Saving Earth from asteroids has ascended from science fiction into the realm of science fact. Loaded with delicate optics, and chips, the DART hurtled through space on a suicide course to crash into the moon of an asteroid. And planetary defense was its mission.
Movies and science fiction stories have immortalized the “need to learn how to save the world from an asteroid…” However, for decades the government has ruled such undertakings as far too expensive.
Please note: This is not ER’s first trip into outer space. We invite you to visit our previous article on the Webb Telescope.
Deflection: A Cheaper Way of Saving Earth
The mission seemed financially doomed until a planetary scientist named Andre Cheng found a way to do it with much less expense. Andrew Cheng works at Johns Hopkins Applied Physics Laboratory in Maryland. Moreover, the D in DART is sort of his big idea. DART stands for Double Action Redirection Test.
Andrew Cheng proved Deflection was better—and cheaper than the direction in this case. (The vehicle’s name works with either word.) Additionally, he also realized that we need not practice on a big fat asteroid. In fact, a smaller moonlet would accomplish the experiment.
“DART was the first-ever mission dedicated to investigating and demonstrating one method of asteroid deflection…” And Cheng pioneered the way to change “an asteroid’s motion in space through kinetic impact.”
To put it simply, he proved that knocking a moonlet off course was a cheaper way to test our theories than blowing up an entire asteroid.
Saving Earth from Asteroids: Five Fast and Fabulous Lessons
Scientists discovered mountains of data from the DART mission. However, let’s take a look at five of the most fascinating ones.
Lesson 1: Deflection is the Key, Both for Funding and Crashing
First, “the key to making the asteroid deflection test” was deflection. Therefore, on Sept. 26, we had front-row seats to the demise of a space vehicle. We saw the doomed 1,300-pound spacecraft crash into a harmless asteroid.
Of course, the target was harmless—after all, this was a practice in case an asteroid actually ever actually threatened the earth.
We were practicing saving the earth by impacting an asteroid 6.8 million miles away. And it only cost us $330 million dollars to see if our theories for saving the world from asteroids would work. In the future, we just might learn that it was a small price to pay.
Lesson 2: The Collision, Just Practice—This Time
To be specific, in the first place we needed to know if a space vehicle could even “nudge an asteroid…the size of a football stadium,” after its journey of millions of miles. Let us add, it made the last few minutes of its journey totally on autopilot, smoothly crashing, without hesitation. And we continue to get data from the experiment, but not from the DART. Read on to see how this experiment continues.
Lesson 3. Optics—Creating Our Eyes-on Experience
Did you realize that breathless crowds of us could observe the crash through a camera mounted on the spacecraft? That meant not only scientists, but the general public could see DART make history. This made the DRACO camera aboard DART critical to the mission. By the way, a name like DRACO must have meaning. It stands for Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO.)
Through the magic of the DRACO camera, we saw the rugged terrain of the 525-foot-wide rock named Dimorphos. At first, it gleamed as a pinpoint of light. Then, as DART moved closer, the rock grew to fill the frame. There was only a 45-second delay as we watched the moments unfold.
Lesson 4. Self-Sacrifice: The End of a World-Saving Spacecraft
Thus, in almost real-time, we watched the “final five-and-a-half minutes of images leading up to the DART spacecraft’s intentional collision” with the moonlet of an asteroid. See the final images of DART at this convenient online resource: https://go.nasa.gov/3Rer1NW.
Keep in mind the 525-foot-wide moonlet, Dimorphos, orbits a larger asteroid named Didymos. Didymos is a 2,560-foot (780-meter) asteroid
Lesson 5. Diligent Data Collection for Saving the World
At the above-linked website, you will find actual videos and images of this moment in history. The final image in the movie shows a patch of Dimorphos that is 51 feet 16 meters) across. At that point, DART crashed into the asteroid.
Thus, the end of the video is a dramatic but partial, final frame.
In simple words, the point of the experiment was not to blow up the entire asteroid. Instead, it was to bump or deflect it off of its pathway to earth. In more scientific language, NASA says,“…DART’s impact with the asteroid Dimorphos demonstrates a viable mitigation technique for protecting the planet from an Earth-bound asteroid or comet…”
In Memory of DART: It was Boxy but Very Smart
Now telescopes all over the world will be engaged cooperatively in making precise measurements. Additionally, they will determine how far DART deflected the asteroid in the aftermath of its explosion.
Thomas Zurbuchen, of the Science Mission Directorate at NASA Headquarters, drew this conclusion. “Just a small change in its speed is all we need to make a significant difference in the path an asteroid travels.”
- In addition to DRACO, the box-shaped 1260 lb. space vehicle also carried a guidance and control system.
- The system worked with the Small body Maneuvering Autonomous Real-Time Navigation (SMART Nav) algorithms.
- Thus, DART was smart enough to identify the two asteroids, and distinguish its target.
An International Plus for Saving the Earth: The LICIACube
We would be remiss if we did not also mention this fact. Fifteen days before DART’s voyage, the Italian Space Agency deployed a satellite named the LICIACube. This stands for “Light Italian CubeSat for Imaging of Asteroids.” Next, let’s look at a few fascinating details about this Italian contribution to saving the earth from asteroids.
- This satellite provided cameras and optics to capture the impact and the ejected matter of DART after its demise. “LICIACube’s images are intended to provide a view of the collision’s effects to help researchers better characterize the effectiveness of kinetic impact in deflecting an asteroid.”
- However, the LICIACube doesn’t carry a large antenna, so we will see those one at a time as they downlink to earth in the coming weeks.
DART’S Legacy for Saving the Earth from Asteroids
Four years from now, the European Space Agency’s Hera project will survey both Dimorphos and Didymos. They will focus on the crater left by DART.
From the NASA Applied Physics Laboratory, APL Director Ralph Semmel stated, “…Capabilities based on DART could one day be used to change the course of an asteroid to protect our planet and preserve life on Earth as we know it.”
At ER Precision Optics, we hope you found the story of the DART as fascinating as we did. Once again, we humbly state that without what we do, NASA could not do what it does.
Be On the Alert: Part II of Saving Earth from Asteroids could arrive in the near future.