Terra Scout
Crew-operated direct-view optical observation system
Terra Scout paired Army imagery analyst Thomas Hennen with the Spaceborne Direct-View Optical System during STS-44. SpaDVOS was a cabin-mounted, folded-path telescope whose computer cued targets while the operator manually acquired them and tracked them manually or with a joystick-driven mirror. Three eyepieces spanned 4× to 67× magnification, and a beam splitter fed both the eyepiece and a CCD recorded on the videotape system. Hardware, weather, and window limitations reduced the usable sample, but the flight demonstrated real-time human target selection and tracking and resolved features as small as 24 feet under favorable conditions.
Parent systems
The larger spacecraft or system this hardware belongs to.
Crew equipment dossier
Identity and integration
- Official designation
- Terra Scout using the Spaceborne Direct-View Optical System (SpaDVOS)
- Flight integration
- STS-44 secondary experiment operated by a career Army imagery analyst
Crew interface and safety
- Cabin mounting interface
- Clamped to the overhead aft-flight-deck window-shade fittings
- Electrical power interface
- Connected to 28-volt direct-current power
- Recorded-data interface
- CCD imagery and operator commentary recorded through the Orbiter videotape-recorder system
- Crew control interface
- Cross-track and along-track LED cues in the eyepiece supported manual acquisition; a joystick controlled along-track mirror velocity
Performance and consumables
- Target-cue capacity
- Internal computer accepted closest-approach time, off-nadir direction, altitude, and velocity for as many as three targets
- Magnification performance range
- Three eyepieces covered 4× to 67× magnification
Dimensions and construction
- Optical construction
- Folded optical-path telescope with a beam splitter feeding the crew eyepiece and a charge-coupled-device video channel
Testing and operations
- Tracking operation
- Manual or semi-automated tracking with crew-adjustable zoom and aperture
- Best flight magnification
- The 21 mm eyepiece at maximum zoom produced about 30× and was judged the most useful flight configuration
- Flight data result
- Eight observation opportunities produced enough data for analysis after weather, window quality, anomalies, and an early landing reduced the sample
- Operational outcome
- The investigators judged the experiment successful for demonstrating human target acquisition, dynamic tasking, anomaly workarounds, and decision-making
Additional specifications
- System developer
- Armstrong Aerospace Medical Research Laboratory; Air Force and Army funding produced two flight units
- Backup optical equipment
- 14×70 Fujinon binoculars and a 15–60× Bausch & Lomb spotting telescope
- Observation plan
- 42 opportunities were scheduled against a minimum sample goal of 20 useful observations
- Resolution result
- Under favorable conditions the operator reported seeing 24-foot disks and 15-foot-wide grid lines
Supported mission records
Missions that carried, used, tested, serviced, or depended on this hardware.
Photo Archive
Documented views of this individual vehicle, with source and credit retained alongside each image.