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 up to impact. The spacecraft carried six television vidicon cameras, 2 full-scan cameras (channel F, one wide-angle, one narrow-angle) and 4 partial scan cameras (channel P, two wide-angle, two narrow-angle) to accomplish these objectives. The cameras were arranged in two separate chains, or channels, each self-contained with separate power supplies, timers, and transmitters so as to afford the greatest reliability and probability of obtaining high-quality video pictures. No other experiments were carried on the spacecraft

Spacecraft and Subsytems
Spacecraft and Subsystems

Rangers 6, 7, 8, and 9 were the so-called Block 3 versions of the Ranger spacecraft. The spacecraft consisted of a hexagonal aluminum frame base 1.5 m across on which was mounted the propulsion and power units, topped by a truncated conical tower which held the TV cameras. Two solar panel wings, each 73.9 cm wide by 153.7 cm long, extended from opposite edges of the base with a full span of 4.6 m, and a pointable high gain dish antenna was hinge mounted at one of the corners of the base away from the solar panels. A cylindrical quasiomnidirectional antenna was seated on top of the conical tower. The overall height of the spacecraft was 3.6 m.

Propulsion for the mid-course trajectory correction was provided by a 224-N thrust monopropellant hydrazine engine with 4 jet-vane vector control. Orientation and attitude control about 3 axes was enabled by 12 nitrogen gas jets coupled to a system of 3 gyros, 4 primary Sun sensors, 2 secondary Sun sensors, and an Earth sensor. Power was supplied by 9792 Si solar cells contained in the two solar panels, giving a total array area of 2.3 square meters and producing 200 W. Two 1200 Watt-hr AgZnO batteries rated at 26.5 V with a capacity for 9 hours of operation provided power to each of the separate communication/TV camera chains. Two 1000 Watt-hr AgZnO batteries stored power for spacecraft operations.

Communications were through the quasiomnidirectional low-gain antenna and the parabolic high-gain antenna. Transmitters aboard the spacecraft included a 60 W TV channel F at 959.52 MHz, a 60 W TV channel P at 960.05 MHz, and a 3 W transponder channel 8 at 960.58 MHz. 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.

Instruments

Television

The television system consisted of a six slow-scan vidicon TV cameras capable of transmitting high-resolution, close-up television pictures of the lunar surface during the final minutes of flight before the spacecraft impacted the lunar surface. These photographs provided large-scale topographic information needed for the Surveyor and Apollo projects. Vidicons 2.54 cm 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-mm focal length) designated the A-camera and one narrow angle (8.4 degree field of view and 76-mm focal length) B-camera. These cameras utilized an active image area of 11 sq mm that contained 1150 lines and was scanned in 2.5 sec. Scan and erase cycles were designed to act alternately resulting in intervals of 5 sec 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 area of these four cameras was 2.8 sq mm which contained 300 lines and was scanned in 0.2 sec. The instrument allowed for camera fields of view, ranging from 25 deg to 2.1 deg, to overlap and produce a 'nesting' sequence of pictures.

Electromagnetically driven slit-type shutters exposed the vidicons. Images were focused on the vidicon target, which was made up of a layer of photoconductive material initially charged by scanning with an electron beam. An electron beam then scanned the surface and recharged the photoconductor. The video signal was amplified several thousand times, sent to the transmitter where amplitude variations were converted to frquency variations, and were then transmitted directly to Earth. At the end of the active scan, the camera entered an erase cycle to prepare it for the next exposure. Twelve P-channel pictures were exposed between each F-channel picture.

The video transmissions were sent to a television receiver and recorded on both kinoscope film recorders and magnetic tape recorders. A cathode-ray tube reconstructed the original image, which was then photographed on 35-mm film. The full-scan camera system began transmitting pictures at 1308 UT on July 31, 1964, 17 min 13 sec prior to impact. The partial-scan system initiated transmission of pictures at 1312 UT, 13 min 40 sec prior to impact. The last full-scan transmission occured between 2.5 and 5 sec before impact, while the last partial-scan picture was taken between 0.2 and 0.4 sec before impact and achieved resolution to 0.5 m. Image motion is more severe in the last pictures. The experiment returned 4308 photographs of excellent quality. Selected photographs and a more complete description of the TV experiment are included in data set 64-041A-01B.

Launch-Orbit Information

Launch Information

Launch Date: 1965-03-21 at 21:37:00 UTC
Launch Vehicle: Atlas-Agena B
Launch Site: Cape Canaveral, United States
Decay Date: 1965-03-24
Mass: 367.0 kg kg Nominal Power: 200.0 W

Type: Lander

Central Body: Moon

Epoch start: Epoch start: 1965-03-24 14:08:20 UTC
Lander Coordinates
Latitude: -12.83°
Longitude: 357.63°
Regions Traversed
Lithosphere
Planet
The Moon

Mission Profile

The Atlas 204D and Agena B 6007 boosters performed nominally, injecting the Agena and Ranger 9 into an Earth parking orbit at 185 km altitude. A 90 second Agena 2nd burn put the spacecraft into lunar transfer trajectory. This was followed by the separation of the Agena and Ranger. 70 minutes after launch the command was given to deploy solar panels, activate attitude control, and switch from the omniantenna to the high-gain antenna. The accuracy of the initial trajectory enabled delay of the planned mid-course correction from 22 March to 23 March when the maneuver was initiated at 12:03 UT. After orientation, a 31 second rocket burn at 12:30 UT, and reorientation, the maneuver was completed at 13:30 UT.

Ranger 9 reached the Moon on 24 March 1965. At 13:31 UT a terminal maneuver was executed to orient the spacecraft so the cameras were more in line with the flight direction to improve the resolution of the pictures. Twenty minutes before impact the one-minute camera system warm-up began. The first image was taken at 13:49:41 at an altitude of 2363 km. Transmission of 5,814 good contrast photographs was made during the final 19 minutes of flight. The final image taken before impact has a resolution of 0.3 meters. 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 at 14:08:19.994 UT at 12.828 S latitude, 357.613 E longitude (as determined from Lunar Reconnaissance Orbiter images) in the crater Alphonsus. Impact velocity was 2.67 km/s. The spacecraft performance was excellent. Real time television coverage with live network broadcasts of many of the F-channel images (primarily camera B but also some camera A pictures) were provided for this flight.

Total research, development, launch, and support costs for the Ranger series of spacecraft (Rangers 1 through 9) was approximately $170 million.

Summary