-and-MIRI-(Mid-Infrare.png?trim=0,1,0,0&width=1200&height=800&crop=1200:800 "Astronomers want to blow up this asteroid using nuclear explosives before it strikes Moon – UK Times")
Astronomers are considering blowing up the “city killer” asteroid, estimated to have a small chance of crashing onto the Moon in 2032, to cut the risk of the collision debris destroying satellites.
The near-Earth space rock, dubbed 2024 YR4, was previously thought to have a small chance of impacting Earth.
Later observations of the 65 metre-long (300ft) rock revealed that the odds of its collision with Earth are almost negligible, while it still had small chances of impacting the Moon.
Estimates of the asteroid’s trajectory suggest it has a 4 per cent chance of hitting the lunar surface in December 2032, with the likely Moon-impact predicted to produce a crater about 1km in diameter.
Researchers previously calculated that 2024 YR4 may generate a lunar debris cloud weighing over 100,000,000 kg, which could “accrete to the Earth on timescales of a few days” and expose satellites orbiting the Earth to meteorites for years.
To avoid this likelihood, astronomers, including those from Nasa, propose blowing up 2024 YR4 altogether as part of what they call a “kinetic disruption mission”.
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The yet-to-be peer-reviewed study assessed three potential missions, including further reconnaissance of the asteroid, deflecting the space rock, and breaking it apart into pieces with explosive devices.
Researchers considered different propulsion options using existing spacecraft as well as new ones.
They also assessed the different timelines involved for each of these missions to reach the asteroid, currently over 379 million miles away.
All these options seem to require several times more planning and resources compared to Nasa’s 2022 Double Asteroid Redirection Test (DART), in which the space agency nudged an asteroid called Dimorphos off course by ramming it with a spacecraft at high speed.
“Deflection missions were assessed and appear impractical,” scientists wrote.
Another proposed option includes detonating 2024 YR4 using “nuclear explosive devices”.
This option is being considered seriously since deflection will likely not be enough due to uncertainty in the asteroid’s size and mass.
Such a mission could open up another way of deflecting any other potentially dangerous space rocks discovered to be on a collision course with Earth in the future, scientists say.
The space rock could weigh anywhere from 72.7 million to 2 billion pounds, and a mission to blow it up into pieces could take anywhere from five to seven years to develop, with the next available launch window from late 2029 to late 2031.
Scientists propose sending two 100-kiloton nuclear devices to the asteroid, each about five to eight times as powerful as the nuclear bombs dropped by the US on Nagasaki and Hiroshima at the end of WWII.
“A second nuclear explosive device is onboard in case it is needed; otherwise, it can be safely disposed of by detonating it in deep space after the asteroid is successfully deflected by the first one,” they say.
“When considering the various mission options we describe herein, it is important to keep in mind that 2024 YR4’s lunar impact probability currently stands at about 4 per cent,” researchers wrote.
