“Incredible Feat” – NASA’s OSIRIS-REx Spacecraft Successfully Touches Asteroid Bennu

NASAOrigins, spectral interpretation, resource identification, security, regolith explorer (OSIRIS-REx) The spaceship unfolded its robotic arm on Tuesday and briefly touched an asteroid in a premiere for the agency to collect dust and pebbles from the surface for delivery to Earth in 2023.

This well-preserved ancient asteroid, known as Bennu, is currently more than 321 million kilometers from Earth. Bennu offers scientists a window into the early solar system as it took shape billions of years ago and hurled ingredients that may have helped sow life on earth. If the sampling on Tuesday, known as “Touch-And-Go” (TAG), delivers enough samples, the mission teams will order the spaceship to stow the precious cargo so that it can begin its return journey to Earth in March 2021. Otherwise, they will prepare for another attempt in January.

“This amazing premiere for NASA shows how an incredible team from around the country came together and faced incredible challenges to push the boundaries of knowledge,” said NASA Administrator Jim Bridenstine. “Our industrial, academic and international partners have made it possible to hold a piece of the oldest solar system in our hands.”

At 1:50 p.m. EDT, OSIRIS-REx fired its engines to move out of orbit around Bennu. It reached out its shoulder, then elbow, and then wrist of its 3.35 meter sampling arm known as the TAGSAM (Touch-and-Go Sample Acquisition Mechanism) and passed over Bennu as it descended about half a mile. 805 meters) to the surface. After a four-hour descent at a height of about 125 meters, the spaceship carried out the “checkpoint” incineration, the first of two maneuvers with which it could aim precisely at the sample collection point known as the “nightingale”.

Ten minutes later, the spaceship fired its engines for the second “matchpoint” combustion to slow the descent and adjust the rotation of the asteroid at the time of contact. Then we continued along a treacherous 11-minute coastline past a boulder the size of a two-story building nicknamed “Mount Doom” to touch down on a vacant spot in a crater on Bennu’s northern hemisphere. The Nightingale site is as big as a small parking lot and one of the few relatively clear spots on this unexpectedly boulder-covered space rock.

“That was an incredible feat – and today we have advanced both science and technology and our prospects for future missions to investigate these mysterious ancient storytellers of the solar system,” said Thomas Zurbuchen, assistant administrator of NASA’s directorate for scientific missions at the agency’s headquarters in Washington. “A piece of bedrock that has seen the entire history of our solar system can now come home to generations of scientific discovery, and we can’t wait to see what comes next.”

“After more than a decade of planning, the team is overjoyed with the success of today’s sample trial,” said Dante Lauretta, OSIRIS-REx investigator at the University of Arizona at Tucson. “Even though we still have some work ahead of us to determine the outcome of the event – the successful contact, the TAGSAM gas fire and Bennu’s retreat are important successes for the team. I look forward to analyzing the data to determine the mass of the samples collected. ”

All telemetry from the spacecraft indicates the TAG event, which ran as expected. However, it will take about a week for the OSIRIS-REx team to confirm how much sample the spaceship has collected.

Real-time data indicates that the TAGSAM has successfully contacted the surface and triggered a nitrogen gas surge. The gas should have kicked up dust and pebbles on Bennu’s surface, some of which should have been collected in the TAGSAM sample collection head. OSIRIS-REx engineers also confirmed that shortly after contacting the surface, the spacecraft fired its engines and safely retreated from Bennu.

“Today’s TAG maneuver was historic,” said Lori Glaze, director of the Planetary Science Division at NASA headquarters in Washington. “The fact that we have safely and successfully touched the surface of Bennu, in addition to all of the other milestones this mission has already reached, is evidence of the living spirit of exploration that continues to uncover the secrets of the solar system.”

“It’s hard to put into words how exciting it was to receive confirmation that the spacecraft successfully touched the surface and fired one of the gas cylinders,” said Michael Moreau, OSIRIS-REx’s assistant project manager at Goddard Space Flight Center’s NASA in Greenbelt, Maryland. “The team can’t wait to get the pictures from the TAG event in the late evening and see how Bennu’s interface reacted to the TAG event.”

The spaceship carried out the TAG autonomously with pre-programmed instructions from engineers on Earth. Now the OSIRIS-REx team begins to assess whether and how much the spaceship has absorbed material. The goal is at least 60 grams, which is roughly the same as a full size candy bar.

OSIRIS-REx engineers and scientists will use various techniques to remotely identify and measure the sample. First, they compare pictures of the Nightingale site before and after the TAG to see how much surface material has moved in response to the gas surge.

“Our first indication of whether we’ve managed to collect a sample will come on October 21, when we link the back-away movie down from the spaceship,” said Moreau. “If TAG has disrupted the surface significantly, we’ve probably gathered a lot of material.”

Next, the team will try to determine the amount of sample collected. One method is to take pictures of the TAGSAM head with a camera known as a SamCam, which documents the process of sampling and determines whether dust and stones have entered the collection head. An indirect indication is the amount of dust that is around the sample collection head. OSIRIS-REx engineers will also attempt to capture photos that, in the right lighting conditions, could show the inside of the head so the engineers can look for evidence of a pattern inside.

A few days after analyzing the SamCam images, the spaceship will attempt another method of measuring the mass of the collected sample by determining the change in the spacecraft’s “moment of inertia”. This formulation describes how the mass is distributed and how it affects the rotation of the body around a central axis. This maneuver involves extending the TAGSAM arm to the side of the spacecraft and slowly rotating the spacecraft about an axis perpendicular to the arm. This technique is analogous to a person spinning with an outstretched arm while holding a string with a ball attached to the end. The person can tell the mass of the ball by the tension in the string. After the engineers perform this maneuver before and after the TAG, they can measure the change in the mass of the collection head as a result of the sample inside.

“We will use the combination of data from the TAG and post-TAG images and the mass measurement to assess our confidence that we have collected at least 60 grams of sample,” said Rich Burns, OSIRIS-REx project manager at Goddard. “If our confidence is high, we will make the decision to stow the sample on October 30.”

To store the sample, engineers command the robotic arm to place the sample collection head in the sample return capsule (SRC) in the body of the spacecraft. The sample arm will then be retracted to the side of the spacecraft for the last time, the SRC will be closed, and the spacecraft will prepare for its departure from Bennu in March 2021 – this will be the next time Bennu will be properly aligned with Earth for the year most economical Return flight.

This (silent) animation shows the OSIRIS-REx spaceship using its Touch-and-Go sample acquisition mechanism (TAGSAM) to collect a sample of regolith (loose stones and debris) from the surface of the asteroid Bennu. The probe head, which holds the regolith safely, will then be sealed in the spacecraft’s sample recovery capsule, which will be returned to Earth in late 2023. Scientists will examine the sample for clues about the early solar system and the origins of life. Photo credit: NASA / Goddard

However, if the spaceship turns out to have not collected enough samples at Nightingale, it will attempt another TAG maneuver on January 12, 2021. In this case, it will set up another relatively boulder-free area in a crater near Bennu’s equator at the safety point called “Osprey”.

OSIRIS-REx took off from Cape Canaveral Air Force Station in Florida on September 8, 2016. It arrived in Bennu on December 3, 2018, and began orbiting the asteroid for the first time on December 31, 2018. The spaceship is slated to return to Earth September 24, 2023 when the SRC will fall in the Utah western desert where scientists are waiting to collect it.

Goddard offers the entire mission management, the system technology as well as the security and mission security for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the lead researcher, and the University of Arizona also leads the science team and the planning and computing of the scientific observation mission. Lockheed Martin Space in Denver built the spacecraft and offers flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, administered by NASA’s Marshall Space Flight Center in Huntsville, Alabama for the agency’s Science Mission Directorate in Washington.