sept. 24 Sample Delivery – OSIRIS-REx Mission

On Sept. 17, NASA’s OSIRIS-REx engineers slightly shifted the spacecraft’s trajectory to refine the landing location of its sample capsule, which the spacecraft will deliver to Earth on Sept. 24. The spacecraft briefly fired its thrusters Sunday to change its velocity by 7 inches per minute (3 millimeters per second) relative to Earth.

This final correction maneuver moved the sample capsule’s predicted landing location east by nearly 8 miles, or 12.5 kilometers, to the center of its predetermined landing zone inside a 36-mile by 8.5-mile (58-kilometer by 14-kilometer) area on the Defense Department’s Utah Test and Training Range.

OSIRIS-REx Sample Capsule Released for Landing on Earth – OSIRIS-REx Mission

Doppler data indicates that NASA’s OSIRIS-REx spacecraft released its sample capsule toward Earth at 6:42 a.m. EDT (4:42 a.m. MDT), as planned, from 63,000 miles of Earth’s surface – about one-third the distance from Earth to the Moon.

OSIRIS-REx Spacecraft Departs for New Mission – OSIRIS-REx Mission

NASA’s OSIRIS-REx spacecraft completed its final task for this mission when it released its sample capsule toward Earth less than an hour ago. About 20 minutes after doing so, the spacecraft fired its engines to divert past Earth toward its new mission to asteroid Apophis and was renamed OSIRIS-APEX.

Roughly 1,000 feet wide, Apophis will come within 20,000 miles of Earth – less than one-tenth the distance between Earth and the Moon – in 2029. OSIRIS-APEX is scheduled to enter orbit of Apophis soon after the asteroid’s close approach of Earth to see how the encounter affected the asteroid’s orbit, spin rate, and surface.

 

[lpetrich]

Capsule Containing Asteroid Bennu Sample Has Landed – OSIRIS-REx Mission
The spacecraft hit the atmosphere at 10:42 a.m. EDT (8:42 a.m. MDT), and it then released its drogue parachute. It released its main parachute at 10:47 am EDT (8:47 pm MDT), which slowed it from hypersonic speed to 11 mph, and it landed on the Department of Defense’s Utah Test and Training Range at 10:52 a.m. EDT (8:52 a.m. MDT).

NASA’s OSIRIS-REx Team in Field for Capsule Recovery – OSIRIS-REx Mission
Arrived in 20 minutes.

A munitions officer went out and cleared a path, then an engineer looked for troublesome gases in the air like SO2 from the battery if it got overheated, then another technician put covers on the capsule vents.

Helicopter Transports Sample Capsule to Clean Room – OSIRIS-REx Mission
This advance team then readied the capsule for its next journey.

They placed the 100-pound capsule into a metal cradle and wrapped it in multiple sheets of Teflon and then a tarp. Next, the team wrapped the crate in a harness and secured it to one end of a 100-foot cable hanging from a helicopter.

NASA’s OSIRIS-REx Capsule Secured in Utah Clean Room – OSIRIS-REx Mission

At 12:37 a.m. EDT (10:37 a.m. MDT), a helicopter gently placed NASA’s OSIRIS-REx sample capsule, attached to the end of a 100-foot cable, on the ground outside a hangar on the Department of Defense’s Utah Test and Training Range. Two technicians on the ground helped guide the capsule down.

Once the helicopter line was detached and the helicopter had departed, the clean room team removed the capsule from its metal transport cradle. They loaded the capsule onto a cart and wheeled it into the hangar where a temporary clean room had been set up. In the hangar, the capsule was fully unwrapped and cleaned, and then taken into the clean room for disassembly.

 

[lpetrich]

OSIRIS-REx Photos from Sample Landing Day – OSIRIS-REx Mission

OSIRIS-REx Asteroid Sample Return (Official 4K NASA Broadcast) - YouTube (3h 20m)

OSIRIS-REx Blog Coverage for Sample Landing Day Concludes – OSIRIS-REx Mission

NASA’s OSIRIS-REx clean room team has finished disassembling the sample capsule and packaging its components, including the unopened sample canister. Now packed in shipping containers – along with the environmental samples the recovery team collected around the capsule’s landing site this morning – the items are scheduled to be delivered on Monday, Sept. 25, to their permanent home at NASA’s Johnson Space Center in Houston.

NASA’s OSIRIS-REx Capsule Arrives in Houston – OSIRIS-REx Mission
It landed on Sept. 24 and was sent to Houston on the next day.

The sample arrived in Houston at 12:40 pm ET (11:40 am CT) aboard a U.S. Air Force C-17 aircraft, which landed at Ellington Field. From there, it was transferred to NASA Johnson.

The OSIRIS-REx Sample Canister Lid is Removed – OSIRIS-REx Mission

NASA scientists found dark powder and sand-sized particles on the avionics deck of the OSIRIS-REx science canister when the initial lid was removed today.

Initial Curation of NASA’s OSIRIS-REx Sample – OSIRIS-REx Mission

The initial curation process for NASA’s OSIRIS-REx sample of asteroid Bennu is moving slower than anticipated, but for the best reason: the sample runneth over. The abundance of material found when the science canister lid was removed earlier this week has meant that the process of disassembling the TAGSAM (Touch-and-Go Sample Acquisition Mechanism) head – which holds the bulk of material from the asteroid – is off to a methodical start.

More successful than they expected.

 

[lpetrich]

NASA’s OSIRIS-REx Spacecraft Views Sample Return Capsule’s Departure – OSIRIS-REx Mission
The last pictures of the capsule from its carrier spacecraft. Not just for keepsakes, but to be able to diagnose problems if anything went wrong.

NASA’s OSIRIS-REx Asteroid Sample Curation Steps Closer to Final Reveal – OSIRIS-REx Mission
They continued their disassembly of the capsule.

Revealing the OSIRIS-REx Asteroid Sample (Official NASA Broadcast in 4K) - YouTube (1h 31m) - a long press conference about the samples, with some initial analysis of them

NASA’s Bennu Asteroid Sample Contains Carbon, Water - NASA

Initial studies of the 4.5-billion-year-old asteroid Bennu sample collected in space and brought to Earth by NASA show evidence of high-carbon content and water, which together could indicate the building blocks of life on Earth may be found in the rock.

... When the science canister lid was first opened, scientists discovered bonus asteroid material covering the outside of the collector head, canister lid, and base. There was so much extra material it slowed down the careful process of collecting and containing the primary sample.

 

[lpetrich]

‘Incredible’ asteroid sample ferried to Earth is rich in the building blocks of life

The Bennu sample includes clay minerals with water trapped inside their crystal structures, bright and dark dust grains that look like flecks of salt and pepper and sulfur-rich minerals such as those that might play a key part in planetary evolution.

...
This bounty comes from the outer surface of OSIRIS-REx’s sample canister. The biggest treasure trove will be revealed in the next few weeks, when mission curators open the canister itself. In the meantime, they have been carefully picking their way through the rocks and dust coating the outside of the canister, photographing and classifying them. Only 1.5 grams have been formally catalogued so far, of an anticipated 250 or more grams brought back by OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification and Security–Regolith Explorer).

The Bennu sample was kept cold on its way to our planet's surface, kept cold by the spacecraft's heat shield, so it does not get chemically altered.

Some of the samples are as much as 4.7% carbon. Elemental carbon? Carbonates? Organic materials? Some of the material fluoresces under UV light.

Under an electron microscope, the clay samples from Bennu look like tiny fibres. Water locked inside those clay minerals might be ancient, originating from the dawn of the Solar System. Asteroids could have carried such water to the early Earth and helped to make it habitable.

Hydrated minerals? How did that water get into these minerals?

Other microscopy images show hexagonal crystals that are probably rich in sulfur. Sulfur compounds play a crucial part in determining the rate at which rocks melt, as well as being involved in biologically interesting chemical reactions. The Bennu samples also contain iron-rich minerals with large flat surfaces, which might have helped to catalyse chemical reactions early in the asteroid’s history.

Sulfur-rich materials? How did that sulfur get concentrated?

This material raises a lot of questions about the protosolar nebula, since one does not expect much liquid water or chemical differentiation. By boiling point, yes, but not much more.

Finally,

It will take another few weeks before researchers know exactly how much of Bennu they captured. When OSIRIS-REx stretched out its robotic arm in 2020 to collect material from the asteroid’s surface, it came away with so much material that the collecting apparatus overflowed.

 

[lpetrich]

At last! NASA finally frees lid of asteroid Bennu sample capsule after battling stuck fasteners | Space - "The asteroid samples aboard NASA's OSIRIS-REx landed in September, but 2 stuck fasteners kept them locked tight."

On Wednesday (Jan. 10), NASA technicians finally removed the stuck fasteners from the sample return capsule of its OSIRIS-REx spacecraft ...

The team created two new multi-part tools, including custom-fabricated bits made from a specific grade of surgical, non-magnetic stainless steel, which is the hardest metal approved for use in the curation gloveboxes. The tools were tested during removal procedures in a rehearsal lab to ensure they would be able to achieve the torque needed without damaging the TAGSAM head or contaminating the samples, according to the statement.

...
Once the team completes the disassembly, they'll be able to weigh the full sample to determine the total mass collected from Bennu. Image specialists will also take ultra-high-resolution pictures of the samples before removing them. NASA plans to distribute a portion of the asteroid samples to the scientific community for further research later this spring.

One might ask whether meteorite samples would be good enough. But meteorites come down at interplanetary speeds, and loose outer layers may be blown off on the way down. They also have the problem of provenance. Some meteorites have been identified as pieces of Vesta, Mars, and the Moon, but from where in them it's hard to say.

 

[lpetrich]

NASA gives green light for OSIRIS-REx spacecraft to visit another asteroid | University of Arizona News - April 25, 2022 - "The extended mission, dubbed OSIRIS-APEX, will study the near-Earth asteroid Apophis, which will have a close encounter with Earth in 2029."

On April 13, 2029 21:46 UT, asteroid  99942 Apophis will make a very close approach to the Earth, getting inside the geosynchronous-orbit distance, though not by much: 32,000 km. OSIRIS-APEX will go into orbit around it a few days later and eventually land on it.

That close encounter? From Wikipedia,

On that date, it will become as bright as magnitude 3.1 (visible to the naked eye from rural as well as darker suburban areas, visible with binoculars from most locations). The close approach will be visible from Europe, Africa, and western Asia. During the approach, Earth will perturb Apophis from an Aten-class orbit with a semi-major axis of 0.92 AU to an Apollo-class orbit with a semi-major axis of 1.1 AU. Perihelion will lift from 0.746 AU to 0.895 AU and aphelion will lift from 1.10 AU to 1.31 AU.