NASA launches spacecraft to test asteroid defense concept11/24/2021
Liftoff! NASA launches its DART mission aboard a SpaceX Falcon 9 rocket to deliberately crash into an asteroid to test Earth’s planetary defenses
- The spacecraft launched this morning atop a SpaceX Falcon 9 rocket
- It will arrive at the small asteroid Dimorphos in September 2022 if all goes well
- When it hits Dimorphos, the 1,210 pound space probe will change the speed of the 525-foot-wide space rock by a fraction of a per cent
NASA’s first ever ‘planetary defence’ mission to deflect an asteroid 6.8 million miles from Earth has launched this morning.
The space agency tweeted the news this morning, writing: ‘And… liftoff! The #DARTMission is now on a nearly one-year journey to crash into a distant asteroid as the world’s first planetary defense test mission.’
Double Asteroid Redirection Test (DART), a box-shaped space probe, launched aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California.
Following its 6.8 million-mile journey, DART will smash into the small asteroid Dimorphos, which orbits a larger asteroid called Didymos, at 13,500 miles per hour (21,700 km per hour) in October 2022.
When it hits Dimorphos, the 1,210 pound space probe will change the speed of the 525-foot-wide space rock by a fraction of a per cent.
Although Dimorphos doesn’t pose a danger to Earth, NASA wants to measure the asteroid’s altered orbit caused by the collision.
This demonstration of ‘planetary defence’ will inform future missions that could one day save Earth from a deadly asteroid impact.
NASA launched a spacecraft Tuesday night on a mission to smash into an asteroid and test whether it would be possible to knock a speeding space rock off course if one were to threaten Earth
WHAT IS THE NASA DART MISSION?
DART will be the world’s first planetary defence test mission.
It is heading for the small moonlet asteroid Dimorphos, which orbits a larger companion asteroid called Didymos.
When it gets there it will be intentionally crashing into the asteroid to slightly change its orbit.
While neither asteroid poses a threat to Earth, DART’s kinetic impact will prove that a spacecraft can autonomously navigate to a target asteroid and kinetically impact it.
Then, using Earth-based telescopes to measure the effects of the impact on the asteroid system, the mission will enhance modeling and predictive capabilities to help us better prepare for an actual asteroid threat should one ever be discovered.
‘This isn’t going to destroy the asteroid. It’s just going to give it a small nudge,’ said mission official Nancy Chabot of Johns Hopkins Applied Physics Laboratory, which is managing the project.
Dimorphos orbits a much larger asteroid called Didymos.
The pair are no danger to Earth but offer scientists a way to measure the effectiveness of the collision.
Dimorphos completes one orbit of Didymos every 11 hours, 55 minutes.
DART’s goal is a crash that will slow Dimorphos down and cause it to fall closer toward the bigger asteroid, shaving 10 minutes off its orbit.
The change in the orbital period will be measured by telescopes on Earth. The minimum change for the mission to be considered a success is 73 seconds.
The DART technique could prove useful for altering the course of an asteroid years or decades before it bears down on Earth with the potential for catastrophe.
A small nudge ‘would add up to a big change in its future position, and then the asteroid and the Earth wouldn’t be on a collision course,’ Chabot said.
Scientists constantly search for asteroids and plot their courses to determine whether they could hit the planet.
‘Although there isn´t a currently known asteroid that’s on an impact course with the Earth, we do know that there is a large population of near-Earth asteroids out there,’ said Lindley Johnson, planetary defense officer at NASA.
‘The key to planetary defense is finding them well before they are an impact threat.’
DART will take 10 months to reach the asteroid pair. The collision will occur about 6.8 million miles (11 million kilometers) from Earth.
Ten days beforehand, DART will release a tiny observation spacecraft supplied by the Italian space agency that will follow it.
DART will stream video until it is destroyed on impact. Three minutes later, the trailing craft will make images of the impact site and material that is ejected.
The DART spacecraft, short for Double Asteroid Redirection Test, lifted off from Vandenberg Space Force Base atop a SpaceX Falcon 9 rocket in a $330 million project with echoes of the Bruce Willis movie ‘Armageddon’
If all goes well, in September 2022 it will slam head-on into Dimorphos, an asteroid 525 feet (160 meters) across, at 15,000 mph (24,139 kph)
The SpaceX Falcon 9 rocket with the Double Asteroid Redirection Test, or DART, spacecraft onboard, is seen ready for launch, Tuesday, Nov. 23, 2021, at Space Launch Complex 4E, Vandenberg Space Force Base in Calif. DART is the world’s first full-scale planetary defense test, demonstrating one method of asteroid deflection technology. The mission was built and is managed by Johns Hopkins APL for NASA’s Planetary Defense Coordination Office. (Bill Ingalls/NASA via AP)
The DART spacecraft, short for Double Asteroid Redirection Test, atop a SpaceX Falcon 9 rocket is seen Tuesday, Nov. 23, 2021, from Simi Valley, Calif. after launching from Vandenberg Space Force Base. (AP Photo/Mark J. Terrill)
In this image taken from NASA video, the SpaceX Falcon 9 rocket with the Double Asteroid Redirection Test, or DART, spacecraft onboard, lifts off Tuesday, Nov. 23, 2021, from Vandenberg Space Force Base in Calif. NASA launched the spacecraft Tuesday night on a mission to smash into an asteroid and test whether it would be possible to knock a speeding space rock off course if one were to threaten Earth. (NASA via AP)
DEFLECTING AN ASTEROID WOULD REQUIRE ‘MULTIPLE BUMPS’, STUDY SAYS
Deflecting an asteroid such as Bennu, which has a small chance of hitting Earth in about a century and a half, could require multiple small impacts from some sort of massive human-made deflection device, according to experts.
Scientists in California have been firing projectiles at meteorites to simulate the best methods of altering the course of an asteroid so that it wouldn’t hit Earth.
According to the results so far, an asteroid like Bennu that is rich in carbon could need several small bumps to charge its course.
Bennu, which is about a third of a mile wide, has a slightly greater chance of hitting Earth than previously thought, NASA revealed earlier this month.
The space agency upgraded the risk of Bennu impacting Earth at some point over the next 300 years to one in 1,750.
Bennu also has a one-in-2,700 chance of hitting Earth on the afternoon of September 24, 2182, according to the NASA study.
Scientists have been seriously considering how to stop an asteroid from ever hitting Earth since the 1960s, but previous approaches have generally involved theories on how to blow the cosmic object into thousands of pieces.
The problem with this is these pieces could potentially zoom towards Earth and present almost as dangerous and humanity-threatening an issue as the original asteroid.
A more recent approach, called kinetic impact deflection (KID), involves firing something into space that more gently bumps the asteroid off course, away from Earth, while keeping it intact.
Recent KID efforts were outlined at the 84th annual meeting of the Meteoritical Society held in Chicago this month and led by Dr George Flynn, a physicist at State University of New York, Plattsburgh.
‘You might have to use multiple impacts,’ Dr Flynn said in conversation with The New York Times. ‘It [Bennu] may barely miss, but barely missing is enough.’
Researchers have been working at NASA’s Ames Vertical Gun Range, built in the 1960s during the Apollo era and based at Moffett Federal Airfield in California’s Silicon Valley, for the recent KID experiments.
They fired small, spherical aluminum projectiles at meteorites suspended by pieces of nylon string.
The team used 32 meteorites – which are fragments of asteroids that have fallen to Earth from space – that were mostly purchased from private dealers.
The tests have allowed them to work out at what point momentum from a human-made object fired towards an asteroid turns it into thousands of fragments, rather than knocking it off course as desired.
‘If you break it into pieces, some of those pieces may still be on a collision course with Earth,’ Dr Flynn said.
Carbonaceous chondrite (C-type) asteroids, such as Bennu, are the most common in the solar system.
They are darker than other asteroids due to the presence of carbon and are some of the most ancient objects in the solar system – dating back to its birth.
According to the findings from experiments at AVGR, the type of asteroid being targeted (and how much carbon it has in it) may dictate how much momentum would be directed at it from any human-made KID device.
From the experiments, the researchers found C-type meteorites could withstand only about one-sixth of the momentum that the other chondrites could withstand before shattering.
‘[C-type] asteroids are much more difficult to deflect without disruption than ordinary chondrite asteroids,’ the experts concluded.
‘These results indicate multiple successive impacts may be required to deflect rather than disrupt asteroids, particularly carbonaceous asteroids.’
Therefore, around 160 years in the future – when Bennu is most likely to collide with Earth, according to NASA – a KID device would have to give it a series of gentle nudges to prevent it from breaking up and sending dangerous splinter fragments flying towards Earth.
NASA’s recent study about Bennu, published in the journal Icarus, did point out there is more than a 99.9 per cent probability Bennu will not smash into Earth over the next three centuries.
‘Although the chances of it hitting Earth are very low, Bennu remains one of the two most hazardous known asteroids in our solar system, along with another asteroid called 1950 DA,’ NASA said in a statement.
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