Ranger 9
Courtesy of NASA's National Space Science Data Center
Launch Date: 1965-03-21
On-orbit dry mass: 361.80 kg
Nominal Power Output: 200.00 W
Description
Ranger 9 was designed to achieve a lunar impact trajectory and to transmit
high-resolution photographs of the lunar surface during the final minutes
of flight. The spacecraft carried six television cameras, an optical earth
sensor and high-gain antenna for optimum communications, and solar panels
to provide power, as well as additional engineering equipment. The
telecommunications equipment converted the composite video signal from the
camera transmitters into an RF Signal For Subsequent Transmission Through
The Spacecraft High-gain Antenna. Sufficient video bandwidth was provided
to allow for rapid framing sequences of both narrow- and wide-angle
television pictures. The spacecraft encountered the lunar surface with an
incoming asymptotic direction at an angle of -5.6 degrees from the lunar
equator. The orbit plane was inclined 15.6 degrees to the lunar equator.
After 64.5 hours of flight, impact occurred in the crater Alphonsus. The
spacecraft performance was excellent. The spacecraft transmitted 5,814
photographs during the final 19 minutes of flight, 1349 UT to 1408 UT on
March 24, 1965.
Ranger 9 Impact Television Imaging
The television system consisted of six slow scan vidicon TV cameras
capable of transmitting high-resolution closeup television pictures of
the lunar surface during the final minutes of flight before the
spacecraft impacted the lunar surface. These photographs provided
small-scale topographic information needed for the Surveyor and Apollo
projects. Vidicons 2.54 centimeters in diameter with an antimony-sulfide
oxy-sulfide (ASOS) photoconductor target were used for image sensing
in all six cameras.
There were two camera channels which had
independent power distribution networks so that the greatest
reliability and probability of obtaining highest quality video
pictures would be afforded. The first channel had two full-scan
cameras, one wide angle (25-degree field of view and 25-millimeter focal
length) designated the A-camera and one narrow angle (8.4-degree field
of view and 76-millimeters focal length) B-camera. These cameras utilized an
active image area of 11 square millimeters that contained 1,150 lines and was
scanned in 2.5 seconds. Scan and erase cycles were designed to act
alternately, resulting in intervals of 5 seconds between consecutive
pictures on a particular camera. The other channel had four
partial-scan (p) cameras, two narrow angle and two wide angle.
The image of these four cameras was 2.8 square millimeters, contained 300 lines, and
was scanned in 0.2 seconds. The instrument allowed for camera fields of
view, which ranged from 25 degrees to 2.1 degrees, to overlap and produce a
'nesting' sequence of pictures. The photographs were recorded on both
kinescope film recorders and magnetic tape recorders. A cathode-ray
tube reconstructed the original image, which was then photographed on
35-millimeter film.
Both full-scan and partial-scan camera systems operated
during the final 19 minutes of flight, 1349 UT to 1408 UT on March 24,
1965. A total of 5,814 photographs were received, all with good
contrast and high shadowing. Three of the cameras obtained a
resolution of 0.3 meters (1 foot).
Space History
Ranger to the Moon
