Date: Tue, 4 Aug 92 05:02:27 From: Space Digest maintainer 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 " 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 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 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 ------------------------------ End of Space Digest Volume 15 : Issue 064 ------------------------------