Engineering topics
Kia, Tooraj
Publications and source records attributed to Kia, Tooraj.
Pointing Control System Architecture for the Eclipse Mission
This paper describes the high performance pointing control system used to point the Eclipse telescope. Eclipse is a new mission under study at Jet Propulsion Laboratory for a proposal as a discovery mission. Eclipse is a space telescope for high-contrast optical astronomy. It will be used to investigate the planetary bodies and environments. The main objective of the Eclipse mission is to study planets around nearby stars. Eclipse is designed to reveal planets or dust structures by reducing the scattered and diffracted light within a few arcseconds of a star to a level three orders of magnitude lower than any instrument on the Hubble Space Telescope (HST). Eclipse achieves this high contrast using a 1.8 meter diameter telescope, a coronagraphic system for control of diffracted light, and active wavefront correction using a Precision Deformable Mirror (DM) for the suppression of scattered light. The observatory will be launched into a Sun-synchronous 690 Km, 98.2(deg) Earth Orbit in 2012.
Control and data systems challenges in design of the Jupiter Icy Moons Orbiter spacecraft.
The objective of this paper is to introduce the readers to some of the challenges facing the Attitude Control and Command and Data Handling subsystems, and give an overview of approaches being considered to deal with these challenges.
Reconfigurable Pointing Control for High Resolution Space Spectroscopy
In this paper, a pointing control performance criteria is established to suppport high resolution space spectroscopy. Results indicate that these pointing control requirements are very stringent, and would typically be difficult to meet using standard 3-axis spacecraft control. To resolve this difficulty, it is shown that performance can be significantly improved using a reconfigurable control architecture that switches among a small bankof detuned Kalman filters. The effectiveness of the control reconfiguration approach is demonstrated by example on the Space Infra-Red Telescope Facility (SIRTF) pointing system, in support of the InfraRed Spectrograph (IRS) payload.
Reconfigurable Pointing Control for High Resolution Space Spectroscopy
In this paper, a pointing control performance criteria is established to support high resolution space spectroscopy. Results indicate that these pointing requirements are very stringent, and would typically be difficult to meet using standard 3-axis spacecraft control. To resolve this difficulty, it is shown that performance can be significantly improved using a reconfigurable control architecture that switches among a small bank of detuned Kalman filters. The effectiveness of the control reconfiguration approach is demonstrated by example on the Space Infra, Red Telescope Facility (SIRTF) pointing system, in support of the Infrared Spectrograph (IRS) payload.
Flight Performance of TOPEX/POSEIDON Star Tracker
The TOPEX/POSEIDON spacecraft was launched on August 10, 1992. This paper will present data on the measured performance of the ASTRA Star Trackers supplied by Hughes Danbury Optical Systems (HDOS) for this satellite.
IRAS known asteroid prediction and association
Techniques and procedures employed to obtain data concerning the known asteroids from IRAS observations are discussed. The IRAS observations covered 95 percent of the sky with at least four scans of the telescope field of view. A search was first carried out for geometrical intersections of the trajectories of a given asteroid and the telescope boresight, following which a matched sighting was sought for each such intersection among the actual IRAS point source detections. By using ground based measurements of visual magnitudes, IRAS observations of IR brightness, and a thermal model, albedos and diameters have been computed for 1,822 known asteroids, increasing the amount of this kind of information by about an order of magnitude.