In accordance with four new studies, NASA's DART mission, which sent a
rocket crashing into the asteroid Dimorphos, altered the asteroid's course
and may one day save Earth if enough time is provided for preparation.
Nearly five months after deliberately crashing a rocket into a far-off
asteroid, NASA has some good news: The mission was a huge success and, in
the future, similar techniques may be able to stop Earth from being
destroyed by planet-killing space rocks, claim four new studies published in
the journal Nature.
In a
statement,
Nicola Fox, assistant administrator for the Science Mission Directorate at NASA
Headquarters, said: "I cheered when DART slammed head on into the asteroid
for the world's first planetary defense technology demonstration, and that
was just the start."These discoveries "build a foundation for how humanity
can defend Earth from a potentially hazardous asteroid by altering its
course" and "add to our fundamental understanding of asteroids."
After five years of preparation, NASA initiated the Double Asteroid
Redirection Test (DART) mission in late November 2021. The objective was to
try a planetary defense hypothesis known as the "kinetic impactor" method,
which is essentially changing an asteroid's course by crashing a rocket into
it quickly.
The asteroid Dimorphos, a 525-foot (160-meter) "moonlet" that circles a
bigger asteroid named Didymos, is about 7 million miles (11 million
kilometers) from Earth. In September 2022, NASA's DART spacecraft safely
collided with it. According to the original NASA report, the impact's power
changed Dimorphos' orbit around Didymos by about 33 minutes and effectively
changed the smaller space rock's course. Although neither asteroid ever
presented a threat to Earth, their size and similar orbits made them perfect
candidates for the expedition.
Four new studies that were just released on March 1 affirm that the
operation was even more effective than NASA engineers had anticipated and
that using kinetic impactors is a practical way to safeguard Earth in the
future against possibly deadly asteroids.
A detailed account of DART's successful collision with the asteroid is
provided in the
first of the new studies, which also recreates the events leading up to the impact, the position
and details of the impact itself, and the dimensions and form of Dimorphos.
The article finds that "kinetic impactor technology is a viable technique to
potentially defend Earth if necessary" because of the successful impact with
the asteroid and the subsequent modification in Dimorphos' orbit.
The research adds that if scientists have several years, or better yet
several decades, to plan for the asteroid's approach, they can intercept an
asteroid about the size of Dimorphos without first conducting a
reconnaissance flight.
The 33-minute slowdown of Dimorphos' orbit is separately confirmed in the
second research by means of two distinct techniques, and in the
third article , momentum from the DART spacecraft to the asteroid is calculated. Both the
velocity of the falling ship and the massive plume of material released from
the asteroid's surface after the collision caused the impact to immediately
reduce the asteroid's orbital speed by at least 0.1 inch per second (2.7
millimeters per second).
Dimorphos became a "active asteroid," a type of little-understood asteroid
that orbits like an asteroid but has a tail like a comet, according to the
final paper. This trail of dusty debris has since been seen extending into
space for thousands of miles. Although scientists have anticipated that
impacts produce active asteroids in the past, the transition has never been
witnessed in the present.
Together, these findings clear the way for "a bright future for planetary
defense," according to a statement from
Jason Kalirai,
mission area executive for civil space at the Johns Hopkins Applied Physics
Laboratory, which co-manages the DART project with NASA.
The European Space Agency intends to send its Hera mission in 2024 to study
the scarred visage of Dimorphos up close, continuing in-depth research into
the DART impact.
