In 1998, Hollywood’s Michael Bay created a film that had Bruce Willis, Ben Affleck and a team of oil drillers fly to a huge asteroid the size of Texas that was headed for Earth on a collision course that would wipe out life on our planet as we know it. The crew was able to land on the asteroid, drill down a significant distance, and plant a nuclear device that destroyed the asteroid and saved the world.
On early Wednesday, NASA (in true life-imitating-art fashion) launched the DART spacecraft. DART will fly to Dimorphos, an asteroid far from Earth, and smash into it. It will not destroy it but nudge it off its course. Currently, Dimorphos is circling Didymos, a much larger asteroid. Neither is on a collision course with us.
DART (Double Asteroid Redirection Test) took off from Vandenberg Space Force Base atop a SpaceX Falcon 9 rocket. The mission cost $330 million.
The mission will test whether the trajectory of an asteroid headed for Earth can be altered.
Dimorphos is approximately 170 meters across, or about the size of a football stadium. Didymos is much larger, at about 780 meters across. According to NASA, the size of these asteroids poses the greatest threat to Earth.
Lindley Johnson, planetary defense officer for NASA, during a news conference before the launch said, “The right time to deflect an asteroid is as far away from the Earth as we can.”
“The farther away in space it is… the less force it takes to change the orbit enough that it will be a miss instead of a hit.”
On our way!
— NASA (@NASA) November 24, 2021
The DART spacecraft will fly a long mission. Its collision with Dimorphos will occur 10 months from now. The kinetic impact of the collision is meant to change the velocity and path of the moonlet’s orbit around Didymos.
The test isn’t expected to make dramatic changes in the course of Dimorphos. Currently, Dimorphos orbits Didymos in 11 hours and 55 minutes. DART’s collision into Dimorphos is expected to change its orbital time to 11 hours 45 minutes. However, NASA said that due to the test being the first of its kind, the actual effects of the kinetic crash could vary.
Ten days before the impact with Dimorphos, DART will release an Italian-built CubeSat known as LICIACube, which will send video images of the impact and the far side of Dimorphos. Sixty minutes before impact, DART’s single instrument, a camera called DRACO (Didymos Reconnaissance and Asteroid Camera for Optical navigation), will start.
The surface of Dimorphos could be either rocky rubble or solid rock. The cameras of DART will relay back valuable information about the body. The DART will autonomously maneuver into the position for the collision and transmit images to NASA until the end.
The LICIACube will video the collision and measure how forceful the impact was. Ground-based telescopes will be used for NASA scientists to learn if the orbit of Dimorphos around Didymos will change. NASA chose the trajectory of DART so that any debris from Dimorphos is not expected to hit the larger asteroid.
NASA chose Didymos for this mission due to its close proximity to Earth although it is no threat to us. Its close proximity allows NASA to test whether nudging a body’s orbit using a not particularly powerful launch vehicle is possible.
According to the Philadelphia Enquirer, in 2013, Ukrainian astronomers found a minor planet that has a one in 63,000 chance of hitting the earth with a force of 2,500 megatons of TNT, or 50 times the size of the largest nuclear bomb ever detonated. Scientists determined that the asteroid will return to our planetary vicinity approximately on August 26, 2032. NASA has said that they will have a better understanding of how close or far that asteroid will come to Earth in 2028.
If the DART test is successful, maybe Bruce Willis and his crew won’t be needed this time.