A NASA mission intentionally smashed a spacecraft into an asteroid — a test run humanity should ever need to prevent a giant space rock from eliminating life on Earth — exploded off California on Tuesday.
It may sound like science fiction, but DART (Double Asteroid Redirection Test) is an actual proof-of-concept experiment that lifted off at 10:21 a.m. Pacific time Tuesday aboard a SpaceX rocket from Vandenberg Space Force Base.
“Asteroid Dimorphos: We’re Coming For You!” NASA tweeted after the launch.
The goal is to slightly change the trajectory of Dimorphos, a “moonlight” about 525 feet wide that circles a much larger asteroid called Didymos (2,500 feet in diameter). This pair orbits the Sun together.
The impact should occur in the fall of 2022, when the binary asteroid system is 11 million kilometers from Earth, the closest point they have ever seen.
“What we’re trying to learn is how to address a threat,” Thomas Zuburchen, top NASA scientist, said of the $330 million project, the first of its kind.
To be clear, the asteroids in question pose no threat to our planet.
But they belong to a class of objects known as Near-Earth Objects (NEOs), which reach within 30m miles.
NASA’s Planetary Defense Coordination Office is most interested in ones larger than 460 feet, which have the potential to flatten entire cities or regions with many times the energy of an average nuclear bomb.
The 10,000 known near-Earth asteroids are 460 feet or more in size, but none have a significant chance of being hit in the next 100 years. One major caveat: Scientists think there are still 15,000 more such objects to be discovered.
15,000 mph kick
Planetary scientists can create miniature impacts in laboratories and use the results to build sophisticated models of how an asteroid is supposed to turn – but the models always fall short of real-world tests.
Scientists say the Didymos-Dimorphos system is an “ideal natural laboratory” because Earth-based telescopes can easily measure the pair’s brightness variations and judge the time it takes the Moon to orbit its bigger brother .
Since the current orbit period is known, the change will reveal the effect of the impact to occur between 26 September and 1 October 2022.
Furthermore, since the orbits of asteroids never intersect our planet, they are considered safe to study.
The DART probe, which is a box the size of a large fridge with limousine-sized solar panels on either side, will hit just 15,000 mph in Dimorphos.
Dart probe team chief Andy Rivkin said the current orbital period is 11 hours 55 minutes, and the team expects Kick to be about 10 minutes past that time.
There is some uncertainty about how much energy will be transferred by the impact, as the internal structure and porosity of moonshine are not known.
The more debris generated, the more pressure will be exerted on the dimorphos.
“Every time we look at an asteroid, we find stuff we don’t expect,” Rivkin said.
The DART spacecraft also carries sophisticated instruments for navigation and imaging, including the Italian Space Agency’s Light Italian CubeSat for Imaging of Asteroids (LysiaCube) to observe the accident and its after-effects.
“CubeSat is going to give us, we hope, the shot, the most spectacular image of Dart’s impact and ejecta plume emanating from the asteroid. It will be a truly historic, spectacular image,” said Dart program scientist Tom Statler.
The so-called “kinetic impactor” method is not the only way to bend an asteroid, but it is the only technique ready to be deployed with current technology.
Others that have been envisaged include flying a spacecraft nearby to provide a small gravitational force.
Another is detonating near the nuclear detonation – but not at the object itself, as in the movies.”armageddon” And “Deep Impact“- which would probably create many more dangerous items.
Scientists estimate that 460-foot asteroids collide once every 20,000 years.
Asteroids six miles or more wide – such as those that struck 66m years ago and caused the extinction of most life on Earth, including the dinosaurs – occur every 100-200m years.