Asteroid Bennu samples spill back into space from jammed Nasa spacecraft OSIRIS-REx

Nasa spacecraft OSIRIS-REx, that collected sample from a diamond-shaped asteroid Bennu earlier this week, is now stuffed with so much rubble from this week's grab that it's jammed open and precious particles are spilling back out into space, scientists said on Friday.

OSIRIS-REx principle investigator Dante Lauretta was quoted by AP as saying that the mission, 200 million miles away, collected far more material than expected for the return to Earth - in the hundreds of grams.

Bennu is a skyscraper-sized asteroid some 200 million miles (320 million km) from Earth. In the "Touch-and-Go" mission carried out on Tuesday, Nasa spacecraft OSIRIS-REx managed to tag asteroid Bennu and collect a sample from its boulder-strewn surface.

The back-away burn is complete I'm now moving to a safe distance away from Bennu. pic.twitter.com/bXk2ufSneS — NASA's OSIRIS-REx (@OSIRISREx) October 20, 2020

THE SPILLOVER

On Tuesday night, Nasa's robotic spacecraft OSIRIS-REx made history by briefly touching down on the rocky surface of asteroid Bennu to collect rock and dust samples.

The spacecraft was supposed to collect at least 60 grams of rubble, but images revealed that it had caught more material than scientists anticipated and was spewing an excess of flaky asteroid rocks into space.

The sample container on the end of the robot arm penetrated so deeply into the asteroid and with such force, however, that rocks got sucked in and became wedged around the rim of the lid. Scientists estimate the sampler pressed as much as 19 inches (48 centimeters) into the rough, crumbly, black terrain, news agency AP reported.

The leakage had the OSIRIS-REx mission team scrambling to stow the collection device to prevent additional spillage.

"Time is of the essence," Reuters quoted Thomas Zurbuchen, Nasa's associate administrator for science, as saying.

Zurbuchen further said that mission teams will skip their chance to measure how much material they collected as originally planned and proceed to the stow phase, a fragile process of tucking the sample collection container in a safe position within the spacecraft without jostling out more valuable material.

Nasa will not know how much material it collected until the sample capsule returns in 2023.

The troubleshooting also led mission leaders to forgo any more chances of redoing a collection attempt and instead commit to begin the spacecraft's return to Earth next March.

"Quite honestly, we could not have performed a better collection experiment," Dante Lauretta of the University of Arizona was quoted by Reuters as saying. He affirmed a hearty sample size.

But with the door lodged open by a rock and the "concerning" images of sample spillage, "we're almost the victim of our own success here," he further said.

WHAT NOW?

Regardless of what's on board, Osiris-Rex will still leave the vicinity of the asteroid in March - that's the earliest possible departure given the relative locations of Earth and Bennu. The samples won't make it back until 2023, seven years after the spacecraft rocketed away from Cape Canaveral.

Osiris-Rex will keep drifting away from Bennu and will not orbit it again, as it waits for its scheduled departure.

Because of the sudden turn of events, scientists won't know how much the sample capsule holds until it's back on Earth. They initially planned to spin the spacecraft to measure the contents, but that manoeuvre was cancelled since it could spill even more debris.

"I think we're going to have to wait until we get home to know precisely how much we have," Lauretta told reporters. "As you can imagine, that's hard. ... But the good news is we see a lot of material."

ALL ABOUT NASA'S OSIRIS-REx MISSION

The roughly $800 million, mini van-sized OSIRIS-REx spacecraft, built by Lockheed Martin, launched in 2016 to grab and return the first US sample of pristine asteroid materials.

This is NASA's first asteroid sample-return mission. Bennu was chosen because its carbon-rich material is believed to hold the preserved building blocks of our solar system. Getting pieces from this cosmic time capsule could help scientists better understand how the planets formed billions of years ago and how life originated on Earth.

Scientists were stunned - and then dismayed - on Thursday when they saw the pictures coming from Osiris-Rex following its wildly successful touch-and-go at Bennu two days earlier.

A cloud of asteroid particles could be seen swirling around the spacecraft as it backed away from Bennu. The situation appeared to stabilize, according to Lauretta, once the robot arm was locked into place. But it was impossible to know exactly how much had already been lost.

The requirement for the $800 million-plus mission was to bring back a minimum 2 ounces (60 grams).

Scientists suspect that asteroid Bennu might contain material that is rich in organic compounds and that are found throughout the Solar System, including in life on Earth. It is believed that on this asteroid, water which is another vital component to the evolution of life may also be trapped in the asteroid's minerals. According to the report, scientists will also investigate Bennu's rocks for ways to protect Earth from asteroids, which zoom past the blue planet almost every day.

New Curious Universe episode drop: Asteroid Hunting

We've sent @OSIRISREx on a journey of over a billion miles #ToBennuAndBack to do something that will make history: collect a sample of an asteroid! Why? What does that mean? What will we learn?

: https://t.co/Ep5Xg7xEX9 pic.twitter.com/E9Rxvj9AUa — NASA (@NASA) October 19, 2020

Japan is the only other country to have accomplished such a feat. Asteroids are among the leftover debris from the solar system's formation some 4.5 billion years ago.

A sample could hold clues to the origins of life on Earth, scientists say.

WHY THE MISSION IS IMPORTANT | NASA EXPLAINS

(With inputs from AP, Reuters)

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