After a series of high-stakes maneuvers performed more than 200 million miles from Earth, NASA’s OSIRIS-REx spacecraft has successfully stowed its precious samples of the asteroid Bennu. The move follows a surprise leak first announced on October 23, as some of the spacecraft’s pristine space rocks slipped out of a jammed sampling mechanism and floated away into the void. The safeguarding of the sample ensures that the material—rocks and dust from the solar system’s origins—will safely make its way to Earth.
On October 22, two days after touching Bennu, engineers realized that OSIRIS-REx’s Touch-and-Go Sample Acquisition Mechanism (TAGSAM) sampling head on was leaking precious rocks and dust. The culprit: a mylar flap designed to keep the material in the head, wedged open by larger rocks.
With the door open, a technician at Kennedy Space Center inspects the inside of the sample return capsule, circular object at right, in 2016 during testing of the door. The leaking sampling head was placed inside this capsule for its journey back to Earth.
The sample was secured after a tense few days following OSIRIS-REx’s October 20 touchdown on Bennu, which made the spacecraft only the third—and NASA’s first—to collect a sample from an asteroid. But OSIRIS-REx did almost too good of a job: It picked up pieces of the asteroid large enough to wedge the sample-collection device partially open.
As soon as the team noticed the debris leak on October 22, OSIRIS-REx personnel canceled several planned maneuvers and tests to minimize any disturbances to the sample-collection device, called TAGSAM (Touch-And-Go Sample Acquisition Mechanism). To protect the material in the device, which will be returned to Earth in 2023, OSIRIS-REx’s controllers quickly acted to tuck the sample into a sealed capsule—a maneuver that was completed on October 28.
The successful stowing process comes as a welcome relief, as OSIRIS-REx’s cache of primordial dirt and rocks could shed light on how the planets—and maybe even life on Earth—came to be. By studying the ingredients that were present in the newborn solar system, scientists hope to unravel the 4.5 billion-year process that produced Earth and everything on it.
Just hours into the effort to safeguard the sample, OSIRIS-REx principal investigator Dante Lauretta acknowledged that the accelerated maneuver came with its own risks, but he stressed that quickly locking down the sample was the most prudent course of action.
“Once it’s in the return capsule, it’s all contained, and anything inside there is coming back to the surface of Earth,” he said on October 27.
The jammed sampling mechanism was the latest surprise thrown at OSIRIS-REx by Bennu, a world shaped like a top and not much wider than the Empire State Building. Bennu’s extremely weak gravity and treacherous, boulder-covered surface pushed the spacecraft and its team to their limits. To descend to the asteroid’s surface, the spacecraft needed to switch to backup navigation software mid-mission, and engineers had to model even the slightest