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July 20, 2022
Currently, the only asteroid defense project to have truly gotten off the ground is the Double Asteroid Redirection Test (DART) Mission (mission in progress), an initiative developed by NASA and John Hopkins University.
An asteroid is seen near Earth in this artistic illustration. Image Credit: PIXABAY
China is planning a new initiative to combat the threat of a potential asteroid impact on Earth, Chinese Defense Minister Wu Yanhua said Sunday morning, according to TASS.
The plan is slated for technology testing to begin either at the end of China's 14th five-year plan (2021-2025) or within the following year, TASS reported, citing China Central Television.
The details of the project are not entirely clear at this time, though what is clear is that the China National Space Administration (CNSA) is working on a ground- and space-based early warning system that could observe incoming asteroids and sound the alarm if they could pose a risk of impacting the Earth. In addition, they also plan on developing a method to prevent these impacts from occurring, with the defense minister specifically being quoted as saying that they will "carry out a collision" to displace this incoming asteroid from its orbit.
A danger of astronomical proportions
Asteroid impacts are one of the worst possible natural disasters that could happen, as the sheer level of destruction they can cause exceeds that of any other. The possible damage an asteroid impact could cause varies based on a number of factors, especially size, with NASA considering asteroids 140 meters or greater in diameter a major concern should they hit the planet.
Image above: MASSIVE ASTEROIDS can veer uncomfortably close to Earth. But while some see them as harbingers of destruction, others see them as a mining alternative. Image Credit: PIXABAY.
According to research from the Davidson Institute of Science, the educational arm of Israel's Weizmann Institute of Science, an asteroid over 140 meters in diameter would release an amount of energy at least a thousand times greater than that released by the first atomic bomb if it impacted Earth.
Something even larger – over 300 meters wide like the asteroid Apophis – could destroy an entire continent. An asteroid over a kilometer in width – like 138971 (2001 CB21), which flew past the Earth in early March – could trigger a worldwide cataclysm.
Even small asteroids have the potential to cause damage, however.
And there are many of them. Asteroids make up one of the most numerous types of objects in the solar system. Currently, over 1,113,000 asteroids are known to exist in the solar system, according to NASA, but those are just the ones definitively identified, with experts always finding more.
Asteroids — Can they be stopped?
A number of projects have been proposed to help humanity destroy an incoming asteroid – and despite what many science fiction movies would suggest, most scientists, barring some, suggest that nuclear bombs would be a bad idea.
Currently, the only project to have truly gotten off the ground thus far is the Double Asteroid Redirection Test (DART) Mission (mission in progress), an initiative developed by NASA and John Hopkins University.
The DART Mission seeks to launch a specially designed rocket to alter the path of an asteroid, effectively punching an asteroid with a rocket with enough speed to change its direction by a fraction of a percent. NASA has likened this to a "pillow fight in microgravity."
The technology involved includes the "kinetic impactor" technique, which should be able to change an asteroid's motion in space.
A spacecraft will crash straight into an asteroid at a speed of around 6.6 kilometers per second, which should force it to change the speed of its orbit.
Even if only by a fraction of a percent, it would be enough to be observed and measured by astronomers.
The mission was launched last November and is slated to crash into its target, the asteroid Dimorphous, in the fall of 2022.
Image above: NASA's DART Mission heads for an asteroid, from behind the NEXT–C ion engine (illustrative). Image Credits: NASA/Johns Hopkins APL.
Is DART our only hope?
Despite it having the most hype around it and being the only major project to have gotten past the theory stage, other ideas have been proposed as well.
One proposal made by researchers at China's National Space Science Center in 2021 claimed that using 23 Long March 5 rockets, some of China's largest rockets, could possibly be effective at changing an asteroid's trajectory by a distance 1.4 times the Earth's radius.
"The proposal of keeping the upper stage of the launch rocket to a guiding spacecraft, making one large 'kinetic impactor' to deflect an asteroid, is a rather nice concept," Prof. Alan Fitzsimmons from the Astrophysics Research Centre at Queen's University Belfast said of the idea at the time, according to Reuters.
"By increasing the mass hitting the asteroid, simple physics should ensure a much greater effect," Fitzsimmons said, although, he added, the actual operation of such a mission needs to be studied in greater detail.
Another idea proposed by the European company Airbus suggested essentially hijacking and repurposing TV satellites, using a special kinetic deflection module to steer and propel the satellite into an incoming asteroid – a suggestion far more ad hoc than the previous two, which would need more time to pull off.
Another proposal made by scientists at the University of California, Santa Barbara suggested using what are called hypervelocity kinetic penetrators to "pulverize" the asteroid, essentially "slicing and dicing" them to avoid an impact. These work by sending the penetrators (some filled with explosives) into the core of the asteroid, fracturing it into many small fragments below 15 meters in diameter at maximum.
These fragments would then be spread out into a cloud of fragments and, if not blown completely off course, would then head into the Earth's atmosphere at speeds of around Mach 60.
But this is where the Earth's atmosphere kicks in, as entering the atmosphere at such a high speed causes it to experience severe levels of heat and pressure. These stresses would in turn cause the fragments to explode further, creating a sonic boom of sorts.
How viable any of these methods are remain purely theoretical, however, and it won't be until the DART Mission concludes that we will know if any of these theories hold water.
China's space ambitions
The announcement of China's planned asteroid defense project is in line with many of Beijing's noted ambitions regarding space.
China, which aims to become a space power by 2030, has already successfully launched probes to explore Mars and became the first country to land a spacecraft on the far side of the Moon.
Currently, China is also setting up its own space station in orbit.
However, they have also been pushing for other potential benefits of space advancement, such as extracting energy and mining materials from space.
“Outer space holds virtually limitless amounts of energy and raw materials, from Helium-3 fuel on the Moon for clean fusion reactors to heavy metals and volatile gases from asteroids, which can be harvested for use on Earth and in space. China will almost certainly use any resources it is able to acquire to the detriment of its adversaries, competitors and bystanders alike,” former CIA space analyst Tim Chrisman said in November 2021.
Related articles:
What’s next for the China Space Station in 2022 and 2023
https://orbiterchspacenews.blogspot.com/2022/04/whats-next-for-china-space-station-in.html
NASA, SpaceX Launch DART: First Test Mission to Defend Planet Earth
https://orbiterchspacenews.blogspot.com/2021/11/nasa-spacex-launch-dart-first-test.html
China Space Station
https://orbiterchspacenews.blogspot.com/2021/05/china-space-station.html
Related links:
China National Space Administration (CNSA): http://www.cnsa.gov.cn/
NASA's Double Asteroid Redirection Test (DART): https://www.nasa.gov/dartmission
Images (mentioned), Text, Credits: TASS/Jerusalem Post/By Aaron REICH.
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