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Date: Tue,  4 Aug 92 05:02:27
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Space Digest                Tue,  4 Aug 92       Volume 15 : Issue 064

Today's Topics:
     Electronic Journal of the ASA (EJASA) - August 1992 [Part 1]

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Date: 3 Aug 92 15:25:09 GMT
From: Larry Klaes <[e-mail]>
Subject: Electronic Journal of the ASA (EJASA) - August 1992 [Part 1]
Newsgroups: sci.astro,sci.space,sci.misc

                          THE ELECTRONIC JOURNAL OF
                  THE ASTRONOMICAL SOCIETY OF THE ATLANTIC

                      Volume 4, Number 1 - August 1992

                         ###########################

                              TABLE OF CONTENTS

                         ###########################

          * ASA Membership and Article Submission Information

          * The Great Moon Race: The Commitment - Andrew J. LePage

                         ###########################

                         ASA MEMBERSHIP INFORMATION

        The Electronic Journal of the Astronomical Society of the Atlantic
    (EJASA) is published monthly by the Astronomical Society of the
    Atlantic, Incorporated.  The ASA is a non-profit organization dedicated
    to the advancement of amateur and professional astronomy and space
    exploration, as well as the social and educational needs of its members.

        ASA membership application is open to all with an interest in
    astronomy and space exploration.  Members receive the Journal of the
    ASA (hardcopy sent through United States Mail - Not a duplicate of this
    Electronic Journal) and the Astronomical League's REFLECTOR magazine.
    Members may also purchase discount subscriptions to ASTRONOMY and
    SKY & TELESCOPE magazines.

        For information on membership, you may contact the Society at any
    of the following addresses:

        Astronomical Society of the Atlantic (ASA)
        c/o Center for High Angular Resolution Astronomy (CHARA)
        Georgia State University (GSU)
        Atlanta, Georgia  30303
        U.S.A.

        [e-mail]

        ASA BBS: [phone], 300/1200/2400 Baud.

        or telephone the Society Recording at [phone] to leave your
    address and/or receive the latest Society news.

        ASA Officers and Council -

        President - Don Barry
        Vice President - Nils Turner
        Secretary - Ingrid Siegert-Tanghe
        Treasurer - Mike Burkhead
        Directors - Bill Bagnuolo, Eric Greene, Tano Scigliano
        Council - Bill Bagnuolo, Bill Black, Mike Burkhead, Frank Guyton,
                  Larry Klaes, Ken Poshedly, Jim Rouse, Tano Scigliano,
                  John Stauter, Wess Stuckey, Harry Taylor, Gary Thompson,
                  Cindy Weaver, Bob Vickers

        ARTICLE SUBMISSIONS -

        Article submissions to the EJASA on astronomy and space exploration
    are most welcome.  Please send your on-line articles in ASCII format to
    Larry Klaes, EJASA Editor, at the following net addresses or the above
    Society addresses:

        [e-mail]
        or - ...!decwrl!verga.enet.dec.com!klaes
        or - [e-mail]
        or - [e-mail]

        You may also use the above addresses for EJASA back issue requests,
    letters to the editor, and ASA membership information.

        When sending your article submissions, please be certain to include
    either a network or regular mail address where you can be reached, a
    telephone number, and a brief biographical sketch.

        DISCLAIMER -

        Submissions are welcome for consideration.  Articles submitted,
    unless otherwise stated, become the property of the Astronomical
    Society of the Atlantic, Incorporated.  Though the articles will not
    be used for profit, they are subject to editing, abridgment, and other
    changes.  Copying or reprinting of the EJASA, in part or in whole, is
    encouraged, provided clear attribution is made to the Astronomical
    Society of the Atlantic, the Electronic Journal, and the author(s).
    Opinions expressed in the EJASA are those of the authors' and not
    necessarily those of the ASA.  This Journal is Copyright (c) 1992
    by the Astronomical Society of the Atlantic, Incorporated.


                THE GREAT MOON RACE: THE COMMITMENT

             Copyright (c) 1992 by Andrew J. LePage

    The author gives permission to any group or individual wishing
    to distribute this article, so long as proper credit is given
    and the article is reproduced in its entirety.

        Introduction

        As the 1950s were drawing to a close, the general perception
    was that the American space program was lagging further behind the
    Soviets.  While the Soviets had their share of failures, these were
    generally unknown outside the small group privy to the needed intel-
    ligence information.  All the public knew was that the Soviets had
    made three spectacular lunar missions, while only one of America's
    PIONEER Moon probes managed to break the gravitational bonds of
    Earth to make it anywhere near its target.

        During 1959, while the Soviets managed one space first after
    another, the newly formed National Aeronautics and Space Admini-
    stration (NASA) was busy consolidating its new empire and began
    formulating plans to meet the formidable Soviet challenge.  In late
    December of 1959, the Jet Propulsion Laboratory (JPL) was directed to
    make plans for five lunar missions to take place in 1961 and 1962.
    Throughout 1959, JPL and the Army Ballistic Missile Agency (ABMA) were
    already studying follow-on lunar missions that would make use of a
    three-stage ATLAS-VEGA launch vehicle specifically designed for lunar
    and planetary missions.  With the cancellation of JPL's home-grown
    ATLAS-VEGA on December 11, 1959, these missions would have to make
    use of the soon to be available ATLAS-AGENA B being developed by the
    United States Air Force (USAF).

        Two of the major problems with the launch vehicles used to date
    for the American lunar missions were the small payloads that could be
    carried and the inaccuracy of these rockets.  The THOR-ABLE, JUNO II,
    and ATLAS-ABLE were far from ideal for lunar missions.  Their upper
    stages were undersized for their booster stages and were essentially
    existing rockets that were quickly kludged together for the task.  In
    addition they could only use direct ascent trajectories to inject their
    payloads, which resulted in large gravity losses as these rockets
    climbed more or less straight out of Earth's gravity well.  This type
    of trajectory greatly magnified any velocity or aiming errors.

        Ideally the upper stage and its payload would first be placed into
    a temporary parking orbit around Earth.  Once the precise orbit had
    been determined, the upper stage would ignite at exactly the right
    moment to insure accuracy.  With the upper stage firing approximately
    in line with the horizon, gravity losses are minimized.  The ATLAS-
    AGENA B was designed to do precisely that.

        Development of the AGENA upper stage began in 1956 under a USAF
    contract with the Lockheed Missiles and Space Company.  This stage
    was specifically designed to be used with a modified THOR or ATLAS D.
    The AGENA B was a greatly modified version of the original AGENA A.
    It was over eight feet (2.5 meters) longer to accommodate a larger
    propellant supply and replaced the A model's Bell Aerospace Hustler
    8048 engine with a slightly more powerful 8081, which also possessed
    an in-orbit restart capability.

        The THOR-AGENA was used to launch the experimental DISCOVERER
    military satellite series into polar orbits.  Flights with the
    THOR-AGENA A had started on February 28, 1959 and flew successfully
    ten times out of fifteen attempts before it was replaced by the
    improved THOR-AGENA B, whose first flight took place on October 26,
    1960.  The AGENA B demonstrated its all-important restart capability
    for the first time with a one-second burn on the flight of DISCOVERER
    21, launched on February 18, 1961.

        The ATLAS-AGENA was originally designed to place large payloads,
    such as the MIDAS experimental early warning satellite and the SAMOS
    reconnaissance satellite, into medium altitude Earth orbits.  The
    ATLAS-AGENA A flew only four times between February of 1960 and
    January of 1961 with limited success.  The first flight of the
    improved ATLAS-AGENA B took place on July 12, 1961 with the success-
    ful launch of MIDAS 3.  The ATLAS D was modified for this task by
    stiffening its forward bulkheads to handle the heavier payload and
    replacing its MA-2 propulsion system with the uprated MA-3 system
    being used on the improved ATLAS E/F silo based ICBM then under
    development.  This change resulted in an eight percent increase in
    liftoff thrust over the basic ATLAS D ICBM.  By the summer of 1961,
    the AGENA had operated successfully twenty-one times out of twenty-
    nine opportunities; a very respectable record in these early years
    of space rocketry.

        RANGER is Born

        By the end of January in 1960, JPL's new lunar project, RANGER,
    had taken form.  The five flights would use two spacecraft designated
    Block I and Block II.  The first two flights would make use of the
    Block I spacecraft.  They were meant to be engineering test flights
    which would place RANGER into an extended Earth orbit with a perigee
    of 37,500 miles (60,300 kilometers) and an apogee of 685,000 miles
    (1.1 million kilometers).  These 675-pound (307-kilogram) three-axis
    stabilized spacecraft would be the forerunner of not only the RANGER
    Moon probes but also the MARINER A and B spacecraft designed to
    explore the planets Venus and Mars, respectively.

        Test flights of this spacecraft were deemed necessary to test the
    interface between the probe and launch vehicle, as well as determine
    whether all the "bugs" had been worked out of controlling a three-axis
    stabilized spacecraft.  Three-axis stabilized spacecraft provide a more
    stable platform for certain instruments, such as cameras, than do spin-
    stabilized probes like ARPA's and NASA's previous PIONEER Moon probes.
    Typically, one axis is pointed towards the Sun to provide illumination
    for the spacecraft's power producing solar panels.  With the RANGER
    probes, the other celestial reference used was Earth itself.

        At RANGER's base was a 430-pound (195-kilogram) hexagon shaped
    magnesium frame bus five feet (1.52 meters) across that contained
    the spacecraft's central computer and sequencer which controlled the
    spacecraft, a 125-pound (57-kilogram) silver-zinc battery providing
    nine kilowatt-hours of backup electrical energy (enough for about two
    days), a one-quarter-watt and a three-watt radio transmitter, and the
    attitude control system.  Attitude reference was provided by six Sun
    sensors, two Earth sensors, and three gyros.

        Extending from the sides of the bus were a pair of solar panels
    containing 8,680 solar cells to provide 155 to 210 watts of power for
    the spacecraft.  Also extending from the base was a hinged dish-shaped
    high-gain communications antenna four feet (1.22 meters) across,
    which would be pointed at Earth with the aid of a light sensor.  The
    spacecraft maintained its attitude with the use of ten nitrogen gas
    jets supplied by 2.4 pounds (1.1 kilograms) of compressed nitrogen
    held in three tanks.

        On top of the bus was an open aluminum truss structure topped
    with a low-gain antenna to aid in communications with Earth when the
    probe's high-gain antenna could not be used.  When deployed in space,
    the Block I spacecraft was about thirteen feet (four meters) tall and
    seventeen feet (5.2 meters) across its extended solar panels.  A total
    of ten scientific instruments would be carried to study solar and
    cosmic radiation, cosmic dust, magnetic and electric fields, and
    perform engineering tests concerning mechanical friction and solar
    cell performance.  These experiments were mounted at various points
    on the bus and open truss structure.  Some of these devices carried
    independent battery power supplies.

        The Block II spacecraft would actually travel to the Moon starting
    in early 1962.  The basic bus was similar to the one used on the Block
    I probe, but the open truss structure above it was replaced with a new
    payload:  A 330-pound (150-kilogram) package consisting of a small hard
    lander with a 5,080-pound (2,300-kilogram) thrust retrorocket.  The
    Ford Aeronutronic-built hard lander was a 25-inch (64-centimeter)
    diameter sphere weighing 94 pounds (43 kilograms).  The exterior was
    composed of balsa wood to help absorb the force of impact.

        Inside was a smaller twelve-inch (31-centimeter), 56-pound
    (25-kilogram) sphere that was free to rotate on a cushion of freon
    inside the balsa shell.  The primary instrument carried inside this
    capsule was a seismometer sensitive enough to detect the impact of a
    five-pound (2.3-kilogram) meteorite on the opposite side of the Moon.
    The sensitive components of the seismometer were protected from the
    impact forces by a cushion of heptane.  Also included in the capsule
    was a fifty-milliwatt transmitter, six silver-cadmium batteries, and a
    temperature sensitive voltage oscillator.  The lander was designed to
    survive an impact of 150 miles per hour (67 meters per second).

        The hard lander's interior temperature was controlled by a capsule
    containing 3.7 pounds (1.7 kilograms) of water.  During the hot lunar
    day, the interior would heat up to 86 degrees Fahrenheit (30 degrees
    Celsius) when the water would start to boil under the ambient condi-
    tions.  The temperature would rise no further until all the water
    would boil away, a process that could take as little as a single lunar
    day (fourteen Earth days) or as long as three lunar days, depending on
    conditions.  During the cold lunar night, this heated water - along
    with the heat generated by the lander's internal electronics - would
    keep the interior above the freezing point.

        The 730-pound (332-kilogram), 10.25-foot (3.1-meter) tall Block
    II RANGER had additional modifications from its predecessor.  First,
    the battery was reduced in size to 25 pounds (11 kilograms), which
    provided one kilowatt hour of reserve power.  Another modification
    included the use of a 36-pound (16-kilogram) hydrazine-fueled course
    correction engine, providing 50 pounds (23 kilograms) of thrust to
    fine tune its aim as it approached the Moon.  This engine could be
    fired for a maximum of 68 seconds, giving a total velocity change of
    one hundred miles per hour (44 meters per second).  Since any torques
    imparted during this engine's operation could not be compensated with
    the small attitude control jets, this engine was fitted with steering
    vanes at the exit nozzle.

        The Block II RANGER also carried an entirely new set of instruments,
    including a radar altimeter to provide ranging information as well as
    data on the lunar surface's radar characteristics, a gamma ray spectro-
    meter mounted on a six-foot (1.8-meter) boom to determine surface
    composition, and a Radio Corporation of America (RCA) built television
    camera with a JPL designed 40-inch (102-millimeter) focal length lens.
    The camera was expected to return over 150 images comprised of two
    hundred scan lines, each starting at an altitude of 2,400 miles (3,860
    kilometers).  The instrument would continue transmitting down to
    fifteen miles (24 kilometers), where objects as small as ten feet
    (three meters) across could be resolved.

        In order to minimize the chances of Earth organisms reaching the
    Moon, the entire spacecraft was sterilized first by baking components
    for 24 hours at 257 degrees Fahrenheit (125 degrees Celsius), then
    cleaning all the parts with alcohol before they were assembled.
    Finally, the spacecraft was saturated in its AGENA B nose faring
    with ethylene oxide gas for 24 hours.

        The Flight Plan

        There were many variables involved with choosing a proper launch
    window.  First, the length of the trip to the Moon was set to about 66
    hours to maximize the payload while insuring that the spacecraft would
    be near the meridian as viewed from the Goldstone tracking antenna
    (the most sensitive in the network) when RANGER impacted on the Moon.
    RANGER also had to approach the Moon almost vertically at a precise
    speed because of the fixed velocity increment of the lander's retro-
    rocket.  Because of the imaging requirements and the position of
    celestial references, the landing could only take place on the Moon's
    visible face during a four or five-day period centered on the Moon's
    last quarter phase.  Finally, the requirement that the hard lander's
    antenna have Earth in view meant that it could not be placed more than
    forty-five degrees from the center of the Moon's visible side.  All of
    these constraints limited impact sites to near the lunar equator in
    the eastern part of Oceanus Procellarum.

        A typical mission sequence for the Block II RANGER started with
    the modified ATLAS D placing the AGENA B and RANGER into a parking
    orbit after a short burn from the AGENA B.  After a certain time
    delay fixed before launch, the AGENA B would reignite to place the
    spacecraft on a path to the Moon.  Once its job was completed, the
    AGENA B separated from the probe and fired small retrorockets to
    distance itself from the craft.  About five minutes after separation
    and forty-eight minutes after launch, RANGER then unfolded its solar
    panels and high-gain antenna to began its search for its first atti-
    tude reference, the Sun.  Once acquired, RANGER switched from its non-
    rechargeable battery to its solar panels for power.  It then began
    a slow roll until its antenna locked on to Earth, its final reference
    point, about four hours after launch.

        Fifteen hours after launch, RANGER would be commanded to make a
    single mid-course correction, if needed, at a distance of 91,000 miles
    (146,000 kilometers) to insure a lunar impact.  During this time,
    internal gyroscopes were used as an attitude reference.  After the
    burn, the fragile gamma ray spectrometer boom was deployed.  As RANGER
    approached the Moon, it began its terminal descent maneuver.  The
    spacecraft switched to its internal battery and turned 180 degrees
    so that its back end was aligned with the Moon.

        After the high-gain antenna was once again pointed at Earth, the
    probe would begin to acquire television images about thirty-two minutes
    before impact at an altitude of 2,400 miles (3,900 kilometers).  Images
    would be taken every thirteen seconds down to an altitude of 37 miles
    (59 kilometers).  Transmission of this last image would have been
    completed as the probe reached an altitude of only 15 miles (24
    kilometers).

        Only 8.1 seconds before the bus crashed into the lunar surface at
    a speed of 6,500 miles per hour (2,900 meters per second), the radar
    altimeter generated a fusing signal at an altitude of 13.3 miles (21.4
    kilometers). At that moment, bolt cutters would free the hard lander
    and retrorocket from the bus.  A three nozzle spin motor fires and
    lifts the package 2.5 feet (0.8 meters) above the bus and imparts a
    three hundred revolutions per minute (rpm) spin.  The retrorocket
    then fires, slowing the capsule to a virtual stop at a height of only
    1,100 feet (335 meters) above the lunar surface.  Explosive bolts cut
    the clamp holding the lander to its retrorocket and the two are
    separated by springs. The hard lander free falls to the surface with
    an impact speed of one hundred miles per hour (45 meters per second),
    give or take twenty miles per hour (nine meters per second).

        Protected from the force of impact by its balsa wood shell, the
    lander rolls to a stop.  The free floating capsule inside the shell
    was made to be bottom heavy so that it would settle into a horizontal
    position.  This allowed its antenna to point towards Earth.  After
    twenty minutes, plugs are blown out, allowing the one-half pint (225
    milliliters) of heptane protecting the seismometer and the freon to
    evaporate into the lunar vacuum, thus fixing the capsule in place and
    allowing the seismometer to operate correctly.  The package would then
    transmit its findings on lunar seismic activity for the next sixty to
    ninety days.  If it worked, the United States would have the first
    high resolution pictures of the Moon as well as the first hard landing
    on its surface.

        More Missions

        Before the ink on the RANGER authorization was even dry, NASA had
    plans for even more ambitious lunar missions.  In May of 1960, JPL's
    SURVEYOR project was authorized.  As originally envisaged, SURVEYOR
    would consist of a single basic spacecraft which could be outfitted
    for two different missions.  SURVEYOR A would be designed to land
    on the lunar surface.  It would weigh about 2,500 pounds (1,100
    kilograms) when launched and carry as much as 345 pounds (157
    kilograms) of instrumentation.  These instruments would include four
    television cameras:  One would be used for approach photography and
    another would be used to monitor a semi-automated drill designed to
    penetrate up to sixty inches (1.5 meters) below the lunar surface.
    Various instruments would then be used to analyze samples from this
    hole.  Other instruments would include a seismometer and magnetometer,
    along with sensors to measure lunar gravity, radiation, atmosphere,
    and surface mechanical properties.

        The lander would make use of a simple triangular frame upon
    which the various instruments and thermally controlled electronic
    compartments would be mounted.  It would stand eleven feet (3.5
    meters) from its three landing legs to the top of its mast mounted
    solar panel and high-gain antenna.  After landing at a speed of six
    miles per hour (three meters per second) with the use of a solid
    rocket motor, it would weigh about 750 pounds (340 kilograms).  The
    mission would last for a minimum of thirty days and hopefully as
    long as ninety days.  The first flight was expected in 1963.

        The second variant considered was SURVEYOR B.  This spacecraft
    would use the same basic structure as the lander but instead would be
    placed into a sixty-mile (one hundred-kilometer) high lunar orbit to
    perform television reconnaissance of the Moon's surface as well as
    perform other measurements of the lunar environment for a period of six
    months.  On January 19, 1961, Hughes Aircraft received the contract to
    build SURVEYOR.

        The launch vehicle for this new lunar spacecraft was to be the
    ATLAS-CENTAUR then under development by NASA.  The CENTAUR was to make
    use of liquid hydrogen and liquid oxygen as propellants; the first
    rocket to do so.  This combination provided about thirty to forty
    percent more thrust pound for pound than most propellants then in use.
    CENTAUR development started officially on August 28, 1958, when the
    USAF received authorization from ARPA to develop a high-energy upper
    stage for use with the USAF's ATLAS D and the ABMA's JUNO V (later
    to become NASA's SATURN I).  By October of that year, Convair had
    received the contract to develop and build CENTAUR.

        Because of the political climate of the time, the development
    program was transferred to NASA in July of 1959 with the USAF relegated
    to an advisory role.  The ATLAS booster to be used with the CENTAUR
    was to be a modified version of the ATLAS D ICBM.  The forward
    propellant tank was modified to accept the wider and heavier upper
    stage and a new MA-5 engine assembly providing ten percent more
    liftoff thrust than when the baseline ATLAS D MA-2 was used.

        The development of a hydrogen fueled rocket proved to be very
    difficult.  One technical problem followed another, delaying the launch
    of the first test article.  Finally, on May 8, 1961, the first ATLAS-
    CENTAUR was launched.  After forty-four seconds of flight, CENTAUR's
    insulation panels started ripping off the ascending launch vehicle.
    Structural failure ensued and the hydrogen fueled CENTAUR exploded
    54.7 seconds into the flight.  The failure was studied and the stage
    was redesigned.  More redesign work added additional weight to this
    highly innovative upper stage and the expected performance dropped.
    As time wore on, it became clear that CENTAUR would not be available
    as soon as engineers and space planners would like.

        The timing could not have been worse.  Within days of the failure
    of ATLAS-CENTAUR 1, President John F. Kennedy (1917-1963) threw down
    the gauntlet and committed the United States to a manned lunar landing
    by the end of the decade.  The RANGER and SURVEYOR program objectives
    were redirected to support this new effort.  In the coming months the
    U.S. Congress appropriated the needed funds.

    In reponse to President Kennedy's challenge, JPL proposed another
    RANGER variant on June 30, 1961.  On August 29, this third RANGER
    variant, Block III, was approved.  Using the same bus as the first two
    versions, the payload to be carried this time was not a hard lander but
    a 375-pound (170-kilogram) package of six high-resolution television
    cameras.  Additional instruments to measure the flux of cosmic dust,
    radiation, and magnetic fields would also be carried.  The mission of
    the 800-pound (360-kilogram) Block III was to take a series of 1,600
    images starting at an altitude of 800 miles (1,300 kilometers) and
    continue down until impact with an expected maximum resolution of only
    eight inches (twenty centimeters).  Four Block III flights were planned
    beginning in 1963, using the same ATLAS-AGENA B used in the Block I and
    II RANGER flights.

        Even more advanced missions were being studied at the time.
    PROSPECTOR was an automated mobile lunar laboratory that would explore
    large areas of the Moon, possibly in conjunction with the manned APOLLO
    missions.  It could also serve as a "space truck" for astronauts.
    Because of its anticipated size, a SATURN I (which at the time was to
    include a modified CENTAUR third stage designated S-V) or even larger
    launch vehicle would be required to get it off the ground.  In the
    meantime, NASA had to get the first RANGER into space.

        The First RANGER Flights

        By the summer of 1961, the first RANGER, payload P-32, and its
    ATLAS-AGENA B launch vehicle were ready.  The first launch attempt was
    scrubbed a few minutes before launch due to a power failure on the
    ground.  Over the following weeks, eight more countdowns were called
    off due to faults on the ground, in the launch vehicle, or in the
    RANGER itself.  Finally, on August 26, RANGER 1 lifted off into a
    perfect 108 by 174-mile (174 by 280-kilometer) parking orbit.

        After coasting for thirteen minutes, the AGENA B escape stage was
    to reignite for ninety seconds and propel RANGER 1 into deep space.  A
    faulty pressure switch circuit in the AGENA's engine starting system
    prevented a valve from opening.  The engine fired only briefly to
    change the orbit to 105.3 by 312.5 miles (169.4 by 502.8 kilometers).
    Stranded in low Earth orbit, RANGER 1 separated from its escape stage,
    obediently unfolded it solar panels and aligned itself with the Sun.

        Although not meant to operate in low orbit with its ninety-minute
    day-night cycle, RANGER 1 did operate as intended.  Every time it went
    into Earth's shadow, nitrogen jets would fire and the disoriented
    RANGER would mindlessly start searching for its lost celestial
    reference.  Once back in the sunlight forty-five minutes later, RANGER
    would reacquire the Sun.  While it was operating as well as it could
    under the circumstances, RANGER depleted its supply of attitude
    control gas the day after launch and started tumbling uncontrollably.

        After 111 orbits, RANGER 1 succumbed to atmospheric drag, fell out
    of orbit, and burned up over the Gulf of Mexico on August 30.  During
    its brief life, RANGER 1 did verify that a three-axis spacecraft could
    be controlled as expected.  It was also able to collect a limited
    amount of data on radiation and cosmic rays but was too close to Earth
    for its magnetometer to operate.

        On November 18, RANGER 2 was launched and entered its parking

    orbit.  Again the AGENA B failed to restart properly and RANGER 2
    was stuck in a quickly decaying 94.9 by 145.7-mile (152.7 by 234.4-
    kilometer) orbit.  No tests were attempted this time and the wayward
    deep space probe burned up in the atmosphere only six hours after
    launch.  This time the problem was traced to a roll gyro whose
    malfunction had gone undetected at launch.  With no way to sense a
    rolling motion, the AGENA B started spinning, forcing its propellants
    to the outside edges of its tanks instead of to the bottom where the
    feed lines to the engine were located.  When the command to reignite
    was given, only a brief firing resulted, due to residual propellant in
    the turbopumps.  More bugs had to be worked out of the ATLAS-AGENA B.

        While the two RANGER Block I spacecraft never made it beyond their
    parking orbits, they did provide enough engineering information to
    prove the basic design.  In September of 1961, it became clear that
    the ATLAS-CENTAUR would not be available in time to launch the 1,100-
    pound (500-kilogram) MARINER A towards Venus the following August.
    NASA switched to the MARINER R, which was nothing more than a stripped
    down, modified RANGER Block I spacecraft weighing 448 pounds (204
    kilograms) and carrying a minimal science instrument payload of about
    twenty pounds (nine kilograms).

        The first American Venus probe attempt, MARINER 1, launched on
    July 22, 1962, ended up taking a swim in the Atlantic Ocean due to yet
    another ATLAS-AGENA B malfunction.  MARINER 2 was successfully launched
    on August 27 and operated until twenty days after its December 14
    encounter with Venus, the first successful flyby of another planet.
    Closer to home, the RANGER Block II spacecraft would not fare quite
    as well.

        The first Block II RANGER, P-34, lifted off on January 26, 1962
    after a four-day delay to fix a ruptured intertank insulation bulkhead
    in the ATLAS D booster.  As the ATLAS-AGENA B ascended towards its
    parking orbit, a component in its guidance system failed, disabling
    the radio command system.  Relying on its internal autopilot system,
    the ATLAS placed the AGENA B escape stage and RANGER 3 into a parking
    orbit slightly off course.  After a short coast, the AGENA B came to
    life again and boosted RANGER 3 into an escape trajectory.  Because of
    an incorrect constant in the AGENA guidance program, RANGER 3 was
    thrown even further off course.  Early tracking indicated that RANGER
    3 was operating properly but would miss the Moon by 20,000 miles
    (32,000 kilometers), far too wide a miss for RANGER's small course
    correction engine to negate.

        Since an impact was out of the question, it was decided to
    exercise the various functions of the new Block II spacecraft and
    perform some flyby photography.  The first test was to perform a
    mid-course correction that would also bring RANGER 3 closer to the
    Moon.  The course correction was performed as instructed with an
    accuracy one quarter of one percent of speed and two and one half
    degrees of direction.  Unfortunately, the instructions sent to the
    RANGER were faulty.  An undetected sign inversion in the instructions
    sent to the spacecraft resulted in the maneuver taking place in the
    wrong direction.  Instead of pushing RANGER closer to the Moon, it
    moved the probe further away, resulting in a flyby distance of
    22,860 miles (36,785 kilometers).

        Forty hours after the course "correction" and some 31,000 miles
    (50,000 kilometers) from the Moon, RANGER 3 was instructed to turn
    towards the Moon and begin imaging this time with instructions
    carrying the proper sign.  Telemetry showed that everything was going
    according to plan, but the spacecraft's high-gain antenna failed to
    properly realign with Earth and the RANGER's computer and sequencer
    failed.  The camera on board did turn on and start transmitting images
    but because of the misaligned antenna, only noisy images containing
    the vidicon camera's reticle marks were received.  Unable to properly
    transmit its images and accept further commands from Earth, RANGER 3
    continued past the Moon and into solar orbit.  The cause of the last
    minute malfunction was never found.  The only scientific data returned
    by the wayward lunar probe were some background radiation readings
    from the gamma ray spectrometer.

        On April 23, 1962, the second Block II spacecraft, RANGER 4, was
    launched - after some delays - in the middle of its allotted launch
    window.  For the first time in the series, the ATLAS-AGENA B operated
    flawlessly, injecting RANGER 4 into a collision course with the Moon.
    Unfortunately, during the first tracking pass of the receding probe,
    it was discovered that RANGER's master clock had stopped and the
    computer was not responding to ground commands.  Unable to perform any
    functions, RANGER 4 continued on to the Moon and was tracked using the
    hard lander's transmitter.

        After sixty-four hours, the now lifeless probe skimmed the limb of
    the Moon and crashed on its far side at 15.5 degrees south latitude
    and 130.5 degrees west longitude in a crater later named Paschen.
    RANGER 4 became the first U.S. probe to land on the Moon, but not
    quite in the manner that its designers had planned.

        All hopes rode with the last Block II flight of RANGER 5.  After
    an analysis of the previous failures, several improvements were made
    to the spacecraft.  A hydraulic backup timer activated by the seperation
    of the AGENA escape stage was included to operate automatic functions
    and a ground commanded backup timer in the command encoder was included
    to allow direct ground control.  Both changes would help avoid a repeat
    of the previous two failures.

        With less than fifty minutes remaining in the countdown, RANGER's
    transponder failed due to an errant flake of solder shorting out a
    cavity.  With a functioning replacement, RANGER 5 finally lifted off
    from Pad 12 at the Atlantic Missile Ranger on October 18, 1962.  As it
    accelerated towards orbit, a portion of the ATLAS D guidance system
    failed - the same component failure that started a chain of events
    which led to the loss of RANGER's cousin, MARINER 1, just three months
    earlier.  Fortunately, the infamous hyphen excluded from the guidance
    program of the ATLAS 145D that carried MARINER 1 was included in
    RANGER's booster's program; RANGER 5 was successfully placed on a
    trajectory towards the Moon.

        RANGER's close brush with failure at launch was all for naught.
    Some seventy-five minutes after launch, as RANGER 5 was obediently
    settling into its cruise attitude, a short circuit developed in the
    solar panels.  Although the panels' isolation diodes protected the
    power supply from immeadiate failure, RANGER had no means of powering
    itself except with the small backup battery.  Within hours, RANGER 5
    died from lack of power.  The probe was tracked for eleven days with
    the lander's transmitter as RANGER 5 passed only 450 miles (724
    kilometers) over the Moon's trailing edge and on into orbit around
    the Sun.

        With the loss of the last Block II RANGER, the entire program was
    deemed to be an utter failure.  Not a single scientific objective was
    met and all three spacecraft had suffered major malfunctions.  A board
    of inquiry composed of officials from NASA, the USAF, and industry
    was formed to investigate the failures and recommend changes in the
    spacecraft design and JPL management of the project.  The launch of
    the Block III RANGERs, the first of which, payload P-53, was nearing
    final mechanical assembly, was postponed from the original 1963 launch
    date pending the outcome of the investigation.

        The Race Begins Again

        RANGER was not the only program experiencing problems.  SURVEYOR
    was having its own set of growing pains.  In the first half of 1962,
    balloon-borne drop tests of retrorocket equipped models started over
    Holloman Air Force Base in New Mexico.  The first test failed and
    subsequent tests had mixed results.  Still, the tests did supply enough
    information to help fine tune SURVEYOR's landing sequence.

        SURVEYOR's launch vehicle, the ATLAS-CENTAUR, was having more than
    its share of difficulties.  Throughout 1962, design changes were made
    to the vehicle to correct various defects found during its first
    failed launch attempt as well as during ground testing.  In October
    the entire development program was transferred from the Marshall Space
    Flight Center to the Lewis Research Center due to the ever-increasing
    work on the SATURN rocket development at Marshall.  Another test of
    the ATLAS-CENTAUR was not expected until the middle of 1963.

        Because of the CENTAUR design changes, SURVEYOR had to shed some
    weight.  The new design called for a 2,100-pound (950-kilogram) lander
    carrying only 114 pounds (52 kilograms) of instruments.  Advanced
    design work continued and several new options were added to the
    lander's design, including the use of a Martin-Marietta SNAP-11
    nuclear generator to supply SURVEYOR A with 18.6 watts of power for
    ninety days.  This generator would supply minimal power during the
    long lunar night when SURVEYOR's solar panels would be useless.

        By the end of 1962, plans called for seven SURVEYOR A landing
    missions starting in late 1964 and five SURVEYOR B orbiters with the
    first launch expected in 1965.  Options for five or more additional
    landers were being considered.

        Unlike SURVEYOR, the PROSPECTOR automated lunar rover continued to
    gain weight and would likely need the services of one of the Advanced
    SATURN launch vehicles - like the SATURN V - to get it to the Moon.
    The weight gain was due to the expanding scope of PROSPECTOR's mission
    as well as the increasing complexity.  By late 1962, four types of
    missions had been assigned to PROSPECTOR.  One included low altitude
    reconnaissance of various lunar sites with the use of a hovering
    spacecraft.  The second called for landing a rover capable of
    exploring up to fifty miles (eighty kilometers) from the landing
    point.  Another type of mission contemplated for PROSPECTOR was as a
    soil sample return probe.  The last mission envisaged used PROSPECTOR
    as an unmanned cargo ship to support manned lunar exploration.  In
    these overly enthusiastic and naive early days of NASA, the first
    launch of PROSPECTOR was expected in 1966.

        The Soviets were far from idle as the United States launched
    one Moon probe after another.  The Soviets, like their American
    counterparts, knew the value of using parking orbits and building even
    more powerful launch vehicles to reach distant targets.  Because of
    this, yet another launcher based on the R-7 ICBM was developed.  Later
    called the MOLNIYA after the communication satellites which made
    extensive use of its services, the new rocket replaced the small
    Block E escape stage used on the first LUNA missions with a pair of
    much larger stages.

        The Block I stage, which would boost an escape stage and payload
    into a low parking orbit, replaced the small R-7 engine of the Block
    E stage with the five times more powerful RD-461.  The stage was
    lengthened by over nineteen feet (six meters) to accommodate three
    times as much propellant.  The 7.4-ton (6.7 metric ton) Block L escape
    stage, after a coasting period, would then ignite and boost as much as
    2,600 pounds (1,200 kilograms) towards Venus or Mars and over 3,500
    pounds (1,600 kilograms) towards the Moon.  This was as much as seventy
    percent more payload than what the American ATLAS-CENTAUR was expected
    to lift once operational.

        As with the American ATLAS-AGENA, the Soviets' MOLNIYA had its
    share of problems.  In no less than ten launch attempts to Venus and
    Mars between 1960 and 1962, the MOLNIYA functioned properly only twice
    to send the ill-fated VENERA 1 and MARS 1 to their intended targets.
    When the Soviets started sending their second wave of spacecraft to
    the Moon in 1963, they encountered similar problems.

        The first suspected launch of the new LUNA probes on January 4,
    1963 ended in failure when its escape stage failed to ignite on
    command and stranded its payload in a 104 by 122-mile (167 by 196-
    kilometer) parking orbit that decayed the following day.  A second
    attempt on February 2 never even made it that far.  What was left of
    the rocket and payload fell into the Pacific Ocean near Midway Island
    shortly after launch.

        Finally, on April 2, the Soviets announced the launch of LUNA 4.
    Some sort of failure occurred during a complicated maneuver enroute to
    the Moon.  As a result, the 3,135-pound (1,422-kilogram) Moon probe
    flew by its target at an altitude of 5,300 miles (8,500 kilometers)
    and continued into an extended 55,800 by 434,000-mile (89,800 by
    698,000-kilometer) Earth orbit which was eventually perturbed into
    a solar orbit.

        The mission of LUNA 4 was never announced to the West.  However,
    subsequent LUNA probes were definitely meant to land on the Moon.
    Only a small amount of data on solar and cosmic rays from LUNA 4 were
    published.  The Soviets took a ten-month hiatus to modify their new
    lunar spacecraft and troubleshoot the unreliable Block L escape stage.
    In the meantime, it became increasingly clear that the American
    SURVEYOR would have some competition in the race to land on the Moon.

               Summary of Lunar Probe Launches, 1961-1963
    _______________________________________________________________________
     Name             Launch          Country      Weight       Launch
              Date                 lbs (kg)      Vehicle
    _______________________________________________________________________

        RANGER 1    Aug 23, 1961    US    675 (307)     ATLAS-AGENA B
            Failed deep space engineering test flight

    RANGER 2    Nov 18, 1961    US    675 (307)     ATLAS-AGENA B
            Failed deep space engineering test flight

    RANGER 3    Jan 26, 1962    US    727 (330)     ATLAS-AGENA B
            Failed lunar hard landing attempt

    RANGER 4    Apr 23, 1962    US    729 (331)     ATLAS-AGENA B
            Failed lunar hard landing attempt

    RANGER 5    Oct 18, 1962    US    754 (342)     ATLAS-AGENA B
            Failed lunar hard landing attempt

    (Unannounced)    Jan  4, 1963    USSR    3130 (1420)?  MOLNIYA
            Failed lunar hard landing attempt

    (Unannounced)    Feb  2, 1963    USSR    3130 (1420)?  MOLNIYA
            Failed lunar hard landing attempt

    LUNA 4        Apr  2, 1963    USSR    3135 (1422)   MOLNIYA
            Failed lunar hard landing attempt
    _____________________________________________________________________
    Notes:    Probe names given in () are used if no official name exists.

        Weights given are the launch weights of the probes and do
        not include any additional equipment that may have been
        carried by the escape stage.
    _____________________________________________________________________

        Bibliography -

        Baker, David, THE ROCKET, 1978

    Blanc, Sam S., Abraham S. Fischler and Olcott Gardner, MODERN
    SCIENCE 3, 1963

        Burrows, William E., EXPLORING SPACE: VOYAGES IN THE SOLAR SYSTEM
    AND BEYOND, 1990

        Clark, Phillip, THE SOVIET MANNED SPACE PROGRAM, 1988

    Emme, Eugene M., AERONAUTICS AND ASTRONAUTICS: AN AMERICAN CHRONOLOGY
    OF SCIENCE AND TECHNOLOGY IN THE EXPLORATION OF SPACE 1915-1960, 1961

        Gatland, Kenneth, ROBOT EXPLORERS, 1972

    Gatland, Kenneth, THE ILLUSTRATED ENCYCLOPEDIA OF SPACE TECHNOLOGY,
    1988

    Heacock, Raymond L., "RANGER: Its Mission and Its Results", TRW
    SPACELOG, Summer 1965

    Johnson, Nicholas, HANDBOOK OF SOVIET LUNAR AND PLANETARY EXPLORATION,
    1979

    Lange, Oswald H. and Richard J. Stein, SPACE CARRIER VEHICLES, 1963

    Martz, E. P., Jr., "Optical Problems of Television Recording of
    the Moon and Planets from Approaching Spacecraft", APPLIED OPTICS,
    January 1963

    Melin, Marshall, "DISCOVERERs XX and XXI", SKY & TELESCOPE,
    April 1961

    Melin, Marshall, "RANGER I", SKY & TELESCOPE, October 1961

    Ordway, Fredrick I., III, "A Chronology of Space Carrier Vehicles,
    1957 through 1962", ASTRONAUTICAL ENGINEERING AND SCIENCE, 1963

        Sartwell, Frank, "Robots to the Moon", NATIONAL GEOGRAPHIC,
    October 1962

    Schurmeier, H. M., "Lunar Exploration", LUNAR MISSIONS AND
    EXPLORATION, 1964

    Von Braun, Wernher and Fredrick I. Ordway III, HISTORY OF ROCKETRY

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End of Space Digest Volume 15 : Issue 064
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