Just now, for the sake of the future of all mankind, DART carried out a suicide mission-the last ignition to accelerate, to complete the final “swan song”, and crash into the asteroid.
Image taken before DART hit asteroid Dimorphos Image taken before DART hit asteroid Dimorphos
The last photo taken by the DART navigation camera The last photo taken by the DART navigation camera
Planetary impacts have long been considered one of the risks to Earth. The most well-known planetary impact on Earth occurred 65 million years ago, causing the extinction of the dinosaurs. No one knows whether there are asteroids that have not yet been discovered and observed by humans.
The goal of the DART mission is to prevent such a catastrophe from happening again — pushing any threatening asteroids out of the way to avoid hitting Earth. DART is NASA’s first spacecraft suicide mission – assassinating an asteroid. Its mission is to destroy, by hitting the asteroid with a spacecraft to deflect it from its orbit towards Earth.
On November 24 last year, the DART probe was launched into space by SpaceX’s Falcon 9 rocket. After a long journey of about 10 months, DART will hit an asteroid called Dimorphos, which orbits a much larger asteroid, Didymos. NASA hopes that the impact will change the orbit and speed of the Dimorphos asteroid — Dimorphos will follow a new path around Didymos after the impact, rather than the path before the impact. Telescopes on the ground will measure this new route by measuring changes in Dimorphos’ orbital period.
In the history of the Milky Way, human beings have existed for a very short time, but only for a moment. This precious gift of life and wisdom is not guaranteed to last forever since it appeared. Astronomers like to say that asteroids are just nature’s way of greeting, asking, “How’s your space program going?”
And now, the DART mission is about to hand over an answer sheet. Today, DART crashed into the asteroid at a speed of more than 22,500 km/h. For the future of all mankind, knowing that it would die, it still did not turn back and completed the final “swan song”. Below, Enjoy:
If dinosaurs had NASA back then, the fate of this species might not have come to an abrupt end 65 million years ago. Of course, if that’s the case, I’m afraid there will be no human beings today…
On November 24, 2021, NASA sent off a satellite with a basic mission. The achievement or disappointment of this mission will decide if the destiny of dinosaurs will one day be arranged on people in the future later on.
A satellite the size of a car took off from the Vanderbilt Space Force Base in California on a SpaceX Falcon 9 rocket.
Today, the satellite will act as a “kinetic weapon” to collide with a set of twin asteroid systems.
DART mission idea mapDART mission idea map
Researchers’ assumption is that the effect could fundamentally steer the parallel space rock framework. This mission has now cost more than $300 million. It will test whether people can redirect the course of space rocks and other galactic items to safeguard Earth, people, and different species.
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How to manage a space rock stirring things up around town?
On February 15, 2013, occupants close to Chelyabinsk, Russia encountered a remarkable cosmic occasion: a bolide entered the World’s environment over the southern Ural Government Locale, started to consume, and wound up in the city of Chelyabinsk Blast above.
The shooting star is something like 17 meters in breadth and has a mass of around 7,000 tons. The blast level is assessed to be in the scope of 30-70 kilometers. It is a little shooting star, and the air blast shock wave brought about by its air blast impact has made almost 1,500 individuals be harmed to changing degrees.
The picture when the meteorite exploded, from the local citizen’s driving recorder
Local buildings are affected by shock waves generated by meteorite explosions Local buildings are affected by shock waves generated by meteorite explosions
The last time humans encountered a meteorite explosion was the Tunguska explosion in Russia, more than a hundred years ago.
The asteroid impact event in 2013 reminded astronomers once again: it is time to start the “planetary defense plan”.
The European Space Agency (ESA) and NASA (NASA) originally had their own internal plans for defending against satellites hitting asteroids. But the two agencies signed a cooperation agreement in 2015 called the Asteroid Impact and Deflection Assessment (AIDA).
The two agencies jointly selected the target for the impact test: the Didymos twin asteroid system.
Model diagram of the Didymos twin asteroid system, from NASA Model diagram of the Didymos twin asteroid system, from NASA
Among the two asteroids, the larger one is called Didymos (Di Di Moss, Chinese name “Twin Star”), with a diameter of about 780 meters; ”), only about 160 meters in diameter. The twin star orbits the twin star once every 12 hours.
The 160-meter-diameter Dimorphos asteroid is the same size as the Colosseum The 160-meter-diameter Dimorphos asteroid is the same size as the Colosseum
Selecting this group of asteroids as the test targets of the “Planetary Defense Program”, astronomers probably thought like this:
First of all, even if the impact is completed, it is almost impossible for these two asteroids to collide with the earth, so they are suitable for “practice martial arts”;
The mass of the twin star is very small. If you want to have a considerable impact on it, you do not need too much satellite mass, and there is a revolution relationship between the twin stars. The small star is the “satellite” of the big star, and the distance is only about 1.2 kilometers. Therefore, hitting a small star can also have a significant impact on the trajectory of the big star, achieving the effect of “four or two moving a thousand pounds”.
The European Union and the United States had originally planned to launch two satellites for the mission at the end of 2020 and the end of 2021.
Among them, the European Union’s AIM orbiter will fly around the big star, analyze the material composition of the binary star and send the data back to Earth, and observe the effect of future collisions at the closest distance.
The U.S. aircraft, the DART launched in November 2021, the full name of which is Double Asteroid Redirection Test, will collide with the small star when the double star moves closer to the earth this year to deflect the orbit of the double star system.
(The English word Dart also means dart, and this group of twin asteroids is our target.)
Later, the EU’s AIM launch mission was cancelled, the material composition of the binary stars is still unknown, and there is no way to make close observations at the time of the collision.
However, this impact is not very big, because the double star is relatively close to the earth, and it is expected to be only 11 million kilometers away at the time of impact, and the orbital plane around the double star is close to the ecliptic plane of the earth. The effect observation is relatively easy, and it can be observed on the ground.
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DART: The first step in a planetary defense program
Next, let’s take a closer look at the DART impactor.
The mass of DART is only about 550 kilograms. It is a very lightweight and low-function aircraft. After all, it is only used as cannon fodder. Its main payload is only a few sensors for navigation and sensing, a long-distance space observation camera. The onboard ion thrusters can make attitude adjustments and eventually crash toward the small star.
Engineers put DART probe into SpaceX processing facility at Vandenberg Space Force Base
It is worth mentioning that, for the first time, DART adopts a new automatic optical navigation system SMART Nav, which allows the aircraft to automatically navigate to the predetermined target without the assistance of the operator, and after reaching the target range, it will start to collide when the collision occurs. In the hours in between, SMART Nav also enables automatic navigation, attitude adjustments, and more.
Developers inspecting DART’s navigation system components Photo Credit: NASA Developers inspecting DART’s navigation system components Photo credit: NASA
DART was also the first spacecraft to employ a Radial Spiral Line Slot Array (Spiral RLSA) antenna. This is a high-gain antenna dedicated to deep space communications, capable of maintaining communications between DART and the ground using the X-band of the Deep Space Network.
DART Ontology Image Credit: NASADART Ontology Image Credit: NASA
DART also has a secondary payload, an Italian-made CubeSat called LICIACube, which detached from the main body of DART 10 days before the impact for temporary image-gathering observations. CubeSats are “disposable” and cannot be recycled after sending back data, becoming space junk.
Interestingly, there are two sets of cameras installed on this CubeSat, named LUKE and LEIA (the name of the Star Wars protagonist).
Developers commissioning the LICIACube CubeSat Image Credit: NASA Developers commissioning the LICIACube CubeSat Image Credit: NASA
They were developed by NASA’s Aircraft Development Laboratory, APL, and assembled in Maryland.
DART at the SpaceX Load Handling Center, ready to be installed on a rocket Photo credit: NASADART at the SpaceX Load Handling Center, ready to be installed on a rocket Photo credit: NASA
According to the plan, when the rocket enters space, DART will detach from the rocket, unfold the solar panel, circle the earth and gradually change its orbit. After continuing to operate for a period of time, DART will re-ignite the ion thruster, and use the earth’s gravity to make the orbit run. Eventually synchronized with the Earth’s orbit.
By the end of September and the beginning of October this year, when the orbits of the twin asteroids are closest to the orbit of the Earth, DART will perform a pose-changing ignition to get closer to the target orbit.
Then, the CubeSat as a secondary payload will be ejected, unfolding its independent solar panels, and preparing to capture and record data around the target asteroid. Then, over a period of several days, DART will continue to approach the small star, and 4 hours before the impact of the final ignition acceleration, complete the final “swan song”, crash into the small star.
The impact of this great “sacrifice” on the revolution speed and orbit of the small star in an instant may be minimal. However, if viewed from a cosmic scale, scientists believe that the impact is expected to have a considerable impact on the trajectory of the twin asteroids in the universe.
Of course, before this, humans have never tried to deflect the orbit of an asteroid by impact. So this mission is also the first test of impact deflection. For the effect, scientists are quite confident. However, the specific impact of the impact remains to be tested.
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Rewrite the relationship between humans and the universe
One of the biggest differences between humans and other creatures is that humans have subjective initiative. This is a philosophical concept that we learned in junior high school. It says that people can actively understand and observe the world, summarize objective laws, and use these laws to transform the world.
In the past, the world that people could transform was limited to where we live. Later, with the development of industry and technology, human activities have caused a huge and far-reaching impact on the environment of the entire earth. Today, we have also left footprints on the moon, sent unmanned vehicles and deep space probes to Mars, Jupiter, and deeper space, and may even colonize Mars in our lifetime.
In the eyes of some astronomers and philosophers, now we are trying to deflect the orbit of asteroids by impact (or any other) method to protect the safety of the earth and the earth’s species, which belongs to the maximum human initiative so far. a move.
Before the DART project, the relationship between humans and the universe was limited to observations and minimal exploration. At the level of larger, cosmic stellar and orbital physics, we humans have been powerless in the past, because here, only gravity can determine everything.
The existence of the DART project is also the first time in the universe we can observe that humans actively use the laws we observe and summarize, as well as the technology we have developed, to deflect the trajectory of objects that already exist in space.
Once this kind of attempt is verified to be effective, it will mean that for the first time, human beings have added their own strokes to the basic rules of the operation of the universe. In the future, human beings will be expected to carry out larger-scale “adjustment” of cosmic stars according to their own wishes.
These adjustments can be aimed at extraterrestrial bodies, or even the earth we live in. Because maybe in the future, the entire solar system is no longer suitable for survival. We may be able to take the earth and start an epic wandering in the universe like in “The Wandering Earth”.
Stills of “The Wandering Earth”, hundreds of huge planetary engines, turning the earth into a planetary spacecraft
However, is it really a good thing that humans have mastered such abilities?
Some philosophers and theorists worry that DART, and more human action in planetary defense in the future, will set a false precedent that is potentially immeasurably harmful.
If we start the association, first of all, human beings may perform more large-scale and uncontrolled stellar orbit modification behaviors in the future. And just like the dark forest law proposed in “Three-Body Problem”, if we discover extraterrestrial civilization, who can guarantee that we will not use this ability to modify the orbit of stars as a weapon, and then lead to an even more unmanageable ending? In such an extreme possibility, the ability that human beings have mastered by themselves may become the fuse of human demise.
For this planetary defense behavior, there is another layer of decision-making mechanism: who decides, how the public participates, and how to establish a sound mechanism to ensure that all human beings/all countries and regions can be at this planetary level. Gain and exercise the right to speak in major decisions?
Of course, we would rather these thoughts and criticisms are just unfounded.
Mastering such capabilities is critical, at least from a planetary defense standpoint. At present, the number of near-Earth asteroids larger than 500 feet (about 152 meters) in diameter has reached tens of thousands. Although known
