An illustration depicting the overall concept of the DART mission. Mathematics DB
It sounds like something out of a science fiction movie, but in February 2013, an asteroid with a diameter of 17m actually exploded in the sky of Chelyabinsk, Russia, and meteorites fell to the ground.
According to the National Aeronautics and Space Administration (NASA), as of November 2022, there are 2304 potentially dangerous asteroids with a high probability of approaching or colliding with Earth, and 22 asteroids that are likely to pose a threat to Earth in the next 100 years. An asteroid with a diameter of 140m can collapse a city, and an asteroid with a diameter of more than 1km has destructive power enough to devastate the whole world.
So NASA planned the ‘DART’ mission, humanity’s first asteroid impact test. DART stands for Twin Asteroid Orbit Correction Test, and is a mission to crash an unmanned spacecraft named DART into an asteroid called ‘Dimorphos’ to change its orbit.
Dimorphos is a satellite asteroid orbiting the asteroid ‘Didimos’, with a diameter of 170 m and a distance of about 10.8 million km from Earth. It is not a threat to Earth in orbit, but considering its size and location, it was selected as a target because it is easy to obtain data necessary to deal with a dangerous situation in which an actual asteroid is about to collide with Earth.
On November 24, 2021, the DART team launched a spacecraft from the Vandenberg Space Force Base in California, USA. Ten months later, on September 26, 2022, the spacecraft succeeded in changing the asteroid’s trajectory as it crashed into Dimorphos. To do this, the researchers calculated using the asteroid’s orbital period, speed, and momentum, and created a 3D simulation of the motion of the asteroid.
In the future, the DART team will continue to observe Dimorphos, collect data, and study the asteroid in detail. And among them are mathematicians. What role did mathematicians play on the DART team?
Wendy Caldwell is a researcher at Los Alamos National Laboratory in the United States. Mathematics DB
● Meticulous calculation to change the orbit of the asteroid
Wendy Caldwell, a researcher at the Los Alamos National Laboratory in the US, a member of the DART team, began her asteroid research while majoring in applied mathematics in graduate school. The asteroid she studied at the time was ’16 Psyche’, the 17th largest and 10th most massive known asteroid. At that time, NASA had a research topic that mathematically modeled 16 psyches, and I was personally interested in it, so I continued to study asteroids from then on.
“When I was an undergraduate, I happened to have a conversation with graduate students who were studying applied mathematics, and I felt that, unlike pure mathematics, which studies theories, in applied mathematics, you can immediately feel the impact of your research. Of course, pure mathematics is also important, but when you study algebra or matrices, you don’t know if this study will lead to the development of the Internet. But in applied mathematics, we can model the spread of a disease like COVID-19. I love that I can understand the world through research. The DART mission officially became a part of it in September 2019 at the recommendation of a doctoral advisor.”
Researcher Wendy belongs to the ‘Collision Modeling Working Group’ of the DART team. This group is working on modeling how an asteroid’s orbit would change if it were impacted. It is the role of verifying the situation where a spaceship collides with an asteroid through simulation.
“I was mainly in charge of 3D simulations. Depending on what material the asteroid is made of, the appearance when it collides will change. Therefore, it is necessary to accurately determine the material properties of the asteroid by synthesizing various data. This requires a lot of testing and a lot of calculations, so I used a very fast supercomputer to do it.”
● Role of DART team members and mathematicians
The DART team includes experts from NASA, the US Institute of Applied Physics, and even Kenya Institute of Technology. Hundreds of experts have participated, and the fields of expertise are diverse. What are the experts in the DART team? In particular, what is the role of mathematicians among them?
role of mathematicians. Mathematics DB
Andrew Lipkin, Research Fellow, Institute of Applied Physics, USA (Director of the DART Research Team). Mathematics DB
It’s hard to say exactly what percentage of people are experts, because most people have expertise in multiple categories. Mathematicians are few in number in the entire membership, but mathematics is critical to the DART mission. Geologists, astronomers, and engineers all have great mathematical expertise and have performed a ton of mathematical calculations.
● Creativity is the essence of mathematics
Q. What kind of work do you do at the Los Alamos National Laboratory, where you are originally affiliated?
“I belong to the verification and analysis group of the Department of Computational Physics. In the lab, I mainly code and simulate physical events such as asteroid impacts. I also study explosions such as underground nuclear tests and the craters they form. Students and lead projects together.”
Q. In graduate school, you studied drug addiction in addition to asteroids. Please explain this research.
“After classifying the drug addicts into five groups, we looked at the changes in each group. For example, those who are addicted to drugs and those who are undergoing rehabilitation to overcome them, etc. These changes are interpreted using ‘partial differential equations’, which describe how one variable changes with another variable, such as the passage of time. It is similar to the asteroid study in that it uses multiple data to establish partial differential equations for variables. I could.”
Q. When you think of mathematicians, you often think of sitting at a desk and solving problems. What do you think about this?
“I love not looking like a typical mathematician. I am a mathematician, but I have dyed my hair flashy and have piercings. I want people to know that I am a mathematician as well as someone who has what people think of me as a mathematician.
I think there is ‘creativity’ in the essence of mathematics. Thinking about difficult problems and thinking about where these problems can be applied are all results of creativity. Both of my parents majored in music, so I think I resemble that kind of creativity. So, in addition to mathematics, I enjoy various activities such as dancing and directing musicals, while expressing my creativity in other ways.”
Q. What are your future plans?
“For the next year or two, I think I need to continue observing Dimorphos and finish the DART mission well. Other than that, I am conducting a research project on craters and rocks with two students, respectively, and I hope that research goes well. Mathematician My husband and I are also conducting mathematical modeling research on social media marketing.
Applied mathematics can be applied to a wide variety of fields, and I like new things very much, so I will continue to conduct new research besides this one. “
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