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Date: Tue, 4 Aug 92 05:02:27
From: Space Digest maintainer <digests@isu.isunet.edu>
Reply-To: Space-request@isu.isunet.edu
Subject: Space Digest V15 #064
To: Space Digest Readers
Precedence: bulk
Space Digest Tue, 4 Aug 92 Volume 15 : Issue 064
Today's Topics:
Electronic Journal of the ASA (EJASA) - August 1992 [Part 1]
Welcome to the Space Digest!! Please send your messages to
"space@isu.isunet.edu", and (un)subscription requests of the form
"Subscribe Space <your name>" to one of these addresses: listserv@uga
(BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
(THENET), or space-REQUEST@isu.isunet.edu (Internet).
----------------------------------------------------------------------
Date: 3 Aug 92 15:25:09 GMT
From: Larry Klaes <klaes@verga.enet.dec.com>
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.
asa@chara.gsu.edu
ASA BBS: (404) 564-9623, 300/1200/2400 Baud.
or telephone the Society Recording at (404) 264-0451 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:
klaes@verga.enet.dec.com
or - ...!decwrl!verga.enet.dec.com!klaes
or - klaes%verga.dec@decwrl.enet.dec.com
or - klaes%verga.enet.dec.com@uunet.uu.net
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
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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,
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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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