Exploring the Unknown - NASA's History Office

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OBSERVING THE EARTH FROM SPACE
of several years. The low-altitude phase, altitudes up to 20,000 feet, is presently being conducted
using the NASA-MSC Convair 240A (NASA 926) over sites in the Continental
United States. It is planned to conduct the second phase at altitudes up to 40,000 feet over
the same test sites and over several overseas sites. The third phase should be conducted at
high altitudes, possibly up to 80,000 feet over the same test sites. Ultimately, it may be
highly desirable during the early Earth-orbital missions to have the ground truth teams on
the site, and the aircraft overhead at the time the orbiting spacecraft overflys the area.
[551] Convair 240A
Implementation of this airplane was initiated in October 1964, and initial survey operations
over geologic test sites got underway in early December 1964. First flights were
made using only the camera systems; other instruments were installed as they became
available. The airplane is now scheduled to its full capability of sensors and no additional
ones are being planned at this time for this aircraft. Following is a list of those sensors
installed on board:
1. Microwave radiometer,
2. Metric camera system,
3. Multiband camera system,
4. Ultraviolet imager,
5. Recon IV imaging IR,
6. Redop scatterometer,
7. Doppler chirping radar.
Lockheed P-3A (Electra)
This airplane was acquired in December 1965 and is ideally suited as a remote sensor
test aircraft for altitudes up to 40,000 feet and contains much of the basic instrumentation
necessary to meet the objectives of the Natural Resources Program. The navigation system
contains the following items:
1. APN 153 doppler navigator,
2. ASA 47 air-mass computer,
3. LN 12 attitude reference system,
4. Inertial platform,
5. ASQ 80 weather and ground point radar,
6. APN 70 LORAN overwater navigation system.
This equipment will provide the flight parameters such as roll, pitch, yaw, ground
speed, heading, altitude, position, etc., for sensor operation, data correlation, and navigation
of the aircraft. The aircraft has both a large cabin area and a bomb-bay area with a
number of radomes and instrument mounting provisions in which to install sensor systems
and other experiments. With the installation of an auxiliary power unit, operation
without the use of ground-based starting equipment and other ground support equipment
will be possible. The P-3A is now being implemented to receive a compliment [sic]
of sensors basically as described in Figure 2 and is planned to be in operation by July or
August of 1966.
Douglas A-3B
This airplane contains a Westinghouse AN/APQ 97 (XE-1) side-looking radar system.
It has completed seventy-two hours of flight time acquiring radar imagery over a number
of test sites and other areas of interest. An additional sixty hours of flight time has been
requested (twenty hours in FY 1966; forty hours in FY 1967).