N€WS 'RELEASE NATIONAL AERONAUTICS and SPACE Admln ISTRATION 400 MARYLAND AVENUE, SW, WASHINGTON 25, D.C

https://ntrs.nasa.gov/search.jsp?R=19630002483 2020-03-11T16:50:02+00:00Z b " N€WS 'RELEASE NATIONAL AERONAUTICS AND SPACE ADMlN ISTRATION 400 MARYLAND AVENUE, SW, WASHINGTON 25, D.C. TELEPHONES WORTH 2-4155-WORTH. 3-1110 RELEASE NO. 62-182 MARINER SPACECRAFT Mariner 2, the second of a series of spacecraft designed for planetary exploration,- will be launched within a few days (no earlier than August 17) from the Atlantic Missile Range, Cape Canaveral, Florida, by the National Aeronautics and Space Administration. Mariner 1, launched at 4:21 a.m. (EST) on July 22, 1962 from AMR, was destroyed by the Range Safety Officer after about 290 seconds of flight because of a deviation from the planned flight path. Measures have been taken to correct the difficulties experienced in the Mariner 1 launch. These measures include a more rigorous checkout of the Atlas rate beacon and revision of the data editing equation. The data editing equation Is designed as a guard against acceptance of faulty databy the ground guidance equipment. The Mariner 2 spacecraft and its mission are identical to the first Mariner. Mariner 2 will carry six experiments. Two of these instruments, infrared and microwave radiometers, will make measurements at close range as Mariner 2 flys by Venus and communicate this in€ormation over an interplanetary distance of 36 million miles, Four other experiments on the spacecraft -- a magnetometer, ion chamber and particle flux detector, cosmic dust detector and solar plasma spectrometer -- will gather Information on interplantetary phenomena during the trip to Venus and in the vicinity of the planet. Flight time will vary from 92 days to 117 days, depending on the launch date. The closest approach of Mariner to Venus will be about 10,000 miles, The overall flight distance will be approximately 191 million miles, based on an August 17 launch. (over) , \ T P NASA assigned two launches for Mariner in 1962 because inherent dLfficulty of an interplanetary mission and to take advantage of the period this year during which Venus will be close to earth. The next launch opportunkty for Venus will not occur for 19 months, in 1964, Several factors make the Venus mission difficult -- the long flight time and the resultant demands in the spacecraft; subjecting of the spacecraft to a prolonged variation in temperature caused by the variation in distance from the sun and the increasing intensity of the sun; radiation effects in inter,planetary space are not fully known; the problem of transmitting a considerable amount of information over an extreme range, and a complex trajectory problem, Project Management for the Venus Mission was assigned to the California Institute of Technology Jet Propulsion Laboratory by the National Aeronautics and Space Administration, This includes responsibility for the spacecraft system and space flight operations, The Marshall Space Flight Center has the responsibility for providing the launch vehicle, with the support of the U.S.A.F. Space Systems Division, The Atlas D first stage is provided by General Dynamics Astronautics, and the Agena B second stage is provided by Lockheed Missiles and Space Company , Key personnel in the Mariner Project are: Fred D, Kochendorfer, Mariner Program Chief, NASA Headquarters; D, L, Forsythe, Agena Program Chief; Roberts J. Parks, Planetary Program Director for JPL; J, N, James, JPL, Mariner Project Manager; W, A, Collier, JPL, Assistant Project Manager; Dan Schneiderman, JPL, Spacecraft System Manager; Friedrich Duerr, MSFC, Launch Vehicle Systems Manager; Major J, G. Albert, Mariner Launch Vehicle Director for AFSSD; and H, T, Uskin, Director for NASA Programs, Iockheed Missiles and Space Company, Mariner tracking and communication will be provided by JPLIs Deep Space Instrumentation Facility with permanent stations at Goldstone, California, Woomera, Australia, and Johannesburg, South Africa and mobile stations at Cape Canaveral and near the permanent station at Johannesburg. Data floMing into these stations from the spacecraft will be routed to JPL's Spacecraft Flight Operations Center for correlation by an IBM 7090 computer sys tem. -2- SPACECRAFT DESCRIPTION The Mariner weighs 447 pounds and, in the launch position, is five feet-in-diameter at the base and 9 feet, 11 inches in height. In the cruise position, with solar panels and high-gain antenna extended , it is 16.5 feet acrws in span ar,d 11 feet, 11 inches i:: height. The design is a variation of the hexagonal concept used for the Ranger series. The hexagon framework base houses a liquid-fuel rocket motor, for trajectory correction, and six modules containing the attitude conuoi system, electronic circuitry for the scientific experiments, power supply, battery and charger, data encoder and command subsystem, digital computer and sequencer, and radio transmitter and receiver. Sun sensors and attitude control jets are mounted on the exterior of the base hexagon. A tubular superstructure extends upward from the base hexagon. Scientific experiments are attached to this framework. An omindirectional antenna is mounted at the peak of the superstructure. A parabolic, high- gain antenna is hinge-mounted below the base hexagon. Two solar panels are also hinged to the base hexagon. They fold up alongside the spacecraft during launch, parking orbit and injection and are folded down, like butter- fly wings when the craft is in space. A command antenna for receiving transmission from earth is mounted on one of the panels. The solar panels contain 9800 solar cells in 27 square feet of area. They will collect energy from the sun and convert it into electrical power at a minimum of 148 watts and a maximum of 222 watts. The amount of power available from the panels is expected io iiicrease slightly during the mission due to the increased intensity of the sun. Each solar cell has a protective glass filter that reduces the amount of heat absorbed from the sun, but does not interfere with the energy conversion process. The glass covers filter out the sun's ultraviolet and infrared radiation that would produce heat but not electrical energy. Prior to deployment of the solar panels, power will be supplied by a 33.3-pound silver-zinc rechargeable battery with a capacity of 1000 watt hours. The recharge capability is used to meet the long-term power -3- requirements of the Venus Mrssion, The battery will supply power directly for sw;tchrng and sharing pesk-leads w;Lh the sojar panels and also supply power c?ur;ng trajzctory correctlor. when the panels will not be directed a: tke s-dn., The power subsystem wi2 convert electricity from the solar panels and battery to 50 vc,t E400 cps; 26 volt, 400 cps and 25 8 to 33.3 volt DZ, Two-way commun_cation aboard the Maricer js supplied by the receiver/transmjtfer two transmitting antennas; the omnidirectional and high-gain antenna; and the commaEd antenna for receiving instruc- tions from earth, Transmilting power will be 3 watts. The high-gain antenna is hinged and equipped with a drive mechanism allowing it to be pointed at the earth on command, Anearth sensor is mounted on the aptenna yoke near the rim of the high-gain dish-shaped antenna to search for and keep the antenna pointed at the earth. Stabilization of the Spacecraft for yaw E pitch ard roll, is provided by ten cold gas jets mounted in four iozatisns (2 3 2 I 2 ,I fed by two titanium bottles containing 4 ., 3 pounds of netrcgen gas pressurized to 3500 PSI. The jets are linked by logic circuztry to three gyros in the attitude control subsystem, to the esrth sensor or! the parabolic antenna and to six sun sensors mounted or, the sgaczcrafr frame and cn the back of the two solar panels, The four primary SUR sensors are mounted on four of the six legs of the hexagon, and the two seccndary sensors on the backs of the solar panels ,, These are light-sensirive diodes which inform the attitude control system--gas jets and gyros--when they seen the sun, The attitude control system responds to these signals by rurning the spacecraft and pointing the longitudinal or roll axis, toward Ehe sun, Torquing of the spacecraft for these maneuvers 1s provided by the cold gas jets fed by the nitrogen gas regulated to 15 pounds per square inch pressure. There is calculated to be enough nitroger, :c operate the gas jets to maintain attitude control for a rrinimrm of 206 days, Computation for the subsystems ana the issuance of commands is a function of the digital 'Central Computer ar,d Sequencer. All events of the spacecraft are contained in three CC&S sequences. The launch sequence controls events from launch through the crilise mcde. The midcourse propulsion sequence controls the midcourse trajectory correction -4 - maneuver a The encounter sequence pc!-Lri des required commands for data collection in the vicinity of Venus, The CCGS provides the basic timing for the spacecraft subsystems. This time base will be supplied by a crystal control oscillator in the CCGS operating at 307.2 kc. This is divided down to 38,4 kc for timing in the power subsystem and dfvidea down again to 2400 and 400 cps for use by various subsystems The control oscillator provides the basic I' counting" rate for the CCGS to determine issuance of commands at the right time in the three CC&S sequences. The s~hsystemclmtered aronnd the base nf the spacecraft are insulated from the sun's heat by a shield covered with layers of aluminurn coated plastic film. At the bottom of the spacecraft,, just below the subsystem modules, is a second Tempera?ure Control Shield. It prevents too rapid loss of heat into space which would make the establishment of required temperatures difficult to maifitain, The two shields form a sandwich that helps to minimize the heat control problem, Temperature control of the attitude control subsysrem is provided by louvers actuated by coiled bimetallic strips.

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