Imaging planets about other stars with UMBRAS: target acquisition and station keeping

Helen M. Hart; Ian J.E. Jordan; Alfred B. Schultz; John L. Hershey; Mark Kochte; Forrest C. Hamilton; Dorothy A. Fraquelli; Daniel J. Schroeder; Fred Bruhweiler; Mike A. DiSanti; Cherie L. Miskey; Bruce Johnson; M. S. Fadali; Melodi Rodrigue; K. P. Cheng; R. Clark

doi:10.1117/12.406339

15 December 2000 Imaging planets about other stars with UMBRAS: target acquisition and station keeping

Helen M. Hart, Ian J.E. Jordan, Alfred B. Schultz, John L. Hershey, Mark Kochte, Forrest C. Hamilton, Dorothy A. Fraquelli, Daniel J. Schroeder, Fred Bruhweiler, Mike A. DiSanti, Cherie L. Miskey, Bruce Johnson, M. S. Fadali, Melodi Rodrigue, K. P. Cheng, R. Clark

Author Affiliations +

Proceedings Volume 4087, Applications of Photonic Technology 4; (2000) https://doi.org/10.1117/12.406339
Event: 2000 International Conference on Application of Photonic Technology (ICAPT 2000), 2000, Quebec City, Canada

Abstract

We present a novel coronagraphic imaging technique and design for space-based telescopes. The Umbral Mission Blocking Radiating Astronomical Sources (UMBRAS) is a space mission design consisting of a free flying occulter, the Solar Powered Ion Driven Eclipsing Rover (SPIDER), and possibly one or two metrology platforms. The UMBRAS spacecraft operate in conjunction with a space-based telescope. The size of the occulting SPIDER is dictated by the size of the telescope with which it will work. The goal of UMBRAS is to provide "paleolithic" (i.e., non-focal plane) coronagraphic capability to enable direct imaging of extrasolar Jovian planets and other bright substellar companions such as brown dwarfs. We discuss two aspects of the operation of a free flying occulter: acquisition of targets and station keeping. Target acquisition is modeled after the onboard schemes used by Hubble Space Telescope (HST) science instruments. For UMBRAS, the onboard commanding sequences would include imaging the field using instruments on the telescope, locating the target and the occulter in the field, and accurately positioning the occulter over the target. Station keeping consists of actively maintaining the occulter position in the telescope line of sight to the target. Velocity matching of the c)cculter with the space-based telescope is essential to mission performance. An appropriate combination of solar electric and cold gas thrusters provide the ability to match velocities using position information derived from communication and from ranging data between telescope, occulter and any metrology stations. The accuracy requirements for target acquisition and station keeping depend upon the science requirements, the occultation geometry, and the sensitivity of the science to changes in occultation geometry during an exposure sequence. Observing modes other than the ideal centered occultation of a target will be discussed.

Citation Download Citation

Helen M. Hart, Ian J.E. Jordan, Alfred B. Schultz, John L. Hershey, Mark Kochte, Forrest C. Hamilton, Dorothy A. Fraquelli, Daniel J. Schroeder, Fred Bruhweiler, Mike A. DiSanti, Cherie L. Miskey, Bruce Johnson, M. S. Fadali, Melodi Rodrigue, K. P. Cheng, and R. Clark "Imaging planets about other stars with UMBRAS: target acquisition and station keeping", Proc. SPIE 4087, Applications of Photonic Technology 4, (15 December 2000); https://doi.org/10.1117/12.406339

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available