NASA F4 Electronic Still Camera article

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NASA F4 Electronic Still Camera article

Post by NikonWeb »

Information and previously unpublished (?) photos of NASA's first Electronic Still Camera:

http://www.nikonweb.com/nasaf4/

Jarle
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Re: NASA F4 Electronic Still Camera article

Post by NikonWeb »

Additional technical info about the F4 based ESC hardware:

2.3.1.1 Hardware Specifications

The configuration of the ESC developed at JSC and employed for this experiment
uses a Nikon F4 body. The 300mm f2.8 lens resolves approximately 62 line pairs per
millimeter. The camera is fully digital with 8 bit accuracy. The imaging system has
a dynamic range of 60 dB and the sensor CCD has a dynamic range of 80 dB.

The sensor is a Loral CCD 1024x1024 pixel array with an active area of 15mm x 15mm
which calculates to an idealize system resolution of 34 line pairs per millimeter.

This calculates to 2.9 degree angular field-of-view. This CCD has a good modulation
transfer function (MTF) (Dereniak and Crowe, 1984) because of a relatively large
pixel size.

The acquisition chip can be replaced on the ground before flight to take advantage of
expected target and lighting parameters, without requiring a redesign of the camera.

The CCD array was set up to operate similarly to a photographic camera equipped
with ASA-200 film (same apertures and shutter speeds). The array's effective
response optimizes contrast, anti-blooming, and signal-to-noise ratio. Future
versions of the ESC will operate at significantly higher ASA numbers to compensate
for low-light-level conditions.

Digital images are stored on removable hard drives.

The current capacity is 40 images per hard disk; future capacity will be 100 images on
a physically smaller hard drive. No hard disk storage errors have been observed
with the ESC in this configuration; however, two analog-to-digital conversion
errors have occurred. Missing pixels (areas which pixel values are incorrectly set to
zero) have been observed on consecutive imagery.

2.3.1.3 Current Power Requirements

The system currently runs from a battery, but can be operated from the Orbiter's
power supply. In the idle mode, it operates at 5 watts. During acquisition, it
operates at 14 watts for approximately 14 seconds. The goal is to reduce the time for
maximum power consumption to 1 second.

2.3.1.4 Operation

The ESC can operate in 4 modes, which are programmable and can be set prior to
launch. Future ESC systems will enable the photographer to tune the imaging
system to take advantage of specific user requirements. The current modes of
operation are:

Take a picture - Store image
Take a picture - Store and downlink image
Downlink all images stored on disk
Self timer mode

Excerpts from the NASA document "Manned Observations Technology Development FY '92 Report", dated November 1992.

Jarle
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