G. Fedorets

The daily processing of asteroid observations by Gaia

Abstract The Gaia mission started its regular observing program in the summer of 2014, and since then it is regularly obtaining observations of asteroids. This paper draws the outline of the data processing for Solar System objects, and in particular on the daily “short-term” processing, from the on-board data acquisition to the ground-based processing. We illustrate the tools developed to compute predictions of asteroid observations, we discuss the procedures implemented by the daily processing, and we illustrate some tests and validations of the processing of the asteroid observations. Our findings are overall consistent with the expectations concerning the performances of Gaia and the effectiveness of the developed software for data reduction.

Small asteroids temporarily captured in the Earth-Moon system

We present an update on our work on understanding the population of natural objects that are temporarily captured in the Earth-Moon system like the 2-3 meter diameter, 2006 RH120 , that was discovered by the Catalina Sky Survey. We use the term ’minimoon’ to refer to objects that are gravitationally bound to the Earth-Moon system, make at least one revolution around the barycenter in a co-rotating frame relative to the Earth-Sun axis, and are within 3 Earth Hill-sphere radii. There are one or two 1 to 2 meter diameter minimoons in the steady state population at any time, and about a dozen larger than 50 cm diameter. ‘Drifters’ are also bound to the Earth-Moon system but make less than one revolution about the barycenter. The combined population of minimoons and drifters provide a new opportunity for scientific exploration of small asteroids and testing concepts for in-situ resource utilization. These objects provide interesting challenges for rendezvous missions because of their limited lifetime and complicated trajectories. Furthermore, they are difficult to detect because they are small, available for a limited time period, and move quickly across the sky.

Earth's Minimoons: Opportunities for Science and Technology

Twelve years ago the Catalina Sky Survey discovered Earths first known natural geocentric object other than the Moon, a few-meter diameter asteroid designated \RH. Despite significant improvements in ground-based asteroid surveying technology in the past decade they have not discovered another temporarily-captured orbiter (TCO; colloquially known as minimoons) but the all-sky fireball system operated in the Czech Republic as part of the European Fireball Network detected a bright natural meteor that was almost certainly in a geocentric orbit before it struck Earths atmosphere. Within a few years the Large Synoptic Survey Telescope (LSST) will either begin to regularly detect TCOs or force a re-analysis of the creation and dynamical evolution of small asteroids in the inner solar system. The first studies of the provenance, properties, and dynamics of Earths minimoons suggested that there should be a steady state population with about one 1- to 2-meter diameter captured objects at any time, with the number of captured meteoroids increasing exponentially for smaller sizes. That model was then improved and extended to include the population of temporarily-captured flybys (TCFs), objects that fail to make an entire revolution around Earth while energetically bound to the Earth-Moon system. Several different techniques for discovering TCOs have been considered but their small diameters, proximity, and rapid motion make them challenging targets for existing ground-based optical, meteor, and radar surveys. However, the LSSTs tremendous light gathering power and short exposure times could allow it to detect and discover many minimoons. We expect that if the TCO population is confirmed, and new objects are frequently discovered, they can provide new opportunities for 1) studying the dynamics of the Earth-Moon system, 2) testing models of the production and dynamical evolution of small asteroids from the asteroid belt, 3) rapid and frequent low delta-v missions to multiple minimoons, and 4) evaluating in-situ resource utilization techniques on asteroidal material. Here we review the past decade of minimoon studies in preparation for capitalizing on the scientific and commercial opportunities of TCOs in the first decade of LSST operations.

Optimizing asteroid orbit computation for Gaia with normal points

Context. In addition to the systematic observations of known solar-system objects (SSOs), a continuous processing of new discoveries requiring fast responses is implemented as the short-term proces ...