For years, scientists from around the world have been working on a number of ways to alter the trajectory of an asteroid or other interstellar body en route to Earth that has the potential to wipe out life from the planet.
On Monday, NASA will broadcast its first attempt to alter an asteroid’s orbit, a capability that will be essential if we discover an asteroid that poses a risk of collision with Earth.
The entire operation focuses on whether DART, a new system for using spacecraft to change an asteroid’s course, works as NASA engineers and scientists hope.
DART stands for Double Asteroid Redirection Test and is a space mission to see if we can place objects in the trajectory of an asteroid or smaller interstellar body and change its course as it heads towards planet Earth.
What is the DART mission NASA will be conducting this week?
The mission, which NASA will conduct Monday, targets a small asteroid called Dimorphos, which orbits the larger 65803 Didymos, forming a binary system. If all goes according to plan, DART will aim for a head-on collision, slowing Dimorphos and altering its orbit around Didymos.
What type of spaceship will this mission use?
The DART spacecraft itself, used for this mission, weighs over 600kg and lacks instruments you would normally find on a spacecraft. Its solar panels include an experimental concentrating solar cell that takes up less space to generate the same amount of power as existing space-based hardware, and its main transmitter is testing a new antenna configuration.
The main piece of equipment on the DART spacecraft is the single camera, the Didymos Reconnaissance and Asteroid Camera for Optical Navigation, or DRACO, a 2,560 × 2,160 pixel camera. DRACO and the transmission hardware are able to send an image back to earth every second.
How should the DART mission develop?
During the final approach to Dimorphos, DART will be so far away that the round-trip transmission will take more than a minute. Therefore, the asteroid’s final approach and orientation will be handled by an onboard navigation system called SMART Nav (Small-body Maneuvering Autonomous Real-Time Navigation).
Once the DART spacecraft is close enough to Dimorphos, the SMART Nav tracks the larger Didymos and uses it for navigation until about 50 minutes before its collision with Dimorphos. Until 2.5 minutes before the collision, the DART spacecraft will remain on course with its internal ion engines.
2.5 minutes before the collision, the ion engine is shut down and DART rolls into a collision at about 6 kilometers per second. Although Dimorphos is only about 120 meters across, it should completely fill DRACO’s view at this point.
We know the collision was successful when we stop receiving images or the transmission stops. DART will be accompanied by a small ship called LICIACube, built by the Italian Space Agency. It was cleared by DART in early September and is on a course that will take it past Dimorphos about three minutes after impact. LICIACube has two cameras (wide and narrow field, one carrying RGB color filters) and will capture images of the asteroid and any material ejected by the impact.
However, it may be several months before NASA knows whether the mission was successful or not before they can be sure that Dimorphos’ orbit was modified successfully.
What happens if the mission is successful?
If the mission is successful, NASA hopes to launch several more of these DART spacecraft and modules to sizable asteroids that we know are heading for Earth, especially if we know for sure a collision will occur becomes.
NASA plans to launch these DART spacecraft at least 10 years or more in advance to give them time to transition to a less threatening orbit. Having a method successfully demonstrated will be a major step forward for NASA’s planetary defense programs.
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