NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
The Athena Microscopic Imager InvestigationThe Athena science payload on the Mars Exploration Rovers (MER) includes the Microscopic Imager (MI) [1]. The MI is a fixed-focus camera mounted on the end of an extendable instrument arm, the Instrument Deployment Device (IDD; see Figure 1).The MI was designed to acquire images at a spatial resolution of 30 microns/pixel over a broad spectral range (400 - 700 nm; see Table 1). Technically, the microscopic imager is not a microscope: it has a fixed magnification of 0.4 and is intended to produce images that simulate a geologist s view through a common hand lens. In photographers parlance, the system makes use of a macro lens. The MI uses the same electronics design as the other MER cameras [2, 3] but has optics that yield a field of view of 31 31 mm across a 1024 1024 pixel CCD image (Figure 2). The MI acquires images using only solar or skylightillumination of the target surface. A contact sensor is used to place the MI slightly closer to the target surface than its best focus distance (about 66 mm), allowing concave surfaces to be imaged in good focus. Because the MI has a relatively small depth of field (3 mm), a single MI image of a rough surface will contain both focused and unfocused areas. Coarse focusing will be achieved by moving the IDD away from a rock target after the contact sensor is activated. Multiple images taken at various distances will be acquired to ensure good focus on all parts of rough surfaces. By combining a set of images acquired in this way, a completely focused image can be assembled. Stereoscopic observations can be obtained by moving the MI laterally relative to its boresight. Estimates of the position and orientation of the MI for each acquired image will be stored in the rover computer and returned to Earth with the image data. The MI optics will be protected from the Martian environment by a retractable dust cover. The dust cover includes a Kapton window that is tinted orange to restrict the spectral bandpass to 500-700 nm, allowing color information to be obtained by taking images with the dust cover open and closed. The MI will image the same materials measured by other Athena instruments (including surfaces prepared by the Rock Abrasion Tool), as well as rock and soil targets of opportunity. Subsets of the full image array can be selected and/or pixels can be binned to reduce data volume. Image compression will be used to maximize the information contained in the data returned to Earth. The resulting MI data will place other MER instrument data in context and aid in petrologic and geologic interpretations of rocks and soils on Mars.
Document ID
20030066751
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
K E Herkenhoff
(United States Geological Survey Reston, Virginia, United States)
Aquyres, S. W.
(Cornell University Ithaca, New York, United States)
Bell, J. F., III
(Cornell University Ithaca, New York, United States)
Maki, J. N.
(Jet Propulsion Lab La Cañada Flintridge, California, United States)
Arneson, H. M.
(Cornell University Ithaca, New York, United States)
Brown, D. I.
(Jet Propulsion Lab La Cañada Flintridge, California, United States)
Collins, S. A.
(Jet Propulsion Lab La Cañada Flintridge, California, United States)
Dingizian, A.
(Jet Propulsion Lab La Cañada Flintridge, California, United States)
Elliot, S. T.
(Jet Propulsion Lab La Cañada Flintridge, California, United States)
Geotz, W.
(University of Copenhagen Copenhagen, Denmark)
Date Acquired
August 21, 2013
Publication Date
July 25, 2003
Publication Information
Publication: Sixth International Conference on Mars
Publisher: LPI
Subject Category
Lunar And Planetary Science And Exploration
Report/Patent Number
3276
Meeting Information
Meeting: Sixth International Conference on Mars
Location: Pasadena, CA
Country: US
Start Date: July 20, 2003
End Date: July 25, 2003
Sponsors: Lunar and Planetary Institute
Funding Number(s)
CONTRACT_GRANT: NCC5-679
Distribution Limits
Public
Copyright
Portions of document may include copyright protected material.
No Preview Available