After greater than two years of sightseeing at an asteroid, a NASA spacecraft is now heading residence. Scientists can not wait to get their palms on the souvenirs it’s bringing again.
Beginning at about Four p.m. Eastern time on Monday, the OSIRIS-REX spacecraft, about 180 million miles away, fired its thrusters for seven minutes to push itself away from Bennu, an asteroid that could be a bit wider than the Empire State Building is tall.
“The burn was right down the middle,” mentioned Jason Dworkin, the mission’s venture scientist on the NASA Goddard Space Flight Center in Maryland. “It looks perfect.”
Dante Lauretta, a professor of planetary science on the University of Arizona who serves because the principal investigator, mentioned he had blended emotions in regards to the finish of this a part of the mission.
“You get used to having a spacecraft at an asteroid and seeing cool new images coming down all the time,” he mentioned.
But the robotic probe’s departure, transferring away at 600 miles per hour, means scientists are getting nearer to performing close-up research of pristine asteroid samples of their laboratories. “We’re getting pretty excited about that, too,” Dr. Lauretta mentioned.
Two years from now, after a 1.Four billion-mile journey that can swing across the solar twice, OSIRIS-REX will catch as much as Earth. The essential spacecraft is not going to land, however it can as an alternative drop off a capsule containing some valuable bits of Bennu it has collected — a minimum of a few ounces however extra doubtless greater than a pound of dust and rubble. Slowed by parachutes, the 32-inch-wide capsule will land on Sept. 24, 2023, on the Utah Test and Training Range, an enormous, desolate expanse within the Great Salt Lake Desert.
By finding out asteroids — chunks of rock that by no means coalesced right into a planet — scientists hope to raised perceive the beginnings of the photo voltaic system greater than 4.5 billion years in the past.
Although items of asteroids have landed on Earth as meteorites, these rocks are melted on the surface, and the minerals inside are sometimes altered by water after they arrive on Earth. Planetary scientists sometimes have no idea which asteroid they originated from.
But with the OSIRIS-REX and Hayabusa2 missions, scientists know the precise places the place the samples had been collected.
“We’re going to get a much better understanding of the most fragile materials that are on these asteroids and in space, that don’t survive passage to the Earth’s atmosphere,” Dr. Lauretta mentioned.
Asteroids hitting Earth within the early days of the photo voltaic system may have introduced most of the carbon-based molecules that had been wanted as constructing blocks for all times to come up.
“There’s likely to be a lot of carbon chemistry that’s captured in those compounds that we’ve been unable to probe before,” Dr. Lauretta mentioned.
Knowledge of this explicit area rock is also helpful if Earth ever must defend itself towards the asteroid. Bennu belongs to a bunch generally known as near-Earth asteroids as a result of their orbits cross that of Earth’s. Late subsequent century, Bennu will repeatedly cross notably close to Earth. Indeed, NASA calculates a slight however not zero likelihood — 1-in-2,700 — of Bennu hitting our planet between 2175 and 2199 with the vitality of greater than a billion tons of TNT. That cataclysm may kill tens of millions of individuals, however it could not be giant sufficient to trigger widespread mass extinctions.
OSIRIS-REX — the identify is a shortening of Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer — launched in September 2016 and arrived at Bennu in December 2018. Its observations included a shock: Bennu was shooting debris from its surface into space.
The essential goal of the mission, to gather a pattern of Bennu, was a problem as a result of the floor was far rockier than anticipated. The staff wanted to plot a brand new technique to information the 20-foot-wide spacecraft to a goal website that was solely 26 ft in diameter whereas avoiding a wall of rocks that included a sharp pillar nicknamed Mount Doom, which was as tall as a two- or three-story constructing.
In October, OSIRIS-REX hit its mark inside lower than a yard.
Its sampling software, which seems like an car air filter on the finish of a robotic arm, bent to remain involved with the asteroid for about 5 seconds. A burst of nitrogen gasoline knocked up rocks and dirt into the gathering filter, after which OSIRIS-REX slowly backed away without landing on Bennu.
Mission managers then rapidly decided to stow the sample that was leaking again to area as a result of a flap didn’t absolutely shut. Dr. Lauretta estimated that 800 grams, or about 1.eight kilos, remained.
Last month, OSIRIS-REX made one final flyby of Bennu, taking pictures to see how the gathering maneuver disrupted the floor.
“We were predicting that we would move maybe 100, 200 kilograms of material,” Dr. Lauretta mentioned. “We have evidence that it was at least 10 times as much and maybe more. Bennu’s surface was really fluid-like.”
That is as a result of the grains on the floor of Bennu are usually not caught collectively and thus didn’t resist the power of the sampling mechanism pushing down. It was extra just like the sampling arm was diving right into a swimming pool than hitting strong rock.
Dr. Lauretta mentioned the scientists had anticipated some binding — maybe the carbon molecules appearing like a sticky tar. “There’s no friction or any kind of force between them,” he mentioned. “They act very much like marbles — nice, smooth, glassy surfaces.”
After OSIRIS-REX passes Earth in 2023 and drops off the samples, its journey might proceed. The spacecraft’s navigators have labored out a trajectory that might take it to the asteroid Apophis in April 2029, simply after that object, a bit smaller than Bennu, zips inside an uncomfortably shut however nonetheless secure 20,000 miles from Earth.