Dr. Cristina Thomas
DART (Double Asteroid Redirection Test): A Telescope Observer's Perspective
DART is NASA's first planetary defense mission, which will test asteroid deflection by kinetic impactor. The spacecraft will impact the satellite of the binary near-Earth asteroid (65803) Didymos in fall 2022. I lead the DART team responsible for observing and understanding the orbit of the moon prior to and after impact. The observed orbit change will be how the team determines the effectiveness of the experiment. We understand the orbit of the binary asteroid system using light curves, a measure of how the brightness of an object changes over time. When Didymos is close to Earth, the moon and the primary eclipse each other from the vantage point of our telescopes on the ground. Each eclipsing event causes a subtle dimming of the lightcurve known as a "mutual event". Observing these events enables us to observe the path of the satellite around the primary and predict the next mutual events. We observed the Didymos system in 2019 and have additional pre-impact observations planned for later in 2020 and early 2021. These observations will establish the state of the system before impact. We will perform similar observations in the period following the fall 2022 impact to determine the change in the satellite orbit. I will discuss how we understand the orbit of the satellite, results from our recent observations, and our future plans for observing the Didymos system.