STUDY OF SPACECRAFT'S TRAJECTORY TOWARDS ASTEROID 2015 JJ THROUGH THE SUN-EARTH LAGRANGEÂ POINTÂ L2

• Main Author: Fairuz Syahda, Alzena
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/81118
• Institution: Institut Teknologi Bandung

Asteroids that potentially hit the Earth are not always grouped as PHAs (Potentially Hazardous Asteroids). Several asteroids listed in Sentry: Earth Impact Monitoring (https://cneos.jpl.nasa.gov/sentry/) are indeed included as objects that potentially hit the Earth, although they are not PHAs according to the institution IAU - Minor Planet Center (https://minorplanetcenter. net/iau/lists/t_phas.html). Providing information on orbital and physical properties is helpful to examine and observe asteroids belong to this category. The aim of this final project is to design a spacecraft’s trajectory towards an asteroid that potentially hit the Earth with the main consideration being energy efficiency. Asteroid 2015 JJ is an asteroid proposed as a target object for the spacecraft since it is predicted to potentially hit the Earth once in 2111. One of the trajectory towards this asteroid is provided by NASA Ames Research Center Trajectory Browser (https://trajbrowser.arc.nasa.gov/index.php). This is a direct trajectory with the opportunity to launch the spacecraft in a range of year 2023 to 2040. The construction of a trajectory in this work uses the non-direct scheme via the Sun–Earth Lagrange point L2, which is based on the Restricted Three-Body Problem. The scheme comprises two segmentations using a Halo orbit encircling the Lagrange point L2. The target asteroid 2015 JJ is principally determined after examining and sorting of parameters of space of possible asteroids. In line with this, the direct trajectory of the spacecraft is carried out which will then be compared with the non-direct trajectory. The non-direct trajectory is finally revealed that the first segmentation yields a trajectory with an initial point of departure at a distance of 752 km above the Earth’s surface, whereas the second segmentation produces a trajectory that has the closest distance to arrive at region of 475 thousands km from the asteroid. This non-direct trajectory to asteroid 2015 JJ requires a total energy of 1.2 km/s, which is significantly lower than the direct trajectory which consumes a total energy of 8.6 km/s.