DART mission a success as NASA spacecraft crashes into asteroid


asteroid Didymos and orbiting moonlet Dimorphos in space
Didymos (bottom left) and its smaller moonlet Dimorphos (center) were the targets of the Double Asteroid Redirection Test. Credit: NASA/Johns Hopkins APL

In a world first, NASA has crashed a spacecraft into an asteroid in an attempt to push the rocky traveler off its trajectory. The Double Asteroid Redirection Test – or DART – is meant to test one potential approach that could prevent an asteroid from colliding with Earth. David Barnhart is a professor of astronautics at the University of Southern California and director of the Space Engineering Research Center there. He watched NASA’s live stream of the successful mission and explains what is known so far.

1. What do the images show?

The first images, taken by a camera aboard DART, show the double asteroid system of Didymos – about 2,500 feet (780 meters) in diameter – being orbited by the smaller asteroid Dimorphos that is about 525 feet (160 meters) long.

closeup image of asteroid moonlet Dimorphos by DART spacecraft
This image of the moonlet Dimorphos was taken 11 seconds before the DART spacecraft crashed into the asteroid. Credit: NASA/Johns Hopkins APL

As the targeting algorithm on DART locked onto Dimorphos, the craft adjusted its flight and began heading towards the smaller of the two asteroids. The image taken at 11 seconds before impact and 42 miles (68 kilometers) from Dimorphos shows the asteroid centered in the camera’s field of view. This meant that the targeting algorithm was fairly accurate and the craft would collide right at the center of Dimorphos.

extreme closeup image of surface asteroid moonlet Dimorphos by DART spacecraft before impact
This photo shows the textured and rock-strewn surface of Dimorphos and was taken two seconds before DART crashed into the surface. Credit: NASA/Johns Hopkins APL

The second-to-last image, taken two seconds before impact shows the rocky surface of Dimorphos, including small shadows. These shadows are interesting because they suggest that the camera aboard the DART spacecraft was seeing Dimorphos directly on but the Sun was at an angle relative to the camera. They imply the DART spacecraft was centered on its trajectory to impact Dimorphos at the moment, but it’s also possible the asteroid was slowly rotating relative to the camera.

final partial image of asteroid taken by DART spacecraft before impact with surface
The final image from DART, taken one second before impact, was not able to fully transmit back to Earth. Credit: NASA/Johns Hopkins APL

The final photo, taken one second before impact, only shows the top slice of an image but this is incredibly exciting. The fact that NASA received only a part of the image implies that the shutter took the picture but DART, traveling at around 14,000 miles per hour (22,500 kilometers per hour) was unable to transmit the complete image before impact.

2. What was supposed to happen?

The point of the DART mission was to test whether it is possible to deflect an asteroid with a kinetic impact – by crashing something into it. NASA used the analogy of a golf cart hitting the side of an Egyptian pyramid to convey the relative difference in size between tiny DART and Dimorphos, the smaller of the two asteroids. Prior to the test, Dimorphos orbited Didymos in roughly 16 hours. NASA expects the impact to shorten Dimorphos’ orbit by about 1%, or roughly 10 minutes. Though small, if done far enough away from Earth, a nudge like this could potentially deflect a future asteroid headed towards Earth just enough to prevent an impact.

3. What do we know already?

The last bits of data that came from the DART spacecraft right before impact show that it was on course. The fact that the images stopped transmitting after the target point was reached can only mean that the impact was a success.

While there is likely a lot of information to be learned from the images taken by DART, the world will have to wait to learn whether the deflection was also a success. Fifteen days before the impact, DART released a small satellite with a camera that was designed to document the entire impact. The small satellite’s sensors should have taken images and collected information, but given that it doesn’t have a large antenna onboard, the images will be transmitted slowly back to Earth, one by one, over the coming weeks.

NASA infographic for DART asteroid redirection space mission
The force from DART’s impact should slightly shift the orbit of Dimorphos around Didymos. Credit: NASA/Johns Hopkins APL

4. What does the test mean for planetary defense?

I believe this test was a great proof of concept for many technologies that the U.S. government has invested in over the years. And importantly, it proves that it is possible to send a craft to intercept with a minuscule target millions of miles away from Earth. From that standpoint, DART has been a great success.

Over the course of the next months and years, researchers will learn just how much deflection the impact caused – and most importantly, whether this type of kinetic impact can actually move a celestial object ever so slightly at a great enough distance to prevent a future asteroid from threatening Earth.The Conversation

This article is republished from The Conversation under a Creative Commons license.

Author

  • David Barnhart

    David Barnhart is a Research Professor in the Department of Astronautical Engineering at USC, the Director/Co-Founder of the USC Space Engineering Research Center, and the Director of Space Systems and Technology Division at USC/ISI. At USC he specializes in developing innovative technologies and architectures for second generation space morphologies, satellite robotics and inspiration-based engineering techniques through hands-on projects with students, faculty and staff amongst the various Schools at USC, with outreach to industry based on the “engineering teaching hospital” construct. David was most recently a senior space Project Manager at DARPA, pioneering cellular spacecraft morphologies, satbotics and space robotics on the Phoenix and SeeMe projects, and represented the first DARPA space project presented at the United Nations COPUOS in Vienna Austria. At the Space Engineering Research Center, he has helped develop innovative solutions in aerospace and small satellite systems and technologies, new satellite design-synthesis tools to cut design time down to days from months and incorporate integration as a design tool, hybrid robotics concepts for satellites with the ability to be demonstrated in very large multi-dimensional low cost ground testbed, the creation which was 2nd only to NASA’s in scope and the largest University research facility of its kind to pioneer small satellite swarm interactions. The SERC created and launched USC’s first two Cubesat’s into space and has clean room and electrical/mechanical labs that can support satellites up to 100kg. Prior to USC David helped initiate two commercial space companies; co-founding and serving as Vice President and CFO of Millennium Space Systems, which has grown into a sustainable aerospace business with both Government and commercial customers in Los Angeles CA; and was the youngest elected member of a three-person international Executive Management board for a German startup in Bremen, Vanguard Space. At Vanguard he energized international space re-insurance and financial institutions on the technical attributes of a new space market, while developing US and European engineering contracts to execute the business plan. David served as an AF civilian for over 13 years and helped birth several notable projects over that time including pioneering demonstration of a miniature lunar lander vehicle modified from KKV technologies, showcased to the Vice President on the 25th Anniversary of Apollo 11; and created and lead the first $150M Small-Satellite Project team for the Air Force that formed the initial basis for US technology infusion in micro-satellite systems. Both the XSS-10 and XSS-11 team’s received the National AIAA Space Systems Award in 2003 and 2007 for pioneering developments and contributions to the aerospace industry. David holds a Bachelor of Science degree in Aerospace Engineering from Boston University and a Masters of Engineering from Virginia Polytechnic Institute, and has authored over 35 research publications and has been a keynote speaker at multiple national and international space conferences on 2nd generation space architectures.

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