NASA spacecraft made a historic impact on Dimorphos, a small moonlet asteroid, on September 26, 2022.
The epic event was part of NASA's first Double Asteroid Redirection Test, or DART, which was to understand more about these space rocks and test if we could change an asteroid's path.
Dimorphos and Didymos: What Are They?
Dimorphos is a small asteroid, just 530 feet across, orbiting a larger asteroid named Didymos, which is 2,560 feet wide.
Both are classified as near-Earth asteroids because they come within 30 million miles of our planet.
Before the crash, the DART spacecraft took detailed images of both asteroids, which gave scientists valuable data about their surfaces and origins.
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Didymos is older, having formed about 12.5 million years ago, while Dimorphos is much younger, forming around 300,000 years ago.
Asteroid in space | Viktor Talashuk
Studies showed that Dimorphos likely came from material ejected from Didymos in a “large mass shedding event.”
The Effects of Thermal Fatigue
Another interesting finding was how thermal fatigue affects these asteroids.
The heating and cooling cycles between day and night cause the rocks on Dimorphos to crack and break up faster than scientists expected.
This process changes the asteroid's surface characteristics more rapidly than previously believed. This discovery came from studying the detailed images taken by the DART spacecraft.
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Olivier Barnouin, a planetary geologist and geophysicist at Johns Hopkins University Applied Physics Laboratory, led one of the studies.
He noted that the images alone provided insights into the geophysical properties of both Didymos and Dimorphos.
"From these images alone, we were able to infer a great deal of information on geophysical properties of both Didymos and Dimorphos," Barnouin said.
The findings also explained why the DART mission effectively moved Dimorphos, proving how NASA space exploration can provide vital data.
A New Tool for Planetary Defense
The DART mission launched in November 2021, traveling for over 10 months before slamming into Dimorphos at about 14,000 mph.
Although neither Didymos nor Dimorphos posed a danger to Earth, this mission was a crucial test.
If an asteroid ever heads towards our planet, the DART method could help deflect it, changing its path and preventing a collision.
The data collected from this mission will also aid the European Space Agency.
Their Hera mission, scheduled for October, will send an uncrewed craft to study the aftermath of the DART impact on Dimorphos. This follow-up mission aims to provide even more detailed observations.
Preparing for Future Threats
NASA is continually working to protect Earth from potential asteroid threats.
The space agency's Planetary Defense Coordination Office, established in 2016, catalogs near-Earth objects that could impact our planet.
They hosted a series of exercises to test readiness for such events.
The most recent exercise in April involved about 100 international representatives working through a scenario involving an inbound asteroid.
In addition, NASA is developing an asteroid-hunting telescope called the NEO Surveyor.
Scheduled to launch no earlier than June 2028, this telescope aims to find 90% of asteroids and comets 460 feet in size or larger within 30 million miles of Earth's orbit. This effort, part of the NASA asteroid tracker program, will enhance our ability to detect and monitor space objects that pose a threat.