Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2018-2019)

Asteroids are abundant celestial objects and represent important research targets to study three relevant aspects,x000D
i) the hazard arising from a potential asteroid impact, ii) the economic benefits originating from asteroidx000D
mining, and iii) the knowledge gain towards improved an understanding of the origin of the solar system. Inx000D
order to address those research questions, a number of asteroid mission concepts are currently underx000D
development at NASA and ESA, namely the Asteroid Redirect Mission (ARM) and the Asteroid Impactx000D
Mission (AIM), respectively. Both missions involve asteroid visits in order to investigate structure, mineralx000D
composition, and potential redirection strategies. The proposed research aims at quantifying the gravity fieldx000D
and the density structure of a simulated asteroid and simulated surface boulders. NASA's Asteroid Redirect andx000D
Robotic Mission (ARRM) proposes to pick-up a boulder of 2-4 m in diameter from the asteroid surface.x000D
Knowledge of boulder mass and integrity is critical to these mission objective. This project will determine thex000D
observation requirements for estimating the mass of selected boulders as well as the density structure ofx000D
potential asteroid targets using gravity observations from two sources (simulated herein); i) spacecraft orbitalx000D
data, and ii) asteroid surface gravity data. Orbital data would be available from spacecraft photogrammetricx000D
data, LiDAR, and orbit determination data (star trackers, accelerometers). Surface data would be available fromx000D
a proposed gravimetry lander mission such as GRASP. The VEctor Gravimeter/Accelerometer (VEGA) builtx000D
by GEDEX has an instrument sensitivity of ~1 nGal in space. Three vector components of the gravity field willx000D
be measured from a lander vehicle designed to survey the entire surface of an asteroid via propulsive hopping.x000D
We will conduct forward/inverse modelling simulations by varying relevant gravity observation parametersx000D
such as station density, sensor accuracy, noise levels and combinations of orbital and surface data. This willx000D
lead to quantifiable estimates of observation sensitivity and sampling requirements for various boulders andx000D
asteroids with direct impact on mission planning and sensor development.