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1993-04-21
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OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE 354-5011
January 9, 1967
FOR IMMEDIATE RELEASE
Surveyor I, on its 220th day on the moon since it
landed in the Ocean of Storms June 1, 1966, was turned on last
Friday and communicated with Earth stations for approximately
twelve hours. The objective for activating the transmitters
aboard the spacecraft was to obtain scientific data on the
motion of the moon. Analysis over the weekend of the
information obtained shows that this objective was met.
The information that can be extracted from the radio
signal is the doppler effect on the radio frequency. Doppler
is a change in frequency due to motion. In this case the
motion of the moon in its orbit alters the radio frequency from
the spacecraft. When accumulated over a period of time this
data allows a refining of the moon's distance from the Earth,
its position in orbit at a given time, constants of its
physical and optical libration and aid in the determination of
the exact location of Surveyor I on the surface of the moon.
One of the spacecraft's two transmitters was turned on
by a command from the Canberra, Australia, tracking station of
the Deep Space Net at 10:22, a.m., PST, Friday. Although the
signal received from the spacecraft was very faint, the tracking
station established a two-way lock with the spacecraft through-
-more- \
-2-
out the day and was successful in alternating between the two
transmitters on the spacecraft. Later in the day communication
with the spacecraft was transferred from the Canberra station
to the Johannesburg, South Africa, tracking station. Doppler
data was recorded continuously until sunset on the moon in the
area of the Surveyor spacecraft, at approximately 11:22 p.m.,
PST.
The objective of the reawakening of the spacecraft was
to obtain the doppler information and no attempt was made to
activate the camera or other systems aboard the spacecraft.
Surveyor returned more than 11,000 pictures of the
lunar surface during June and July last year and has been
successfully reawakened in October and November of last year
for short periods. It is now in its eighth lunar night.
The Surveyor project is assigned to the Jet Propulsion
Laboratory by the National Aeronautics and Space Administration.
The Surveyor spacecraft was designed and manufactured under
contract to JPL by the Hughes Aircraft Company in Culver City,
California.
429-1/9/67 H