Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/jplnews1/0595.pr

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OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA.  TELEPHONE [phone]


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 Admin-
istration 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.
         Originally Mariner H was assigned a basic mission ob-
jective of mapping 70% of Mars and Mariner I a mission object-
ive 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 in-
clination 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.

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         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 photo-
graphy 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 two-
spacecraft mission would have yielded three tapeloads per day.
         The variable features experiment is changed from re-
peat 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 [phone]


                        _____E_R__________

         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 Atlas-
Centaur 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 objec-
tive 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 in-
clination 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.

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                              -2-
         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 orig-
inal 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 two-
spacecraft 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 per-
iapsis 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.


                              ###
5/27/71

OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA.  TELEPHONE [phone]


FOR IMMEDIATE RELEASE                           May 27, 1971
(Release from NASA Headquarters)

_____________________________
         National Aeronautics and Space Administration Admini-
strator 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 fail-
ure 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 pro-
tecting 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

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Mariner H failure analysis, and of the Mariner I Launch Readi-
ness 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 com-
ponents that must function perfectly, and that a finite proba-
bility 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 pro-
pellant 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 sur-
face and in the atmosphere.


                              ###

OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA.  TELEPHONE [phone]


                        ________________

         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.

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         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 vibra-
tion 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.

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                              -3-
         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.


                              ###

OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA.  TELEPHONE [phone]


____________________________

         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 Admin-
istration 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 alti-
tude 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.

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         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 dura-
tion 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 pro-
pulsion subsystem's propellant lines.
         The scan platform which carries the science instru-
ments, was unlatched Monday.  This allows the turret-like plat-
form 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.

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         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 in-
clination 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.


                              ###

OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA.  TELEPHONE [phone]


         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 offi-
cials 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 alti-
tude of about 750 miles.
         The arrival 20 hours earlier than on the present tra-
jectory was selected to take advantage of the viewing period of
the Goldstone tracking antennas and to achieve the desired ap-
proach velocity.

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         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 man-
euver 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 pro-
pulsion 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.


                              ###

OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA.  TELEPHONE [phone]


                                           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, trans-
mitted the DC-52, manuever initiate command, at 3:09 p.m. PDT
today.  The rocket engine thrusted for the required 5.11

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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 [phone]


                  ____________________________

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)
         (3 minute delay)

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 5:32:12            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                     6,838     MPH
time of motor burn
Distance when Earth no longer                       1,550,000 Mi.
major gravity influence on
June 8th
Distance when Mars begins to
influence spacecraft on Nov. 6                      1,240,000 Mi.

OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA.  TELEPHONE [phone]


FOR RELEASE:  THURSDAY, JULY 15, 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 in-
tersect 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 [phone]


FOR RELEASE:  THURSDAY, JULY 22, 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 com-
mands 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 capa-
bility 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.
                              ###
7/21/71

OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA.  TELEPHONE [phone]


FOR RELEASE:  THURSDAY, JULY 23, 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 com-
mands 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 cap-
ability 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.

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         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 ephe-
meris of Mars (its position in its solar orbit at a given time).

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         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 bore-
sighted 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 (16,090-
kilometer) 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 kilo-
grams) 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 miles-
per-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

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                              -5-
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 contamin-
ation of the planet before studies are conducted on the surface
by landing spacecraft.
         Following successful injection into solar orbit, a mid-
course 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 correc-
tions (trims) required to yield precise orbits.  The trims will
be provided by the retro-engine.
         The maximum data transmission rate will be 16,200 bits-
per-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 as-
signed project responsibility including mission operations and
tracking and data acquisition to the Jet Propulsion Laboratory

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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 [phone]


FOR RELEASE:  SEPTEMBER 16, 1971

         The ruddy planet Mars, object of centuries of theoret-
ical 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 infor-
mation 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 sea-
sonal weather patterns."
         Spacecraft engineers of Caltech's Jet Propulsion Labor-
atory 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.

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                              -2-
         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 trans-
mitted 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 pic-
tures, 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 atmo-
spheric conditions in each area pictured.

                             -more-

                              -3-
         "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 experi-
ment.
         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 space-
craft will arrive at the peak of this seasonal darkening period
in the southern hemisphere.

                              more

                              -4-
         Detection of any life forms on Mars is beyond the reso-
lution capabilities of the camera.  However, correlation of the
photographs with data from the other instruments may yield in-
formation on the suitability of Mars as a habitat for some type
of life.
         The chances of some primitive form of life were en-
hanced this year by the laboratory findings of a team ofJPL
researchers.  In ultraviolet radiation tests under simulated
Martian cotions, the researchers produced three organic com-
pounds (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 exper-
iment.  As the planet occults--that is, intercepts--the space-
craft radio signal, it will be possible for scientists to get
such information, plus measurements of atmospheric and iono-
spheric density and pressure.

                              more

                              -5-
         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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