OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE 354-5011
MARINER MARS '71

       Due to the launch failure of Mariner H on May 8, a new mission plan has been adopted for the Mariner I spacecraft, to be launched to Mars bythe National Aeronautics and Space Administration no earlier than May 29. The new plan provides high quality data return for all the original experiments although the amount of data will be decreased from the original twospacecraft mission.

       Originally Mariner H was assigned a basic mission objective of mapping 70% of Mars and Mariner I a mission objective of studying changes in the atmosphere and on the surface over a period of time (variable features mission).

       Each basic objective required a certain orbital inclination period and periapsis: 80 degrees, 12 hours and 750 miles for H, 50 degrees, 20.5 hours and 550 miles for I.

       The new mission plan assigns an inclination of 65 degrees to Mariner I with a period of 12 hours and a periapsis of 750 miles.

       The arrival date is November 14, 1971, identical to the orignal mission A.

       The new inclination will yield a map covering 70% of Mars with the same resolution as in the original mission. The only exception is at the South Pole. The slant range of photography in this area will be greater and the resolution of the pictures will be decreased.

       The 12 hour period was selected to insure a maximum data return of two tapeloads per day. The orignal twospacecraft mission would have yielded three tapeloads per day.

       The variable features experiment is changed from repeat study of 6 given areas every five days to repeat study of 17 areas every 17 days. However, in the new mission plan the areas studied are smaller and single area could be studied for three straight days (at increasing slant ranges) if desired.

       The objective of the new mission plan is to insure high quality data return for each scientific objective. This has been achieved by selection of inclination, period and periapsis and will also be a key factor in budgeting of time for the various objectives during the 90 days at Mars.

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5/26/71
OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE 354-5011

       A new mission plan has been adopted for the Mariner I spacecraft, to be launched to Mars by the National Aeronautics and Space Administration no earlier than May 29.

       The new plan provides high quality data return for all the original experiments although the amount of data will be decreased from the original two-spacecraft mission. An AtlasCentaur failed in an effort to launch Mariner H on May 8.

       Originally Mariner H was assigned a basic mission objective of mapping 70% of Mars and Mariner I a mission objective of studying changes in the atmosphere and on the surface over a period of time (variable features mission).

       Each basic objective required a certain orbital inclination period and periapsis: 80 degrees, 12 hours and 750 miles for H, 50 degrees, 20.5 hours and 550 miles for I.

       The new mission plan assigns an inclination of 65 degrees to Mariner I with a period of 12 hours and a periapsis of 750 miles.

       The arrival date is November 14, 1971, identical to the original mission A.

       The orbit could be modified as late as 5 days before orbital injection if desired.

       The new inclination will yield a map covering somewhat less than 70% of Mars with the same resolution as in the original mission. At the North and South Poles, the slant range of photography will be greater and the resolution of the picutres will be decreased.

       The 12 hour period was selected to insure a maximum data return of two tapeloads per day. The orignal twospacecraft mission would have yielded more than three tapeloads per day.

       The variable features experiment is changed from repeated study of 6 given areas every five days to repeated study of selected smaller areas every 17 days.

       The objective of the new mission plan is to insure high quality data return for each scientific objective. This has been achieved by selection of inclination, period and periapsis and will also be a key factor in the budgeting of time for the various objectives during the basic 90-day orbital period at Mars.

      
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5/27/71
OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE 354-5011
FOR IMMEDIATE RELEASE
May 27, 1971 (Release from NASA Headquarters)

       National Aeronautics and Space Administration Administrator James C. Fletcher announced today that he has approved the launch of the Mariner I spacecraft toward the planet Mars. The earliest launch attempt time is 6:21 p.m. EDT, on Saturday, May 29.

       The first of two planned flights during the 1971 launch window failed May 8, when the Centaur upper stage of the launch vehicle malfunctioned. A careful investigation has revealed that a small part -- an integrated circuit -- failed, apparently because a protective device, a diode, malfunctioned. This failure of the integrated circuit in the Centaur autopilot caused the vehicle to tumble. (See NASA Release No. 71-90). Tests were devised to assure that the integrated circuit and its protecting diode are sound in the vehicle that is now being readied for launch. These tests have been completed successfully.

       In announcing his decision to proceed with the launch, Dr. Fletcher stated: "I have reviewed the results of the Mariner H failure analysis, and of the Mariner I Launch Readiness Review. I am satisified that a complete and thorough job has been done, that the failure has been identified, and that proper corrective action has been taken. At the same time, I fully recognize that the Atlas/Centaur is an extremely complex vehicle, that there are literally thousands of parts and components that must function perfectly, and that a finite probability of failure must exist on each launch."

       The launch window, in 1971, remains open until June 4, and can be extended to mid-June with a somewhat reduced propellant reserve. The next opportunity is not available to the Atlas/Centaur/Mariner combination because of much higher energy requirements.

       The planned trajectory (for a launch between May 28 and June 4) will bring the spacecraft to Mars on November 14. There it will be placed into an orbit that will meet, at least partially, the objectives of both previously planned Mariner 1971 flights: to map a major portion of the planet; and to repeatedly study selected areas to observe changes on the surface and in the atmosphere.

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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

       Project officials said today they hope to Launch the Mariner Mars mission before June 6.

       Determination of a firm launch date awaits completion of work, tests and reviews yet to be accomplished at NASA's KSC. Final decision will be made by Administrator James C. Fletcher.

       An investigation into the cause of a Centaur stage failure was begun immediately after the unsuccessful first attempt to launch a Mariner Mars (Mariner H) mission on May 8.

       Ground simulations indicate that the failure of a single piece part -- an integrated circuit chip one twentieth of an inch square -- duplicates flight records telemetered from Atlas-Centaur 24 in the May 8 failure.

       The integrated circuit or chip was in the pitch channel of the rate gyro preamplifier in the Centaur stage autopilot. Signals from the rate gyros to the actuators which steered the centaur engines in pitch first suffered from low gain and then ceased about 25 seconds after centaur engine start. The engines stopped gimballing in the pitch plane causing the centaur stage to tumble andit landed some 900 miles downrange in the Atlantic Ocean.

       A likely explanation is that a protective diode could have failed to protect the integrated circuit from an electrical transient or surge of voltage sometime after T-30 minutes in the countdown when the autopilot was last tested and found operable.

       As a result, the autopilot to be used in Atlas-Centaur 23 for the launch of Mariner I has been retested for faulty integrated circuits and has been given extra thermal and vibration tests. In addition, a special test has been devised to assure that the protective diodes are capable of preventing faulty electrical signals from reaching the integrated circuits.

       Meanwhile a problem has developed in the centaur stage's propellant utilization system. This is an arrangement of sensors inside centaur to monitor usage of propellants during powered flight.

       During electrical check, a short was discovered in the propellant utilization equipment inside the tank. Mariner I and its protective nose fairing have been demated from centaur so that the problem can be corrected.

       Following installation of the autopilot and remate of the spacecraft, The Joint Flight Acceptance Composite Test (J-FACT) completed on May 17, will be repeated. A new launch date will be established after completion of the J-FACT. The earliest launch planning date would be approximately five days after J-FACT.

       If Mariner I (which will be designated Mariner 8 if successfuly launched) is not launched by June 6, it could still be launched later in June, but there would be some constraints on its mission.

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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

       Mariner 9, on its 166-day cruise to Mars, will have its trajectory slightly altered on June 4 to carry it close enough to the planet so that it can be injected into Martian orbit.

       Officials of the National Aeronautics and Space Administration and the Jet Propulsion Laboratory, Pasadena, Calif., said the planned mid-course maneuver requires a velocity change of about 15.6 miles per hour (seven meters per second).

       The maneuver will change the arrival date at Mars from November 14 to November 13 to assure that orbital injection is well within the viewing period of NASA's Deep Space Network station at Goldstone, Calif., and that Mariner has the desired approach velocity.

       On its present trajectory deliverately targeted away from Mars to satisfy planetary quarantine requirements, the 2,200 pound spacecraft would cross the Mars orbit at an altitude of about 16,000 miles (25,750 kilometers). The highly accurate launch from Cape Kennedy, Fla., on May 30 was provided by an Atlas Centaur launch vehicle.

       The commands which align the spacecraft's rocket engine in the correct position for the maneuver will be prepared in JPL's Space Flight Operations Facility and transmitted from the DSN station in Woomera, Australia.

       Woomera will send a command to initiate the maneuver at 6:00 p.m. EDT on June 4, with rocket engine firing for a duration of 5.3 seconds scheduled for 8:22 p.m. The DSN station in Johannesburg, South Africa, also will be in view of Mariner and both will monitor maneuver performance.

       Earth-spacecraft range at engine firing will be about 838,000 miles (1,340,800 kilometers). After the maneuver, Mariner will resume its cruise attitude by reacquiring the Sun and the star Canopus.

       Following the successsful launch phase of the mission, the spacecraft was prepared for the maneuver by venting the propulsion subsystem's propellant lines.

       The scan platform which carries the science instruments, was unlatched Monday. This allows the turret-like platform to slew in two planes for instrument calibation en route to Mars and for scientific experiments at the planet.

       NASA and JPL officials report that all systems aboard Mariner 9 are working well.

       Mars was 63 million miles (100.8 million km) from Earth when Mariner 9 was launched at 6:23 p.m. EDT May 30.

       About half-way through the trip, on August 11, Mars will make its closest approach to Earth -- 34.9 million miles (55.8 million km). When Mariner arrives at Mars on November 13, the planet will be 75.5 million miles (120.8 million km) from Earth. The spacecraft's arcing tracjetory will have covered 247 million miles (395.2 million km).

       At Mars, Mariner 9 will aim for an orbit with an inclination of 65 degrees, a period of 12 hours, a periapsis of 750 miles (1,200 km) and an apoapsis of 10,700 miles (17,265 km). This mission plan is designed to allow Mariner 9 to accomplish as many mission objectives as possible of the two missions orignally planned in Mariner Mars '71. A launch vehicle failure on May 8 prevented Mariner 8 from achieving a tracjectory to Mars.

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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

       Mariner 9, launched toward Mars on May 30, will execute a mid-course maneuver on Friday, June 4, to achieve the desired orbit insertion altitude at the planet next November 13, a day earlier than on the present trajectory. Mariner Project officials at the Jet Propulsion Laboratory in Pasadena, Calif., said the planned maneuver requires a velocity change of 15.7 miles per hour (seen meters per second).

       On its present tracjectory, deliberately targeted away from Mars to satisfy planetary quarantine requirements, the 2200-pound spacecraft would cross the Mars orbit at an altitude of about 16,000 miles. The highly accurate launch from Cape Kennedy was provided by the Atlas-Centaur rocket combination.

       A successful maneuver will cause Mariner 9 to arrive at the planet at about 3:30 p.m. PST on November 13 at an altitude of about 750 miles.

       The arrival 20 hours earlier than on the present trajectory was selected to take advantage of the viewing period of the Goldstone tracking antennas and to achieve the desired approach velocity.

       Commands, which align the spacecraft's rocket engine in the correct position for the maneuver, will be prepared in the Space Flight Operations Facility at JPL and transmitted from the Deep Space Network Station in Woomera, Australia. Woomera will send command to initiate the maneuver at 3 p.m. PDT Friday with the rocket engine firing for a duration of 5.3 seconds at 5:22 p.m. The DSN station in Johannesburg, South Africa, also will be in view of the Mariner and both will monitor the maneuver performance.

       Earth-spacecraft range at engine firing will be about 838,000 miles. Mariner 9 will resume its cruise attitude after the maneuver by re-acquiring the sun and the star Canopus.

       Following the successful launch phase of the mission, the spacecraft was prepared for the maneuver by venting the propulsion system's propellant lines. The scan platform, which carries the science instruments, was unlatched Monday. This allows the turret-like platform to slew in two planes for instrument calibration enroute to Mars and science experiments at the planet.

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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

Friday, June 4, 1971
       Mariner 9, launched toward Mars five days ago, today (Friday) executed a trajectory correction maneuver to achieve a Mars arrival on November 13 at the desired approach velocity and altitude.

       The maneuver, which culminated with the firing of Mariner's 300-pound-thrust rocket engine for 5.11 seconds, placed the spacecraft on a slightly altered trajectory for an arrival 750 miles from the Martain surface at 4:29 pm. PST, November 13.

       The launch by an Atlas-Centaur from Cape Kennedy on May 30 targeted the spacecraft for a deliberate planet miss of more than 16,000 miles to assure that neither the spacecraft nor the second stage of the launch vehicle would contaminate the planet.

       Maneuver commands, stored in the Mariner 9 on-board computer yesterday, were: roll minus 140.987 degrees; yaw minus 44.725 degrees; and burn for a duration of 5.11 seconds.

       Deep Space Station 41 at Woomera, Australia, transmitted the DC-52, manuever initiate command, at 3:09 p.m. PDT today. The rocket engine thrusted for the required 5.11 seconds at 5:22 p.m., changing Mariner 9's velocity by 6.731 meters per second (15.08 miles per hour).

       Both DSS 41 and DSS 51 at Johannesburg, South Africa, monitored the performance of the apparently successful maneuver. Earth-spacecraft range at engine firing was about 838,000 miles.

       Several days of tracking data will be required to determine the accuracy of the maneuver.

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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

       Stored into CC&S by coded commmands on Thursday, June 3:

                   Roll -140.91?o

                   Yaw - 44.74?o

                   Burn - 5.11 sec.

       ______

       3:09:03 pm PDT            Xmit DC-52 (initiate maneuver)

       3:09:35 pm PT            DC-52 acted upon (30 minute delay)

       3:39:35 pm PDT            Gyros on (68:16 min-sec warmup)

       4:47:51            start roll turn (12 min, 58 sec. duration -140.91?0)

       5:00:49            end roll turn (8 min, 32 sec. delay)

       5:09:21            start yaw turn (4 min, 7 sec. duration - 44.74?o)

       5:13:28            end yaw turn (8 min., 32 sec. delay)

       5:22:00            engine burn (5.11 second duration)

       5:22:05.11            end engine firing (3 minute delay)

       5:25:05            start yaw unwind (4 min, 7 sec. duration)

       5:29:12            end yaw, unwind (sun acquisition) start roll unwind (13 minute, 25 second duration)

       5:45:37            end roll unwind (Canopus acquisition)

       Earth Time                                                            ~W~V change

       All others spacecraft time 6.731 meters per sec. (15.08 miles per hour)

       Distance from Earth at motor burn                                                838,000 Mi.

       Travel Distance at motor burn                                                            8,893,000 Mi.

       Velocity (relative to Earth) at time of motor burn                                      6,838 MPH

       Distance when Earth no longer major gravity influence on June 8th                          1,550,000 Mi.

       Distance when Mars begins to influence spacecraft on Nov. 6                                    1,240,000 Mi.

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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
May 27, 1971

       The Mariner 9 spacecraft will complete its 46th day of travel today having covered 77,400,000 miles on its 247 million mile journey to Mars since launch on May 30.

       The 2200 pound spacecraft is 7,966,000 miles from Earth as it slowly draws away from Earth towards the orbit of Mars. It is traveling on a curving path around the sun at 67,200 miles per hour, some 8,850 mph faster than Earth is moving in its orbit.

       On November 13th the flight path of Mariner 9 will intersect the oribtal path of Mars and the firing of a 300 pound thrust retro engine will insert Mariner into a Mars orbit.

       Basic objective of the mission is 90 days in orbit and mapping of about 70% of the Martian surface with two television cameras. Other experiments will record atmospheric and surface data.

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7/14/71
OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE 354-5011
May 27, 1971

       The Mariner 9 spacecraft is in its 53rd day of flight today in its 167 day journey to Mars.

       It has covered 88,600,000 miles in its 247 million mile journey and is 9.5 million miles from Earth.

       Both Earth and Mariner 9 are moving around the Sun together with the spacecraft traveling faster and moving away from the orbit of Earth towards the orbit of Mars.

       Since launch on May 30 this year, more than 600 commands have been sent to the spacecraft. Many of the commands were routine, but one block of commands has programmed the on-board computer for automatic insertion of the spacecraft into Mars orbit on November 13th. In the event command capability should be lost during the flight, the spacecraft, acting only on internal commands, is capable of orbiting Mars and returning scientific data.

       Basic objective of the mission is 9 days in orbit and mapping of about 70% of the Martian surface with two television cameras. Other experiments will record atmospheric and surface data.

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7/21/71
OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE 354-5011
May 27, 1971

       The Mariner 9 spacecraft is in its 54th day of flight today and has traveled 90 million miles on its 247 million mile journey to Mars.

       Its distance from Earth is 9.7 million miles. Both Earth and Mariner 9 are moving around the Sun together with the spacecraft traveling faster and moving away from the orbit of Earth towards the orbit of Mars.

       Since launch on May 30 this year, more than 600 commands have been sent to the spacecraft. Many of the commands were routine, but one block of commands has programmed the on-board computer for automatic insertion of the spacecraft into Mars orbit on November 13th. In the event command capability should be lost during the flight, the spacecraft, acting only on internal commands, is capable of orbiting Mars and returning scientific data.

       Basic objective of the mission is 90 days in orbit and mapping of about 70% of the Martian surface with two television cameras. Other experiments will record atmospheric and surface data.

       The objective of the Mariner mission is to study the surface and atmosphere of Mars in detail and over a period of time, to provide a broad picture of the history of the planet and natural processes currently shaping the Martian environment. Recurring phenomena such as dust storms, clouds and seasonal changes in the appearance of the planet's surface have been observed on Mars. The orbital mission will allow scientists to study these phenomena daily at close range.

       The Mariner carries a payload of instruments to conduct six scientific investigations:

       - Martian topography and variable features with two television cameras, one with a wide-angle lens and one with a telephoto lens;

       - surface temperature measurements with an infrared radiometer;

       - composition and structure of the atmosphere with an ultraviolet spectrometer;

       - studies of the planet's surface and composition and temperature of its atmosphere with an infrared interferometer spectrometer;

       - atmospheric pressure and structure with an S-Band occultation experiment;

       - and a more accurate description of Mar's gravity field and the orbits of its two moons, and an improved ephemeris of Mars (its position in its solar orbit at a given time).

       The latter two experiments involve measurements of the Mariner's radio signals back to Earth and do not require special insruments on the spacecraft.

       The scientific experiments have been teamed together to provide a maximum correlation of the data they gather. The three instruments on the scan platform, for instance, are boresighted with the television cameras so that the photography can be correlated with measurements of the Martian atmospheric and surface characteristics.

       Mariner 9 will orbit Mars once each 12 hours, inclined 65 degrees to the Martian equator, with a 10,700 mile (16,090kilometer) high point in the orbit (apoapsis) and a 750-mile (1,200-kilometer) low point (periapsis).

       The spacecraft weighed approximately 2,200 pounds, (1,000 kilograms) at launch, with about 1,000 pounds (454 kilograms) of fuel for the 300-pound thrust retro-engine. After injection into Mars orbit, the spacecraft will weight approx- imately 1,200 pounds (544 kilograms).

       Orbit insertion will require about a 14-minute burn of the retro-engine slowing the spacecraft by about 3,250 milesper-hour (1,450 meters-per-second). The spacecraft velocity relative to Mars prior to the burn will be about 11,00 mph (4,920 m/sec).

       The launch was direct ascent without a parking orbit. The launch aiming point was away from Mars to insure that neither spacecraft nor the Centaur second state would impact Mars in the event of loss of control during the launch phase. The orbit of the spacecraft is designed to guarantee that it will not impact Mars for at least 17 years, to avoid contamination of the planet before studies are conducted on the surface by landing spacecraft.

       Following successful injection into solar orbit, a midcourse maneuver was performed to correct the trajectory and refine the aiming point. A second manuever will be performed in late October. The retro-engine is used for midcourse maneuvers.

       The accuracy required to orbit Mars is unprecedented in a flight into deep space. The aiming zone at the end of the 287-million-mile (462-million-kilometer) flight is an area about 435 miles (70-kilometer) on a side.

       After insertion into Mars orbit, the spacecraft will be tracked for a sufficient period to determine the orbital corrections (trims) required to yield precise orbits. The trims will be provided by the retro-engine.

       The maximum data transmission rate will be 16,200 bitsper-second when the spacecraft can transmit to the sensitive 210-foot (64-meter) antenna at the Goldstone station of the Deep Space Network in the California Mojave Desert. Other stations will receive at a maximum rate of 2,025 bits-per-second.

       NASA's Office of Space Science and Applications assigned project responsibility including mission operations and tracking and data acquisition to the Jet Propulsion Laboratory managed by the California Institute of Technology. The launch vehicle is the responsibility of the Lewis Research Center, Cleveland. The contractor to Lewis is General Dynamics/ Convair, San Diego.

       Tracking and communications is assigned to the Deep Space Net operated by JPL for NASA's Office of Tracking and Data Acquisition.

       Cost of the basic 90-day Mariner Mars '71 mission is $129 million, exclusive of launch vehicles and data acquisition.

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7/21/71
OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA. TELEPHONE 354-5011
May 27, 1971

       The ruddy planet Mars, object of centuries of theoretical speculation, will be put to a stern day-by-day scientific scrutiny in November when the Mariner 9 spacecraft begins at least three months of orbital study.

       With two 1969 Mariner flybys having indicated Mars is really more pink than red and having revealed uncratered areas which might involve recently active processes, space scientists hope the 1971 mission will produce a scientific bonanza without parallel in planetary exploration.

       "If all goes well, we anticipate a veritable information explosion about the Mars terrain, climate and atmosphere, even its two tiny moons," says Robert H. Steinbacher, Mariner 9 project scientist. "We even hope to establish daily and seasonal weather patterns."

       Spacecraft engineers of Caltech's Jet Propulsion Laboratory predict that this year's National Aeronautics and Space Administration planetary mission could send back 15 times as much data for scientific investigators to study as the twin 1969 flybys yielded. TAB> Scheduled to arrive at Mars Nov. 13, Mariner 9 is set to radio back from 25 to 30 billion computer bits of information gathered in six scientific experiments. Mariner 6 and 7 transmitted a total of 2 billion bits. The first Martian flyby by Mariner 4 in 1965 yielded but 215 million data bits.

       The knowledge explosion should be qualitative as well as quantitative. For example, the 1971-2 mission is expected to produce more than 5,000 television pictures--with hundreds of telescopic shots having football-field resolution (100 yards or less of Martian surface). The 1969 mission produced 205 pictures, the 1965 flight 22.

       Moreover, the photographs and scientific measurements will be taken from as close as 750 miles-compared to previous flyby distances of 2,000 to 6,500 miles. In its twice-a-day elliptical orbit, Mariner 9 will swing out to 10,700 miles from the planet. The orbit will give good planet coverage at a 65-degree inclination from the Martian equator, with highest resolution from South to North at low orbit.

       Mariner's two TV cameras, with wide and narrow fields of view, are mounted on a swiveling scan platform also carrying an infrared radiometer, infrared spectrometer and ultraviolet spectrometer. All these instruments are boresighted--that is, visually aligned--to observe what the cameras are pointed at.

       In this way, teams of scientists hope to map more than 70 per cent of Mars, and determine temperature, terrain and atmospheric conditions in each area pictured.

       "The cutting edge of this mission," says Steinbacher, "is twofold. Not only will we examine Mars in detail on a daily basis, but we plan to correlate data from the instruments to derive more than the sum total of the parts."

       The instruments will view an early summer atmosphere and surface in the South and early winter in the North. The Martian surface is to be examined by photography and in the infrared wavelengths. Its atmosphere will be studied in both ultraviolet and infrared, and by a radio occultation experiment.

       While probing the atmosphere the UV spectrometer also may provide an elevation profile of the surface. Photographs will be correlated with surface temperatures taken by the IR radiometer plus pressures and constituents of the atmosphere supplied by the IR spectrometer.

       The instrument complex will study certain phenomena which have aroused curiosity through observations from Earth and previous Mariner missions. These phenomena include clouds, hazes, bright spots and dust storms.

       A specific objective is the study of the apparent "wave of darkening" which seasonally sweeps across Mars. The spacecraft will arrive at the peak of this seasonal darkening period in the southern hemisphere.

       Detection of any life forms on Mars is beyond the resolution capabilities of the camera. However, correlation of the photographs with data from the other instruments may yield information on the suitability of Mars as a habitat for some type of life.

       The chances of some primitive form of life were enhanced this year by the laboratory findings of a team ofJPL researchers. In ultraviolet radiation tests under simulated Martian cotions, the researchers produced three organic compounds (formaldehyde, acetaldehyde and glycolic acid) believed to have been precursors of biological molecules on primitive Earth.

       Another mission goal is to fix the true orbit of Mars. This experiment, called celestial mechanics, depends upon radio tracking data. Details of the Martian gravity field also will be revealed by the spacecraft's repeated orbits about the planet.

       Each successive flight to Mars has corrected the planet's ephemeris, the astronomers' term for orbital path.

       The size and shape of the planet--particularly its radius--will be measured by the radio S-band occultation experiment. As the planet occults--that is, intercepts--the spacecraft radio signal, it will be possible for scientists to get such information, plus measurements of atmospheric and ionospheric density and pressure.

       In previous Mariner occultation experiments, it was first learned that the Martian atmospheric pressure is only about one-hundredth that of Earth and that the planet's surface has altitude variations of up to 5,000 meters or 16,500 feet.

       Mission planners haven't overlooked the two tiny Martian moons. Mariner's rounds will carry it between Phobos, which orbits Mars about 4,000 miles out, and Deimos, at 12,000 miles.

       Phobos, photographed by both Mariners 6 and 7, was shown to be a strange dark, potato-shaped body only 11 miles in diameter from pole to pole, but 14 miles in diameter at its equator. Deimos may be only 5 or 6 miles in diameter.

       There is a possibility, scientists say, that Mariner may have to go through a moondust belt. Both Phobos and Deimos could be shedding trails of dust in near-Martian space.

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9/10/71 BB
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