Natural Regions Near the Collinear Libration Points Ideal for Space Observations with Large Formations
- PDF / 2,243,986 Bytes
- 22 Pages / 439.642 x 666.49 pts Page_size
- 74 Downloads / 167 Views
Natural Regions Near the Collinear Libration Points Ideal for Space Observations with Large Formations Aur´elie H´eritier · Kathleen C. Howell
Published online: 17 December 2014 © American Astronautical Society 2014
Abstract This investigation explores regions near libration points that might prove suitable for space observations with large formations. Recent analyses have considered occulters located at relatively large distances from the telescope near the L2 Sun-Earth libration point for detection of exoplanets. During the science mode, the telescope-occulter distance, as well as the pointing direction toward the star, are typically fixed. Quasi-periodic Lissajous trajectories are employed as a tool to determine regions near the telescope orbit where the large formation can be maintained. By placing the occulter in these locations, the control required to maintain the line-of-sight is reduced.
Introduction In the last decade, hundreds of planets orbiting other stars, called extrasolar planets or exoplanets, have been detected. Thus far, all of them are gas giants like Jupiter, but improvements in technology are moving the detection limits to planets with smaller masses. Using multiple spacecraft to create a large observation platform enables the detection of smaller and smaller planets. Additional investigations on formation flying in multi-body regimes have emerged to support space astronomy missions. Some new concepts using large formations can detect not only Earth-like planets, but can
A. H´eritier () Advanced Concepts Team, ESA/ESTEC, PPC-PF, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands e-mail: [email protected] K. C. Howell School of Aeronautics and Astronautics, Purdue University, West Lafayette, IN 47907, USA e-mail: [email protected]
88
J of Astronaut Sci (2013) 60:87–108
also characterize them via spectroscopy, providing information such as atmospheric conditions, internal structure, mass estimates, as well as life signs. For example, the original New Worlds Observer (NWO) design concept employed an external occulter placed at a relatively large distance (∼80,000 km) from its telescope for the detection and characterization of extrasolar planets [1]. In the science mode, the occulter is maintained along the line-of-sight from the telescope to the target star to block out the starlight. It suppresses the starlight by many orders of magnitude, to enable the observation of habitable terrestrial planets. From a control perspective, the telescope-occulter architecture concept can be decomposed into two mission phases. • •
The observation phase: the occulter must be maintained precisely along the telescope line-of-sight to some inertially fixed target stars. The reconfiguration phase: the occulter is realigned between each observation from one target star line-of-sight to the next.
During the observation mode, the two spacecraft must be aligned within a few meters along the line-of-sight. This is most easily accomplished if these spacecraft are in a low-acceleration environment such as th
Data Loading...
